import { NextRequest, NextResponse } from 'next/server';
import { z } from 'zod';

const GenerateSchema = z.object({
  destination: z.string().min(2),
  startDate: z.string(),
  numDays: z.number().int().min(1).max(14),
  budget: z.number().positive(),
  currency: z.string(),
  experienceMode: z.string(),
  preferences: z.array(z.string()),
});

export async function POST(req: NextRequest) {
  try {
    const body = await req.json();
    const data = GenerateSchema.parse(body);

    // Stub response (Phase 3 will replace with real Geoapify + LLM)
    const days = Array.from({ length: data.numDays }, (_, i) => ({
      day: i + 1,
      activities: [
        {
          time: '09:30',
          title: `Highlight ${i + 1} (${data.experienceMode})`,
          type: data.experienceMode === 'foodie' ? 'restaurant' : 'attraction',
          cost: Math.round(data.budget / (data.numDays * 3)),
        },
        {
          time: '13:30',
          title: 'Recommended meal',
          type: 'restaurant',
          cost: 22,
        },
      ],
    }));

    return NextResponse.json({
      tripId: 'trip_' + Date.now(),
      destination: data.destination,
      numDays: data.numDays,
      experienceMode: data.experienceMode,
      summary: `Stub plan for ${data.destination} — ${data.numDays} days in ${data.experienceMode} mode.`,
      days,
      estimatedCost: Math.round(data.budget * 0.82),
    });
  } catch (err) {
    console.error(err);
    return NextResponse.json({ error: 'Invalid input' }, { status: 400 });
  }
}