/**
 * Budget Planner integration tests.
 * Covers BUDGET-001 to BUDGET-010.
 */
import { buildApp } from '../../src/bootstrap';
import { db as testDb } from '../../src/db/database';
import { AppSettings } from '../../src/db/entities/AppSettings.entity';
import { BudgetItems } from '../../src/db/entities/BudgetItems.entity';
import { Reservations } from '../../src/db/entities/Reservations.entity';
import { authCookie } from '../helpers/auth';
import { createUser, createTrip, createBudgetItem, addTripMember, createReservation } from '../helpers/factories';
import { deleteRows, findRow, insertRow } from '../helpers/factories/rows';
import { setAppSetting } from '../helpers/factories/settings';
import { resetTestDb, resetRateLimits } from '../helpers/test-db';
import { MikroORM } from '@mikro-orm/core';
import type { INestApplication } from '@nestjs/common';

import type { Application } from 'express';
import request from 'supertest';
import { describe, it, expect, vi, beforeAll, beforeEach, afterAll } from 'vitest';

vi.mock('../../src/db/database', async () => {
  const { createSnapshotTestDb, buildDbMock } = await import('../helpers/db-mock');
  return buildDbMock(createSnapshotTestDb());
});

let nestApp: INestApplication;
let app: Application;
let orm: MikroORM;

beforeAll(async () => {
  nestApp = await buildApp();
  app = nestApp.getHttpAdapter().getInstance();
  orm = nestApp.get(MikroORM);
});

/** A hotel expense linked to the booking. */
function seedBookedExpense(tripId: number, reservationId: number, totalPrice: number): Promise<number> {
  return insertRow(orm, BudgetItems, {
    trip: tripId,
    name: 'Hotel Cost',
    category: 'Accommodation',
    total_price: totalPrice,
    reservation: reservationId,
  });
}

beforeEach(async () => {
  resetTestDb(testDb);
  await resetRateLimits(nestApp);
  // GET /budget/settlement reaches ExchangeRatesService.getRates unconditionally
  // (budget.service.ts settlement()), and that is a real fetch to
  // api.frankfurter.dev with a 10 s abort. Without this stub the suite talks to
  // the internet: slow, offline-dependent, and it makes the run take minutes
  // longer on a machine that cannot reach it. Fail closed — every assertion here
  // is single-currency, so rates never enter the arithmetic.
  vi.stubGlobal(
    'fetch',
    vi.fn(async () => {
      throw new Error('offline');
    }),
  );
});

afterAll(async () => {
  vi.unstubAllGlobals();
  await nestApp.close();
  testDb.close();
});

// ─────────────────────────────────────────────────────────────────────────────
// Create budget item
// ─────────────────────────────────────────────────────────────────────────────

describe('Create budget item', () => {
  it('BUDGET-001 — POST creates budget item', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);

    const res = await request(app)
      .post(`/api/trips/${trip.id}/budget`)
      .set('Cookie', authCookie(user.id))
      .send({ name: 'Flights', category: 'Transport', total_price: 500, currency: 'EUR' });
    expect(res.status).toBe(201);
    expect(res.body.item.name).toBe('Flights');
    expect(res.body.item.total_price).toBe(500);
  });

  it('BUDGET-001 — POST without name returns 400', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);

    const res = await request(app)
      .post(`/api/trips/${trip.id}/budget`)
      .set('Cookie', authCookie(user.id))
      .send({ category: 'Transport', total_price: 200 });
    expect(res.status).toBe(400);
  });

  it('BUDGET-010 — non-member cannot create budget item', async () => {
    const { user: owner } = createUser(testDb);
    const { user: other } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);

    const res = await request(app)
      .post(`/api/trips/${trip.id}/budget`)
      .set('Cookie', authCookie(other.id))
      .send({ name: 'Hotels', total_price: 300 });
    expect(res.status).toBe(404);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// List budget items
// ─────────────────────────────────────────────────────────────────────────────

describe('List budget items', () => {
  it('BUDGET-002 — GET /api/trips/:tripId/budget returns all items', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    createBudgetItem(testDb, trip.id, { name: 'Flight', total_price: 300 });
    createBudgetItem(testDb, trip.id, { name: 'Hotel', total_price: 500 });

    const res = await request(app).get(`/api/trips/${trip.id}/budget`).set('Cookie', authCookie(user.id));
    expect(res.status).toBe(200);
    expect(res.body.items).toHaveLength(2);
  });

