import { AutoRouter } from 'itty-router';
import {
  InteractionResponseType,
  InteractionType,
  verifyKey,
} from 'discord-interactions';
import { HOT_COMMAND, ROLEPLAY_COMMAND } from './commands.js';
import { getCutePost, getRoleplayPost } from './reddit.js';

class JSONResponse extends Response {
  constructor(body, init) {
    const jsonBody = JSON.stringify(body);

    init = init || {
      headers: {
        'content-type': 'application/json;charset=UTF-8',
      },
    };

    super(jsonBody, init);
  }
}

const router = AutoRouter();

function createPostEmbed(post) {
  const mediaUrl =
    post.media?.reddit_video?.fallback_url ||
    post.secure_media?.reddit_video?.fallback_url ||
    post.url;

  let description = post.selftext || '';

  if (description.length > 1000)
    description = description.substring(0, 997).trim() + ' ...';

  const embed = {
    title: post.title,
    description: description,
    url: `https://reddit.com${post.permalink}`,
    color: 0xff4500,
    author: {
      name: `u/${post.author}`,
      url: `https://reddit.com/u/${post.author}`,
    },
    fields: [
      {
        name: 'Score',
        value: `${post.score} ⬆️`,
        inline: true,
      },
      {
        name: 'Comments',
        value: `${post.num_comments} 💬`,
        inline: true,
      },
    ],
    timestamp: new Date(post.created_utc * 1000).toISOString(),
    footer: {
      text: 'r/okbuddyumamusume',
    },
  };

  if (mediaUrl)
    if (post.media?.reddit_video || post.secure_media?.reddit_video)
      embed.video = { url: mediaUrl };
    else embed.image = { url: mediaUrl };

  return embed;
}

router.get('/', (_request, environment) => {
  return new Response(`👋 ${environment.DISCORD_APPLICATION_ID}`);
});

router.post('/', async (request, environment) => {
  const { isValid, interaction } = await server.verifyDiscordRequest(
    request,
    environment,
  );

  if (!isValid || !interaction)
    return new Response('Bad request signature.', { status: 401 });

  if (interaction.type === InteractionType.PING)
    return new JSONResponse({
      type: InteractionResponseType.PONG,
    });

  if (interaction.type === InteractionType.APPLICATION_COMMAND) {
    switch (interaction.data.name.toLowerCase()) {
      case HOT_COMMAND.name.toLowerCase(): {
        const post = await getCutePost();
        const embed = createPostEmbed(post);

        return new JSONResponse({
          type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
          data: {
            embeds: [embed],
          },
        });
      }

      case ROLEPLAY_COMMAND.name.toLowerCase(): {
        const post = await getRoleplayPost();
        const embed = createPostEmbed(post);

        return new JSONResponse({
          type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
          data: {
            embeds: [embed],
          },
        });
      }

      default:
        return new JSONResponse({ error: 'Unknown Type' }, { status: 400 });
    }
  }

  console.error('Unknown Type');

  return new JSONResponse({ error: 'Unknown Type' }, { status: 400 });
});

router.all('*', () => new Response('Not Found.', { status: 404 }));

async function verifyDiscordRequest(request, environment) {
  const signature = request.headers.get('x-signature-ed25519');
  const timestamp = request.headers.get('x-signature-timestamp');
  const body = await request.text();
  const isValidRequest =
    signature &&
    timestamp &&
    (await verifyKey(
      body,
      signature,
      timestamp,
      environment.DISCORD_PUBLIC_KEY,
    ));

  if (!isValidRequest) return { isValid: false };

  return { interaction: JSON.parse(body), isValid: true };
}

const server = {
  verifyDiscordRequest,
  fetch: router.fetch,
};

export default server;