import { NextResponse } from 'next/server';
import db from '@/lib/db';

export const dynamic = 'force-dynamic';

type Params = { params: Promise<{ id: string }> };

export async function POST(request: Request, { params }: Params) {
  const { id } = await params;
  const { date, delta } = await request.json();

  if (!date || typeof date !== 'string' || !/^\d{4}-\d{2}-\d{2}$/.test(date)) {
    return NextResponse.json({ error: 'Invalid date' }, { status: 400 });
  }
  if (delta !== 1 && delta !== -1) {
    return NextResponse.json({ error: 'Delta must be 1 or -1' }, { status: 400 });
  }

  const existing = db.prepare('SELECT * FROM counters WHERE id = ? AND archived_at IS NULL').get(Number(id)) as Record<string, unknown> | undefined;
  if (!existing) return NextResponse.json({ error: 'Not found' }, { status: 404 });

  // Store at noon local server time so SQLite's 'localtime' grouping matches the picked date
  const createdAt = new Date(`${date}T12:00:00`).getTime();
  if (isNaN(createdAt)) return NextResponse.json({ error: 'Invalid date' }, { status: 400 });

  const result = db.transaction(() => {
    const updated = db.prepare(
      delta === 1
        ? 'UPDATE counters SET value = value + 1 WHERE id = ? RETURNING *'
        : 'UPDATE counters SET value = value - 1 WHERE id = ? AND value > 0 RETURNING *'
    ).get(Number(id)) as Record<string, unknown> | undefined;
    if (!updated) return null;
    db.prepare('INSERT INTO events (counter_id, delta, created_at) VALUES (?, ?, ?)').run(Number(id), delta, createdAt);
    return updated;
  })();

  if (!result) return NextResponse.json({ error: 'Counter cannot go below 0' }, { status: 400 });
  return NextResponse.json(result);
}