# -*- coding: utf-8 -*-
"""
Generate 100% authentic, pixel-perfect 8x8 IBM VGA bitmap font for CP1251 in font8x8.inc.
Extracts official IBM VGA 8x8 font resources directly from C:\\Windows\\Fonts\\app866.fon,
mapping CP1251 characters to the corresponding CP866 Cyrillic glyphs.
"""
import struct
from pathlib import Path

REPO_ROOT = Path(__file__).resolve().parents[2]
FONT_INC = REPO_ROOT / 'font8x8.inc'

# Load authentic 8x8 font from app866.fon (Resource at offset 8784: 8x8, 256 glyphs)
with open('C:/Windows/Fonts/app866.fon', 'rb') as f:
    fon_data = f.read()

font_res = fon_data[8784:8784+3211]
raw_glyphs = {}
for ch in range(256):
    entry_off = 0x76 + ch * 4
    w, off = struct.unpack('<HH', font_res[entry_off:entry_off+4])
    raw_glyphs[ch] = list(font_res[off:off+8])

# Build complete 256-glyph CP1251 table
cp1251_font = []
for b in range(256):
    if b < 128:
        cp1251_font.append(raw_glyphs[b])
    else:
        try:
            char = bytes([b]).decode('cp1251')
            b866 = char.encode('cp866')[0]
            cp1251_font.append(raw_glyphs[b866])
        except Exception:
            cp1251_font.append(raw_glyphs[ord('?')])

# Write font8x8.inc in CP1251 encoding
with open(FONT_INC, 'w', encoding='cp1251') as f:
    f.write("; --- 8x8 BITMAP FONT FOR CP1251 (Authentic IBM VGA CP866/1251) ---\n")
    f.write(".data\nALIGN 4\nfont8x8 label byte\n")
    for idx, glyph in enumerate(cp1251_font):
        b_str = ", ".join(f"0{b:02X}h" for b in glyph)
        f.write(f"db {b_str} ; char 0x{idx:02X}\n")

print(f"[SUCCESS] Generated authentic, pixel-perfect font8x8.inc ({len(cp1251_font)} glyphs)")