Backend Big Update (document later)

2025-05-15 23:00:15 -07:00 · 2022-04-17 03:20:37 +08:00 · 2022-04-17 03:20:37 +08:00 · 205f5ad5ca
commit 205f5ad5ca
parent 1f3c16cf16
34 changed files with 1567 additions and 980 deletions
--- a/.gitignore
+++ b/.gitignore
@ -3,9 +3,6 @@ __pycache__
 # Compatibility version of script, for old-old webView,
 # generated by typescript tsc
 www/main.comp.js
-# https://github.com/roddeh/i18njs
-www/i18n.js
-www/i18n.d.ts
 # https://www.npmjs.com/package/vconsole
 www/vconsole.js
 # https://github.com/delight-im/Android-AdvancedWebView
@ -15,6 +12,7 @@ build-android/advancedwebview
 # releases
 build-android/dist
 *.apk
+*.apk.*
 cat-printer*.zip
 # bleak, the bare pip package as a folder
 build-common/bleak
@ -22,6 +20,8 @@ build-common/bleak
 build-common/python-win32*
 # dev config
 config.json
+# dev backup
+*.bak
 # test files
 *.dump
 *.pf2
--- a/.pylintrc
+++ b/.pylintrc
@ -7,15 +7,15 @@
 jobs=4

 [BASIC]
-class-const-naming-style=snake_case
-const-naming-style=snake_case
+class-const-naming-style=PascalCase
+const-naming-style=PascalCase

 [MESSAGES CONTROL]
 disable=broad-except,
        global-statement,
-        fixme,
+        fixme, too-few-public-methods,
        import-outside-toplevel

 [BASIC]
-good-names=i, j, k, ex, x, y, _, e,
+good-names=i, j, k, ex, x, y, _, e, b, u, s,
           Run, do_GET, do_POST, do_HEAD, do_PUT
--- a/.vscode/launch.json
+++ b/.vscode/launch.json
@ -4,13 +4,24 @@
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
+        {
+            "name": "Python: Bitmap Print",
+            "type": "python",
+            "request": "launch",
+            "program": "printer.py",
+            "args": [
+                "-m", "-s", "1", "dump.pbm"
+            ],
+            "console": "integratedTerminal",
+            "justMyCode": true
+        },
        {
            "name": "Python: Text Print",
            "type": "python",
            "request": "launch",
            "program": "printer.py",
            "args": [
-                "-m", "-t", "-d", "-s", "1", "-"
+                "-mt", "-f", "GB02", "COPYING"
            ],
            "console": "integratedTerminal",
            "justMyCode": true
--- a/0-transpile.sh
+++ b/0-transpile.sh
@ -1,4 +1,4 @@
 #!/bin/sh
 cd www
-npx tsc  --allowJs  --outFile main.comp.js  polyfill.js i18n.js image.js main.js
+npx tsc  --allowJs  --outFile main.comp.js  polyfill.js i18n-ext.js i18n.js image.js main.js
 cd ..
--- a/README.md
+++ b/README.md
@ -11,34 +11,35 @@ English | [Deutsch](./readme.i18n/README.de_DE.md) | [简体中文](./readme.i18
 Currently:

 |    |    |
-|-------------|-------------------|
-| Supported   | GB01, GB02, GT01  |
-| Maybe       | GB03              |
-| Planned     | N/A               |
+|----|----|
+| Supported | GB01, GB02, GT01, GB03  |
+<!-- | Maybe     | N/A | -->
+<!-- | Planned   | N/A | -->

 ## Features

 *Currently it's in development. More will be here soon!*

-| Available       | Partial   | Planned       |
-|-----------------|-----------|---------------|
-| Web Interface   | CUPS/IPP* | Visual Editor |
-| Print a Picture |           | Help/Manual   |
-| Command-line    |           | Text Printing |
-
-<!-- May comment the line below if there are no * -->
-\* In development code. Will be released in a short period.
-
-*Along with...*
-
 - Simple!
-  - Operate via a Web UI just in browser,
+  - Operate via Web UI just in browser,
  - or get the Android release!
+  - Even no problem with command line hackers!

 - Friendly!
  - Language support! You can participate in translation!
  - Good user interface, adaptive to PC/mobile and light/dark theme!

