import type { FastifyInstance } from 'fastify';
import type { DB } from '../db.js';
import type {
  Bar,
  BarConfig,
  CreateTransactionRequest,
  CreateTransactionResponse,
  Drink,
} from '@wutzcalc/shared';

export function registerPublicRoutes(app: FastifyInstance, db: DB) {
  app.get('/api/bars', async () => {
    const rows = db.prepare('SELECT id, name, pfand_cents FROM bars ORDER BY id').all() as Bar[];
    return rows;
  });

  app.get<{ Querystring: { bar: string } }>('/api/config', async (req, reply) => {
    const barId = Number(req.query.bar);
    if (!Number.isInteger(barId)) return reply.code(400).send({ error: 'bar required' });

    const bar = db
      .prepare('SELECT id, name, pfand_cents FROM bars WHERE id = ?')
      .get(barId) as Bar | undefined;
    if (!bar) return reply.code(404).send({ error: 'bar not found' });

    const drinks = db
      .prepare(
        `SELECT d.id, d.name, d.price_cents, d.archived
           FROM drinks d
           JOIN bar_drinks bd ON bd.drink_id = d.id
          WHERE bd.bar_id = ? AND d.archived = 0
          ORDER BY bd.sort_order, d.id`
      )
      .all(barId) as Drink[];

    const config: BarConfig = { bar, drinks };
    return config;
  });

  app.post<{ Body: CreateTransactionRequest }>('/api/transactions', async (req, reply) => {
    const body = req.body ?? ({} as CreateTransactionRequest);
    const { client_uuid, bar_id, crew, items } = body;
    const pfand_returns = Math.max(0, Math.floor(body.pfand_returns ?? 0));

    if (!client_uuid || typeof client_uuid !== 'string') {
      return reply.code(400).send({ error: 'client_uuid required' });
    }
    if (!Number.isInteger(bar_id)) {
      return reply.code(400).send({ error: 'bar_id required' });
    }
    if (!Array.isArray(items)) {
      return reply.code(400).send({ error: 'items required' });
    }
    if (items.length === 0 && pfand_returns === 0) {
      return reply.code(400).send({ error: 'empty transaction' });
    }

    const existing = db
      .prepare('SELECT id, total_cents FROM transactions WHERE client_uuid = ?')
      .get(client_uuid) as { id: number; total_cents: number } | undefined;
    if (existing) {
      const res: CreateTransactionResponse = { id: existing.id, total_cents: existing.total_cents };
      return res;
    }

    const bar = db
      .prepare('SELECT id, pfand_cents FROM bars WHERE id = ?')
      .get(bar_id) as { id: number; pfand_cents: number } | undefined;
    if (!bar) return reply.code(404).send({ error: 'bar not found' });

    const drinkStmt = db.prepare(
      `SELECT d.id, d.price_cents
         FROM drinks d
         JOIN bar_drinks bd ON bd.drink_id = d.id
        WHERE bd.bar_id = ? AND d.id = ? AND d.archived = 0`
    );

    let total = 0;
    const priced: Array<{
      drink_id: number;
      qty: number;
      unit_price_cents: number;
      pfand_cents_per_unit: number;
    }> = [];

    for (const item of items) {
      if (!Number.isInteger(item.drink_id) || !Number.isInteger(item.qty) || item.qty <= 0) {
        return reply.code(400).send({ error: 'invalid item' });
      }
      const drink = drinkStmt.get(bar_id, item.drink_id) as
        | { id: number; price_cents: number }
        | undefined;
      if (!drink) return reply.code(400).send({ error: `drink ${item.drink_id} not at bar` });

      const lineUnit = drink.price_cents + bar.pfand_cents;
      total += lineUnit * item.qty;
      priced.push({
        drink_id: drink.id,
        qty: item.qty,
        unit_price_cents: drink.price_cents,
        pfand_cents_per_unit: bar.pfand_cents,
      });
    }

    total -= bar.pfand_cents * pfand_returns;

    const paidTotal = crew ? 0 : total;
    const clientIp = req.ip ?? null;

    const insertTx = db.prepare(
      `INSERT INTO transactions (bar_id, total_cents, crew, pfand_returns, client_ip, client_uuid)
       VALUES (?, ?, ?, ?, ?, ?)`
    );
    const insertItem = db.prepare(
      `INSERT INTO transaction_items
         (transaction_id, drink_id, qty, unit_price_cents, pfand_cents_per_unit, is_return)
       VALUES (?, ?, ?, ?, ?, 0)`
    );

    const txId = db.transaction(() => {
      const info = insertTx.run(bar_id, paidTotal, crew ? 1 : 0, pfand_returns, clientIp, client_uuid);
      const id = Number(info.lastInsertRowid);
      for (const p of priced) {
        insertItem.run(id, p.drink_id, p.qty, p.unit_price_cents, p.pfand_cents_per_unit);
      }
      return id;
    })();

    const res: CreateTransactionResponse = { id: txId, total_cents: paidTotal };
    return res;
  });
}