#!/usr/bin/env python3
"""Convert Doc/UI 0831 trial PNG slices to RGB565 C arrays for mode-select."""
from PIL import Image, ImageDraw
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
SRC = ROOT / "tools" / "assets_0831"
OUT_C = ROOT / "device" / "LCD_ILI9341" / "Drv_ILI9341_Lcd_Image_ModeSelect0831.c"
OUT_H = ROOT / "device" / "LCD_ILI9341" / "Drv_ILI9341_Lcd_Image_ModeSelect0831.h"
PREV = SRC / "preview_mode_select.png"

# Only emit composite rows (icon+MiSans text) to save Flash.
ROW_W, ROW_H = 180, 52

NAMES = [
    ("Universal", "mode_row_0.png"),  # 万能
    ("Normal", "mode_row_1.png"),     # 普通
    ("Expert", "mode_row_2.png"),     # 专业
]


def rgba_to_rgb565_bytes(im: Image.Image) -> bytes:
    im = im.convert("RGBA")
    px = im.load()
    w, h = im.size
    out = bytearray(w * h * 2)
    i = 0
    for y in range(h):
        for x in range(w):
            r, g, b, a = px[x, y]
            if a < 40 or (r < 12 and g < 12 and b < 12):
                out[i] = 0
                out[i + 1] = 0
            else:
                r = (r * a) // 255
                g = (g * a) // 255
                b = (b * a) // 255
                c = ((r >> 3) << 11) | ((g >> 2) << 5) | (b >> 3)
                out[i] = (c >> 8) & 0xFF
                out[i + 1] = c & 0xFF
            i += 2
    return bytes(out)


def fit_on_canvas(src_im: Image.Image, cw: int, ch: int) -> Image.Image:
    im = src_im.convert("RGBA")
    bbox = im.getbbox()
    if bbox:
        im = im.crop(bbox)
    sw, sh = im.size
    scale = min(cw / sw, ch / sh)
    nw = max(1, int(round(sw * scale)))
    nh = max(1, int(round(sh * scale)))
    im = im.resize((nw, nh), Image.Resampling.LANCZOS)
    canvas = Image.new("RGBA", (cw, ch), (0, 0, 0, 255))
    ox = (cw - nw) // 2
    oy = (ch - nh) // 2
    canvas.paste(im, (ox, oy), im)
    return canvas


def emit_array(name: str, data: bytes, w: int, h: int, lines: list) -> None:
    lines.append(f"const unsigned char {name}[{len(data)}] = {{ /* {w}x{h} RGB565 BE */")
    for i in range(0, len(data), 16):
        chunk = data[i : i + 16]
        hexes = ",".join(f"0x{b:02X}" for b in chunk)
        lines.append(hexes + ",")
    lines.append("};")
    lines.append("")


def main() -> None:
    c_lines = [
        '#include "Drv_ILI9341_Lcd_Image_ModeSelect0831.h"',
        "",
        "/* Auto-generated from Doc/UI 0831 trial PNG. Do not hand-edit. */",
        "",
    ]
    h_lines = [
        "#ifndef __DRV_ILI9341_LCD_IMAGE_MODESELECT0831_H",
        "#define __DRV_ILI9341_LCD_IMAGE_MODESELECT0831_H",
        "",
        '#include "stdint.h"',
        "",
        f"#define UI_MODE0831_ROW_W   {ROW_W}",
        f"#define UI_MODE0831_ROW_H   {ROW_H}",
        "",
    ]

    screen = Image.new("RGBA", (240, 320), (0, 0, 0, 255))
    d = ImageDraw.Draw(screen)
    d.rectangle([0, 0, 239, 27], fill=(20, 28, 40, 255))

    btn_ys = [40, 132, 224]
    btn_w, btn_h, btn_r = 220, 87, 10
    total = 0

    for idx, (tag, row_n) in enumerate(NAMES):
        row = fit_on_canvas(Image.open(SRC / row_n), ROW_W, ROW_H)
        row.save(SRC / f"gen_{tag.lower()}_row.png")

        rdata = rgba_to_rgb565_bytes(row)
        total += len(rdata)

        rname = f"gImage_Mode0831_{tag}_Row_{ROW_W}_{ROW_H}"
        emit_array(rname, rdata, ROW_W, ROW_H, c_lines)
        h_lines.append(f"extern const unsigned char {rname}[];")
        h_lines.append("")

        by = btn_ys[idx]
        bx = (240 - btn_w) // 2
        fill = (47, 54, 71, 255) if idx == 0 else (25, 32, 45, 255)
        d.rounded_rectangle([bx, by, bx + btn_w - 1, by + btn_h - 1], radius=btn_r, fill=fill)
        rx = bx + (btn_w - ROW_W) // 2
        ry = by + (btn_h - ROW_H) // 2
        screen.paste(row, (rx, ry), row)

    h_lines += ["#endif", ""]
    OUT_H.write_text("\n".join(h_lines), encoding="utf-8")
    OUT_C.write_text("\n".join(c_lines), encoding="utf-8")
    screen.convert("RGB").save(PREV)
    print(f"wrote {OUT_C} ({OUT_C.stat().st_size} bytes)")
    print(f"wrote {OUT_H}")
    print(f"flash payload ~{total} bytes")
    print(f"preview {PREV}")


if __name__ == "__main__":
    main()