+- Feature-rich!
+  - Web UI, for most people!
+    - Take full control of printer config
+    - Print picture, or just test if it works
+  - Command line, for geeks & hackers!
+    - Control printer with a few parameters
+    - Simplified text printing
+    - Make use of every part of the program
+  - Some other goodies!
+    - Server program is also CUPS/IPP capable
+
 - Cross platform!
  - Newer Windows 10 and above
  - GNU/Linux
@ -78,33 +79,36 @@ On Arch Linux based distros you may first install `bluez`, as it's often missing
 sudo pacman -S bluez bluez-utils
 ```

+*Packaging is also on the way!*
+
 ### MacOS

-For MacOS please install [Python 3](https://www.python.org/).
+For MacOS please install [Python 3](https://www.python.org/),  
+then install `pyobjc` and `bleak` via `pip` in terminal:  
+```bash
+pip3 install pyobjc bleak
+```

-Fetch a "pure" release and do the same in a shell:  
+After that, fetch a "bare" release and do the same in a shell:  
 ```bash
 python3 server.py
 ```

 Currently in Mac the browser will not pop up automatically. Please run manually and go to `http://127.0.0.1:8095`, or just click [here](http://127.0.0.1:8095).

-
 ### Worth to Note

 For all supported platforms,  
 You can also use "pure" edition once you have [Python 3](https://www.python.org/) installed,  
 or "bare" edition if you also managed to install `bleak` via `pip`.

-Command line hackers? Just use `printer.py`!
-
 See the [releases](https://github.com/NaitLee/Cat-Printer/releases) now!

 ## Problems?

-Please open an issue if there's something in your mind!
+Please talk in Discussion if there's something in your mind!

-Of course PRs are welcome if you can handle them!
+Of course Pull Requests are welcome if you can handle them!

 ## License

@ -125,7 +129,7 @@ Also interested in code development? See [development.md](development.md)!

 - Of course, Python & the Web!
 - [Bleak](https://bleak.readthedocs.io/en/latest/) BLE lib! The overall Hero!
- [roddeh-i18n](https://github.com/roddeh/i18njs), good work!
+- [roddeh-i18n](https://github.com/roddeh/i18njs), the current built-in i18n is inspired by this
 - [python-for-android](https://python-for-android.readthedocs.io/en/latest/), though there are some painful troubles
 - [AdvancedWebView](https://github.com/delight-im/Android-AdvancedWebView) for saving my life from Java
 - Stack Overflow & the whole Internet, you let me know Android `Activity` all from beginning
--- a/31
+++ b/31
@ -1,26 +1,23 @@

 Note: not ordered. do whatever I/you want

-+ Check GB03, again
-+ Hacky text printing, typewriter-like, with PF2 font
-  ok I won't forget frontend, but it's different
-+ Better CLI, e.g. invoke imagemagick if input is not PBM
-+ Consider better MTU adaption
-+ Consider better BLE traffic regulation, with BLE notification
-+ Consider the printer 'text' mode, it can make things faster
-+ Consider more control to something like 'energy'
-+ Consider keeping server backend (more) secure to be used by IPP
-+ Clean up CUPS/IPP code
-+ Make a build guide for android:
-  Summary the hacks to p4a, bleak p4a recipe, p4a webview bootstrap, and AdvancedWebView
-+ More frontend usability, more functions
-+ A better layout for mobile?
-+ Better Canvas mode, (re-)consider fabric.js
-+ Implement Document mode, (re-)consider html2canvas.js
+ Cookbook of basic things
 + Write good help/manual
 + Make error notice short while let users see detailed help/manual for what-to-do
+ Even Better CLI, e.g. invoke imagemagick if input is not PBM
+ Even better CUPS/IPP support
+ Even better frontend usability, more functions
+ A better layout for mobile?
+ Make a build guide for android:
+  Summary the hacks to p4a, bleak p4a recipe, p4a webview bootstrap, and AdvancedWebView
+ Try to implement enough without more dependencies
+ Better Canvas mode, (re-)consider fabric.js
+ Implement Document mode, (re-)consider html2canvas.js
 + ...

-? Compression for GB03 data
+? Consider more control to something like 'energy'
+  This have no effect on my GB02
+? Data compression for GB03. Optional
 ? Put Android APP on F-Droid? But it needs automatic build system...
  Android guys can help this!
+? ... Or put to APKPure?
--- a/additional/i18n.py
+++ b/additional/i18n.py
@ -1,66 +0,0 @@
-'Minimal internationalization lib'
-
-import os
-import math
-import json
-import locale
-
-class I18n():
-    ''' Minimal implementation of current frontend i18n in Python
-        Not Complete (yet)!
-    '''
-
-    lang: str
-    fallback: str
-    data: dict = {
-        'values': {},
-        'contexts': []
-    }
-
-    def __init__(self, search_path='lang', lang=None, fallback=None):
-        self.lang = lang or locale.getdefaultlocale()[0]
-        self.fallback = fallback or 'en_US'
-        self.load_file(os.path.join(search_path, self.fallback.replace('_', '-') + '.json'))
-        for name in os.listdir(search_path):
-            if name == self.lang.replace('_', '-') + '.json':
-                self.load_file(os.path.join(search_path, name))
-
-    def load_file(self, name):
-        'Load an i18n json file'
-        with open(name, 'r', encoding='utf-8') as file:
-            self.load_data(file.read())
-
-    def load_data(self, raw_json):
-        'Load i18n json data (from str)'
-        data = json.loads(raw_json)
-        for key in data['values']:
-            self.data['values'][key] = data['values'][key]
-        if data.get('contexts') is not None:
-            self.data['contexts'] = data['contexts']
-
-    def __getitem__(self, keys):
-        if not isinstance(keys, tuple):
-            keys = (keys, )
-        data = self.data['values'].get(keys[0], keys[0])
-        string = data[0][2] if isinstance(data, list) else data
-        for i in keys:
-            if isinstance(i, (int, float)):
-                if string is None:
-                    string = data
-                if isinstance(data, list):
-                    for j in data:
-                        if j[0] is None:
-                            j[0] = -math.inf
-                        if j[1] is None:
-                            j[1] = math.inf
-                        if j[0] < i < j[1]:
-                            template = j[2]
-                            break
-                string = template.replace('%%n', i).replace('-%%n', -i)
-            elif isinstance(i, dict):
-                # not verified if would work
-                if string is None:
-                    string = data
-                for j in i:
-                    string = string.replace(f'%%{j}', i[j])
-        return string
--- a/build-android/0-build-android.sh
+++ b/build-android/0-build-android.sh
@ -1,6 +1,6 @@
 #!/bin/sh
 p4a apk --private .. --dist_name="cat-printer" --package="io.github.naitlee.catprinter" --name="Cat Printer" \
-    --icon=icon.png --version="0.1.1" --bootstrap=webview --window --requirements=android,pyjnius,bleak \
+    --icon=icon.png --version="0.2.0" --bootstrap=webview --window --requirements=android,pyjnius,bleak \
    --blacklist-requirements=sqlite3,openssl --port=8095 --arch=arm64-v8a --blacklist="blacklist.txt" \
    --presplash=blank.png --presplash-color=black --add-source="advancedwebview" --orientation=user \
    --permission=BLUETOOTH --permission=BLUETOOTH_SCAN --permission=BLUETOOTH_CONNECT \
--- a/build-android/3-formal-build.sh
+++ b/build-android/3-formal-build.sh
@ -4,7 +4,7 @@ unzip -q "../cat-printer-bare-$1.zip"
 mv "cat-printer" "dist"
 p4a apk --private "dist" --dist_name="cat-printer" --package="io.github.naitlee.catprinter" --name="Cat Printer" \
    --icon=icon.png --version="$1" --bootstrap=webview --window --requirements=android,pyjnius,bleak \
-    --blacklist-requirements=sqlite3,openssl --port=8095 --arch=arm64-v8a \
+    --blacklist-requirements=sqlite3,openssl --port=8095 --arch=arm64-v8a --release \
    --presplash=blank.png --presplash-color=black --add-source="advancedwebview" --orientation=user \
    --permission=BLUETOOTH --permission=BLUETOOTH_SCAN --permission=BLUETOOTH_CONNECT \
    --permission=BLUETOOTH_ADMIN --permission=ACCESS_FINE_LOCATION --permission=ACCESS_COARSE_LOCATION
--- a/build-common/bundle.py
+++ b/build-common/bundle.py
@ -22,23 +22,20 @@ if not sys.argv[-1].startswith('-'):
 bundle_name %= (edition, version)

 ignore_whitelist = (
-    'www/i18n.js',
    'www/main.comp.js'
 )

 additional_ignore = (
    # prevent recurse
    bundle_name,
+    # non-production (yet)
+    'PKGBUILD', 'systemd',
    # build helpers
-    'build-*',
-    '?-*.sh',
+    'build-*', '?-*.sh',
    # no need
-    '.git',
-    '.vscode',
-    '.pylintrc',
-    '.gitignore',
-    'dev-diary.txt',
-    'TODO',
+    '.git', '.gitignore',
+    '.vscode', '.pylintrc',
+    'dev-diary.txt', 'TODO',
    # cache
    '*.pyc',
    # other
--- a/dev-diary.txt
+++ b/dev-diary.txt
@ -55,3 +55,40 @@ It's finally ready...
 Documentation.

 What else? First Release!
+
+... ...
+
+(some day)
+
+Determined to make backend better,
+but resulting in full rewrite.
+
+... ... (worked hard)
+
+15th
+
+Feeling it's there.
+
+Oh, asyncio always quits like a mad cat, throwing bleak there
+and just ends everything, uncleanly.
+
+16th
+
+Solved many things left yesterday.
+
+Thought i18n needs be universal across there, so made one by myself.
+
+Tried to implement flip, rtl and wrap in text printing,
+wasted some time, but didn't regret.
+
+Well, slightly update document and try compiling,
+give everyone a surprise.
+
+Try --release on p4a build. It worked. 5.9MiB apk, satisfied now?
+Don't forget -Djava.net.useSystemProxies=true on gradle anymore,
+when a proxy to google is needed.
+
+Phone says a release apk should be signed to be installed.
+Satisfy it. https://stackoverflow.com/questions/4853011/how-to-sign-an-android-apk-file
+
+Okay, it's 17th 3 a.m.  publish it and sleep.
--- a/development.md
+++ b/development.md
@ -1,6 +1,8 @@

 # Development

+**Note: Some maybe outdated at the moment**
+
 ## Overview

 This application have a Client/Server module, but it's just locally.
@ -9,7 +11,6 @@ The backend is in Python 3, aiming to have fewest dependencies, and in fact curr
 This can ensure the simplicity of the core part.

 And the frontend is in a "old good" way, that use no "framework".  
-It needs [roddeh-i18n](https://www.npmjs.com/package/roddeh-i18n) lib for localization, and optionally [vConsole](https://www.npmjs.com/package/vconsole) for debugging on mobile.

 My workspace stack is Linux/GNU/Artix/KDE/VSCodium, if you're interested.  
 For Android, GNU/Linux is required, though.
@ -27,12 +28,11 @@ Just clone this repo first!

 1. Get Bleak BLE lib:  
  `pip install bleak`
-2. Grab i18n.js [here](https://github.com/roddeh/i18njs/tree/master/dist), put to `www` as `i18n.js`

-You are already well done for basic development. See [files](#files) section for what all the files do.  
+Alright, you are already well done for basic development. See [files](#files) section for what all the files do.  
 For more, read on...

-### Additional
+### Optional

 Sorry, I'm not a dev package manager enthusiast.

@ -48,19 +48,13 @@ If there are something better to organize these, feel free to discuss in issue.
 - Get an Windows 64-bit embeddable Python, extract to `build-common/python-win32-amd64-embed`
  - You may remove the "bloated" parts inside, notably `libssl`, `libcrypto`, `sqlite3` and `pydoc`, of both `dll`/`pyd` files and in `python<version>.zip`, if have any.
