/**
 * Concurrency / RMW safety — temp SQLite only.
 * Run: npm run test:concurrency
 */
import assert from 'node:assert/strict'
import { mkdtempSync, rmSync } from 'node:fs'
import { tmpdir } from 'node:os'
import { join } from 'node:path'
import { ValidationPipe } from '@nestjs/common'
import { Test } from '@nestjs/testing'
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify'
import { ApiExceptionFilter } from '../src/common/filters/api-exception.filter'
import { DatabaseService } from '../src/database/database.service'
import { getGradableQuestions } from '../src/gold-land/lessons/lesson.grader'
import { loadLessonForLevel } from '../src/gold-land/lessons/lesson.loader'
import { createDefaultUserState } from '../src/shared/catalog/default-user-state'

const testDir = mkdtempSync(join(tmpdir(), 'gold-land-concurrency-'))
process.env.DB_PATH = join(testDir, 'test.db')
process.env.NODE_ENV = 'test'
process.env.PORT = '3997'
process.env.JWT_SECRET = 'gold-land-dev-secret-change-in-production'

function parseJson<T>(payload: string): T {
  return JSON.parse(payload) as T
}

function authHeader(token: string) {
  return { authorization: `Bearer ${token}` }
}

async function createApp(): Promise<NestFastifyApplication> {
  const { AppModule } = await import('../src/app.module')
  const moduleRef = await Test.createTestingModule({ imports: [AppModule] }).compile()
  const app = moduleRef.createNestApplication<NestFastifyApplication>(new FastifyAdapter())
  app.useGlobalPipes(
    new ValidationPipe({ transform: true, whitelist: true, forbidNonWhitelisted: true }),
  )
  app.useGlobalFilters(new ApiExceptionFilter())
  await app.init()
  await app.getHttpAdapter().getInstance().ready()
  return app
}

async function registerUser(app: NestFastifyApplication, username: string): Promise<string> {
  const res = await app.inject({
    method: 'POST',
    url: '/api/auth/register',
    payload: { username, password: '123456', name: username },
  })
  assert.ok(res.statusCode === 200 || res.statusCode === 201, `register status ${res.statusCode}`)
  return parseJson<{ token: string }>(res.payload).token
}

function setUserCoins(db: DatabaseService, userId: string, coins: number) {
  const row = db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as
    | { state_json: string }
    | undefined
  assert.ok(row)
  const state = JSON.parse(row.state_json) as ReturnType<typeof createDefaultUserState>
  state.coins = coins
  db.getDb()
    .prepare('UPDATE users SET state_json = ?, updated_at = ? WHERE id = ?')
    .run(JSON.stringify(state), new Date().toISOString(), userId)
}

function setUserCash(db: DatabaseService, userId: string, cash: number, goldGrams = 0) {
  const row = db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as
    | { state_json: string }
    | undefined
  assert.ok(row)
  const state = JSON.parse(row.state_json) as ReturnType<typeof createDefaultUserState>
  state.cash = cash
  state.goldGrams = goldGrams
  db.getDb()
    .prepare('UPDATE users SET state_json = ?, updated_at = ? WHERE id = ?')
    .run(JSON.stringify(state), new Date().toISOString(), userId)
}

function readCoins(db: DatabaseService, userId: string): number {
  const row = db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as {
    state_json: string
  }
  return (JSON.parse(row.state_json) as { coins: number }).coins
}

function countLedger(db: DatabaseService, userId: string, rewardKey: string): number {
  const row = db
    .getDb()
    .prepare('SELECT COUNT(*) AS c FROM reward_ledger WHERE user_id = ? AND reward_key = ?')
    .get(userId, rewardKey) as { c: number }
  return row.c
}

async function runTests() {
  const app = await createApp()
  const db = app.get(DatabaseService)

  try {
    // --- parallel store purchases: combined cost exceeds balance ---
    {
      const token = await registerUser(app, `store-race-${Date.now()}`)
      const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const userId = parseJson<{ user: { id: string } }>(me.payload).user.id
      setUserCoins(db, userId, 6000)

      const [castle, crown] = await Promise.all([
        app.inject({
          method: 'POST',
          url: '/api/store/purchases',
          headers: authHeader(token),
          payload: { productId: 'castle' },
        }),
        app.inject({
          method: 'POST',
          url: '/api/store/purchases',
          headers: authHeader(token),
          payload: { productId: 'crown' },
        }),
      ])

      const okCount = [castle, crown].filter((r) => r.statusCode === 200).length
      const failCount = [castle, crown].filter((r) => r.statusCode >= 400).length
      assert.equal(okCount, 1)
      assert.equal(failCount, 1)
      const finalCoins = readCoins(db, userId)
      assert.ok(finalCoins >= 0)
      assert.ok(finalCoins < 6000)
    }

