/**
 * Users Routes – Admin user management
 */
import type { FastifyInstance, FastifyRequest, FastifyReply } from 'fastify';
import type { DatabaseInterface, DBUser } from '../database/DatabaseInterface.js';
import type { AuthService } from '../auth/AuthService.js';

function extractToken(request: FastifyRequest): string | null {
  const auth = request.headers?.authorization;
  if (auth && auth.startsWith('Bearer ')) {
    return auth.slice(7);
  }
  return null;
}

function requireAdmin(request: FastifyRequest, reply: FastifyReply, authService: AuthService): DBUser | null {
  const token = extractToken(request);
  if (!token) {
    reply.code(401).send({ error: 'Authentication required' });
    return null;
  }
  const user = authService.getUserFromSession(token);
  if (!user) {
    reply.code(401).send({ error: 'Invalid or expired session' });
    return null;
  }
  if (user.role !== 'admin') {
    reply.code(403).send({ error: 'Admin access required' });
    return null;
  }
  return user;
}

export function registerUserRoutes(fastify: FastifyInstance, db: DatabaseInterface, authService: AuthService) {
  // List all users (admin only)
  fastify.get('/api/users', async (request, reply) => {
    if (!requireAdmin(request, reply, authService)) return;
    const users = db.listUsers();
    return users.map(({ password_hash, ...safe }) => safe);
  });

  // Get single user (admin only)
  fastify.get('/api/users/:id', async (request, reply) => {
    if (!requireAdmin(request, reply, authService)) return;
    const { id } = request.params as { id: string };
    const user = db.getUser(id);
    if (!user) return reply.code(404).send({ error: 'User not found' });
    const { password_hash, ...safe } = user;
    return safe;
  });

  // Update user (admin only)
  fastify.patch('/api/users/:id', async (request, reply) => {
    if (!requireAdmin(request, reply, authService)) return;
    const { id } = request.params as { id: string };
    const body = request.body as Partial<DBUser>;
    // Prevent password update via this endpoint
    delete body.password_hash;
    const updated = db.updateUser(id, body);
    if (!updated) return reply.code(404).send({ error: 'User not found' });
    const { password_hash, ...safe } = updated;
    return safe;
  });

  // Delete user (admin only)
  fastify.delete('/api/users/:id', async (request, reply) => {
    if (!requireAdmin(request, reply, authService)) return;
    const { id } = request.params as { id: string };
    const ok = db.deleteUser(id);
    if (!ok) return reply.code(404).send({ error: 'User not found' });
    return reply.code(204).send();
  });
}