  - Now you're able to bundle a "windows" edition, via `python3 bundle.py -w`
- Grab i18n.js typings `index.d.ts` from [here](https://github.com/roddeh/i18njs/tree/master/typings), put to `www` as `i18n.d.ts`  
-  In the file, replace the last line:  
-  `export = roddeh_i18n;`  
-  with:  
-  `declare var i18n = roddeh_i18n;`  
-  Now you are ready to do more with i18n lib with the typing hint
 - Get a [vConsole](https://www.npmjs.com/package/vconsole) script, put to `www` as `vconsole.js`  
  Now you're ready to debug in browsers without a dev panel, by double-tapping "Cat Printer" title in the UI

 ## Files

 - `server.py` - A Web server that:
-  - Is single threaded, to work with Android/pyjnius
+  - Is single threaded & with static handler, for some reasons
  - Serves static Web files, that are in folder `www`
  - Opens a Web browser once launched, unless specify the `-s` command-line parameter
  - Only listen to localhost, unless specify the `-a` command-line parameter
@ -83,6 +77,10 @@ If there are something better to organize these, feel free to discuss in issue.
  - Transpiled with TypeScript, for fallback on old browsers
  - Bundled all required scripts, see file `0-transpile.sh`
  - Is not there by default. Transpile it yourself
+- `www/i18n*` - Scripts about I18n:
+  - TODO. In fact it worth a dedicated document to describe it
+  - (Mostly) Depends on "extensions" to work in the correct way,
+    feel free to extend, as it's *your* turn
 - `www/*.js` - Other scripts:
  - Small but useful, just look at them directly
 - `www/jslicense.html` - Dedicated JavaScript License information
@ -93,6 +91,7 @@ If there are something better to organize these, feel free to discuss in issue.
  - Quickly invoke with `./N<tab><enter>`
 - `build-common/bundle.py` - Bundler for "windows", "pure" and "bare" editions
  - You can define what to include or not in this script, just modify directly, while trying to not alter other
+  - Adviced to transpile scripts before bundling
  - To do the builds you should be in the build dir: `cd build-common`
  - With `bleak` there you're able to bundle a "pure" edition via just `python3 bundle.py`
  - In any case you're able to bundle a "bare" edition, via `python3 bundle.py -b`
--- a/printer.py
+++ b/printer.py
--- a/printer_lib/init.py
+++ b/printer_lib/init.py
--- a/printer_lib/commander.py
+++ b/printer_lib/commander.py
@ -0,0 +1,133 @@
+'Printer Commander'
+
+from abc import ABCMeta, abstractmethod
+
+crc8_table = [
+    0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15, 0x38, 0x3f, 0x36, 0x31,
+    0x24, 0x23, 0x2a, 0x2d, 0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
+    0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d, 0xe0, 0xe7, 0xee, 0xe9,
+    0xfc, 0xfb, 0xf2, 0xf5, 0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
+    0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85, 0xa8, 0xaf, 0xa6, 0xa1,
+    0xb4, 0xb3, 0xba, 0xbd, 0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
+    0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea, 0xb7, 0xb0, 0xb9, 0xbe,
+    0xab, 0xac, 0xa5, 0xa2, 0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
+    0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32, 0x1f, 0x18, 0x11, 0x16,
+    0x03, 0x04, 0x0d, 0x0a, 0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
+    0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a, 0x89, 0x8e, 0x87, 0x80,
+    0x95, 0x92, 0x9b, 0x9c, 0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
+    0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec, 0xc1, 0xc6, 0xcf, 0xc8,
+    0xdd, 0xda, 0xd3, 0xd4, 0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
+    0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44, 0x19, 0x1e, 0x17, 0x10,
+    0x05, 0x02, 0x0b, 0x0c, 0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
+    0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b, 0x76, 0x71, 0x78, 0x7f,
+    0x6a, 0x6d, 0x64, 0x63, 0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
+    0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13, 0xae, 0xa9, 0xa0, 0xa7,
+    0xb2, 0xb5, 0xbc, 0xbb, 0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
+    0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb, 0xe6, 0xe1, 0xe8, 0xef,
+    0xfa, 0xfd, 0xf4, 0xf3
+]
+
+def crc8(data):
+    'crc8 checksum'
+    crc = 0
+    for byte in data:
+        crc = crc8_table[(crc ^ byte) & 0xff]
+    return crc & 0xff
+
+def reverse_bits(i: int):
+    'Reverse the bits of this byte (as `int`)'
+    return (
+        (i & 0b10000000) >> 7 |
+        (i & 0b01000000) >> 5 |
+        (i & 0b00100000) >> 3 |
+        (i & 0b00010000) >> 1 |
+        (i & 0b00001000) << 1 |
+        (i & 0b00000100) << 3 |
+        (i & 0b00000010) << 5 |
+        (i & 0b00000001) << 7
+    )
+
+def int_to_bytes(i: int, big_endian=False):
+    ''' Turn `int` into `bytearray`, that have
+        least bytes possible to represent the int
+    '''
+    result = bytearray()
+    while i != 0:
+        result.append(i & 0xff)
+        i >>= 8
+    if big_endian:
+        result.reverse()
+    return result
+
+class Commander(metaclass=ABCMeta):
+    'Semi-abstract class, to be inherited by `PrinterDriver`'
+
+    dry_run: bool = False
+
+    def make_command(self, command_bit, payload: bytearray, *,
+                     prefix=bytearray(), suffix=bytearray()):
+        'Make bytes that to be used to control printer'
+        payload_size = len(payload)
+        if payload_size > 0xff:
+            raise ValueError(f'Command payload too big ({payload_size} > 255)')
+        return prefix + bytearray(
+            [ 0x51, 0x78, command_bit, 0x00, payload_size, 0x00 ]
+        ) + payload + bytearray( [ crc8(payload), 0xff ] ) + suffix
+
+    def start_printing(self):
+        'Start printing'
+        self.send( bytearray([0x51, 0x78, 0xa3, 0x00, 0x01, 0x00, 0x00, 0x00, 0xff]) )
+
+    def start_printing_new(self):
+        'Start printing on newer printers'
+        self.send( bytearray([0x12, 0x51, 0x78, 0xa3, 0x00, 0x01, 0x00, 0x00, 0x00, 0xff]) )
+
+    def image_mode(self):
+        'Enable Image Mode on the printer. Lighter, slower.'
+        self.send( self.make_command(0xbe, int_to_bytes(0x00)) )
+
+    def text_mode(self):
+        'Enable Text Mode on the printer. Darker, faster.'
+        self.send( self.make_command(0xbe, int_to_bytes(0x01)) )
+
+    def update_device(self):
+        '(unknown)'
+        self.send( self.make_command(0xa9, int_to_bytes(0x00)) )
+
+    def start_lattice(self):
+        'Start rolling paper'
+        self.send( self.make_command(0xa6, bytearray(
+            [0xaa, 0x55, 0x17, 0x38, 0x44, 0x5f, 0x5f, 0x5f, 0x44, 0x38, 0x2c]
+        )) )
+
+    def end_lattice(self):
+        'End rolling paper'
+        self.send( self.make_command(0xa6, bytearray(
+            [ 0xaa, 0x55, 0x17, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17 ]
+        )) )
+
+    def retract_paper(self, steps: int):
+        'Retract the paper for `steps`'
+        self.send( self.make_command(0xa0, int_to_bytes(steps)) )
+
+    def feed_paper(self, steps: int):
+        'Feed the paper for `steps`'
+        self.send( self.make_command(0xa1, int_to_bytes(steps)) )
+
+    def set_energy(self, amount: int):
+        'Set thermal energy, max to `0xffff`'
+        self.send( self.make_command(0xbe, int_to_bytes(amount)) )
+
+    def draw_bitmap(self, bitmap_data: bytearray):
+        'Print `bitmap_data`. Also does the bit-reversing job.'
+        data = bytearray( map(reverse_bits, bitmap_data) )
+        self.send( self.make_command(0xa2, data) )
+
+    def draw_compressed_bitmap(self, bitmap_data: bytearray):
+        'TODO. Print `bitmap_data`, compress if worthy so'
+        self.draw_bitmap(bitmap_data)
+
+    @abstractmethod
+    def send(self, data):
+        'Send data to device, or whatever'
+        ...
--- a/printer_lib/i18n.py
+++ b/printer_lib/i18n.py
@ -0,0 +1,38 @@
+'Minimal internationalization lib'
+
+import os
+import json
+import locale
+
+class I18nLib():
+    ''' Minimal implementation of current frontend i18n in Python.
+        Not Complete (yet)!
+    '''
+
+    lang: str
+    fallback: str
+    data: dict = {}
+
+    def __init__(self, search_path='lang', lang=None, fallback=None):
+        self.lang = lang or locale.getdefaultlocale()[0].replace('_', '-')
+        self.fallback = fallback or 'en-US'
+        with open(os.path.join(search_path, self.fallback + '.json'),
+                  'r', encoding='utf-8') as file:
+            self.data = json.load(file)
+        path = self.lang + '.json'
+        if path in os.listdir(search_path):
+            with open(os.path.join(search_path, path), 'r', encoding='utf-8') as file:
+                data = json.load(file)
+                for key in data:
+                    self.data[key] = data[key]
+
+    def __getitem__(self, keys):
+        if not isinstance(keys, tuple):
+            keys = (keys, )
+        string = self.data.get(keys[0], keys[0])
+        if len(keys) > 1:
+            if isinstance(keys[-1], dict):
+                string = string.format(*keys[1:-1], **keys[-1])
+            else:
+                string = string.format(*keys[1:])
+        return string
--- a/printer_lib/ipp.py
+++ b/printer_lib/ipp.py
@ -1,56 +1,45 @@
 ''' Provide *very* basic CUPS/IPP support
-    Extracted from version 0.0.2, do more cleaning later...
 '''

+import io
 import platform
 import subprocess

+from .pf2 import int16be, int32be
+
+def int8(b: bytes):
+    'Translate 1 byte as signed 8-bit int'
+    u = b[0]
+    return u - ((u >> 7 & 0b1) << 8)
+
 class IPP():
    'https://datatracker.ietf.org/doc/html/rfc8010'
    server = None
-    printer = None
-    def __init__(self, server, printer):
+    def __init__(self, server):
        self.server = server
-        self.printer = printer
-    async def handle_ipp(self, data):
+    def handle_ipp(self):
        'Handle an IPP protocol request'
        server = self.server
-        # len_data = len(data)
-        # ipp_version_number = data[0:2]
-        # ipp_operation_id = data[2:4]
-        # ipp_request_id = data[4:8]
-        ipp_operation_attributes_tag = data[8]
+        content_length = int(server.headers.get('Content-Length'))
+        buffer = io.BytesIO(server.rfile.read(content_length))
+        _ipp_version = (int8(buffer.read(1)), int8(buffer.read(1)))
+        _ipp_operation_id = int16be(buffer.read(2))
+        _ipp_request_id = int32be(buffer.read(4))
+        ipp_operation_attributes_tag = int8(buffer.read(1))
        attributes = {}
-        data_to_print = b''
-        # this is silly. i want to use io.BytesIO
+        data = b''
        if ipp_operation_attributes_tag == 0x01:
-            pointer = 9
-            next_name_length_at = 10
-            next_value_length_at = 10
-            name = b''
-            value = b''
-            while data[pointer] != 0x03:
-                tag = data[pointer:pointer + 1]
-                pointer += 1
-                if tag[0] < 0x10:   # delimiter-tag
+            while int8(buffer.read(1)) != 0x03:
+                buffer.seek(-1, 1)
+                tag = int8(buffer.read(1))
+                if tag < 0x10:   # delimiter-tag
                    continue
