#!/usr/bin/env python

import io
import sys
import json
import typing
import os.path
import argparse
import subprocess

class FontArg(object):
    def __init__(self, d):
        self.font = d['font']
        self.range = d.get('range')
        self.symbols = d.get('symbols')


def gen_lvconv_line(dest: str, size: int, bpp: int, fonts: typing.List[FontArg], compress:bool=False):
    args = ['lv_font_conv', '--size', str(size), '--output', dest, '--bpp', str(bpp), '--format', 'lvgl']
    if not compress:
        args.append('--no-compress')
    for font in fonts:
        args.extend(['--font', font.font])
        if font.range:
            args.extend(['--range', font.range])
        if font.symbols:
            args.extend(['--symbols', font.symbols])

    return args

def main():
    ap = argparse.ArgumentParser(description='auto generate lvGL font files from fonts')
    ap.add_argument('config', type=str, help='config file to use')
    ap.add_argument('-e', '--enable', type=str, action='append', help='optional feature to enable in font generation', default=[], metavar='features', dest='features')
    ap.add_argument('-f', '--font', type=str, action='append', help='Choose specific fonts to generate (default: all)', default=[])
    args = ap.parse_args()

    if not os.path.exists(args.config):
        sys.exit(f'Error: the config file {args.config} does not exist.')
    if not os.access(args.config, os.R_OK):
        sys.exit(f'Error: the config file {args.config} is not accessable (permissions?).')
    with open(args.config, 'r') as fd:
        data = json.load(fd)

    for enabled_feature in args.features:
        if enabled_feature not in data['features']:
            sys.exit(f'Error: the requested feature {enabled_feature} does not exist in {args.config}.')

    for (name,font) in data['fonts'].items():
        if args.font and name not in args.font:
            continue
        sources = font.pop('sources')
        if 'patches' in font:
            patches = font.pop('patches')
        else:
            patches = None
        for enabled_feature in args.features:
            if name in data['features'][enabled_feature]:
                sources.extend(data['features'][enabled_feature][name])
        font['fonts'] = [FontArg(thing) for thing in sources]
        line = gen_lvconv_line(f'{name}.c', **font)
        subprocess.check_call(line)
        if patches:
            for patch in patches:
                subprocess.check_call(patch)



if __name__ == '__main__':
    main()