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

import { logger } from "../utils/logger.js";
import type { Amari } from "../interfaces/amari.js";
import type {
  IssueCreated,
  PullRequestCreated,
  GithubPayload,
} from "../interfaces/github.js";
import type { FastifyRequest, FastifyReply } from "fastify";

const isIssue = (body: GithubPayload): body is IssueCreated => {
  return "issue" in body;
};

const isPull = (body: GithubPayload): body is PullRequestCreated => {
  return "pull_request" in body;
};

/**
 * Handles a newly opened GitHub issue by auto-assigning Naomi.
 * @param amari - Amari's instance.
 * @param body - The parsed issue webhook payload.
 */
const handleIssueOpened = async(
  amari: Amari,
  body: IssueCreated,
): Promise<void> => {
  await logger.log("info", "Processing new issue");
  const { issue, repository } = body;
  const { number, user } = issue;
  const { owner, name } = repository;
  try {
    await amari.github.rest.issues.addAssignees({
      assignees:    [ "naomi-lgbt" ],
      // eslint-disable-next-line @typescript-eslint/naming-convention -- Github SDK requirement.
      issue_number: number,
      owner:        owner.login,
      repo:         name,
    });
    await logger.metric("processed_github_event", 1, {
      action: "opened",
      event:  "issue",
      user:   user.login,
    });
  } catch (error) {
    if (error instanceof Error) {
      await logger.error("processGitHubEvent module", error);
    }
  }
};

/**
 * Handles a newly opened GitHub pull request by requesting Naomi's review.
 * @param amari - Amari's instance.
 * @param body - The parsed pull request webhook payload.
 */
const handlePrOpened = async(
  amari: Amari,
  body: PullRequestCreated,
): Promise<void> => {
  const { pull_request: pr, repository } = body;
  const { number, user } = pr;
  await logger.log("info", "Processing new PR");
  const { owner, name } = repository;
  try {
    await amari.github.rest.pulls.requestReviewers({
      owner:       owner.login,
      // eslint-disable-next-line @typescript-eslint/naming-convention -- Github SDK requirement.
      pull_number: number,
      repo:        name,
      reviewers:   [ "naomi-lgbt" ],
    });
    await logger.metric("processed_github_event", 1, {
      action: "opened",
      event:  "pull_request",
      user:   user.login,
    });
  } catch (error) {
    if (error instanceof Error) {
      await logger.error("processGitHubEvent module", error);
    }
  }
};

/**
 * Handles a payload from a GitHub webhook.
 * @param amari - Amari's instance.
 * @param request - The Fastify request payload.
 * @param response - The Fastify reply class.
 */
export const processGithubEvent = async(
  amari: Amari,
  request: FastifyRequest<{
    // eslint-disable-next-line @typescript-eslint/naming-convention -- Fastify standard.
    Body:        GithubPayload;
    // eslint-disable-next-line @typescript-eslint/naming-convention -- Fastify standard.
    Querystring: { secret: string };
  }>,
  response: FastifyReply,
): Promise<void> => {
  const { secret } = request.query;
  if (secret !== process.env.GH_WEBHOOK_SECRET) {
    await response.status(403).send({
      message: "Invalid secret provided!",
    });
  }
  const event = request.headers["x-github-event"];
  if (typeof event !== "string") {
    await response.
      status(400).
      send({ message: "Invalid GitHub event header." });
    return;
  }
  if (event === "ping") {
    await response.status(200).send({ message: "Pong!" });
    return;
  }
  const { action } = request.body;
  await response.status(200).send({ message: "Payload received!" });
  if (action === "opened" && event === "issues" && isIssue(request.body)) {
    await handleIssueOpened(amari, request.body);
    return;
  }
  if (action === "opened" && event === "pull_request" && isPull(request.body)) {
    await handlePrOpened(amari, request.body);
  }
};