-                next_name_length_at = pointer + data[pointer] * 0x0100 + data[pointer + 1] + 2
-                pointer += 2
-                while pointer < next_name_length_at:
-                    name = name + data[pointer:pointer + 1]
-                    pointer += 1
-                next_value_length_at = pointer + data[pointer] * 0x0100 + data[pointer + 1] + 2
-                pointer += 2
-                while pointer < next_value_length_at:
-                    value = value + data[pointer:pointer + 1]
-                    pointer += 1
+                name = buffer.read(int16be(buffer.read(2)))
+                value = buffer.read(int16be(buffer.read(2)))
                attributes[name] = (tag, value)
-                name = b''
-                value = b''
-            pointer += 1
-            data_to_print = data[pointer:]
+            data = buffer.read()
        # there are hard coded minimal response. this "just works" on cups
-        if data_to_print == b'':
+        if data == b'':
            try:
                server.send_response(200)
                server.send_header('Content-Type', 'application/ipp')
@ -61,6 +50,14 @@ class IPP():
            except BrokenPipeError:
                pass
            return
+        if data.startswith(b'%!PS-Adobe'):
+            self.handle_postscript(data)
+        else:
+            identifier = server.path[1:]
+            server.printer.print(io.BytesIO(data), mode='text', identifier=identifier)
+    def handle_postscript(self, data):
+        'Print PostScript data to printer, converting to PBM first with GhostScript `gs`'
+        server = self.server
        platform_system = platform.system()
        # https://ghostscript.com/doc/9.54.0/Use.htm#Output_device
        if platform_system == 'Windows':
@ -76,15 +73,12 @@ class IPP():
            '-dFitPage', '-dFitPage',
            '-sOutputFile=-', '-'
        ], executable=gsexe, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
-        pbm_data, _ = gsproc.communicate(data_to_print)
+        pbm_data, _ = gsproc.communicate(data)
        try:
            if gsproc.wait() == 0:
-                info = server.path[1:]
-                is_found = await server.printer.filter_device(info, server.settings.scan_time)
-                if not is_found:
-                    ... # TODO: Make IPP can report some errors
-                    raise Exception(f'No printer found with info: {info}')
-                await server.printer.print_data(pbm_data)
+                identifier = server.path[1:]
+                # TODO: Make IPP can report some errors
+                server.printer.print(io.BytesIO(pbm_data), mode='pbm', identifier=identifier)
            else:
                raise Exception('Error on invoking Ghostscript')
            server.send_response(200)
@ -97,4 +91,3 @@ class IPP():
            server.send_response(500)
            server.send_header('Content-Type', 'application/ipp')
            server.end_headers()
-            server.wfile.write(b'')
--- a/printer_lib/models.py
+++ b/printer_lib/models.py
@ -0,0 +1,16 @@
+'Printer model specifications'
+
+class Model():
+    'A printer model'
+    paper_width: int
+    is_new_kind: bool
+    def __init__(self, width, is_new):
+        self.paper_width = width
+        self.is_new_kind = is_new
+
+Models = {
+    'GB01': Model(384, False),
+    'GB02': Model(384, False),
+    'GB03': Model(384, True),
+    'GT01': Model(384, False),
+}
--- a/printer_lib/pf2.py
+++ b/printer_lib/pf2.py
@ -1,4 +1,7 @@
-'Python lib to read PF2 font file: http://grub.gibibit.com/New_font_format'
+''' Python lib for reading PF2 font files: http://grub.gibibit.com/New_font_format
+    I'd like to put it in Public Domain.
+    Don't forget to see how it's used in `text_print.py`
+'''

 import io
 from typing import Dict, Tuple
@ -57,12 +60,16 @@ class PF2():
    descent: int
    character_index: Dict[int, Tuple[int, int]]
    data_offset: int
-    data_io: io.IOBase
+    data_io: io.BufferedIOBase

-    def __init__(self, path='font.pf2', *, read_to_mem=False, missing_character: str='?'):
+    def __init__(self, path='font.pf2', *, read_to_mem=True, missing_character: str='?'):
        self.missing_character_code = ord(missing_character)
        self.in_memory = read_to_mem
        file = open(path, 'rb')
+        if read_to_mem:
+            self.data_io = io.BytesIO(file.read())
+            file.close()
+            file = self.data_io
        self.is_pf2 = (file.read(12) == b'FILE\x00\x00\x00\x04PFF2')
        if not self.is_pf2:
            return
@ -80,13 +87,7 @@ class PF2():
                    )
                continue
            elif name == b'DATA':
-                if read_to_mem:
-                    self.data_io = io.BytesIO(file.read())
-                    self.data_offset = -file.tell()
-                    file.close()
-                else:
-                    self.data_io = file
-                    self.data_offset = 0
+                file.seek(0)
                break
            data = file.read(data_length)
            if name == b'NAME':
@ -116,7 +117,7 @@ class PF2():
            info = self.character_index[self.missing_character_code]
        _compression, offset = info
        data = self.data_io
-        data.seek(offset + self.data_offset)
+        data.seek(offset)
        char = Character()
        char.width = uint16be(data.read(2))
        char.height = uint16be(data.read(2))
@ -130,7 +131,5 @@ class PF2():

    __getitem__ = get_char

-    def close(self):
-        'Close the data IO, if it\'s a real file'
-        if not self.in_memory:
+    def __del__(self):
        self.data_io.close()
--- a/printer_lib/text_print.py
+++ b/printer_lib/text_print.py
@ -0,0 +1,87 @@
+'Things used by Text Printing feature'
+
+from .pf2 import PF2
+
+class TextCanvas():
+    'Canvas for text printing, requires PF2 lib'
+    width: int
+    height: int
+    canvas: bytearray = None
+    rtl: bool
+    wrap: bool
+    pf2 = None
+    def __init__(self, width, *, wrap=False, rtl=False):
+        self.pf2 = PF2()
+        self.width = width
+        self.wrap = wrap
+        self.rtl = rtl
+        self.height = self.pf2.max_height + self.pf2.descent
+        self.flush_canvas()
+    def flush_canvas(self):
+        'Flush the canvas, returning the canvas data'
+        if self.canvas is None:
+            pbm_data = None
+        else:
+            pbm_data = bytearray(self.canvas)
+        self.canvas = bytearray(self.width * self.height // 8)
+        return pbm_data
+    def puttext(self, text):
+        ''' Put the specified text to canvas.
+            It's a generator, will `yield` the data produced, per line.
+        '''
+        text = text.replace('\t', ' ' * 4)
+        canvas_length = len(self.canvas)
+        pf2 = self.pf2
+        current_width = 0
+        last_space_at = -1
+        width_at_last_space = 0
+        break_points = set()
+        characters = {}
+        for i, s in enumerate(text):
+            if s not in characters:
+                characters[s] = pf2[s]
+            char = characters[s]
+            if s == ' ':
+                last_space_at = i
+                width_at_last_space = current_width
+            if (current_width > self.width and
+                last_space_at != -1):
+                break_points.add(last_space_at)
+                current_width -= width_at_last_space
+            if s == '\n':
+                current_width = 0
+                continue
+            current_width += pf2.point_size // 2 # + char.x_offset
+        current_width = 0
+        for i, s in enumerate(text):
+            char = characters[s]
+            if (i in break_points or s == '\n' or
+                current_width + char.width > self.width):
+                # print(current_width, end=' ')
+                yield self.flush_canvas()
+                current_width = 0
+                if s in ' ':
+                    continue
+            if ord(s) in range(0x00, 0x20):   # glyphs that should not be printed out
+                continue
+            for x in range(char.width):
+                for y in range(char.height):
+                    rtl_current_width = self.width - current_width - char.width - 1
+                    target_x = x + char.x_offset
+                    target_y = pf2.ascent + (y - char.height) - char.y_offset
+                    canvas_byte = (self.width * target_y + current_width + target_x) // 8
+                    canvas_bit = 7 - (self.width * target_y + current_width + target_x) % 8
+                    if self.rtl:
+                        canvas_byte = (self.width * target_y + rtl_current_width + target_x) // 8
+                        canvas_bit = 7 - (self.width * target_y + rtl_current_width + target_x) % 8
+                    else:
+                        canvas_byte = (self.width * target_y + current_width + target_x) // 8
+                        canvas_bit = 7 - (self.width * target_y + current_width + target_x) % 8
+                    if canvas_byte < 0 or canvas_byte >= canvas_length:
+                        continue
+                    char_byte = (char.width * y + x) // 8
+                    char_bit = 7 - (char.width * y + x) % 8
+                    self.canvas[canvas_byte] |= (
+                        char.bitmap_data[char_byte] & (0b1 << char_bit)
+                    ) >> char_bit << canvas_bit
+            current_width += char.device_width
--- a/readme.i18n/README.de_DE.md
+++ b/readme.i18n/README.de_DE.md
@ -10,26 +10,15 @@
 Gegenwärtig:

 |    |    |
-|-------------|-------------------|
-| Supported   | GB01, GB02, GT01  |
-| Maybe       | GB03              |
-| Planned     | N/A               |
+|----|----|
+| Supported | GB01, GB02, GT01, GB03  |
+<!-- | Maybe     | N/A | -->
+<!-- | Planned   | N/A | -->

 ## Funktionen

 *Derzeit befindet sich die Software im Alpha-Stadium. Mehr wird es bald geben!*

-| Available       | Partial   | Planned       |
-|-----------------|-----------|---------------|
-| Web Interface   | CUPS/IPP* | Visual Editor |
-| Print a Picture |           | Help/Manual   |
-| Command-line    |           | Text Printing |
-
-<!-- May comment the line below if there are none -->
-\* In development code. Will be released in a short period.
-
-*Along with…*
-
 - Simple!
  - Bedienung über eine Web-UI direkt im Browser,
  - oder besorgen Sie sich die Android-Version!
--- a/readme.i18n/README.zh_CN.md
+++ b/readme.i18n/README.zh_CN.md
@ -10,26 +10,13 @@
 目前有：

 |    |    |
-|-----------|-------------------|
-| 支持      | GB01, GB02, GT01  |
-| 可能支持  | GB03              |
-| 计划      | 暂无              |
+|----|----|
+| 支持 | GB01, GB02, GT01, GB03  |

 ## 特性

 *当前仍在继续开发。以后会有更多！*

-| 可用      | 部分      | 计划          |
-|-----------|-----------|---------------|
-| 网页界面  | CUPS/IPP* | 可视化编辑器  |
-| 打印图片  |           | 帮助/文档     |
-| 命令行    |           | 文本打印      |
-
-<!-- 若没有 *，可注释下一句 -->
-\* 存在于开发代码中。将在短时间内发布。
-
-*当然还有……*
-
 - 简易！
  - 在网页界面进行操作，
  - 或者获取安卓应用！
@ -38,6 +25,17 @@
  - 语言支持！您可参与翻译！
  - 良好的用户界面，可适应桌面/移动端/明暗主题！

+- 功能丰富！
+  - 网页界面，所有人都可以用！
+    - 控制打印机配置
+    - 打印照片，或单纯地进行测试
+  - 命令行，技术爱好者必备！
+    - 使用一些参数控制打印机
+    - 简易、简化的文字打印
+    - 让程序的每一部分发挥作用
+  - 其他一些好东西！
+    - 服务器也具有 CUPS/IPP 能力
+
 - 跨平台！
  - 较新的 Windows 10 及以上
  - GNU/Linux
@ -76,11 +74,17 @@ python3 server.py
 sudo pacman -S bluez bluez-utils
 ```

