import gulp from "gulp";
import gulpIf from "gulp-if";
import MemoryFS from "memory-fs";
import syncBrowser from "browser-sync";
const browserSync = syncBrowser.create();
const __dirname = process.cwd();

// 创建内存文件系统实例
const mfs = new MemoryFS();
import htmlmin from "gulp-htmlmin"; // 压缩html文件
import uglify from "gulp-uglify"; // 压缩js文件
import babel from "gulp-babel"; // ES6转ES5
import sass from "gulp-sass"; // sass编译
import cleanCss from "gulp-clean-css"; // 压缩css文件
import replace from "gulp-replace"; // 替换文件内容
import ignore from "gulp-ignore"; // 排除文件不进入打包结果
import { deleteAsync } from "del"; // 清除打包目标目录
import fs from "fs/promises";
import path from "path";
import map from "map-stream";
import { createProxyMiddleware } from "http-proxy-middleware";

const devAssetsDir = "src";
const htmlGlob = `${devAssetsDir}/**/*.html`;
const cssGlob = `${devAssetsDir}/**/*.css`;
const jsGlob = `${devAssetsDir}/**/*.js`;
const staticGlob = `${devAssetsDir}/static/**/*`;
const modulesGlob = "modules/**/*";
const allFileGlob = `${devAssetsDir}/**/*`;

/**
 * @type {"dev" | "prod"} 环境变量
 */
let env = "dev";
function setEnv(currEnv) {
  return async () => {
    env = currEnv;
  };
}
import config from "./config.js";
let { moduleMap, assetsDir, devServer } = config;
let { browsersync: browsersyncOptions, httpProxy } = devServer && typeof devServer === "object" ? devServer : {};
moduleMap = parseModuleMap(moduleMap);
// 异步读取文件内容
async function getCode(path) {
  return await fs.readFile(path, "utf8");
}

// 清除dist目录的任务
async function cleanTask() {
  return deleteAsync([assetsDir]); // 使用 del 删除 dist 目录及其内容
}

export const clean = cleanTask;

/**
 * @description 注入模块
 * @param {NodeJS.ReadWriteStream} ctx
 * @returns {NodeJS.ReadWriteStream}
 */
async function injectModules(ctx) {
  // 遍历模块文件，将每个模块文件的内容替换到对应的模块标签中
  for (const key in moduleMap) {
    const filePath = path.join(__dirname, moduleMap[key]);
    const code = await getCode(filePath);
    const replaceStream = replace(key, code);
    ctx = ctx.pipe(replaceStream);
  }
  return ctx;
}

// 制定html任务
async function htmlTask() {
  const condition = env === "prod";
  let ctx = gulp.src(htmlGlob, {
    ignore: [staticGlob],
  });
  ctx = await injectModules(ctx);
  return (
    ctx
      .pipe(
        htmlmin({
          removeComments: condition, // 生产环境下移除注释
          collapseWhitespace: condition, // //压缩HTML
          collapseBooleanAttributes: condition, //省略布尔属性的值 <input checked="true"/> ==> <input />
          removeEmptyAttributes: env === "prod", //删除所有空格作属性值 <input id="" /> ==> <input />
          removeScriptTypeAttributes: false, //删除<script>的type="text/javascript"
          removeStyleLinkTypeAttributes: condition, //删除<style>和<link>的type="text/css"
          minifyJS: condition, //压缩页面JS
          minifyCSS: condition, //压缩页面CSS
        })
      )
      .pipe(ignore.exclude(modulesGlob)) // 忽略模块文件
      .pipe(gulpIf(condition, writeFileToFileSystem(assetsDir)))
      // 将处理后的文件写入内存文件系统
      .pipe(gulpIf(!condition, writeFileToMemory()))
  );
}

// 定义Gulp任务
export const html = htmlTask;

// 制定js任务：ES6转ES5，再压缩js
async function jsTask() {
  const ctx = gulp.src(jsGlob, {
    ignore: [staticGlob],
  });
  const condition = env === "prod";
  return ctx
    .pipe(
      gulpIf(
        condition,
        babel({
          presets: ["@babel/preset-env"],
        })
      )
    )
    .pipe(
      gulpIf(
        condition,
        uglify({
          compress: {
            drop_console: false, // 移除console语句
            drop_debugger: true, // 移除debugger语句
          },
        })
      )
    )
    .pipe(gulpIf(condition, writeFileToFileSystem(path.join(assetsDir))))
    .pipe(gulpIf(!condition, writeFileToMemory()));
}

export const js = jsTask;

// css任务：压缩css
async function cssTask() {
  const ctx = gulp.src(cssGlob, {
    ignore: [staticGlob],
  });
  const condition = env === "prod";
  return ctx
    .pipe(gulpIf(condition, cleanCss())) // css样式压缩
    .pipe(gulpIf(condition, writeFileToFileSystem(path.join(assetsDir))))
    .pipe(gulpIf(!condition, writeFileToMemory()));
}

export const css = cssTask;

