import esbuild from "esbuild";
import path from "path";
import fs from "fs";
import sass from "sass";
import { PluginBuild } from "esbuild";

// this should give us the current directory where
// the project is being built
const BASE = process.cwd();
const distProd = path.join(BASE, "dist", "prod");
const distDev = path.join(BASE, "dist", "dev");
const sourceDir = path.join(BASE, "src");

const preact = path.join(
  BASE,
  "node_modules",
  "preact",
  "compat",
  "dist",
  "compat.module.js",
);

// https://preactjs.com/guide/v8/switching-to-preact/#how-to-alias-preact-compat
const preactCompatPlugin: esbuild.Plugin = {
  name: "preact-compat",
  setup(build) {
    build.onResolve({ filter: /^(react-dom|react)$/ }, (args) => {
      return {
        path: preact,
      };
    });
  },
};

export function getFilesInSource(regex: RegExp): string[] {
  return getFilesInDirectory(sourceDir, regex);
}

function getFilesInDirectory(startPath: string, regex: RegExp): string[] {
  if (!fs.existsSync(startPath)) {
    return [];
  }
  const files = fs.readdirSync(startPath);
  const result = files
    .flatMap((file) => {
      const filename = path.join(startPath, file);

      const stat = fs.lstatSync(filename);
      if (stat.isDirectory()) {
        return getFilesInDirectory(filename, regex);
      }
      if (regex.test(filename)) {
        return [filename];
      }
      return [];
    })
    .filter((x) => !!x);

  return result;
}

let GIT_ROOT = BASE;
while (!fs.existsSync(path.join(GIT_ROOT, ".git")) && GIT_ROOT !== "/") {
  GIT_ROOT = path.join(GIT_ROOT, "../");
}
if (GIT_ROOT === "/") {
  // eslint-disable-next-line no-undef
  console.log("not found");
  // eslint-disable-next-line no-undef
  process.exit(1);
}
const GIT_HASH = GIT_ROOT === "/" ? undefined : git_hash();

const buf = fs.readFileSync(path.join(BASE, "package.json"));
let _package = JSON.parse(buf.toString("utf-8"));

function git_hash() {
  const rev = fs
    .readFileSync(path.join(GIT_ROOT, ".git", "HEAD"))
    .toString()
    .trim()
    .split(/.*[: ]/)
    .slice(-1)[0];
  if (rev.indexOf("/") === -1) {
    return rev;
  } else {
    return fs.readFileSync(path.join(GIT_ROOT, ".git", rev)).toString().trim();
  }
}

// FIXME: Put this into some helper library.
function copyFilesPlugin(files: Array<string>) {
  return {
    name: "copy-files",
    setup(build: PluginBuild) {
      const outDir = build.initialOptions.outdir;
      if (outDir === undefined)
        throw Error("esbuild build options does not specify outdir");
      build.onEnd(() => {
        for (const file of files) {
          const name = path.parse(file).base;
          fs.copyFileSync(file, path.join(outDir, name));
        }
      });
    },
  };
}

const DEFAULT_SASS_FILTER = /\.(s[ac]ss|css)$/;

const buildSassPlugin: esbuild.Plugin = {
  name: "custom-build-sass",
  setup(build) {
    build.onLoad({ filter: DEFAULT_SASS_FILTER }, ({ path: file }) => {
      const resolveDir = path.dirname(file);
      const { css: contents } = sass.compile(file, { loadPaths: ["./"] });

      return {
        resolveDir,
        loader: "css",
        contents,
      };
    });
  },
};

const buildConfig: esbuild.BuildOptions = {
  bundle: true,
  minify: false,
  loader: {
    ".svg": "file",
    ".png": "dataurl",
    ".jpeg": "dataurl",
    ".ttf": "file",
    ".woff": "file",
    ".woff2": "file",
    ".eot": "file",
  },
  target: ["es6"],
  format: "esm",
  platform: "browser",
  sourcemap: true,
  jsxFactory: "h",
  jsxFragment: "Fragment",
  define: {
    __VERSION__: `"${_package.version}"`,
    __GIT_HASH__: `"${GIT_HASH}"`,
  },
  plugins: [
    preactCompatPlugin,
    copyFilesPlugin(["./src/index.html"]),
    buildSassPlugin,
  ],
};

/**
 * Build sources for prod environment
 */
export function buildProd(entryPoints: string[]) {
  return esbuild.build({
    ...buildConfig,
    entryPoints,
    outdir: distProd,
  });
}

/**
 * Build sources for dev environment
 */
function buildDev(entryPoints: string[]): Promise<esbuild.BuildResult> {
  return esbuild.build({
    ...buildConfig,
    entryPoints,
    outdir: distDev,
  });
}

/**
 * Do startup for development environment
 */
export function initializeDev(
  entryPoints: string[],
): () => Promise<esbuild.BuildResult> {
  buildConfig.inject = [
    "./node_modules/@gnu-taler/web-util/lib/live-reload.mjs",
  ];
  return () => buildDev(entryPoints);
}