+*以后将有软件包！*
+
 ### MacOS

-MacOS 用户请首先安装 [Python 3](https://www.python.org/)。
+MacOS 用户请首先安装 [Python 3](https://www.python.org/)，  
+然后在终端使用 `pip` 安装 `pyobjc` 和 `bleak`：
+```bash
+pip3 install pyobjc bleak
+```

-然后获取“纯净(pure)”版，并做同样的事情：  
+然后获取“单一(bare)”版，并做同样的事情：  
 ```bash
 python3 server.py
 ```
@ -94,15 +98,13 @@ python3 server.py
 当已安装 [Python 3](https://www.python.org/) 时，您可以直接获取“纯净(pure)”版，  
 或在已使用 `pip` 安装 `bleak` 时使用“单一(bare)”版。

-命令行高手？直接用 `printer.py`！
-
 查看所有[发布版本](https://github.com/NaitLee/Cat-Printer/releases)！

 ## 有问题？

-有想法？开个 issue！
+有想法？去 Discussion 讨论！

-如果能行，PR 也可以！
+如果能行，Pull Request 也可以！

 ## 许可证

@ -126,7 +128,7 @@ Copyright © 2022 NaitLee Soft. 保留一些权利。

 - 当然不能没有 Python 和 Web 技术！
 - [Bleak](https://bleak.readthedocs.io/en/latest/) 跨平台蓝牙低功耗库，牛！
- [roddeh-i18n](https://github.com/roddeh/i18njs)，很好！
+- [roddeh-i18n](https://github.com/roddeh/i18njs)，当前内置的国际化脚本受此启发
 - [python-for-android](https://python-for-android.readthedocs.io/en/latest/)，虽然有些麻烦的地方
 - [AdvancedWebView](https://github.com/delight-im/Android-AdvancedWebView) 从 Java 拯救了我的生命
 - Stack Overflow 和整个互联网，你们让我从零开始了解了安卓“活动” `Activity`
--- a/server.py
+++ b/server.py
@ -1,16 +1,25 @@
 'Cat Printer - Serve a Web UI'

-# if pylint is annoying you, see file .pylint-rc
+# if pylint is annoying you, see file .pylintrc

 import os
+import io
 import sys
 import json
-import asyncio
 import platform
-# Don't use ThreadingHTTPServer if you're going to use pyjnius!
-from http.server import BaseHTTPRequestHandler, HTTPServer #, ThreadingHTTPServer
-from bleak.exc import BleakDBusError, BleakError
-from printer import PrinterDriver
+from http.server import BaseHTTPRequestHandler
+
+# For now we can't use `ThreadingHTTPServer`
+from http.server import HTTPServer
+
+# import `printer` first, to diagnostic some common errors
+from printer import PrinterDriver, PrinterError, I18n, info
+
+from bleak.exc import BleakDBusError, BleakError    # pylint: disable=wrong-import-order
+
+from printer_lib.ipp import IPP
+
+IsAndroid = (os.environ.get("P4A_BOOTSTRAP") is not None)

 class DictAsObject(dict):
    """ Let you use a dict like an object in JavaScript.
@ -20,23 +29,8 @@ class DictAsObject(dict):
    def __setattr__(self, key, value):
        self[key] = value

-class PrinterServerError(Exception):
+class PrinterServerError(PrinterError):
    'Error of PrinterServer'
-    code: int
-    name: str
-    details: str
-    def __init__(self, *args, code=1):
-        super().__init__(*args)
-        len_args = len(args)
-        self.code = code
-        if len_args > 0:
-            self.name = args[0]
-        if len_args > 1:
-            self.details = args[1]
-
-def log(message):
-    'For logging a message'
-    print(message)

 mime_type = {
    'html': 'text/html;charset=utf-8',
@ -51,24 +45,34 @@ def mime(url: str):
    'Get pre-defined MIME type of a certain url by extension name'
    return mime_type.get(url.rsplit('.', 1)[-1], mime_type['octet-stream'])

