/**
 * @copyright nhcarrigan
 * @license Naomi's Public License
 * @author Naomi Carrigan
 */

import { isValidString } from "../utils/typeguards.js";

interface ThreadsErrorResponse {
  error: {
    message: string;
    type:    string;
    code:    number;
  };
}

interface ThreadsSuccessResponse {
  id: string;
}

type ThreadsResponse = ThreadsErrorResponse | ThreadsSuccessResponse;

/**
 * Forwards an announcement to our Threads account.
 * @param content - The main body of the announcement.
 * @returns A message indicating the success or failure of the operation.
 */
// eslint-disable-next-line max-lines-per-function, max-statements, complexity -- This is a big function.
export const announceOnThreads = async(
  content: Array<string>,
): Promise<string> => {
  if (
    process.env.THREADS_ACCESS_TOKEN === undefined
  ) {
    return "Threads credentials are not set.";
  }
  const [ firstPost, ...restOfPosts ] = content;
  const failedReplies: Array<string> = [];
  if (firstPost === undefined) {
    return "No posts to send to Threads.";
  }
  const accessToken = process.env.THREADS_ACCESS_TOKEN;
  const apiUrl = `https://graph.threads.net/v1.0/me/threads`;
  // Step 1: Create the first post
  const firstPostParameters = new URLSearchParams({
    // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
    access_token: accessToken,
    // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
    media_type:   "TEXT",
    text:         firstPost,
  });
  const firstPostResponse = await fetch(
    `${apiUrl}?${firstPostParameters.toString()}`,
    {
      headers: {
        // eslint-disable-next-line @typescript-eslint/naming-convention -- HTTP header name.
        "Content-Type": "application/x-www-form-urlencoded",
      },
      method: "POST",
    },
  ).catch((error: unknown) => {
    return error instanceof Error
      ? error.message
      : String(error);
  });
  if (typeof firstPostResponse === "string") {
    return `Failed to send initial post to Threads. ${firstPostResponse}`;
  }
  if (!firstPostResponse.ok) {
    const errorText = await firstPostResponse.text().catch(() => {
      return firstPostResponse.statusText;
    });
    return `Failed to send initial post to Threads. Status: ${firstPostResponse.status.toString()} ${errorText}`;
  }
  // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- Fetch does not accept generics.
  const firstPostData = await firstPostResponse.json() as ThreadsResponse;
  if ("error" in firstPostData) {
    return `Failed to send initial post to Threads. ${firstPostData.error.message}`;
  }
  if (!isValidString(firstPostData.id)) {
    return `Failed to parse initial post ID from Threads. ${JSON.stringify(firstPostData)}`;
  }
  // Step 2: Publish the first post
  const publishUrl = `https://graph.threads.net/v1.0/me/threads_publish`;
  const publishParameters = new URLSearchParams({
    // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
    access_token: accessToken,
    // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
    creation_id:  firstPostData.id,
  });
  const publishResponse = await fetch(
    `${publishUrl}?${publishParameters.toString()}`,
    {
      headers: {
        // eslint-disable-next-line @typescript-eslint/naming-convention -- HTTP header name.
        "Content-Type": "application/x-www-form-urlencoded",
      },
      method: "POST",
    },
  ).catch((error: unknown) => {
    return error instanceof Error
      ? error.message
      : String(error);
  });
  if (typeof publishResponse === "string") {
    return `Failed to publish initial post to Threads. ${publishResponse}`;
  }
  if (!publishResponse.ok) {
    const errorText = await publishResponse.text().catch(() => {
      return publishResponse.statusText;
    });
    return `Failed to publish initial post to Threads. Status: ${publishResponse.status.toString()} ${errorText}`;
  }
  // eslint-disable-next-line @typescript-eslint/consistent-type-assertions -- Fetch does not accept generics.
  const publishData = await publishResponse.json() as ThreadsSuccessResponse;
  let parentThreadId = publishData.id;
  // Step 3: Create replies for the rest of the posts
  for (const post of restOfPosts) {
    const replyParameters = new URLSearchParams({
      // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
      access_token: accessToken,
      // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
      media_type:   "TEXT",
      // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
      reply_to_id:  parentThreadId,
      text:         post,
    });
    // eslint-disable-next-line no-await-in-loop -- We need to do this sequentially.
    const replyResponse = await fetch(
      `${apiUrl}?${replyParameters.toString()}`,
      {
        headers: {
          // eslint-disable-next-line @typescript-eslint/naming-convention -- HTTP header name.
          "Content-Type": "application/x-www-form-urlencoded",
        },
      },
    ).catch((error: unknown) => {
      return error instanceof Error
        ? error.message
        : String(error);
    });
    if (typeof replyResponse === "string") {
      failedReplies.push(post);
      continue;
    }
    if (!replyResponse.ok) {
      failedReplies.push(post);
      continue;
    }
    // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, no-await-in-loop -- Fetch does not accept generics.
    const replyData = await replyResponse.json() as ThreadsResponse;
    if ("error" in replyData) {
      failedReplies.push(post);
      continue;
    }
    if (!isValidString(replyData.id)) {
      failedReplies.push(post);
      continue;
    }
    // Publish the reply
    const replyPublishUrl = `https://graph.threads.net/v1.0/me/threads_publish`;
    const replyPublishParameters = new URLSearchParams({
      // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
      access_token: accessToken,
      // eslint-disable-next-line @typescript-eslint/naming-convention -- API requirement.
      creation_id:  replyData.id,
    });
    // eslint-disable-next-line no-await-in-loop -- We need to do this sequentially.
    const replyPublishResponse = await fetch(
      `${replyPublishUrl}?${replyPublishParameters.toString()}`,
      {
        method: "POST",
      },
    ).catch(() => {
      return null;
    });
    if (replyPublishResponse?.ok !== true) {
      failedReplies.push(post);
      continue;
    }
    const replyPublishData
    // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, no-await-in-loop -- Fetch does not accept generics.
    = await replyPublishResponse.json() as ThreadsSuccessResponse;
    parentThreadId = replyPublishData.id;
  }
  return `Successfully sent initial post to Threads. ${failedReplies.length > 0
    ? `Failed to send ${failedReplies.length.toString()} replies: ${failedReplies.join(", ")}`
    : `All ${(content.length - 1).toString()} replies were sent successfully.`}`;
};