  it('BUDGET-002 — member can list budget items', async () => {
    const { user: owner } = createUser(testDb);
    const { user: member } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);
    addTripMember(testDb, trip.id, member.id);
    createBudgetItem(testDb, trip.id, { name: 'Rental', total_price: 200 });

    const res = await request(app).get(`/api/trips/${trip.id}/budget`).set('Cookie', authCookie(member.id));
    expect(res.status).toBe(200);
    expect(res.body.items).toHaveLength(1);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Update budget item
// ─────────────────────────────────────────────────────────────────────────────

describe('Update budget item', () => {
  it('BUDGET-003 — PUT updates budget item fields', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id, { name: 'Old Name', total_price: 100 });

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}`)
      .set('Cookie', authCookie(user.id))
      .send({ name: 'New Name', total_price: 250 });
    expect(res.status).toBe(200);
    expect(res.body.item.name).toBe('New Name');
    expect(res.body.item.total_price).toBe(250);
  });

  it('BUDGET-003 — PUT non-existent item returns 404', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/99999`)
      .set('Cookie', authCookie(user.id))
      .send({ name: 'Updated' });
    expect(res.status).toBe(404);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Delete budget item
// ─────────────────────────────────────────────────────────────────────────────

describe('Delete budget item', () => {
  it('BUDGET-004 — DELETE removes item', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id);

    const del = await request(app).delete(`/api/trips/${trip.id}/budget/${item.id}`).set('Cookie', authCookie(user.id));
    expect(del.status).toBe(200);
    expect(del.body.success).toBe(true);

    const list = await request(app).get(`/api/trips/${trip.id}/budget`).set('Cookie', authCookie(user.id));
    expect(list.body.items).toHaveLength(0);
  });

  it('BUDGET-004b — DELETE budget item does NOT delete its linked reservation', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const reservation = createReservation(testDb, trip.id, { title: 'Hotel Booking', type: 'hotel' });

    const itemId = await seedBookedExpense(trip.id, reservation.id, 250);

    const del = await request(app).delete(`/api/trips/${trip.id}/budget/${itemId}`).set('Cookie', authCookie(user.id));
    expect(del.status).toBe(200);

    const reservationAfter = await findRow(orm, Reservations, { id: reservation.id });
    expect(reservationAfter).not.toBeNull();
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Members
// ─────────────────────────────────────────────────────────────────────────────

describe('Budget item members', () => {
  it('BUDGET-005 — PUT /members assigns members to budget item', async () => {
    const { user } = createUser(testDb);
    const { user: member } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    addTripMember(testDb, trip.id, member.id);
    const item = createBudgetItem(testDb, trip.id);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [user.id, member.id] });
    expect(res.status).toBe(200);
    expect(res.body.members).toBeDefined();

    // After assigning members, list items should include them (covers loadBudgetItems member loop)
    const listRes = await request(app).get(`/api/trips/${trip.id}/budget`).set('Cookie', authCookie(user.id));
    expect(listRes.status).toBe(200);
    const foundItem = (listRes.body.items as any[]).find((i: any) => i.id === item.id);
    expect(foundItem).toBeDefined();
    expect(foundItem.members).toHaveLength(2);
  });

  it('BUDGET-005b — PUT /members with empty user_ids clears members', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id);

    // First assign a member
    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [user.id] });

    // Then clear members with empty array
    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [] });
    expect(res.status).toBe(200);
    expect(res.body.members).toHaveLength(0);
  });

  it('BUDGET-005 — PUT /members with non-array user_ids returns 400', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: 'not-an-array' });
    expect(res.status).toBe(400);
  });

  it('BUDGET-006 — PUT /members/:userId/paid toggles paid status', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id);

    // Assign user as member first
    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [user.id] });

    // Toggle to paid=true
    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members/${user.id}/paid`)
      .set('Cookie', authCookie(user.id))
      .send({ paid: true });
    expect(res.status).toBe(200);
    expect(res.body.member).toBeDefined();
    expect(res.body.member.paid).toBe(1); // SQLite stores as integer

    // Toggle back to paid=false
    const res2 = await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members/${user.id}/paid`)
      .set('Cookie', authCookie(user.id))
      .send({ paid: false });
    expect(res2.status).toBe(200);
    expect(res2.body.member.paid).toBe(0);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Summary & Settlement
// ─────────────────────────────────────────────────────────────────────────────

describe('Budget summary and settlement', () => {
  it('BUDGET-007 — GET /summary/per-person returns per-person breakdown', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item = createBudgetItem(testDb, trip.id, { name: 'Dinner', total_price: 60 });