-class PrinterServer(BaseHTTPRequestHandler):
-    '(Local) server for Cat Printer Web interface'
+class PrinterServerHandler(BaseHTTPRequestHandler):
+    '(Local) server handler for Cat Printer Web interface'
+
    buffer = 4 * 1024 * 1024
+
    max_payload = buffer * 16
+
    settings = DictAsObject({
        'config_path': 'config.json',
+        'version': 1,
        'is_android': False,
-        'printer': None,
-        'scan_time': 3,
-        'frequency': 0.8,
+        'scan_timeout': 5.0,
        'dry_run': False
    })
-    printer = PrinterDriver()
-    ipp = None
+    _settings_blacklist = (
+        'printer', 'is_android'
+    )
+
+    printer: PrinterDriver = PrinterDriver()
+
+    ipp: IPP = None
+
    def log_request(self, _code=200, _size=0):
        pass
+
    def log_error(self, *_args):
        pass
+
    def do_GET(self):
        'Called when server get a GET http request'
        path = 'www' + self.path
@ -91,24 +95,28 @@ class PrinterServer(BaseHTTPRequestHandler):
                if not self.wfile.write(chunk):
                    break
        return
-    def api_success(self):
-        'Called when a simple API call is being considered successful'
+
+    def api_success(self, body_json=None):
+        'Called when an API call is being considered successful'
        self.send_response(200)
        self.send_header('Content-Type', mime('json'))
        self.end_headers()
+        if body_json is None:
            self.wfile.write(b'{}')
-    def api_fail(self, error_json, error=None):
+        else:
+            self.wfile.write(json.dumps(body_json).encode('utf-8'))
+
+    def api_fail(self, error_json):
        'Called when an API call is failed'
        self.send_response(500)
        self.send_header('Content-Type', mime('json'))
        self.end_headers()
        self.wfile.write(json.dumps(error_json).encode('utf-8'))
        self.wfile.flush()
-        if isinstance(error, Exception):
-            raise error
+
    def load_config(self):
        'Load config file, or if not exist, create one with default'
-        if os.environ.get("P4A_BOOTSTRAP") is not None:
+        if IsAndroid:
            self.settings['is_android'] = True
            from android.storage import app_storage_path    # pylint: disable=import-error
            settings_path = app_storage_path()
@ -118,19 +126,38 @@ class PrinterServer(BaseHTTPRequestHandler):
            )
        if os.path.exists(self.settings.config_path):
            with open(self.settings.config_path, 'r', encoding='utf-8') as file:
-                self.settings = DictAsObject(json.load(file))
+                settings = DictAsObject(json.load(file))
+                if (settings.version is None or
+                    settings.version < self.settings.version):
+                    # Version too old, start over
+                    # TODO: selective?
+                    self.save_config()
+                    return
+                self.settings = settings
        else:
            self.save_config()
+
    def save_config(self):
        'Save config file'
        with open(self.settings.config_path, 'w', encoding='utf-8') as file:
-            json.dump(self.settings, file, indent=4)
+            settings = {}
+            for i in self.settings:
+                if i not in self._settings_blacklist:
+                    settings[i] = self.settings[i]
+            json.dump(settings, file, indent=4)
+
    def update_printer(self):
        'Update `PrinterDriver` state/config'
        self.printer.dry_run = self.settings.dry_run
-        self.printer.frequency = float(self.settings.frequency)
+        self.printer.scan_timeout = self.settings.scan_timeout
+        self.printer.fake = self.settings.fake
+        self.printer.dump = self.settings.dump
+        self.printer.flip_h = self.settings.flip_h
+        self.printer.flip_v = self.settings.flip_v
        if self.settings.printer is not None:
-            self.printer.name, self.printer.address = self.settings.printer.split(',')
+            name, address = self.settings.printer.split(',')
+            self.printer.connect(name, address)
+
    def handle_api(self):
        'Handle API request from POST'
        content_length = int(self.headers.get('Content-Length'))
@ -138,121 +165,110 @@ class PrinterServer(BaseHTTPRequestHandler):
        api = self.path[1:]
        if api == 'print':
            self.update_printer()
-            loop = asyncio.new_event_loop()
-            try:
-                devices = loop.run_until_complete(
-                    self.printer.print_data(body)
-                )
+            self.printer.print(io.BytesIO(body))
            self.api_success()
-            finally:
-                loop.close()
            return
        data = DictAsObject(json.loads(body))
        if api == 'devices':
-            loop = asyncio.new_event_loop()
-            try:
-                devices = loop.run_until_complete(
-                    self.printer.search_all_printers(float(self.settings.scan_time))
-                )
-            finally:
-                loop.close()
+            self.printer.connect(None)
            devices_list = [{
                'name': device.name,
                'address': device.address
-            } for device in devices]
-            self.send_response(200)
-            self.send_header('Content-Type', mime('json'))
-            self.end_headers()
-            self.wfile.write(json.dumps({
+            } for device in self.printer.scan()]
+            self.api_success({
                'devices': devices_list
-            }).encode('utf-8'))
+            })
            return
        if api == 'query':
            self.load_config()
-            self.send_response(200)
-            self.send_header('Content-Type', mime('json'))
-            self.end_headers()
-            self.wfile.write(json.dumps(self.settings).encode('utf-8'))
+            self.api_success(self.settings)
            return
        if api == 'set':
            for key in data:
                self.settings[key] = data[key]
            self.save_config()
+            self.update_printer()
            self.api_success()
            return
        if api == 'exit':
            self.api_success()
+            self.exit()
+
+    def exit(self):
+        'Stop correctly & cleanly'
        self.save_config()
-            # Only usable when using ThreadingHTTPServer
-            # server.shutdown()
+        self.printer.unload()
        sys.exit(0)
+
    def do_POST(self):
        'Called when server get a POST http request'
        content_length = int(self.headers.get('Content-Length', -1))
-        if (content_length == -1 or
+        if (content_length < -1 or
            content_length > self.max_payload
        ):
-            self.send_response(400)
-            self.send_header('Content-Type', mime('txt'))
-            self.end_headers()
            return
        if self.headers.get('Content-Type') == 'application/ipp':
            if self.ipp is None:
-                try:
-                    from additional.ipp import IPP
-                    self.load_config()
-                except ImportError:
-                    # TODO: Better response?
-                    return
-                self.ipp = IPP(self, self.printer)
-            self.update_printer()
-            body = self.rfile.read(content_length)
-            loop = asyncio.new_event_loop()
-            try:
-                loop.run_until_complete(self.ipp.handle_ipp(body))
-            finally:
-                loop.close()
+                self.ipp = IPP(self)
+            self.ipp.handle_ipp()
            return
        try:
            self.handle_api()
            return
        except BleakDBusError as e:
+            # TODO: better error reporting
            self.api_fail({
-                'code': -2,
                'name': e.dbus_error,
                'details': e.dbus_error_details
            })
        except BleakError as e:
            self.api_fail({
-                'code': -3,
                'name': 'BleakError',
                'details': str(e)
            })
-        except PrinterServerError as e:
+        except PrinterError as e:
            self.api_fail({
-                'code': e.code,
-                'name': e.name,
-                'details': e.details
+                'name': e.message,
+                'details': e.message_localized
            })
        except Exception as e:
            self.api_fail({
-                'code': -1,
                'name': 'Exception',
                'details': str(e)
-            }, e)
+            })
+            raise
+
+class PrinterServer(HTTPServer):
+    ''' (local) server for Cat Printer Web Interface
+        The reason to override is to only init the handler once,
+        avoiding confliction, and stop cleanly
+    '''
+
+    handler: PrinterServerHandler = None
+
+    def finish_request(self, request, client_address):
+        if self.handler is None:
+            self.handler = PrinterServerHandler(request, client_address, self)
+            return
+        self.handler.__init__(request, client_address, self)
+
+    def server_close(self):
+        if self.handler is not None:
+            self.handler.exit()
+        super().server_close()
+

 def serve():
    'Start server'
    address, port = '127.0.0.1', 8095
    listen_all = False
    if '-a' in sys.argv:
-        print('Will listen on ALL addresses')
+        info(I18n['will-listen-on-all-addresses'])
        listen_all = True
-    # Again, Don't use ThreadingHTTPServer if you're going to use pyjnius!
-    server = HTTPServer(('' if listen_all else address, port), PrinterServer)
+    server = PrinterServer(('' if listen_all else address, port), PrinterServer)
    service_url = f'http://{address}:{port}/'
    if '-s' in sys.argv:
-        print(service_url)
+        info(I18n['serving-at-0', service_url])
    else:
        operating_system = platform.uname().system
        if operating_system == 'Windows':
@ -262,11 +278,11 @@ def serve():
        # TODO: I don't know about macOS
        # elif operating_system == 'macOS':
        else:
-            print(f'Will serve application at: {service_url}')
+            info(I18n['serving-at-0', service_url])
    try:
        server.serve_forever()
    except KeyboardInterrupt:
-        pass
+        server.server_close()

