import type { FastifyPluginAsync } from 'fastify';
import { z } from 'zod';
import { hashPassword, verifyPassword } from '../auth/passwords.js';
import { hashToken } from '../auth/account-tokens.js';
import type { AuthUser } from '../auth/plugin.js';
import { pool } from '../db/pool.js';
import { config } from '../config.js';

const credentialsSchema = z.object({
  email: z.string().email().transform((email) => email.toLowerCase()),
  password: z.string().min(12).max(200),
});

const registerSchema = credentialsSchema.extend({
  name: z.string().trim().min(2).max(120),
});
const tokenPasswordSchema = z.object({ token: z.string().min(20), password: z.string().min(12).max(200), name: z.string().trim().min(2).max(120).optional() });

type UserRow = {
  id: string;
  email: string;
  display_name: string;
  role: AuthUser['role'];
  password_hash: string;
  is_active: boolean;
};

const serializeUser = (user: UserRow): AuthUser => ({
  id: user.id,
  email: user.email,
  name: user.display_name,
  role: user.role,
});

export const authRoutes: FastifyPluginAsync = async (app) => {
  const publicAttempts = new Map<string, number[]>();
  const allowPublicAuthAttempt = (ip: string) => {
    const now = Date.now();
    const earliestAllowed = now - config.AUTH_RATE_LIMIT_WINDOW_SECONDS * 1000;
    const attempts = (publicAttempts.get(ip) || []).filter((timestamp) => timestamp > earliestAllowed);
    if (attempts.length >= config.AUTH_RATE_LIMIT_MAX) {
      publicAttempts.set(ip, attempts);
      return false;
    }
    attempts.push(now);
    publicAttempts.set(ip, attempts);
    return true;
  };
  const rejectIfRateLimited = (ip: string, reply: { code: (status: number) => { send: (payload: object) => unknown } }) => {
    if (allowPublicAuthAttempt(ip)) return false;
    reply.code(429).send({ error: 'Too many attempts. Please try again later.' });
    return true;
  };

  app.post('/accept-invitation', async (request, reply) => {
    if (rejectIfRateLimited(request.ip, reply)) return;
    const input = tokenPasswordSchema.extend({ name: z.string().trim().min(2).max(120) }).parse(request.body);
    const client = await pool.connect();
    try {
      await client.query('begin');
      const token = await client.query<{ email: string; role: AuthUser['role'] }>(
        `update account_access_tokens set used_at = now()
         where token_hash = $1 and purpose = 'invitation'::account_token_purpose and used_at is null and expires_at > now()
         returning email, role`, [hashToken(input.token)],
      );
      if (!token.rows[0]) {
        await client.query('rollback');
        return reply.code(400).send({ error: 'This invitation is invalid or expired' });
      }
      const result = await client.query<UserRow>(
        `insert into users (email, password_hash, display_name, role) values ($1, $2, $3, $4)
         returning id, email, display_name, role, password_hash, is_active`,
        [token.rows[0].email, await hashPassword(input.password), input.name, token.rows[0].role],
      );
      await client.query('commit');
      const user = serializeUser(result.rows[0]);
      return reply.code(201).send({ token: await reply.jwtSign(user, { expiresIn: '7d' }), user });
    } catch {
      await client.query('rollback');
      return reply.code(409).send({ error: 'This invitation email already has an account' });
    } finally {
      client.release();
    }
  });

  app.post('/reset-password', async (request, reply) => {
    if (rejectIfRateLimited(request.ip, reply)) return;
    const input = tokenPasswordSchema.parse(request.body);
    const client = await pool.connect();
    try {
      await client.query('begin');
      const token = await client.query<{ email: string }>(
        `update account_access_tokens set used_at = now()
         where token_hash = $1 and purpose = 'password_reset'::account_token_purpose and used_at is null and expires_at > now()
         returning email`, [hashToken(input.token)],
      );
      if (!token.rows[0]) {
        await client.query('rollback');
        return reply.code(400).send({ error: 'This reset link is invalid or expired' });
      }
      await client.query('update users set password_hash = $2 where email = $1', [token.rows[0].email, await hashPassword(input.password)]);
      await client.query('commit');
      return reply.code(204).send();
    } catch (error) {
      await client.query('rollback');
      throw error;
    } finally {
      client.release();
    }
  });
  app.post('/register', async (request, reply) => {
    if (rejectIfRateLimited(request.ip, reply)) return;
    const input = registerSchema.parse(request.body);
    const passwordHash = await hashPassword(input.password);

    try {
      const result = await pool.query<UserRow>(
        `insert into users (email, password_hash, display_name)
         values ($1, $2, $3)
         returning id, email, display_name, role, password_hash, is_active`,
        [input.email, passwordHash, input.name],
      );
      const user = serializeUser(result.rows[0]);
      const token = await reply.jwtSign(user, { expiresIn: '7d' });
      return reply.code(201).send({ token, user });
    } catch (error: unknown) {
      if (typeof error === 'object' && error && 'code' in error && error.code === '23505') {
        return reply.code(409).send({ error: 'An account with this email already exists' });
      }
      throw error;
    }
  });

  app.post('/login', async (request, reply) => {
    if (rejectIfRateLimited(request.ip, reply)) return;
    const input = credentialsSchema.parse(request.body);
    const result = await pool.query<UserRow>(
      `select id, email, display_name, role, password_hash, is_active from users where email = $1`,
      [input.email],
    );
    const account = result.rows[0];

    if (!account || !account.is_active || !(await verifyPassword(input.password, account.password_hash))) {
      return reply.code(401).send({ error: 'Invalid email or password' });
    }

    const user = serializeUser(account);
    const token = await reply.jwtSign(user, { expiresIn: '7d' });
    return { token, user };
  });

  app.get('/me', { preHandler: app.authenticate }, async (request) => ({ user: request.user }));
};