"""
将 PNG 图片转换为 C 头文件（RGBA5551 / uint16_t 像素数组）。

用法:
    python tools/png_to_header.py input.png output.h [var_name]

像素格式: RGBA5551（5-bit R, 5-bit G, 5-bit B, 1-bit A）
运行时 sprite 主路径只保留 1-bit 透明：A=0 跳过，A=1 覆写。
"""

import sys
import os

from PIL import Image


def convert(input_path: str, output_path: str, var_name: str):
    img = Image.open(input_path).convert("RGBA")
    w, h = img.size
    pixels = list(img.getdata()) if not hasattr(img, "get_flattened_data") else list(img.get_flattened_data())

    packed = []
    for r, g, b, a in pixels:
        packed.append(
            ((r >> 3) << 11)
            | ((g >> 3) << 6)
            | ((b >> 3) << 1)
            | (1 if a else 0)
        )

    with open(output_path, "w", encoding="utf-8") as f:
        f.write("// Auto-generated by tools/png_to_header.py\n")
        f.write(f"#pragma once\n#include <cstdint>\n\n")
        f.write(f"static const int32_t {var_name}_width = {w};\n")
        f.write(f"static const int32_t {var_name}_height = {h};\n\n")
        f.write(f"static const uint16_t {var_name}_pixels[] = {{\n")

        for i in range(0, len(packed), 16):
            chunk = packed[i : i + 16]
            line = ", ".join(f"0x{p:04X}" for p in chunk)
            f.write(f"    {line},\n")

        f.write("};\n")


def main():
    if len(sys.argv) < 3:
        print(f"用法: {sys.argv[0]} input.png output.h [var_name]")
        sys.exit(1)

    input_path = sys.argv[1]
    output_path = sys.argv[2]

    if len(sys.argv) >= 4:
        var_name = sys.argv[3]
    else:
        # 从文件名生成变量名: player_idle.png -> player_idle
        var_name = os.path.splitext(os.path.basename(input_path))[0]

    convert(input_path, output_path, var_name)
    print(f"已生成: {output_path}  (var: {var_name}, 像素数: {var_name}_width * {var_name}_height)")


if __name__ == "__main__":
    main()