"""ModelTranslator CLI：FBX -> 纯模型 FBX + XPbr 贴图 + Unity .mat/.meta。
用法：python model_translator.py src/tong.fbx [-o out] [--max-size 2048] [--blender exe]"""
import argparse
import json
import os
import shutil
import subprocess
import sys

import unity_assets as ua

DEFAULT_BLENDER = r"D:\tools\blender-5.0.0-windows-x64\blender.exe"
HERE = os.path.dirname(os.path.abspath(__file__))


def find_blender(cli_arg):
    for cand in (cli_arg, os.environ.get("BLENDER_EXE"), DEFAULT_BLENDER,
                 shutil.which("blender")):
        if cand and os.path.isfile(cand):
            return cand
    sys.exit("找不到 blender.exe，请用 --blender 指定或设置环境变量 BLENDER_EXE")


def run_blender(blender, src, outdir, max_size):
    cmd = [blender, "-b", "--factory-startup",
           "--python", os.path.join(HERE, "bl_convert.py"),
           "--", src, outdir, str(max_size)]
    proc = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8",
                          errors="replace")
    summary = None
    for line in (proc.stdout or "").splitlines():
        if line.startswith("MT_SUMMARY "):
            summary = json.loads(line[len("MT_SUMMARY "):])
    if proc.returncode != 0 or summary is None:
        sys.stderr.write(proc.stdout[-2000:] + "\n" + proc.stderr[-2000:] + "\n")
        sys.exit("Blender 转换失败：%s" % src)
    return summary


def write_unity_assets(outdir, summary, max_size):
    remaps = []
    for m in summary["materials"]:
        base_png = os.path.join(outdir, m["base_png"])
        mix_png = os.path.join(outdir, m["mix_png"])
        base_guid = ua.guid_for(base_png)
        mix_guid = ua.guid_for(mix_png)
        with open(base_png + ".meta", "w", encoding="utf-8", newline="\n") as f:
            f.write(ua.texture_meta(base_guid, srgb=True, max_size=max_size))
        with open(mix_png + ".meta", "w", encoding="utf-8", newline="\n") as f:
            f.write(ua.texture_meta(mix_guid, srgb=False, max_size=max_size))

        mat_name = "%s_%s" % (summary["model"], m["safe_name"])
        mat_path = os.path.join(outdir, mat_name + ".mat")
        mat_guid = ua.guid_for(mat_path)
        alpha_test = m["alpha_mode"] == "transparency"
        with open(mat_path, "w", encoding="utf-8", newline="\n") as f:
            f.write(ua.material_yaml(mat_name, ua.XPBR_SHADER_GUID,
                                     base_guid, mix_guid, alpha_test))
        with open(mat_path + ".meta", "w", encoding="utf-8", newline="\n") as f:
            f.write(ua.material_meta(mat_guid))
        remaps.append((m["name"], mat_guid))

    fbx_path = os.path.join(outdir, summary["fbx"])
    fbx_guid = ua.guid_for(fbx_path)  # 必须在 open("w") 截断文件之前读取，否则复用失效
    with open(fbx_path + ".meta", "w", encoding="utf-8", newline="\n") as f:
        f.write(ua.model_meta(fbx_guid, remaps))


def report(summary, outdir):
    print("== %s -> %s" % (summary["model"], outdir))
    for m in summary["materials"]:
        print("  材质 %-24s A通道=%s 尺寸=%dx%d" %
              (m["name"], m["alpha_mode"], m["size"][0], m["size"][1]))
        for k, v in m["sources"].items():
            print("    %-10s %s" % (k, v or "(常量)"))
        for w in m["warnings"]:
            print("    [警告] %s" % w)


def main():
    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("input", help="FBX 文件或目录")
    ap.add_argument("-o", "--out", default=os.path.join(HERE, "out"))
    ap.add_argument("--max-size", type=int, default=2048)
    ap.add_argument("--blender", default=None)
    args = ap.parse_args()

    blender = find_blender(args.blender)
    if os.path.isdir(args.input):
        srcs = [os.path.join(args.input, f) for f in sorted(os.listdir(args.input))
                if f.lower().endswith(".fbx")]
        if not srcs:
            sys.exit("目录中没有 FBX：%s" % args.input)
    else:
        srcs = [args.input]

    for src in srcs:
        name = os.path.splitext(os.path.basename(src))[0]
        outdir = os.path.join(args.out, name)
        summary = run_blender(blender, src, outdir, args.max_size)
        write_unity_assets(outdir, summary, args.max_size)
        report(summary, outdir)


if __name__ == "__main__":
    main()