import { get } from "node:https";
import { createWriteStream } from "node:fs";
import path from "node:path";

export interface Thumbnail {
  mimetype: string;
  size: null | number;
  width: number;
  height: number;
  duration: null | number;
  url: string;
}

export interface Page {
  id: number;
  key: string;
  title: string;
  excerpt: string;
  description: string;
  thumbnail?: Thumbnail;
}

interface SearchResult {
  pages: Array<Page>;
}

// //u.wiki.org/wiki/commons/thumb/2/23/elon.jpg/121px-elon.jpg
const parseRawImg = (src: string) => {
  const splitted = src.split("/");
  splitted.pop(); // we dont need the last 121px-elon
  splitted.splice(5, 1); // get rid of thumb
  return `https:${splitted.join("/")}`; // put everything back
};

const saveImg = (page: Page, dir: string) => {
  const rawThumbUrl = parseRawImg(page.thumbnail.url);
  // eg image/jpeg
  const fileExt = page.thumbnail.mimetype.split("/")[1];

  return new Promise((resolve, reject) => {
    const addr = new URL(rawThumbUrl);
    const imgreq = get(
      {
        host: addr.host,
        method: "GET",
        port: 443,
        path: addr.pathname,
        headers: {
          Accept:
            "text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8",
          "User-Agent": "Mozilla/5.0 ",
        },
      },
      (res) => {
        if (res.statusCode == 200) {
          const imgPath = path.resolve(dir, `${page.key}.${fileExt}`);
          const fstream = createWriteStream(imgPath, {
            encoding: "binary",
          });
          // res.pipe(process.stdout);
          res.pipe(fstream);
          fstream.on("error", reject);
          fstream.on("finish", () => {
            resolve(true);
          });
          return;
        }
        reject(`Failed to get img with status ${res.statusMessage}`);
      }
    );

    imgreq.end();
  });
};
/**
 * Query and download image from wikipedia
 * @param {string} query - Search term for wikipedia
 * @param {string} dir  - Relative path of image to be saved
 * @returns {Promise} Promise with info about the search
 * @example
  // get lady gaga image in celebs directory
  getWikiImg("Lady gaga", "./celebs")
    .then((res) => console.log(res))
    .catch((err) => console.log("failed to get img", err));

 */
export const getWikiImg = (
  query: string,
  dir: string = "./"
): Promise<Page | Error> => {
  return new Promise((resolve, reject) => {
    const path = "https://api.wikimedia.org/core/v1/wikipedia/en/search";
    const imgreq = get(`${path}/title?q=${query}&limit=1`);

    imgreq.on("response", (res) => {
      let body = "";
      res.on("data", (d) => {
        body += d;
      });

      res.on("end", async () => {
        const json: SearchResult = JSON.parse(body);

        const page = json.pages[0];
        const thumb = page?.thumbnail?.url;

        if (!thumb) {
          return reject("No thumbnail found");
        }

        try {
          await saveImg(page, dir);
          resolve(page);
        } catch (err) {
          reject(err);
        }
      });
    });
  });
};