import { NextRequest, NextResponse } from 'next/server';
import { withDb } from '@/lib/api-handler';
import { db } from '@/lib/db';
import { z } from 'zod';
import { hashPassword } from '@/lib/auth';
import { getClientIp } from '@/lib/validation';
import { rateLimit } from '@/lib/rate-limit';

const resetPasswordSchema = z.object({
  email: z.string().email('Please enter a valid email address'),
  code: z.string().length(6, 'Code must be exactly 6 digits'),
  newPassword: z
    .string()
    .min(8, 'Password must be at least 8 characters')
    .refine((pw) => /[A-Z]/.test(pw), 'Password must contain at least one uppercase letter')
    .refine((pw) => /[a-z]/.test(pw), 'Password must contain at least one lowercase letter')
    .refine((pw) => /[0-9]/.test(pw), 'Password must contain at least one number'),
});

async function handler(request: NextRequest) {
  try {
    // ── Rate Limit: 5 per 15 minutes ─────────────────────────────────
    const ip = getClientIp(request);
    const { allowed, retryAfterMs } = await rateLimit(`reset-pw:${ip}`, 5, 15 * 60_000);
    if (!allowed) {
      return NextResponse.json(
        { error: 'Too many reset attempts. Please try again later.' },
        {
          status: 429,
          headers: { 'Retry-After': String(Math.ceil(retryAfterMs / 1000)) },
        }
      );
    }

    // ── Parse & Validate Body ─────────────────────────────────────────
    const body = await request.json();
    const parsed = resetPasswordSchema.safeParse(body);
    if (!parsed.success) {
      return NextResponse.json(
        { error: parsed.error.issues[0].message },
        { status: 400 }
      );
    }

    const { email, code, newPassword } = parsed.data;

    // ── Find valid reset token ────────────────────────────────────────
    const resetToken = await db.resetToken.findFirst({
      where: {
        email,
        token: code,
        usedAt: null,
        expiresAt: { gt: new Date() },
      },
    });

    if (!resetToken) {
      return NextResponse.json(
        { error: 'Invalid or expired reset code. Please request a new one.' },
        { status: 400 }
      );
    }

    // ── Find user ─────────────────────────────────────────────────────
    const user = await db.user.findUnique({ where: { email } });
    if (!user) {
      return NextResponse.json(
        { error: 'No account found with this email address.' },
        { status: 404 }
      );
    }

    // ── Hash new password and update user ─────────────────────────────
    const hashedPassword = await hashPassword(newPassword);

    await db.user.update({
      where: { id: user.id },
      data: { password: hashedPassword },
    });

    // ── Mark token as used ────────────────────────────────────────────
    await db.resetToken.update({
      where: { id: resetToken.id },
      data: { usedAt: new Date() },
    });

    // ── Delete all sessions for the user ──────────────────────────────
    await db.session.deleteMany({
      where: { userId: user.id },
    });

    return NextResponse.json({
      success: true,
      message: 'Password has been reset successfully. Please log in with your new password.',
    });
  } catch (error) {
    console.error('[RESET_PASSWORD_ERROR]', error);
    return NextResponse.json(
      { error: 'Internal server error' },
      { status: 500 }
    );
  }
}

export const POST = withDb(handler);