#!/usr/bin/env python3
from pathlib import Path
import gettext
import json

import pyray as rl

FONT_DIR = Path(__file__).resolve().parent
SELFDRIVE_DIR = FONT_DIR.parents[1]
TRANSLATIONS_DIR = SELFDRIVE_DIR / "ui" / "translations"
LANGUAGES_FILE = TRANSLATIONS_DIR / "languages.json"

GLYPH_PADDING = 6
EXTRA_CHARS = "–‑✓×°§•X⚙✕◀▶✔⌫⇧␣○●↳çêüñ–‑✓×°§•€£¥"
UNIFONT_LANGUAGES = {"th", "zh-CHT", "zh-CHS", "ko", "ja"}


def _languages():
  if not LANGUAGES_FILE.exists():
    return {}
  with LANGUAGES_FILE.open(encoding="utf-8") as f:
    return json.load(f)


def _dragonpilot_chars(code: str) -> set[str]:
  """Characters used by dragonpilot's own translations (dragonpilot_{code}.po).

  dp settings translate via a separate catalog from openpilot's app_{code}.po,
  so their glyphs must be baked too — otherwise translated dp settings render
  as '?'. We parse the .po file directly to get translated strings, avoiding
  .mo encoding issues with GNUTranslations."""
  po_path = TRANSLATIONS_DIR / f"dragonpilot_{code}.po"
  if not po_path.exists():
    return set()
  import re
  text = po_path.read_text(encoding="utf-8")
  chars: set[str] = set()
  # Extract all msgstr values
  for m in re.finditer(r'^msgstr\s+"(.*)"', text, re.MULTILINE):
    chars |= set(m.group(1))
  # Also handle multi-line msgstr
  in_msgstr = False
  for line in text.splitlines():
    if line.startswith('msgstr "') or (in_msgstr and line.startswith('"')):
      in_msgstr = True
      content = line.removeprefix('msgstr "').removesuffix('"') if line.startswith('msgstr "') else line.strip('"')
      content = content.replace('\\\\n', '\n').replace('\\n', '\n').replace('\\"', '"')
      chars |= set(content)
    else:
      in_msgstr = False
  return chars


def _char_sets():
  base = set(map(chr, range(32, 127))) | set(EXTRA_CHARS)
  labels = set(base)
  per_lang: dict[str, tuple[int, ...]] = {}

  for language, code in _languages().items():
    labels.update(language)
    po_path = TRANSLATIONS_DIR / f"app_{code}.po"
    try:
      chars = set(po_path.read_text(encoding="utf-8"))
    except FileNotFoundError:
      continue
    chars |= _dragonpilot_chars(code)
    if code in UNIFONT_LANGUAGES:
      lang_chars = set(base) | chars
      per_lang[code] = tuple(sorted(ord(c) for c in lang_chars))
    else:
      base.update(chars)

  base_cp = tuple(sorted(ord(c) for c in base))
  labels_cp = tuple(sorted(ord(c) for c in labels))
  return base_cp, labels_cp, per_lang


def _glyph_metrics(glyphs, rects, glyph_count: int):
  entries = []
  min_offset_y, max_extent = None, 0
  for idx in range(glyph_count):
    glyph = glyphs[idx]
    rect = rects[idx]
    width = int(round(rect.width))
    height = int(round(rect.height))
    offset_y = int(round(glyph.offsetY))
    min_offset_y = offset_y if min_offset_y is None else min(min_offset_y, offset_y)
    max_extent = max(max_extent, offset_y + height)
    entries.append({
      "id": glyph.value,
      "x": int(round(rect.x)),
      "y": int(round(rect.y)),
      "width": width,
      "height": height,
      "xoffset": int(round(glyph.offsetX)),
      "yoffset": offset_y,
      "xadvance": int(round(glyph.advanceX)),
    })

  if min_offset_y is None:
    raise RuntimeError("No glyphs were generated")

  line_height = int(round(max_extent - min_offset_y))
  base = int(round(max_extent))
  return entries, line_height, base


