import { FastifyInstance } from 'fastify';
import crypto from 'crypto';
import prisma from '../../config/database';
import { requireAuth } from '../../middleware/auth';
import { success, error } from '../../utils/response';

function hashToken(token: string): string {
  return crypto.createHash('sha256').update(token).digest('hex');
}

/** Parse user-agent string into browser, OS, and device icon */
function parseUserAgent(ua: string | null): { browser: string; os: string; icon: string } {
  if (!ua) return { browser: 'Neznámý prohlížeč', os: 'Neznámý systém', icon: 'monitor' };

  // Browser detection
  let browser = 'Neznámý prohlížeč';
  if (ua.includes('Edg/')) browser = 'Edge';
  else if (ua.includes('OPR/') || ua.includes('Opera')) browser = 'Opera';
  else if (ua.includes('Chrome/')) browser = 'Chrome';
  else if (ua.includes('Safari/') && !ua.includes('Chrome')) browser = 'Safari';
  else if (ua.includes('Firefox/')) browser = 'Firefox';

  // OS detection
  let os = 'Neznámý systém';
  if (ua.includes('Windows')) os = 'Windows';
  else if (ua.includes('Mac OS X') || ua.includes('Macintosh')) os = 'macOS';
  else if (ua.includes('Linux') && !ua.includes('Android')) os = 'Linux';
  else if (ua.includes('Android')) os = 'Android';
  else if (ua.includes('iPhone') || ua.includes('iPad')) os = 'iOS';

  // Device icon
  let icon = 'monitor';
  if (ua.includes('Mobile') || ua.includes('iPhone') || ua.includes('Android')) {
    icon = ua.includes('iPad') || ua.includes('Tablet') ? 'tablet' : 'smartphone';
  }

  return { browser, os, icon };
}

export default async function sessionsRoutes(fastify: FastifyInstance): Promise<void> {
  // GET /api/admin/sessions — list active sessions for current user
  fastify.get('/', { preHandler: requireAuth }, async (request, reply) => {
    const authData = request.authData!;
    const currentToken = request.cookies?.refresh_token;
    const currentHash = currentToken ? hashToken(currentToken) : null;

    const sessions = await prisma.refresh_tokens.findMany({
      where: { user_id: authData.userId, replaced_at: null, expires_at: { gt: new Date() } },
      orderBy: { created_at: 'desc' },
    });

    const enriched = sessions.map(s => {
      const device_info = parseUserAgent(s.user_agent);
      return {
        id: s.id,
        is_current: currentHash ? s.token_hash === currentHash : false,
        device_info,
        ip_address: s.ip_address || '',
        created_at: s.created_at ? s.created_at.toISOString() : '',
      };
    });

    return success(reply, enriched);
  });

  // DELETE /api/admin/sessions/:id — delete specific session
  fastify.delete<{ Params: { id: string } }>('/:id', { preHandler: requireAuth }, async (request, reply) => {
    const id = parseInt(request.params.id, 10);
    const authData = request.authData!;

    const session = await prisma.refresh_tokens.findFirst({
      where: { id, user_id: authData.userId },
    });
    if (!session) return error(reply, 'Relace nenalezena', 404);

    await prisma.refresh_tokens.update({
      where: { id },
      data: { replaced_at: new Date() },
    });
    return success(reply, null, 200, 'Relace ukončena');
  });

  // DELETE /api/admin/sessions — delete all sessions except current
  fastify.delete('/', { preHandler: requireAuth }, async (request, reply) => {
    const authData = request.authData!;
    const query = request.query as Record<string, unknown>;

    if (query.action === 'all') {
      // Get current token from cookie to exclude (hash it to match stored token_hash)
      const currentToken = request.cookies?.refresh_token;
      const currentHash = currentToken ? hashToken(currentToken) : null;

      await prisma.refresh_tokens.updateMany({
        where: {
          user_id: authData.userId,
          replaced_at: null,
          ...(currentHash ? { token_hash: { not: currentHash } } : {}),
        },
        data: { replaced_at: new Date() },
      });
      return success(reply, null, 200, 'Všechny ostatní relace ukončeny');
    }

    return error(reply, 'Neplatná akce', 400);
  });
}