"""FBX 减面 CLI：减到指定三角面数并重展 UV（默认 RizomUV 自动展开），输出 <名>_low.fbx。
用法：python model_decimate.py src/well1500.fbx --tris 5000 [-o dir]
     [--unwrap rizom|seam|smart] [--rizom exe] [--blender exe]"""
import argparse
import os

from mt_run import find_blender, run_blender_script


def main():
    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("input", help="FBX 文件")
    ap.add_argument("--tris", type=int, required=True, help="目标三角面数")
    ap.add_argument("-o", "--out", default=None, help="输出目录（默认源文件同目录）")
    ap.add_argument("--unwrap", choices=("rizom", "seam", "smart"), default="rizom",
                    help="UV 展开：rizom=RizomUV 自动切缝（默认，不可用回退 seam），"
                         "seam=锐边接缝整岛展开，smart=Smart UV Project")
    ap.add_argument("--rizom", default=None, help="rizomuv.exe 路径（默认自动发现）")
    ap.add_argument("--blender", default=None)
    args = ap.parse_args()
    if args.tris <= 0:
        ap.error("--tris 必须为正整数")

    blender = find_blender(args.blender)
    name = os.path.splitext(os.path.basename(args.input))[0]
    outdir = args.out or os.path.dirname(os.path.abspath(args.input))
    out_fbx = os.path.join(outdir, name + "_low.fbx")

    if args.unwrap == "rizom":
        # 三步：Blender 减面（不展UV）-> RizomUV 展开 -> Blender 质量门（不达标就地 seam 重展）
        s = run_blender_script(blender, "bl_decimate.py",
                               [args.input, out_fbx, str(args.tris), "none"])
        warnings = list(s["warnings"])
        # 惰性导入：seam/smart 路径不依赖 rizom 模块
        from rizom_unwrap import RizomError, find_rizomuv, rizom_unwrap
        try:
            rizom_unwrap(out_fbx, find_rizomuv(args.rizom))
        except RizomError as e:
            warnings.append("RizomUV 不可用：%s" % e)
        except Exception as e:   # 意外异常也不中断管线：记警告，交 bl_uvgate 回退 seam
            warnings.append("RizomUV 异常：%r" % e)
        g = run_blender_script(blender, "bl_uvgate.py", [out_fbx, "rizom"])
        s["uv"] = g["uv"]
        s["warnings"] = warnings + g["warnings"]
    else:
        s = run_blender_script(blender, "bl_decimate.py",
                               [args.input, out_fbx, str(args.tris), args.unwrap])

    print("== %s: %d -> %d 面（目标 %d）-> %s" %
          (s["src"], s["tris_before"], s["tris_after"], s["target"], out_fbx))
    u = s["uv"]
    overlap = "%.1f%%" % (u["overlap"] * 100) if u["overlap"] is not None else "n/a"
    print("  UV: 模式=%s 岛数=%d 利用率=%.1f%% 翻转=%.1f%% 重叠=%s" %
          (u["mode"], u["islands"], u["fill"] * 100, u["flipped"] * 100, overlap))
    for w in s["warnings"]:
        print("  [警告] %s" % w)


if __name__ == "__main__":
    main()