const DISCORD_API_BASE = 'https://discord.com/api/v10';

function getToken(account: string): string {
  const envKey = `DISCORD_${account.toUpperCase()}_BOT_TOKEN`;
  return process.env[envKey] ?? '';
}

async function discordRequest(
  token: string,
  endpoint: string,
  method: 'GET' | 'POST' = 'GET',
  body?: unknown
) {
  const url = `${DISCORD_API_BASE}${endpoint}`;
  const res = await fetch(url, {
    method,
    headers: {
      'Authorization': `Bot ${token}`,
      'Content-Type': 'application/json',
    },
    body: body ? JSON.stringify(body) : undefined,
    signal: AbortSignal.timeout(15000),
  });

  if (!res.ok) {
    const error = await res.text();
    throw new Error(`Discord API error (${res.status}): ${error}`);
  }

  return res.json();
}

export async function getMe(args: { account?: string }): Promise<{
  id: string;
  username: string;
  bot: boolean;
}> {
  const token = getToken(args.account ?? 'default');
  if (!token) {
    throw new Error('Missing Discord credentials. Set DISCORD_{ACCOUNT}_BOT_TOKEN');
  }
  return discordRequest(token, '/users/@me');
}

export async function getGuilds(args: { account?: string }): Promise<Array<{
  id: string;
  name: string;
  icon?: string;
}>> {
  const token = getToken(args.account ?? 'default');
  if (!token) {
    throw new Error('Missing Discord credentials. Set DISCORD_{ACCOUNT}_BOT_TOKEN');
  }
  return discordRequest(token, '/users/@me/guilds');
}

export async function getChannels(args: { guild_id: string; account?: string }): Promise<Array<{
  id: string;
  name: string;
  type: number;
}>> {
  const token = getToken(args.account ?? 'default');
  if (!token) {
    throw new Error('Missing Discord credentials. Set DISCORD_{ACCOUNT}_BOT_TOKEN');
  }
  return discordRequest(token, `/guilds/${args.guild_id}/channels`);
}

export async function sendMessage(args: {
  channel_id: string;
  content: string;
  account?: string;
}): Promise<{ id: string; channel_id: string }> {
  const token = getToken(args.account ?? 'default');
  if (!token) {
    throw new Error('Missing Discord credentials. Set DISCORD_{ACCOUNT}_BOT_TOKEN');
  }

  return discordRequest(token, `/channels/${args.channel_id}/messages`, 'POST', {
    content: args.content,
  });
}

export async function getMessages(args: {
  channel_id: string;
  limit?: number;
  account?: string;
}): Promise<Array<{
  id: string;
  content: string;
  author: { username: string; id: string };
  timestamp: string;
}>> {
  const token = getToken(args.account ?? 'default');
  if (!token) {
    throw new Error('Missing Discord credentials. Set DISCORD_{ACCOUNT}_BOT_TOKEN');
  }

  const limit = args.limit ?? 10;
  return discordRequest(token, `/channels/${args.channel_id}/messages?limit=${limit}`);
}