import type express from 'express';
import crypto from 'node:crypto';
import { Client, EmbedBuilder, TextChannel, ChannelType } from 'discord.js';
import type { Plugin, PluginContext } from '../../core/plugin.js';
import { getState, setState } from '../../core/persistence.js';

const NB = '[Notifications]';

// ── Types ──

interface NotifyChannelConfig {
  channelId: string;
  channelName: string;
  guildId: string;
  guildName: string;
  events: string[];  // e.g. ['stream_start', 'stream_end']
}

interface NotificationConfig {
  channels: NotifyChannelConfig[];
}

// ── Module-level state ──

let _client: Client | null = null;
let _ctx: PluginContext | null = null;
let _publicUrl = '';

// ── Admin Auth (JWT-like with HMAC) ──

type AdminPayload = { iat: number; exp: number };

function readCookie(req: express.Request, name: string): string | undefined {
  const header = req.headers.cookie;
  if (!header) return undefined;
  const match = header.split(';').map(s => s.trim()).find(s => s.startsWith(`${name}=`));
  return match?.split('=').slice(1).join('=');
}

function b64url(str: string): string {
  return Buffer.from(str).toString('base64url');
}

function verifyAdminToken(adminPwd: string, token: string | undefined): boolean {
  if (!adminPwd || !token) return false;
  const parts = token.split('.');
  if (parts.length !== 2) return false;
  const [body, sig] = parts;
  const expected = crypto.createHmac('sha256', adminPwd).update(body).digest('base64url');
  if (expected !== sig) return false;
  try {
    const payload = JSON.parse(Buffer.from(body, 'base64url').toString('utf8')) as AdminPayload;
    return typeof payload.exp === 'number' && Date.now() < payload.exp;
  } catch { return false; }
}

function signAdminToken(adminPwd: string): string {
  const payload: AdminPayload = { iat: Date.now(), exp: Date.now() + 7 * 24 * 3600_000 };
  const body = b64url(JSON.stringify(payload));
  const sig = crypto.createHmac('sha256', adminPwd).update(body).digest('base64url');
  return `${body}.${sig}`;
}

// ── Exported notification functions (called by other plugins) ──

export async function notifyStreamStart(info: {
  streamId: string;
  broadcasterName: string;
  title: string;
  hasPassword: boolean;
}): Promise<void> {
  if (!_client?.isReady()) return;
  const config = getState<NotificationConfig>('notifications_config', { channels: [] });
  const targets = config.channels.filter(c => c.events.includes('stream_start'));
  if (targets.length === 0) return;

  const streamUrl = _publicUrl ? `${_publicUrl}?viewStream=${info.streamId}` : null;

  const embed = new EmbedBuilder()
    .setColor(0x57F287) // green
    .setTitle('🔴 Stream gestartet')
    .addFields(
      { name: 'Titel', value: info.title, inline: true },
      { name: 'Streamer', value: info.broadcasterName, inline: true },
    )
    .setTimestamp();

  if (info.hasPassword) {
    embed.addFields({ name: '🔒', value: 'Passwortgeschützt', inline: true });
  }
  if (streamUrl) {
    embed.addFields({ name: 'Link', value: `[Stream öffnen](${streamUrl})` });
  }

  for (const target of targets) {
    try {
      const channel = await _client.channels.fetch(target.channelId);
      if (channel?.type === ChannelType.GuildText) {
        await (channel as TextChannel).send({ embeds: [embed] });
      }
    } catch (err) {
      console.error(`${NB} Failed to send to ${target.channelId}:`, err);
    }
  }
  console.log(`${NB} Stream-start notification sent to ${targets.length} channel(s)`);
}

export async function notifyStreamEnd(info: {
  broadcasterName: string;
  title: string;
  viewerCount: number;
  duration: string; // human readable e.g. "1h 23m"
}): Promise<void> {
  if (!_client?.isReady()) return;
  const config = getState<NotificationConfig>('notifications_config', { channels: [] });
  const targets = config.channels.filter(c => c.events.includes('stream_end'));
  if (targets.length === 0) return;

  const embed = new EmbedBuilder()
    .setColor(0xED4245) // red
    .setTitle('⏹️ Stream beendet')
    .addFields(
      { name: 'Titel', value: info.title, inline: true },
      { name: 'Streamer', value: info.broadcasterName, inline: true },
      { name: 'Zuschauer', value: String(info.viewerCount), inline: true },
      { name: 'Dauer', value: info.duration, inline: true },
    )
    .setTimestamp();

  for (const target of targets) {
    try {
      const channel = await _client.channels.fetch(target.channelId);
      if (channel?.type === ChannelType.GuildText) {
        await (channel as TextChannel).send({ embeds: [embed] });
      }
    } catch (err) {
      console.error(`${NB} Failed to send to ${target.channelId}:`, err);
    }
  }
  console.log(`${NB} Stream-end notification sent to ${targets.length} channel(s)`);
}