 if __name__ == '__main__':
    serve()
--- a/www/i18n-ext.js
+++ b/www/i18n-ext.js
@ -0,0 +1,49 @@
+
+/**
+ * Methods to know which string to use, per language
+ */
+var I18nExtensions = (function() {
+
+    /** @type {ExtensionOf<'en-US'>} */
+    function english(things, conditions) {
+        let text = conditions;
+        for (let index in things) {
+            let value = things[index];
+            if (value == 1) text = conditions['single'];
+            else text = conditions['multiple'];
+            if (!text && typeof value === 'number') {
+                if (value < 10 || value > 20) {
+                    if (value % 10 === 1) text = conditions['1st'];
+                    else if (value % 10 === 2) text = conditions['2nd'];
+                    else if (value % 10 === 3) text = conditions['3rd'];
+                    else text = conditions['nth'];
+                } else text = conditions['nth'];
+            }
+        }
+        return text;
+    }
+
+    /** @type {ExtensionOf<'zh-CN'>} */
+    function chinese(things, conditions) {
+        let text = conditions;
+        return text;
+    }
+
+    /** @type {ExtensionOf<'de-DE'>} */
+    function german(things, conditions) {
+        let text = conditions;
+        for (let index in things) {
+            let value = things[index];
+            if (value == 1) text = conditions['single'];
+            else text = conditions['multiple'];
+        }
+        return text;
+    }
+
+    return {
+        'en-US': english,
+        'zh-CN': chinese,
+        'de-DE': german
+    }
+
+})();
--- a/www/i18n.d.ts
+++ b/www/i18n.d.ts
@ -0,0 +1,32 @@
+
+type DictOf<T> = { [key: string]: T };
+type Conditions = DictOf<string>;
+type ConditionsOf<K extends Languages> = AllConditions[K];
+type LanguageData = DictOf<Conditions | string>;
+type Things = { [index: number | string]: number | string } | Array<number | string>;
+type Extension = (things: Things, conditions: Conditions) => string;
+type ExtensionOf<K extends Languages> = (things: Things, conditions: ConditionsOf<K>) => string;
+type Languages = keyof AllConditions;
+
+/**
+ * All known possible condition keys, per language
+ */
+type AllConditions = {
+    'en-US': {
+        'single': string,
+        'multiple': string,
+        '1st': string,
+        '2nd': string,
+        '3rd': string,
+        'nth': string
+    },
+    'de-DE': {
+        'single': string,
+        'multiple': string
+    },
+    'zh-CN': {}
+};
+
+interface I18nCallable extends I18n {
+    (text: string, things: Things, can_change_things: boolean): string;
+}
--- a/www/i18n.js
+++ b/www/i18n.js
@ -0,0 +1,109 @@
+
+'use strict';
+
+/**
+ * Yet another i18n solution
+ */
+class I18n {
+    /** @type {DictOf<LanguageData>} */
+    database;
+    /** @type {DictOf<Extension>} */
+    extensions;
+    /** @type {Languages} */
+    language;
+    constructor(language = 'en') {
+        this.database = {};
+        this.extensions = {};
+        this.useLanguage(language);
+    }
+    /**
+     * Use this language as main language
+     * @param {Languages} language
+     */
+    useLanguage(language) {
+        this.language = language;
+        if (!this.database[language])
+            this.database[language] = {};
+    }
+    /**
+     * Add data as corresponding language, also to
+     * other (added) languages as fallback
+     * @param {Languages} language
+     * @param {LanguageData} data
+     */
+    add(language, data) {
+        if (!this.database[language])
+            this.database[language] = {};
+        for (let key in data) {
+            let value = data[key];
+            this.database[language][key] = value;
+            for (let lang in this.database)
+                if (!this.database[lang][key])
+                    this.database[lang][key] = value;
+        }
+    }
+    /**
+     * Use extension in the language
+     * @param {Languages} language
+     * @param {Extension} extension
+     */
+    extend(language, extension) {
+        this.extensions[language] = extension;
+    }
+    /**
+     * Alias a language code to another, usually formal/more used/as fallback
+     * @param {DictOf<Languages>} aliases 
+     */
+    alias(aliases) {
+        for (let alt_code in aliases) {
+            let code = aliases[alt_code];
+            this.database[alt_code] = this.database[code];
+            this.extensions[alt_code] = this.extensions[code];
+        }
+    }
+    /**
+     * Translate a string ("text"), using "things" such as numbers
+     * @param {string} text
+     * @param {Things} things
+     * @param {boolean} can_change_things
+     */
+    translate(text, things, can_change_things = true) {
+        let conditions = this.database[this.language][text] || text;
+        if (!things) return conditions;
+        if (!can_change_things) things = { ... things };
+        if (this.extensions[this.language] && typeof conditions !== 'string')
+            text = this.extensions[this.language](things, conditions);
+        else text = conditions;
+        for (let key in things) {
+            text = text.replace(`{${key}}`, things[key].toString());
+        }
+        return text;
+    }
+}
+
+/**
+ * A i18n instance that is directly callable
+ * @type {I18nCallable}
+ */
+var i18n = (function() {
+
+    let instance = new I18n();
+
+    /**
+     * @param {string} text
+     * @param {Things} things 
+     * @param {boolean} can_change_things
+     */
+    let i18n_callable = function(text, things, can_change_things = true) {
+        return instance.translate.call(i18n_callable, text, things, can_change_things);
+    }
+
+    Object.setPrototypeOf(i18n_callable, instance);
+
+    if (typeof I18nExtensions === 'object') {
+        for (let key in I18nExtensions)
+            instance.extend(key, I18nExtensions[key]);
+    }
+
+    return i18n_callable;
+})();
--- a/www/index.html
+++ b/www/index.html
@ -87,15 +87,15 @@
                    <input type="number" name="scan-time" id="scan-time" min="1" max="10" value="3" />
                    <span data-i18n="-seconds">seconds</span>
                    <br />
-                    <label for="frequency" data-i18n="transmission-speed-">Data Speed:</label>
-                    <select id="frequency">
-                        <option value="1.0" data-i18n="low">Low</option>
-                        <option value="0.8" data-i18n="moderate" selected>Moderate</option>
-                        <option value="0.6" data-i18n="high">High</option>
-                    </select>
+                    <input type="checkbox" name="flip-h" id="flip-h" />
+                    <label for="flip-h" data-i18n="flip-horizontally">Flip Horizontally</label>
+                    <input type="checkbox" name="flip-v" id="flip-v" />
+                    <label for="flip-v" data-i18n="flip-vertically">Flip Vertically</label>
                    <br />
                    <input type="checkbox" name="dry-run" id="dry-run" />
                    <label for="dry-run" data-i18n="dry-run">Dry Run</label>
+                    <input type="checkbox" name="dump" id="dump" />
+                    <label for="dump" data-i18n="dump-traffic">Dump Traffic</label>
                </div>
                <div class="sub panel">
                    <a href="#" data-i18n="system">System</a>
--- a/www/jslicense.html
+++ b/www/jslicense.html
@ -42,10 +42,16 @@
                        </tr>
                        <tr>
                            <td><a href="i18n.js">i18n.js</a></td>
-                            <td><a href="http://www.jclark.com/xml/copying.txt">Expat</a></td>
-                            <td><a href="https://github.com/roddeh/i18njs">i18n.js</a></td>
+                            <td><a href="http://creativecommons.org/publicdomain/zero/1.0/legalcode">CC0-1.0-only</a></td>
+                            <td><a href="i18n.js">i18n.js</a></td>
                            <td>For internationalization (language support)</td>
                        </tr>
+                        <tr>
+                            <td><a href="i18n-ext.js">i18n-ext.js</a></td>
+                            <td><a href="http://creativecommons.org/publicdomain/zero/1.0/legalcode">CC0-1.0-only</a></td>
+                            <td><a href="i18n-ext.js">i18n-ext.js</a></td>
+                            <td>I18n "extensions"</td>
+                        </tr>
                        <tr>
                            <td><a href="main.js">main.js</a></td>
                            <td><a href="https://www.gnu.org/licenses/gpl-3.0.html">GNU-GPL-3.0-or-later</a></td>
--- a/www/lang/de-DE.json
+++ b/www/lang/de-DE.json
@ -1,5 +1,4 @@
 {
-    "values": {
    "cat-printer": "Cat Printer",
    "printer": "Drucker",
    "device-": "Gerät:",
@ -38,10 +37,10 @@
    "scan-time-": "Scanzeit:",
    "-seconds": "Sekunden",
    "no-available-devices-found": "Keine verfügbaren Geräte gefunden",
-        "found-1-available-devices": [
-            [1, 1, "1 verfügbares Gerät gefunden"],
-            [2, null, "%n verfügbare Geräte gefunden"]
-        ],
+    "found-0-available-devices": {
+        "single": "{0} verfügbares Gerät gefunden",
+        "multiple": "{0} verfügbare Geräte gefunden"
+    },
    "please-check-if-the-printer-is-down": "Bitte prüfe, ob der Drucker ausgeschaltet ist",
    "printing": "Drucken…",
    "finished": "Fertiggestellt",
@ -51,15 +50,12 @@
    "you-can-close-this-page-manually": "Sie können diese Seite manuell schließen",
    "please-enable-bluetooth": "Bitte aktivieren Sie Bluetooth",
    "error-happened-please-check-error-message": "Fehler aufgetreten, bitte Fehlermeldung einsehen",
-        "you-can-seek-for-help-with-detailed-info-below": "Sie können mit den nachstehenden ausführlichen Informationen Hilfe bekommen.",
+    "you-can-seek-for-help-with-detailed-info-below": "Sie können mit den nachstehenden ausführlichen Informationen Hilfe bekommen",
    "or-try-to-scan-longer": "Oder versuchen Sie, länger zu suchen",
-        "print-pbm-image-to-cat-printer": "PBM-Bild auf Cat Printer drucken.",
+    "print-to-cat-printer": "PBM-Bild auf Cat Printer drucken",
    "supported-models-": "Unterstützte Modelle:",
-        "path-to-pbm-file-dash-for-stdin": "Pfad zur PBM-Datei. '-' für stdin.",
+    "path-to-input-file-dash-for-stdin": "Pfad zur Datei. '-' für stdin",
    "scan-for-specified-seconds": "Suchlauf für die angegebenen Sekunden",
-        "specify-printer-mac-address": "Geben Sie die MAC-Adresse des Druckers an",
-        "communication-frequency-0.8-or-1-recommended": "Übermittlungsfrequenz. 0,8 oder 1 empfohlen.",
-        "dump-the-traffic-to-printer-and-pbm-image-when-text-printing": "Den Datenverkehr auf dem Drucker ausgeben und PBM-Bild beim Textdruck.",
-        "text-printing-mode-input-text-from-stdin": "Textdruckmodus, Eingabe von stdin."
-    }
+    "dump-the-traffic": "Den Datenverkehr auf dem Drucker ausgeben und PBM-Bild beim Textdruck",
+    "text-printing-mode": "Textdruckmodus"
 }
--- a/www/lang/en-US.json
+++ b/www/lang/en-US.json
@ -1,5 +1,4 @@
 {
-    "values": {
    "cat-printer": "Cat Printer",
    "printer": "Printer",
    "device-": "Device:",
@ -38,10 +37,10 @@
    "scan-time-": "Scan time:",
    "-seconds": "seconds",
    "no-available-devices-found": "No available devices found",
-        "found-1-available-devices": [
-            [1, 1, "Found 1 available device"],
-            [2, null, "Found %n available devices"]
-        ],
+    "found-0-available-devices": {
+        "single": "Found {0} available device",
+        "multiple": "Found {0} available devices"
+    },
    "please-check-if-the-printer-is-down": "Please check if the printer is down",
    "printing": "Printing…",
    "finished": "Finished",
@ -51,17 +50,38 @@
    "you-can-close-this-page-manually": "You can close this page manually",
    "please-enable-bluetooth": "Please enable Bluetooth",
    "error-happened-please-check-error-message": "Error happened, please check error message",
-        "you-can-seek-for-help-with-detailed-info-below": "You can seek for help with detailed info below.",
+    "you-can-seek-for-help-with-detailed-info-below": "You can seek for help with detailed info below",

    "or-try-to-scan-longer": "Or try to scan longer",
-        "print-pbm-image-to-cat-printer": "Print PBM image to Cat Printer.",
+    "print-to-cat-printer": "Print to Cat Printer",
    "supported-models-": "Supported models:",
-        "path-to-pbm-file-dash-for-stdin": "Path to PBM file. '-' for stdin.",
+    "path-to-input-file-dash-for-stdin": "Path to input file. '-' for stdin",
    "scan-for-specified-seconds": "Scan for specified seconds",
-        "specify-printer-mac-address": "Specify printer MAC address",
-        "communication-frequency-0.8-or-1-recommended": "Communication frequency. 0.8 or 1 recommended.",

