/**
 * A bar terminal on the command line, speaking the terminal protocol (docs/terminal-protocol.md): open tabs, ring up
 * drinks, settle, and watch the dashboard follow. Keeps its own outbox like the app does.
 *
 *   pnpm simulate                      # as the seeded demo terminal
 *   pnpm simulate --pair <code>        # pairs as a new terminal first
 *
 * API_URL (default http://localhost:3001/api/v1) and TERMINAL_TOKEN override the defaults.
 */
import { randomUUID } from 'crypto';
import * as readline from 'readline/promises';
import { stdin, stdout } from 'process';
import type { SyncResponse, TerminalEvent } from '@kooltap/shared';

const API_URL = process.env.API_URL ?? 'http://localhost:3001/api/v1';
const HEADERS = { 'Content-Type': 'application/json', 'x-app-version': '2.0.0' };

let token = process.env.TERMINAL_TOKEN ?? 'kt_demo-terminal-token';
let state: SyncResponse | null = null;
let outbox: TerminalEvent[] = [];

async function call<T>(path: string, body: unknown, auth = true): Promise<T> {
  const res = await fetch(`${API_URL}${path}`, {
    method: 'POST',
    headers: { ...HEADERS, ...(auth ? { Authorization: `Bearer ${token}` } : {}) },
    body: JSON.stringify(body),
  });
  const json = await res.json();
  if (!res.ok) throw new Error(`${res.status} ${json.error?.code}: ${json.error?.message}`);
  return json;
}

/** Sends the outbox and takes over the venue's state, as the app does on every sync. */
async function sync() {
  const sent = outbox;
  state = await call<SyncResponse>('/terminal/sync', {
    events: sent,
    settlementsCursor: state?.settlementsCursor,
    catalogVersion: state?.catalogVersion,
  }).then((next) => ({ ...next, catalog: next.catalog ?? state?.catalog ?? [] }));
  const acknowledged = new Set(state.acknowledgedEventIds);
  outbox = outbox.filter((event) => !acknowledged.has(event.id));
  for (const rejected of state.rejectedEvents) console.log(`  rejected ${rejected.id}: ${rejected.reason}`);
  for (const settlement of state.settlements) console.log(`  paid: ${settlement.customerName} € ${(settlement.amountInCents / 100).toFixed(2)} (${settlement.paymentMethod})`);
  show();
}

function show() {
  const tabs = state?.tabs ?? [];
  console.log(`\n${tabs.length} open tabs${outbox.length ? `, ${outbox.length} events unsent` : ''}`);
  tabs.forEach((tab, i) => {
    const total = tab.lines.reduce((sum, line) => sum + line.quantity * line.unitPriceInCents, 0);
    const drinks = tab.lines.filter((l) => l.quantity > 0).map((l) => `${l.quantity}× ${l.productName}`).join(', ');
    console.log(`  ${i + 1}. ${tab.customerName.padEnd(16)} € ${(total / 100).toFixed(2).padStart(7)}  ${drinks}`);
  });
}

const event = <T extends TerminalEvent['type']>(type: T, fields: object) =>
  ({ id: randomUUID(), type, occurredAt: new Date().toISOString(), ...fields }) as Extract<TerminalEvent, { type: T }>;

async function main() {
  const rl = readline.createInterface({ input: stdin, output: stdout });
  const pairAt = process.argv.indexOf('--pair');
  if (pairAt >= 0) {
    const paired = await call<{ token: string; deviceId: string }>('/terminal/register', { registrationCode: process.argv[pairAt + 1], name: 'Simulator' }, false);
    token = paired.token;
    console.log(`Paired as ${paired.deviceId}`);
  }
  await sync();

  for (;;) {
    // Input that ends (a pipe) quits
    const choice = (await rl.question('\n[s]ync  [o]pen tab  [a]dd drinks  [r]emove drink  [p]ay  [q]uit > ').catch(() => 'q')).trim().toLowerCase();
    try {
      const tabs = state!.tabs;
      const pickTab = async () => tabs[Number(await rl.question('Tab number: ')) - 1];
      if (choice === 'q') break;
      if (choice === 's') await sync();
      if (choice === 'o') {
        outbox.push(event('tab_opened', { tabId: randomUUID(), customerName: (await rl.question('Customer name: ')).trim() }));
        await sync();
      }
      if (choice === 'a') {
        const tab = await pickTab();
        const products = state!.catalog!.filter((p) => !p.archived);
        products.forEach((p, i) => console.log(`  ${i + 1}. ${p.name} € ${(p.priceInCents / 100).toFixed(2)}`));
        const product = products[Number(await rl.question('Product number: ')) - 1];
        const quantity = Number(await rl.question('How many: ')) || 1;
        const line = tab.lines.find((l) => l.productId === product.id);
        outbox.push(event('line_added', {
          tabId: tab.id, customerName: tab.customerName, lineId: line?.id ?? randomUUID(), orderId: randomUUID(),
          productId: product.id, productName: product.name, unitPriceInCents: product.priceInCents, quantity,
        }));
        await sync();
      }
      if (choice === 'r') {
        const tab = await pickTab();
        const line = tab.lines.find((l) => l.quantity > 0);
        const unit = line?.units.filter((u) => !u.removedAt).at(-1);
        if (line && unit?.orderId) outbox.push(event('line_removed', { tabId: tab.id, lineId: line.id, orderId: unit.orderId, quantity: 1 }));
        await sync();
      }
      if (choice === 'p') {
        const tab = await pickTab();
        const method = (await rl.question('cash / payconiq / payment_pending / other: ')).trim() || 'cash';
        const items = tab.lines.filter((l) => l.quantity > 0)
          .map((l) => ({ lineId: l.id, productId: l.productId, productName: l.productName, unitPriceInCents: l.unitPriceInCents, quantity: l.quantity }));
        const amountInCents = items.reduce((sum, item) => sum + item.quantity * item.unitPriceInCents, 0);
        outbox.push(event('settled', { tabId: tab.id, customerName: tab.customerName, amountInCents, paymentMethod: method, items }));
        await sync();
      }
    } catch (error) {
      console.log(`  ${(error as Error).message}`);
    }
  }
  rl.close();
}

main().catch((error) => {
  console.error(error.message ?? error);
  process.exitCode = 1;
});