// ── Plugin ──

const notificationsPlugin: Plugin = {
  name: 'notifications',
  version: '1.0.0',
  description: 'Discord Notification Bot',

  async init(ctx) {
    _ctx = ctx;
    _client = ctx.client;
    _publicUrl = process.env.PUBLIC_URL?.replace(/\/$/, '') ?? '';
    console.log(`${NB} Initialized${_publicUrl ? ` (PUBLIC_URL=${_publicUrl})` : ' (no PUBLIC_URL set)'}`);
  },

  async onReady(ctx) {
    console.log(`${NB} Bot ready as ${ctx.client.user?.tag}`);
  },

  registerRoutes(app, ctx) {
    const requireAdmin = (req: express.Request, res: express.Response, next: () => void): void => {
      if (!ctx.adminPwd) { res.status(503).json({ error: 'Admin nicht konfiguriert' }); return; }
      if (!verifyAdminToken(ctx.adminPwd, readCookie(req, 'admin'))) { res.status(401).json({ error: 'Nicht eingeloggt' }); return; }
      next();
    };

    // Admin status
    app.get('/api/notifications/admin/status', (req, res) => {
      if (!ctx.adminPwd) { res.json({ admin: false }); return; }
      res.json({ admin: verifyAdminToken(ctx.adminPwd, readCookie(req, 'admin')) });
    });

    // Admin login
    app.post('/api/notifications/admin/login', (req, res) => {
      if (!ctx.adminPwd) { res.status(503).json({ error: 'Admin nicht konfiguriert' }); return; }
      const { password } = req.body ?? {};
      if (password !== ctx.adminPwd) { res.status(401).json({ error: 'Falsches Passwort' }); return; }
      const token = signAdminToken(ctx.adminPwd);
      res.setHeader('Set-Cookie', `admin=${token}; Path=/; HttpOnly; SameSite=Lax; Max-Age=${7 * 86400}`);
      res.json({ ok: true });
    });

    // Admin logout
    app.post('/api/notifications/admin/logout', (_req, res) => {
      res.setHeader('Set-Cookie', 'admin=; Path=/; HttpOnly; SameSite=Lax; Max-Age=0');
      res.json({ ok: true });
    });

    // List available text channels (requires admin)
    app.get('/api/notifications/channels', requireAdmin, async (_req, res) => {
      if (!ctx.client.isReady()) {
        res.status(503).json({ error: 'Bot nicht verbunden' });
        return;
      }
      const result: Array<{ channelId: string; channelName: string; guildId: string; guildName: string }> = [];
      for (const guild of ctx.client.guilds.cache.values()) {
        // Filter by allowed guilds if configured
        if (ctx.allowedGuildIds.length > 0 && !ctx.allowedGuildIds.includes(guild.id)) continue;
        try {
          const channels = await guild.channels.fetch();
          for (const channel of channels.values()) {
            if (channel && channel.type === ChannelType.GuildText) {
              result.push({
                channelId: channel.id,
                channelName: channel.name,
                guildId: guild.id,
                guildName: guild.name,
              });
            }
          }
        } catch (err) {
          console.error(`${NB} Failed to fetch channels for guild ${guild.name}:`, err);
        }
      }
      res.json({ channels: result });
    });

    // Get current config
    app.get('/api/notifications/config', requireAdmin, (_req, res) => {
      const config = getState<NotificationConfig>('notifications_config', { channels: [] });
      res.json(config);
    });

    // Save config
    app.post('/api/notifications/config', requireAdmin, (req, res) => {
      const { channels } = req.body ?? {};
      if (!Array.isArray(channels)) { res.status(400).json({ error: 'channels array erforderlich' }); return; }
      // Validate each channel config
      const validChannels: NotifyChannelConfig[] = channels.map((c: any) => ({
        channelId: String(c.channelId || ''),
        channelName: String(c.channelName || ''),
        guildId: String(c.guildId || ''),
        guildName: String(c.guildName || ''),
        events: Array.isArray(c.events) ? c.events.filter((e: string) => ['stream_start', 'stream_end'].includes(e)) : [],
      })).filter((c: NotifyChannelConfig) => c.channelId && c.events.length > 0);
      setState('notifications_config', { channels: validChannels });
      console.log(`${NB} Config saved: ${validChannels.length} channel(s)`);
      res.json({ ok: true, channels: validChannels });
    });

    // Bot status (public)
    app.get('/api/notifications/status', (_req, res) => {
      res.json({
        online: ctx.client.isReady(),
        botTag: ctx.client.user?.tag ?? null,
        configuredChannels: getState<NotificationConfig>('notifications_config', { channels: [] }).channels.length,
      });
    });
  },

  getSnapshot() {
    return {
      notifications: {
        online: _client?.isReady() ?? false,
        botTag: _client?.user?.tag ?? null,
      },
    };
  },

  async destroy() {
    console.log(`${NB} Destroyed`);
  },
};

export default notificationsPlugin;