-        "dump-the-traffic-to-printer-and-pbm-image-when-text-printing": "Dump the traffic to printer, and PBM image when text printing.",
-        "text-printing-mode-input-text-from-stdin": "Text printing mode, input from stdin."
-    }
+    "dump-the-traffic": "Dump the traffic",
+    "text-printing-mode": "Text printing mode",
+
+    "please-install-pyobjc-via-pip": "Please install `pyobjc` via pip",
+    "please-install-bleak-via-pip": "Please install `bleak` via pip",
+    "folder-printer_lib-is-incomplete-or-missing-please-check": "Folder `printer_lib` is incomplete or missing, please check",
+    "input-is-not-pbm-image": "Input is not PBM image",
+    "unsuitable-image-width-expected-0-got-1": "Unsuitable image width, expected {0}, got {1}",
+    "broken-pbm-image": "Broken PBM image",
+    "input-is-not-text-file": "Input is not text file",
+    "match-printer-with-this-name-or-address": "Match printer with this name or address",
+    "virtual-run-on-specified-model": "Virtual run on specified model",
+    "font-size-0": "Font size {0}",
+    "stopping": "Stopping",
+    "connecting": "Connecting",
+    "model-0-is-not-supported-yet": "Model '{0}' is not supported yet",
+    "invalid-address-0": "Invalid address: '{0}'",
+    "will-listen-on-all-addresses": "Will listen on ALL addresses",
+    "serving-at-0": "Serving at {0}",
+    "disconnecting-from-printer": "Disconnecting from printer",
+    "connected-to-0-1": "Connected to {0} {1}",
+    "flip-horizontally": "Flip Horizontally",
+    "flip-vertically": "Flip Vertically",
+    "dump-traffic": "Dump Traffic",
+    "right-to-left-text-order": "Right-to-left text order",
+    "auto-wrap-line": "Auto wrap line"
 }
--- a/www/lang/zh-CN.json
+++ b/www/lang/zh-CN.json
@ -1,5 +1,4 @@
 {
-    "values": {
    "cat-printer": "猫咪打印机",
    "printer": "打印机",
    "device-": "设备：",
@ -38,9 +37,7 @@
    "scan-time-": "扫描时间：",
    "-seconds": "秒",
    "no-available-devices-found": "未发现可用设备",
-        "found-1-available-devices": [
-            [1, null, "发现 %n 个可用设备"]
-        ],
+    "found-0-available-devices": "发现 {0} 个可用设备",
    "please-check-if-the-printer-is-down": "请检查打印机是否已关闭",
    "printing": "打印中……",
    "finished": "完成",
@ -50,17 +47,37 @@
    "you-can-close-this-page-manually": "您可手动关闭此页面",
    "please-enable-bluetooth": "请启用蓝牙",
    "error-happened-please-check-error-message": "发生错误，请检查错误消息",
-        "you-can-seek-for-help-with-detailed-info-below": "您可以使用以下详细信息寻求帮助。",
+    "you-can-seek-for-help-with-detailed-info-below": "您可以使用以下详细信息寻求帮助",

    "or-try-to-scan-longer": "或者尝试延长扫描时间",
-        "print-pbm-image-to-cat-printer": "打印 PBM 图片到猫咪打印机。",
+    "print-to-cat-printer": "打印到猫咪打印机。",
    "supported-models-": "支持的型号：",
-        "path-to-pbm-file-dash-for-stdin": "PBM 文件的位置。“-” 作为标准输入。",
-        "scan-for-specified-seconds": "扫描指定的时长。",
-        "specify-printer-mac-address": "指定打印机的 MAC 地址",
-        "communication-frequency-0.8-or-1-recommended": "通讯频率。推荐 0.8 或 1。",
+    "path-to-input-file-dash-for-stdin": "输入文件的位置。使用 '-' 作为标准输入",
+    "scan-for-specified-seconds": "扫描指定的时长",

-        "dump-the-traffic-to-printer-and-pbm-image-when-text-printing": "转储到打印机的数据，和文字打印模式的 PBM 图像。",
-        "text-printing-mode-input-text-from-stdin": "文字打印模式，将从标准输入读取文字。"
-    }
+    "dump-the-traffic": "转储数据",
+    "text-printing-mode": "文字打印模式",
+
+    "please-install-pyobjc-via-pip": "请从 pip 安装 `pyobjc`",
+    "please-install-bleak-via-pip": "请从 pip 安装 `bleak`",
+    "folder-printer_lib-is-incomplete-or-missing-please-check": "文件夹 `printer_lib` 不完整或丢失，请检查",
+    "input-is-not-pbm-image": "输入不是 PBM 图像",
+    "unsuitable-image-width-expected-0-got-1": "不适合的图像宽度，需要 {0}, 输入为 {1}",
+    "broken-pbm-image": "损坏的 PBM 图像",
+    "input-is-not-text-file": "输入不是文本文件",
+    "match-printer-with-this-name-or-address": "使用符合此名称或地址的打印机",
+    "virtual-run-on-specified-model": "在指定的型号模拟运行",
+    "font-size-0": "字体大小 {0}",
+    "stopping": "停止中",
+    "connecting": "正在连接",
+    "model-0-is-not-supported-yet": "型号 '{0}' 仍未支持",
+    "invalid-address-0": "无效的地址：'{0}'",
+    "will-listen-on-all-addresses": "将接受所有地址的连接",
+    "serving-at-0": "服务器在 {0}",
+    "disconnecting-from-printer": "正在从打印机断开连接",
+    "flip-horizontally": "水平翻转",
+    "flip-vertically": "垂直翻转",
+    "dump-traffic": "转储数据",
+    "right-to-left-text-order": "从右到左的文字顺序",
+    "auto-wrap-line": "自动折行"
 }
--- a/www/loader.js
+++ b/www/loader.js
@ -6,7 +6,7 @@

    var fallbacks = [
        // main scripts, which we will directly modify
-        'i18n.js', 'image.js', 'main.js',
+        'i18n-ext.js', 'i18n.js', 'image.js', 'main.js',
        // "compatibility" script, produced with eg. typescript tsc
        'main.comp.js'
    ];
--- a/www/main.js
+++ b/www/main.js
@ -38,13 +38,13 @@ class _Notice {
    constructor() {
        this.element = document.getElementById('notice');
    }
-    _message(message, ...args) {
-        this.element.innerText = i18n(message, ...args) || message;
+    _message(message, things) {
+        this.element.innerText = i18n(message, things) || message;
    }
    makeLogger(class_name) {
-        return (message, ...args) => {
+        return (message, things) => {
            this.element.classList.value = class_name;
-            this._message(message, ...args);
+            this._message(message, things);
        }
    }
    notice = this.makeLogger('notice');
@ -373,7 +373,7 @@ class Main {
            putEvent('#button-exit', 'click', this.exit, this);
            putEvent('#button-print', 'click', this.print, this);
            putEvent('#device-refresh', 'click', this.searchDevices, this);
-            this.attachSetter('#scan-time', 'change', 'scan_time');
+            this.attachSetter('#scan-time', 'change', 'scan_timeout');
            this.attachSetter('#device-options', 'input', 'printer');
            this.attachSetter('input[name="algo"]', 'change', 'mono_algorithm');
            this.attachSetter('#transparent-as-white', 'change', 'transparent_as_white');
@ -387,7 +387,9 @@ class Main {
            this.attachSetter('#threshold', 'change', 'threshold',
                (value) => this.canvasController.threshold = value
            );
-            this.attachSetter('#frequency', 'change', 'frequency');
+            this.attachSetter('#flip-h', 'change', 'flip_h');
+            this.attachSetter('#flip-v', 'change', 'flip_v');
+            this.attachSetter('#dump', 'change', 'dump');
            await this.loadConfig();
            this.searchDevices();
            resolve();
@ -488,7 +490,7 @@ class Main {
            hint('#device-refresh');
            return;
        }
-        Notice.notice('found-1-available-devices', devices.length);
+        Notice.notice('found-0-available-devices', [devices.length]);
        hint('#insert-picture');
        devices.forEach(device => {
            let option = document.createElement('option');
@ -519,18 +521,15 @@ class Main {
    }
    async initI18n() {
        if (typeof i18n === 'undefined') return;
-        let language_list = navigator.languages;
-        let loaded_languages = [];
-        let data;
-        for (let i = language_list.length - 1; i >= 0; i--) {
-            data = await fetch(`/lang/${language_list[i]}.json`)
+        i18n.useLanguage(navigator.languages[0]);
+        for (let language of navigator.languages) {
+            let data = await fetch(`/lang/${language}.json`)
                .then(response => response.ok ? response.json() : null);
            if (data !== null) {
-                i18n.translator.add(data);
-                loaded_languages.unshift(language_list[i]);
+                i18n.add(language, data);
+                console.log('Loaded language:', language);
            }
        }
-        console.log('Language stack:', loaded_languages);
        let elements = document.querySelectorAll('*[data-i18n]');
        let i18n_data, translated_string;
        elements.forEach(element => {