import fs from "fs";

export const BACKUP_SUFFIX = "_备份";

// 检查当前目录是否有 gltf 文件
export function hasGltfFile() {
  return listGltfFiles().length > 0;
}

// 获取当前目录下可用的 gltf 文件列表
export function listGltfFiles() {
  const cwd = process.cwd();
  return fs.readdirSync(cwd).filter(f => f.toLowerCase().endsWith(".gltf") && !f.includes(BACKUP_SUFFIX));
}

// 获取 glTF / GLB 模型文件
export function listModelFiles() {
  const cwd = process.cwd();
  return fs
    .readdirSync(cwd)
    .filter(file => /\.(gltf|glb)$/i.test(file) && !file.includes(BACKUP_SUFFIX));
}

// 获取所有支持的模型文件（包括需要转换的格式）
export function listAllModelFiles() {
  const cwd = process.cwd();
  return fs
    .readdirSync(cwd)
    .filter(file => /\.(gltf|glb|obj|fbx)$/i.test(file) && !file.includes(BACKUP_SUFFIX));
}

// 判断是否需要先转换
export function needsConversion(file) {
  return /\.(obj|fbx)$/i.test(file);
}

// 检查是否满足执行条件（有 ktx2、gltf、bin 文件）
export function checkRequiredFiles() {
  const cwd = process.cwd();
  const files = fs.readdirSync(cwd);
  const hasKtx2 = files.some(f => f.toLowerCase().endsWith(".ktx2"));
  const hasGltf = files.some(f => f.toLowerCase().endsWith(".gltf"));
  const hasBin = files.some(f => f.toLowerCase().endsWith(".bin"));

  const missing = [];
  if (!hasKtx2) missing.push("ktx2");
  if (!hasGltf) missing.push("gltf");
  if (!hasBin) missing.push("bin");

  return { ok: missing.length === 0, missing };
}

// 修改 gltf 文件，根据选项添加扩展
export function modifyGltfContent(gltfPath, options = ["textureBasisu"]) {
  const content = fs.readFileSync(gltfPath, "utf-8");
  const gltf = JSON.parse(content);

  if (options.includes("textureBasisu")) {
    if (!gltf.extensionsUsed) gltf.extensionsUsed = [];
    if (!gltf.extensionsUsed.includes("KHR_texture_basisu")) {
      gltf.extensionsUsed.push("KHR_texture_basisu");
    }

    if (gltf.textures) {
      gltf.textures = gltf.textures.map(tex => ({
        extensions: { KHR_texture_basisu: { source: tex.source } }
      }));
    }

    if (gltf.images) {
      gltf.images = gltf.images.map(img => {
        const uri = img.uri || "";
        const newUri = uri.replace(/\.(png|jpg|jpeg|webp|tga)$/i, ".ktx2");
        return { uri: newUri, mimeType: "image/ktx2" };
      });
    }
  }

  // placeholder1, placeholder2, placeholder3 预留扩展点

  return gltf;
}