// 静态文件目录，直接复制
async function staticFile() {
  const condition = env === "prod";
  const staticDir = "/static";
  return gulp
    .src(staticGlob)
    .pipe(gulpIf(condition, writeFileToFileSystem(assetsDir)))
    .pipe(gulpIf(!condition, writeFileToMemory(staticDir)));
}

export const staticFileTask = staticFile;

// 其他文件：直接复制（除了html, css，js文件和static目录）
async function otherFile() {
  const condition = env === "prod";
  return gulp
    .src(allFileGlob, {
      ignore: [htmlGlob, cssGlob, jsGlob, staticGlob],
    })
    .pipe(gulpIf(condition, writeFileToFileSystem(assetsDir)))
    .pipe(gulpIf(!condition, writeFileToMemory()));
}

export const otherFileTask = otherFile;

// 打包任务：清除dist目录，然后并行执行html、js、css、其他文件、static等任务
export const build = gulp.series(setEnv("prod"), cleanTask, gulp.parallel(html, js, css, otherFileTask, staticFileTask));
// server任务：开启一个本地服务器
async function serverTask() {
  browsersyncOptions = browsersyncOptions && typeof browsersyncOptions === "object" ? browsersyncOptions : {};

  const httpProxyList = Object.keys(httpProxy).map((prefix) => createProxyMiddleware(prefix, httpProxy[prefix]));
  return browserSync.init({
    ...browsersyncOptions,
    middleware: [
      ...httpProxyList,
      // 自定义中间件来从内存文件系统中提供文件
      function (req, res, next) {
        let fileLogicPath = req.url.split("?")[0];
        let url = fileLogicPath === "/" ? "/index.html" : fileLogicPath;
        let filePath = path.join(__dirname, "/", devAssetsDir, ...url.split("/"));
        mfs.readFile(decodeURIComponent(filePath), (err, data) => {
          if (err) {
            const map = {
              ENOENT: () => console.error(`\x1b[31m找不到文件或目录：${err.path}\x1b[0m`),
            };
            map[err.code] ? map[err.code]() : console.error(err);
            res.statusCode = 404;
            res.end(`not found  ${req.url}`);
          } else {
            res.end(data);
          }
        });
      },
    ],
    server: true,
  });
}

export const server = serverTask;

// 监听文件的修改，执行对应的任务
async function watchTask() {
  gulp.watch(htmlGlob, gulp.series(html)).on("change", browserSync.reload);
  gulp.watch(jsGlob, gulp.series(js)).on("change", browserSync.reload);
  gulp.watch(cssGlob, gulp.series(css)).on("change", browserSync.reload);
  gulp.watch(staticGlob, gulp.series(staticFileTask)).on("change", browserSync.reload);
  gulp.watch(allFileGlob, gulp.series(otherFileTask)).on("change", browserSync.reload);
}

export const watch = watchTask;

// 开发服务
export const dev = gulp.series(setEnv("dev"), gulp.parallel(html, js, css, staticFileTask, otherFileTask), (cb) => setTimeout(() => cb(), 3000), server, watch);

/**
 * 解析模块映射
 * @param {Object} moduleMap
 * @returns
 */
function parseModuleMap(moduleMap) {
  const newModuleMap = {};
  Object.keys(moduleMap).forEach((fileId) => {
    const newId = `#include(${fileId})`;
    newModuleMap[newId] = moduleMap[fileId];
  });
  return newModuleMap;
}
/**
 * @description 把文件流写入到内存中
 * @returns
 */
function writeFileToMemory() {
  return map(function mapFile(file, cb) {
    const filepath = path.resolve(file.path);
    const dir = path.dirname(filepath);
    if (!mfs.existsSync(dir)) {
      mfs.mkdirpSync(dir);
    }
    file.contents && mfs.writeFileSync(filepath, file.contents);
    cb(null, file);
  });
}

/**
 * @description 把文件流写入到硬盘中
 * @param {String} assetsDir 写入到哪个目录，如根目录的dist,则assetsDir位'dist'
 * @returns
 */
function writeFileToFileSystem(assetsDir) {
  return map(async function mapFile(file, cb) {
    const relativePath = path.relative(path.join(process.cwd(), devAssetsDir), file.path);
    const destFilePath = path.join(process.cwd(), assetsDir, relativePath);
    const dirPath = path.dirname(destFilePath);
    try {
      if (file.contents) {
        await fs.access(dirPath).catch(() => fs.mkdir(dirPath, { recursive: true }));
        await fs.writeFile(destFilePath, file.contents);
      }
    } catch (error) {
      console.log(error);
    }
    cb(null, file);
  });
}