def _write_bmfont(path: Path, font_size: int, face: str, atlas_name: str, line_height: int, base: int, atlas_size, entries):
  # TODO: why doesn't raylib calculate these metrics correctly?
  if line_height != font_size:
    print("using font size for line height", atlas_name)
    line_height = font_size
  lines = [
    f"info face=\"{face}\" size=-{font_size} bold=0 italic=0 charset=\"\" unicode=1 stretchH=100 smooth=0 aa=1 padding=0,0,0,0 spacing=0,0 outline=0",
    f"common lineHeight={line_height} base={base} scaleW={atlas_size[0]} scaleH={atlas_size[1]} pages=1 packed=0 alphaChnl=0 redChnl=4 greenChnl=4 blueChnl=4",
    f"page id=0 file=\"{atlas_name}\"",
    f"chars count={len(entries)}",
  ]
  for entry in entries:
    lines.append(
      ("char id={id:<4} x={x:<5} y={y:<5} width={width:<5} height={height:<5} " +
       "xoffset={xoffset:<5} yoffset={yoffset:<5} xadvance={xadvance:<5} page=0  chnl=15").format(**entry)
    )
  path.write_text("\n".join(lines) + "\n")


def _init_window():
  """Initialize raylib window (required for font rendering with GPU)."""
  # Reuse the lib loaded once
  if not hasattr(_init_window, '_done'):
    lib = rl.ffi.dlopen(None)
    lib.InitWindow(64, 64, b'fontgen')
    lib.SetWindowState(0x00000080)  # FLAG_WINDOW_HIDDEN
    lib.SetTargetFPS(0)
    _init_window._lib = lib
    _init_window._done = True
  return _init_window._lib


def _process_font(font_path: Path, codepoints: tuple[int, ...], output_name: str | None = None):
  stem = output_name or font_path.stem
  font_size = 48 if font_path.stem.lower().startswith("opfont") else 200
  print(f"Processing {font_path.name} -> {stem} ({len(codepoints)} glyphs @ {font_size}px)...")

  lib = _init_window()

  load_font_ex = rl.ffi.cast('struct Font(*)(const char *, int, int *, int)', lib.LoadFontEx)
  gen_atlas = rl.ffi.cast('struct Image(*)(struct GlyphInfo *, struct Rectangle **, int, int, int, int)', lib.GenImageFontAtlas)
  export_img = rl.ffi.cast('bool(*)(struct Image, const char *)', lib.ExportImage)
  unload_font = rl.ffi.cast('void(*)(struct Font)', lib.UnloadFont)

  fnt_path = font_path.as_posix()
  cp_buffer = rl.ffi.new("int[]", codepoints)
  glyph_count = len(codepoints)
  font = load_font_ex(fnt_path.encode('utf-8'), font_size, cp_buffer, glyph_count)
  if font.glyphCount == 0:
    raise RuntimeError("raylib failed to load font data")

  rects_ptr = rl.ffi.new("struct Rectangle **")
  image = gen_atlas(font.glyphs, rects_ptr, font.glyphCount, font_size, GLYPH_PADDING, 0)
  if image.width == 0 or image.height == 0:
    unload_font(font)
    raise RuntimeError("raylib returned an empty atlas")

  rects = rects_ptr[0]
  atlas_name = f"{stem}.png"
  atlas_path = FONT_DIR / atlas_name
  entries, line_height, base = _glyph_metrics(font.glyphs, rects, font.glyphCount)

  if not export_img(image, atlas_path.as_posix().encode('utf-8')):
    unload_font(font)
    raise RuntimeError("Failed to export atlas image")

  _write_bmfont(FONT_DIR / f"{stem}.fnt", font_size, stem, atlas_name, line_height, base, (image.width, image.height), entries)
  unload_font(font)


def main():
  base_cp, labels_cp, per_lang = _char_sets()
  fonts = sorted(FONT_DIR.glob("*.ttf")) + sorted(FONT_DIR.glob("*.otf"))
  opfonts: list[Path] = []

  for font in fonts:
    if "emoji" in font.name.lower() or font.name == "unifont.otf":
      continue
    if font.stem.lower().startswith("opfont"):
      opfonts.append(font)
      continue
    _process_font(font, base_cp)

  if not opfonts:
    raise RuntimeError("OpFont not found (expected OpFont-*.otf in fonts dir)")

  for opfont_path in opfonts:
    weight = opfont_path.stem  # e.g. "OpFont-Regular"

    # Labels atlas: language display names + ASCII (for language selector)
    _process_font(opfont_path, labels_cp, output_name=f"{weight}-Labels")

    # Per-language atlases: ASCII + that language's .po chars
    for lang_code, lang_cp in per_lang.items():
      _process_font(opfont_path, lang_cp, output_name=f"{weight}-{lang_code}")

  return 0


if __name__ == "__main__":
  raise SystemExit(main())