import { Handlers } from "$fresh/server.ts";
import { Defuddle } from "defuddle/node";
import { AccessDeniedError, BadRequestError } from "@lib/errors.ts";
import { createStreamResponse, isValidUrl } from "@lib/helpers.ts";
import * as openai from "@lib/openai.ts";

import { Article } from "@lib/resource/articles.ts";
import { getYoutubeVideoDetails } from "@lib/youtube.ts";
import {
  extractYoutubeId,
  isYoutubeLink,
  toUrlSafeString,
} from "@lib/string.ts";
import { createLogger } from "@lib/log/index.ts";
import { createResource } from "@lib/marka.ts";
import { webScrape } from "@lib/webScraper.ts";

const log = createLogger("api/article");

async function processCreateArticle(
  { fetchUrl, streamResponse }: {
    fetchUrl: string;
    streamResponse: ReturnType<typeof createStreamResponse>;
  },
) {
  log.info("create article from url", { url: fetchUrl });

  streamResponse.enqueue("downloading article");

  const doc = await webScrape(fetchUrl, streamResponse);

  const result = await Defuddle(doc, fetchUrl, {
    markdown: true,
  });

  log.debug("downloaded and parse parsed", {
    url: fetchUrl,
    content: result.content,
  });

  streamResponse.enqueue("parsed article, creating tags with openai");

  const aiMeta = await openai.extractArticleMetadata(result.content);

  streamResponse.enqueue("postprocessing article");

  const title = result?.title || aiMeta?.headline || "";
  const id = toUrlSafeString(title);

  const newArticle: Article = {
    _type: "Article",
    headline: title,
    articleBody: result.content,
    url: fetchUrl,
    datePublished: result?.published || aiMeta?.datePublished ||
      new Date().toISOString(),
    image: result?.image,
    author: {
      _type: "Person",
      name: (result.schemaOrgData?.author?.name || aiMeta?.author || "")
        .replace(
          "@",
          "twitter:",
        ),
    },
  } as const;

  streamResponse.enqueue("writing to disk");

  await createResource(`articles/${id}.md`, newArticle);

  streamResponse.enqueue("id: " + id);
}

async function processCreateYoutubeVideo(
  { fetchUrl, streamResponse }: {
    fetchUrl: string;
    streamResponse: ReturnType<typeof createStreamResponse>;
  },
) {
  log.info("create youtube article from url", {
    url: fetchUrl,
  });

  streamResponse.enqueue("getting video infos from youtube api");

  const youtubeId = extractYoutubeId(fetchUrl);

  const video = await getYoutubeVideoDetails(youtubeId);

  streamResponse.enqueue("shortening title with openai");
  const newId = await openai.shortenTitle(video.snippet.title);

  const id = newId || youtubeId;

  const newArticle: Article = {
    _type: "Article",
    headline: video.snippet.title,
    articleBody: video.snippet.description,
    url: fetchUrl,
    datePublished: new Date(video.snippet.publishedAt).toISOString(),
    author: {
      _type: "Person",
      name: video.snippet.channelTitle,
    },
  };

  streamResponse.enqueue("creating article");

  await createResource(`articles/${id}.md`, newArticle);

  streamResponse.enqueue("finished");

  streamResponse.enqueue("id: " + id);
}

export const handler: Handlers = {
  GET(req, ctx) {
    const session = ctx.state.session;
    if (!session) {
      throw new AccessDeniedError();
    }

    const url = new URL(req.url);
    const fetchUrl = url.searchParams.get("url");

    if (!fetchUrl || !isValidUrl(fetchUrl)) {
      throw new BadRequestError();
    }

    const streamResponse = createStreamResponse();

    if (isYoutubeLink(fetchUrl)) {
      processCreateYoutubeVideo({ fetchUrl, streamResponse }).then(
        (article) => {
          log.debug("created article from youtube", { article });
        },
      ).catch((err) => {
        log.error(err);
      }).finally(() => {
        streamResponse.cancel();
      });
    } else {
      processCreateArticle({ fetchUrl, streamResponse }).then((article) => {
        log.debug("created article from link", { article });
      }).catch((err) => {
        log.error(err);
      }).finally(() => {
        streamResponse.cancel();
      });
    }

    return streamResponse.response;
  },
};