#!/usr/bin/env python3
"""Bake an 8x16 1-bpp bitmap font (ASCII 32..127) from DejaVu Sans Mono 13px.

Output: Go source file with the atlas. One byte per glyph row, bit n = pixel
at column n (LSB = leftmost), matching the kernel's (row >> col) & 1 lookup.
"""
from PIL import Image, ImageDraw, ImageFont

FONT = "/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf"
SIZE = 13
BASELINE = 12   # baseline row inside the 16px cell
THRESH = 110

font = ImageFont.truetype(FONT, SIZE)
atlas = []
for c in range(32, 128):
    img = Image.new("L", (8, 16), 0)
    d = ImageDraw.Draw(img)
    d.text((0, BASELINE), chr(c), font=font, fill=255, anchor="ls")
    px = img.load()
    for y in range(16):
        b = 0
        for x in range(8):
            if px[x, y] >= THRESH:
                b |= 1 << x
        atlas.append(b)

def art(c):
    print(f"--- '{chr(c)}' ---")
    for y in range(16):
        row = atlas[(c - 32) * 16 + y]
        print("".join("#" if (row >> x) & 1 else "." for x in range(8)))

for c in "AgM%m0(":
    art(ord(c))

lines = []
for i in range(0, len(atlas), 16):
    chunk = ", ".join(f"0x{b:02X}" for b in atlas[i:i+16])
    lines.append(f"\t{chunk},")
body = "\n".join(lines)

src = f'''package generator

// 8x16 1-bpp bitmap font baked from DejaVu Sans Mono {SIZE}px (public-domain
// style console glyphs). ASCII 32..127, one byte per row, LSB = leftmost pixel.
var fontAtlas8x16 = [96 * 16]byte{{
{body}
}}
'''
with open("internal/generator/font.go", "w") as f:
    f.write(src)
print("wrote internal/generator/font.go,", len(atlas), "bytes of glyph data")