    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [user.id] });
    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members/${user.id}/paid`)
      .set('Cookie', authCookie(user.id))
      .send({ paid: true });

    const res = await request(app)
      .get(`/api/trips/${trip.id}/budget/summary/per-person`)
      .set('Cookie', authCookie(user.id));
    expect(res.status).toBe(200);
    expect(res.body.summary).toHaveLength(1);
    const entry = res.body.summary[0];
    expect(entry.user_id).toBe(user.id);
    expect(typeof entry.total_paid).toBe('number');
    expect(entry.total_paid).toBeGreaterThan(0);
  });

  it('BUDGET-008 — GET /settlement returns settlement transactions', async () => {
    const { user } = createUser(testDb);
    const { user: user2 } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    addTripMember(testDb, trip.id, user2.id);
    const item = createBudgetItem(testDb, trip.id, { name: 'Dinner', total_price: 60 });

    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/members`)
      .set('Cookie', authCookie(user.id))
      .send({ user_ids: [user.id, user2.id] });
    // New model: who actually paid is recorded as an explicit payer (amount in
    // the expense currency), not a per-member "paid" toggle.
    await request(app)
      .put(`/api/trips/${trip.id}/budget/${item.id}/payers`)
      .set('Cookie', authCookie(user.id))
      .send({ payers: [{ user_id: user.id, amount: 60 }] });

    const res = await request(app).get(`/api/trips/${trip.id}/budget/settlement`).set('Cookie', authCookie(user.id));
    expect(res.status).toBe(200);
    expect(Array.isArray(res.body.balances)).toBe(true);
    expect(Array.isArray(res.body.flows)).toBe(true);

    const payerBalance = res.body.balances.find((b: any) => b.user_id === user.id);
    const nonPayerBalance = res.body.balances.find((b: any) => b.user_id === user2.id);
    expect(payerBalance.balance).toBeCloseTo(30);
    expect(nonPayerBalance.balance).toBeCloseTo(-30);

    expect(res.body.flows).toHaveLength(1);
    expect(res.body.flows[0].from.user_id).toBe(user2.id);
    expect(res.body.flows[0].to.user_id).toBe(user.id);
    expect(res.body.flows[0].amount).toBeCloseTo(30);
  });

  it('BUDGET-009 — settlement with no payers returns empty transactions', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    createBudgetItem(testDb, trip.id, { name: 'Train', total_price: 40 });

    const res = await request(app).get(`/api/trips/${trip.id}/budget/settlement`).set('Cookie', authCookie(user.id));
    expect(res.status).toBe(200);
    expect(res.body.balances).toEqual([]);
    expect(res.body.flows).toEqual([]);
    // Additive since the VND/AUD report: what the amounts are in, and what was left out.
    expect(res.body.currency).toBe('EUR');
    expect(res.body.unconverted).toEqual({ item_ids: [], settlement_ids: [], currencies: [] });
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Reorder items
// ─────────────────────────────────────────────────────────────────────────────

describe('Reorder budget items', () => {
  it('BUDGET-011 — non-member gets 404 on PUT /reorder/items', async () => {
    const { user: owner } = createUser(testDb);
    const { user: other } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);
    const item = createBudgetItem(testDb, trip.id);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/items`)
      .set('Cookie', authCookie(other.id))
      .send({ orderedIds: [item.id] });
    expect(res.status).toBe(404);
  });

  it('BUDGET-012 — member without permission gets 403 on PUT /reorder/items', async () => {
    const { user: owner } = createUser(testDb);
    const { user: member } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);
    addTripMember(testDb, trip.id, member.id);
    const item = createBudgetItem(testDb, trip.id);

    // Restrict budget_edit to trip_owner only
    await setAppSetting(orm, 'perm_budget_edit', 'trip_owner');
    const { invalidatePermissionsCache } = await import('../../src/nest/permissions/permissions-cache');
    await invalidatePermissionsCache();

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/items`)
      .set('Cookie', authCookie(member.id))
      .send({ orderedIds: [item.id] });
    expect(res.status).toBe(403);

