// plugins/vite-plugin-gen-index-css.ts
import type { Plugin } from "vite";
import fs from "fs";
import path from "path";
import { globSync } from "glob";

interface Config {
  targetDirs: string[];
  includeExtensions: string[];
  importSyntax: "@import";
  importSyntaxTail?: string;
  excludeFilePattern: RegExp[];
  excludeDirs: string[];
  warnDuplicateTailwindImport: boolean;
  indexFileName: string;
}

const CONFIG: Config = {
  targetDirs: ["src"],
  includeExtensions: [".css"],
  importSyntax: "@import",
  excludeFilePattern: [/index\.css/, /index\.scss/, /\.(test|spec)\./],
  excludeDirs: [
    "__tests__",
    "tests",
    "story",
    "stories",
    "types",
    "node_modules",
    "dist",
    "build",
  ],
  warnDuplicateTailwindImport: true,
  indexFileName: "index.css",
};

const normalizePath = (p: string) => p.replace(/\\/g, "/");

function isValidFile(filePath: string, config: Config): boolean {
  const filenameWithExt = filePath.split(/[\\/]/).pop()!;
  const shouldExcludeFile = config.excludeFilePattern.some((p) =>
    p.test(filenameWithExt),
  );
  if (shouldExcludeFile) return false;

  const normalized = normalizePath(filePath);
  const shouldExcludeDir = config.excludeDirs.some((dir) =>
    normalized.includes(`/${dir}/`),
  );
  if (shouldExcludeDir) return false;

  const ext = path.extname(filePath);
  if (!config.includeExtensions.includes(ext)) return false;

  if (config.warnDuplicateTailwindImport) {
    try {
      const content = fs.readFileSync(filePath, "utf-8");
      if (
        content.includes('@import "tailwindcss"') ||
        content.includes("@import 'tailwindcss'")
      ) {
        console.warn(
          `[gen-index-css] ${filePath} 含有重复的 @import "tailwindcss"，建议删除`,
        );
      }
    } catch {
      // ignore
    }
  }

  return true;
}

function generateIndexFile(config: Config) {
  const [targetDir] = config.targetDirs;
  const dirPath = path.resolve(process.cwd(), targetDir);

  const searchPattern = path.resolve(dirPath, "**", "*.*");

  const allFiles = globSync(searchPattern, {
    nodir: true,
    absolute: true,
    windowsPathsNoEscape: true,
    dot: false,
    follow: true,
  });

  const validFiles = allFiles.filter((f) => isValidFile(f, config));

  console.log(`✅ 有效 CSS 文件数量: ${validFiles.length}`);
  validFiles.sort();

  const importStatements = validFiles.map((file) => {
    const relPath = path.relative(dirPath, file);
    const importPath = "./" + relPath.replace(/\\/g, "/");
    return `${config.importSyntax} '${importPath}';`;
  });

  const indexContent = `
@import "tailwindcss";
${importStatements.join("\n")}
`.trim();

  const indexFilePath = path.resolve(dirPath, config.indexFileName);

  // ✅ 内容比对，防止无限 rebuild
  if (fs.existsSync(indexFilePath)) {
    const old = fs.readFileSync(indexFilePath, "utf8");
    if (old === indexContent) return;
  }

  fs.writeFileSync(indexFilePath, indexContent, "utf8");
  console.log(`✅ 成功生成 ${config.indexFileName}: ${indexFilePath}`);
}

export function genIndexCssPlugin(): Plugin {
  return {
    name: "vite-plugin-gen-index-css",
    apply: "build",

    buildStart() {
      try {
        generateIndexFile(CONFIG);
      } catch (err) {
        const msg = err instanceof Error ? err.message : String(err);
        this.error(`[gen-index-css] failed: ${msg}`);
        throw err;
      }
    },

    handleHotUpdate({ file }) {
      if (normalizePath(file).endsWith(`/src/${CONFIG.indexFileName}`)) {
        return [];
      }
    },
  };
}