path: root/src/server.ts

import { AutoRouter } from 'itty-router';
import {
  InteractionResponseType,
  InteractionType,
  verifyKey,
} from 'discord-interactions';
import {
  HOT_COMMAND,
  ROLEPLAY_COMMAND,
  NSFW_COMMAND,
  TOP_COMMAND,
} from './commands.ts';
import {
  getCutePost,
  getRoleplayPost,
  getNSFWPost,
  getTopPost,
  type RedditPost,
} from './reddit.ts';
import type { TimePeriod } from './commands.ts';

interface Environment {
  DISCORD_APPLICATION_ID: string;
  DISCORD_PUBLIC_KEY: string;
  DISCORD_TOKEN: string;
}

interface DiscordInteraction {
  type: number;
  data: {
    name: string;
    options?: Array<{
      name: string;
      value: string;
    }>;
  };
  channel_id?: string;
  channel?: {
    nsfw: boolean;
  };
}

interface DiscordEmbed {
  title: string;
  description: string;
  url: string;
  color: number;
  author: {
    name: string;
    url: string;
  };
  fields: Array<{
    name: string;
    value: string;
    inline: boolean;
  }>;
  timestamp: string;
  footer: {
    text: string;
  };
  video?: { url: string };
  image?: { url: string };
}

interface DiscordResponse {
  type: number;
  data?: {
    content?: string;
    embeds?: DiscordEmbed[];
    flags?: number;
  };
}

class JSONResponse extends Response {
  constructor(body: DiscordResponse | { error: string }, init?: ResponseInit) {
    const jsonBody = JSON.stringify(body);

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

    super(jsonBody, init);
  }
}

const router = AutoRouter();

function createPostEmbed(post: RedditPost): DiscordEmbed {
  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: DiscordEmbed = {
    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: Request, environment: Environment) => {
  return new Response(`👋 ${environment.DISCORD_APPLICATION_ID}`);
});

router.post('/', async (request: Request, environment: 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(): {
        try {
          const post = await getCutePost();
          const embed = createPostEmbed(post);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              embeds: [embed],
            },
          });
        } catch (error) {
          console.error('Error in hot command:', error);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              content: '❌ No posts found. Try again later!',
              flags: 64,
            },
          });
        }
      }

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

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              embeds: [embed],
            },
          });
        } catch (error) {
          console.error('Error in roleplay command:', error);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              content: '❌ No roleplay posts found. Try again later!',
              flags: 64,
            },
          });
        }
      }

      case NSFW_COMMAND.name.toLowerCase(): {
        if (!interaction.channel_id || !interaction.channel?.nsfw) {
          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              content: '❌ This command can only be used in NSFW channels.',
              flags: 64,
            },
          });
        }

        try {
          const post = await getNSFWPost();
          const embed = createPostEmbed(post);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              embeds: [embed],
            },
          });
        } catch (error) {
          console.error('Error in NSFW command:', error);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              content: '❌ No NSFW posts found. Try again later!',
              flags: 64,
            },
          });
        }
      }

      case TOP_COMMAND.name.toLowerCase(): {
        try {
          const time =
            (interaction.data.options?.[0]?.value as TimePeriod) || 'day';
          const post = await getTopPost(time);
          const embed = createPostEmbed(post);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              embeds: [embed],
            },
          });
        } catch (error) {
          console.error('Error in top command:', error);

          return new JSONResponse({
            type: InteractionResponseType.CHANNEL_MESSAGE_WITH_SOURCE,
            data: {
              content: '❌ No top posts found. Try again later!',
              flags: 64,
            },
          });
        }
      }

      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: Request,
  environment: Environment,
): Promise<{ isValid: boolean; interaction?: DiscordInteraction }> {
  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) as DiscordInteraction, isValid: true };
}

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

export default server;