    // Restore default
    await deleteRows(orm, AppSettings, { key: 'perm_budget_edit' });
    await invalidatePermissionsCache();
  });

  it('BUDGET-013 — owner can reorder budget items — returns 200', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const item1 = createBudgetItem(testDb, trip.id, { name: 'First' });
    const item2 = createBudgetItem(testDb, trip.id, { name: 'Second' });

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/items`)
      .set('Cookie', authCookie(user.id))
      .send({ orderedIds: [item2.id, item1.id] });
    expect(res.status).toBe(200);
    expect(res.body.success).toBe(true);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Reorder categories
// ─────────────────────────────────────────────────────────────────────────────

describe('Reorder budget categories', () => {
  it('BUDGET-014 — non-member gets 404 on PUT /reorder/categories', async () => {
    const { user: owner } = createUser(testDb);
    const { user: other } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/categories`)
      .set('Cookie', authCookie(other.id))
      .send({ orderedCategories: ['Transport'] });
    expect(res.status).toBe(404);
  });

  it('BUDGET-015 — owner can reorder categories — returns 200', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    createBudgetItem(testDb, trip.id, { name: 'Flight', category: 'Transport' });
    createBudgetItem(testDb, trip.id, { name: 'Hotel', category: 'Accommodation' });

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/categories`)
      .set('Cookie', authCookie(user.id))
      .send({ orderedCategories: ['Accommodation', 'Transport'] });
    expect(res.status).toBe(200);
    expect(res.body.success).toBe(true);
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Reservation price sync
// ─────────────────────────────────────────────────────────────────────────────

describe('Reservation price sync on budget item update', () => {
  it('BUDGET-016 — updating total_price syncs to linked reservation metadata', async () => {
    const { user } = createUser(testDb);
    const trip = createTrip(testDb, user.id);
    const reservation = createReservation(testDb, trip.id, { title: 'Hotel Booking', type: 'hotel' });

    // Create a budget item linked to the reservation
    const itemId = await seedBookedExpense(trip.id, reservation.id, 200);

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/${itemId}`)
      .set('Cookie', authCookie(user.id))
      .send({ total_price: 350 });
    expect(res.status).toBe(200);
    expect(res.body.item.total_price).toBe(350);

    // Verify reservation metadata was synced
    const updatedReservation = await findRow(orm, Reservations, { id: reservation.id });
    expect(updatedReservation).not.toBeNull();
    const meta = JSON.parse(updatedReservation!.metadata || '{}');
    expect(meta.price).toBe('350');
  });
});

// ─────────────────────────────────────────────────────────────────────────────
// Permission check — non-owner member trying to edit (when locked to trip_owner)
// ─────────────────────────────────────────────────────────────────────────────

describe('Budget edit permission enforcement', () => {
  it('BUDGET-017 — member cannot create item when budget_edit is restricted to trip_owner', async () => {
    const { user: owner } = createUser(testDb);
    const { user: member } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);
    addTripMember(testDb, trip.id, member.id);

    const { invalidatePermissionsCache } = await import('../../src/nest/permissions/permissions-cache');
    await setAppSetting(orm, 'perm_budget_edit', 'trip_owner');
    await invalidatePermissionsCache();

    const res = await request(app)
      .post(`/api/trips/${trip.id}/budget`)
      .set('Cookie', authCookie(member.id))
      .send({ name: 'Sneaky Expense', total_price: 100 });
    expect(res.status).toBe(403);

    await deleteRows(orm, AppSettings, { key: 'perm_budget_edit' });
    await invalidatePermissionsCache();
  });

  it('BUDGET-018 — member cannot reorder categories when budget_edit is restricted to trip_owner', async () => {
    const { user: owner } = createUser(testDb);
    const { user: member } = createUser(testDb);
    const trip = createTrip(testDb, owner.id);
    addTripMember(testDb, trip.id, member.id);
    createBudgetItem(testDb, trip.id, { name: 'Item', category: 'Transport' });

    const { invalidatePermissionsCache } = await import('../../src/nest/permissions/permissions-cache');
    await setAppSetting(orm, 'perm_budget_edit', 'trip_owner');
    await invalidatePermissionsCache();

    const res = await request(app)
      .put(`/api/trips/${trip.id}/budget/reorder/categories`)
      .set('Cookie', authCookie(member.id))
      .send({ orderedCategories: ['Transport'] });
    expect(res.status).toBe(403);

    await deleteRows(orm, AppSettings, { key: 'perm_budget_edit' });
    await invalidatePermissionsCache();
  });
});