    // --- parallel lesson completes: first-completion ledger once ---
    {
      const token = await registerUser(app, `lesson-race-${Date.now()}`)
      const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const userId = parseJson<{ user: { id: string } }>(me.payload).user.id

      await app.inject({
        method: 'POST',
        url: '/api/gold-land/levels/1/start',
        headers: authHeader(token),
      })

      const lesson = loadLessonForLevel('what-is-money')
      assert.ok(lesson)
      const answers = getGradableQuestions(lesson).map(({ questionId, step }) => {
        if (step.type === 'sort') {
          return { questionId, orderedItemIds: [...step.correctOrder] }
        }
        return { questionId, answerId: step.correctAnswerId }
      })
      const payload = JSON.stringify({ answers, durationMs: 3000 })

      const [a, b] = await Promise.all([
        app.inject({
          method: 'POST',
          url: '/api/gold-land/levels/1/complete',
          headers: { ...authHeader(token), 'content-type': 'application/json' },
          payload,
        }),
        app.inject({
          method: 'POST',
          url: '/api/gold-land/levels/1/complete',
          headers: { ...authHeader(token), 'content-type': 'application/json' },
          payload,
        }),
      ])

      assert.ok(a.statusCode === 200 || b.statusCode === 200)
      assert.equal(countLedger(db, userId, 'level:1:first-completion'), 1)
    }

    // --- parallel daily challenge completes ---
    {
      const token = await registerUser(app, `challenge-race-${Date.now()}`)
      const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const userId = parseJson<{ user: { id: string } }>(me.payload).user.id
      const coinsBefore = readCoins(db, userId)

      const [a, b] = await Promise.all([
        app.inject({
          method: 'POST',
          url: '/api/challenges/daily/complete',
          headers: authHeader(token),
          payload: { optionId: 'gold' },
        }),
        app.inject({
          method: 'POST',
          url: '/api/challenges/daily/complete',
          headers: authHeader(token),
          payload: { optionId: 'gold' },
        }),
      ])

      assert.equal(a.statusCode, 200)
      assert.equal(b.statusCode, 200)
      const coinsAfter = readCoins(db, userId)
      assert.equal(coinsAfter, coinsBefore + 50)
    }

    // --- parallel gold buys: only one should succeed when cash fits one ---
    {
      const token = await registerUser(app, `wallet-race-${Date.now()}`)
      const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const userId = parseJson<{ user: { id: string } }>(me.payload).user.id
      const { GOLD_PRICE } = await import('../src/shared/catalog/market.constants')
      setUserCash(db, userId, GOLD_PRICE * 2, 0)

      const [buy1, buy2] = await Promise.all([
        app.inject({
          method: 'POST',
          url: '/api/wallet/gold/buy',
          headers: authHeader(token),
          payload: { grams: 2 },
        }),
        app.inject({
          method: 'POST',
          url: '/api/wallet/gold/buy',
          headers: authHeader(token),
          payload: { grams: 2 },
        }),
      ])

      const results = [buy1, buy2]
      const ok = results.filter((r) => r.statusCode === 200).length
      const bad = results.filter((r) => r.statusCode >= 400).length
      assert.equal(ok, 1)
      assert.equal(bad, 1)
      const state = JSON.parse(
        (db.getDb().prepare('SELECT state_json FROM users WHERE id = ?').get(userId) as {
          state_json: string
        }).state_json,
      ) as { cash: number; goldGrams: number }
      assert.ok(state.cash >= 0)
      assert.equal(state.goldGrams, 2)
      assert.ok(state.cash < GOLD_PRICE * 2)
    }

    // --- parallel game complete: first-completion reward once ---
    {
      const token = await registerUser(app, `game-race-${Date.now()}`)
      const me = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const userId = parseJson<{ user: { id: string; coins: number; xp: number } }>(me.payload).user
      const coinsBefore = userId.coins
      const xpBefore = userId.xp

      const [g1, g2] = await Promise.all([
        app.inject({
          method: 'POST',
          url: '/api/games/gold-guess/complete',
          headers: authHeader(token),
          payload: {},
        }),
        app.inject({
          method: 'POST',
          url: '/api/games/gold-guess/complete',
          headers: authHeader(token),
          payload: {},
        }),
      ])

      assert.equal(g1.statusCode, 200)
      assert.equal(g2.statusCode, 200)
      const after = await app.inject({ method: 'GET', url: '/api/me', headers: authHeader(token) })
      const body = parseJson<{ user: { coins: number; xp: number } }>(after.payload)
      assert.equal(body.user.coins, coinsBefore + 20)
      assert.equal(body.user.xp, xpBefore + 50)
    }

    // Level 7 stays locked until level 6 has a star. Inactive level 8 is covered in budgeting tests.
    {
      const token = await registerUser(app, `locked7-${Date.now()}`)
      const res = await app.inject({
        method: 'POST',
        url: '/api/gold-land/levels/7/start',
        headers: authHeader(token),
      })
      assert.equal(res.statusCode, 403)
    }

    console.log('concurrency tests passed')
  } finally {
    await app.close()
    try {
      rmSync(testDir, { recursive: true, force: true })
    } catch {
      // ignore
    }
  }
}

runTests().catch((error) => {
  console.error(error)
  process.exit(1)
})