import fs from "node:fs";
import path from "node:path";

import { readChunkSync } from "read-chunk";
import imageType from "image-type";
import isSvg from "is-svg";

import {
  ANY_IMAGE_EXT,
  AUDIO_EXT,
  DEFAULT_LOCALE,
  FONT_EXT,
  VIDEO_EXT,
  createRegExpFromExtensions,
} from "../libs/constants/index.js";
import { ROOTS } from "../libs/env/index.js";
import { memoize, slugToFolder } from "./utils.js";

function isFileAttachment(filePath: string) {
  if (fs.statSync(filePath).isDirectory()) {
    return false;
  }

  return (
    isAudio(filePath) ||
    isFont(filePath) ||
    isVideo(filePath) ||
    isImage(filePath)
  );
}

const AUDIO_FILE_REGEXP = createRegExpFromExtensions(...AUDIO_EXT);
const FONT_FILE_REGEXP = createRegExpFromExtensions(...FONT_EXT);
const VIDEO_FILE_REGEXP = createRegExpFromExtensions(...VIDEO_EXT);
const IMAGE_FILE_REGEXP = createRegExpFromExtensions(...ANY_IMAGE_EXT);

function isAudio(filePath: string) {
  return AUDIO_FILE_REGEXP.test(filePath);
}

function isFont(filePath: string) {
  return FONT_FILE_REGEXP.test(filePath);
}

function isVideo(filePath: string) {
  return VIDEO_FILE_REGEXP.test(filePath);
}

function isImage(filePath: string) {
  if (!IMAGE_FILE_REGEXP.test(filePath)) {
    return false;
  }

  if (filePath.toLowerCase().endsWith(".svg")) {
    return isSvg(fs.readFileSync(filePath, "utf-8"));
  }
  const chunk = readChunkSync(filePath, { length: 12 });
  if (chunk.length === 0) {
    return false;
  }
  const type = imageType(chunk);
  if (!type) {
    // This happens when there's no match on the "Supported file types"
    // https://github.com/sindresorhus/image-type#supported-file-types
    return false;
  }

  return true;
}

function urlToFilePath(url: string) {
  const [, locale, , ...slugParts] = decodeURI(url).split("/");
  return path.join(locale.toLowerCase(), slugToFolder(slugParts.join("/")));
}

const find = memoize((relativePath: string) => {
  return ROOTS.map((root) => path.join(root, relativePath)).find(
    (filePath) => fs.existsSync(filePath) && isFileAttachment(filePath)
  );
});

export function findByURL(url: string) {
  return find(urlToFilePath(url));
}

export function findByURLWithFallback(url: string): string {
  let filePath = findByURL(url);
  const urlParts = url.split("/");
  const locale = urlParts[1].toLowerCase();
  if (!filePath && locale !== DEFAULT_LOCALE) {
    urlParts[1] = DEFAULT_LOCALE;
    const defaultLocaleURL = urlParts.join("/");
    filePath = findByURL(defaultLocaleURL);
  }
  return filePath;
}