/**
 * Contract Test for HedgingAccountPool Interface
 *
 * Tests the hedging account pool functionality following TDD principles.
 * These tests MUST fail initially and pass after implementation.
 */

import { HedgingAccountPool, LoadBalanceStrategy, AccountSelectionCriteria } from '@/core/credential-manager/HedgingAccountPool'
import { Platform } from '@/types/credential'

describe('HedgingAccountPool Contract Test', () => {
  let pool: HedgingAccountPool

  beforeEach(() => {
    const config = {
      platforms: {
        [Platform.PACIFICA]: {
          enabled: true,
          primaryAccounts: ['pac-1', 'pac-2'],
          backupAccounts: ['pac-backup-1'],
          loadBalanceStrategy: LoadBalanceStrategy.ROUND_ROBIN,
          healthCheckInterval: 30000,
          failoverThreshold: 3
        },
        [Platform.ASTER]: {
          enabled: true,
          primaryAccounts: ['ast-1', 'ast-2'],
          backupAccounts: ['ast-backup-1'],
          loadBalanceStrategy: LoadBalanceStrategy.WEIGHTED,
          healthCheckInterval: 30000,
          failoverThreshold: 3
        },
        [Platform.BINANCE]: {
          enabled: false,
          primaryAccounts: [],
          backupAccounts: [],
          loadBalanceStrategy: LoadBalanceStrategy.RANDOM,
          healthCheckInterval: 30000,
          failoverThreshold: 3
        }
      },
      hedging: {
        enableCrossplatformBalancing: true,
        maxAccountsPerPlatform: 10,
        reservationTimeoutMs: 60000
      }
    }

    pool = new HedgingAccountPool(config)
  })

  describe('Account Selection', () => {
    test('should select primary account by default', async () => {
      const selection = await pool.selectAccount(Platform.PACIFICA)

      expect(selection).toBeDefined()
      expect(selection.accountId).toMatch(/^pac-[12]$/)
      expect(selection.platform).toBe(Platform.PACIFICA)
      expect(selection.isPrimary).toBe(true)
    })

    test('should respect load balancing strategy', async () => {
      const selections = []

      // Make multiple selections to test round-robin
      for (let i = 0; i < 4; i++) {
        const selection = await pool.selectAccount(Platform.PACIFICA)
        selections.push(selection.accountId)
      }

      // With round-robin, should cycle through accounts
      expect(selections).toContain('pac-1')
      expect(selections).toContain('pac-2')
    })

    test('should handle account selection criteria', async () => {
      const criteria: AccountSelectionCriteria = {
        preferPrimary: false,
        excludeAccounts: ['pac-1'],
        minBalance: 1000,
        riskTolerance: 'low'
      }

      const selection = await pool.selectAccount(Platform.PACIFICA, criteria)

      expect(selection.accountId).not.toBe('pac-1')
    })

    test('should failover to backup accounts when primary unavailable', async () => {
      // Mark primary accounts as failed
      pool.markAccountFailed('pac-1', new Error('Primary account failed'))
      pool.markAccountFailed('pac-2', new Error('Primary account failed'))

      const selection = await pool.selectAccount(Platform.PACIFICA)

      expect(selection.accountId).toBe('pac-backup-1')
      expect(selection.isPrimary).toBe(false)
    })

    test('should throw error when no accounts available', async () => {
      await expect(pool.selectAccount(Platform.BINANCE))
        .rejects.toThrow('No available accounts for platform BINANCE')
    })
  })

  describe('Multiple Account Selection', () => {
    test('should select multiple accounts for hedging', async () => {
      const accounts = await pool.selectMultipleAccounts(Platform.PACIFICA, 2)

      expect(accounts).toHaveLength(2)
      expect(accounts[0].platform).toBe(Platform.PACIFICA)
      expect(accounts[1].platform).toBe(Platform.PACIFICA)
      expect(accounts[0].accountId).not.toBe(accounts[1].accountId)
    })

    test('should respect maximum account limit', async () => {
      const accounts = await pool.selectMultipleAccounts(Platform.PACIFICA, 10)

      // Should not exceed available accounts (3 total: 2 primary + 1 backup)
      expect(accounts.length).toBeLessThanOrEqual(3)
    })

    test('should distribute across primary and backup accounts', async () => {
      const accounts = await pool.selectMultipleAccounts(Platform.PACIFICA, 3)

      const primaryAccounts = accounts.filter(a => a.isPrimary)
      const backupAccounts = accounts.filter(a => !a.isPrimary)

      expect(primaryAccounts.length).toBeGreaterThan(0)
      expect(backupAccounts.length).toBeGreaterThan(0)
    })
  })

  describe('Account Health Management', () => {
    test('should track account success', () => {
      pool.markAccountSuccess('pac-1')

      const status = pool.getAccountStatus('pac-1')
      expect(status?.isHealthy).toBe(true)
      expect(status?.consecutiveFailures).toBe(0)
    })

    test('should track account failures', () => {
      const error = new Error('Test failure')
      pool.markAccountFailed('pac-1', error)

      const status = pool.getAccountStatus('pac-1')
      expect(status?.isHealthy).toBe(false)
      expect(status?.consecutiveFailures).toBe(1)
      expect(status?.lastError).toBe(error.message)
    })

    test('should auto-disable accounts after threshold failures', () => {
      const error = new Error('Repeated failure')

      // Fail account multiple times
      for (let i = 0; i < 3; i++) {
        pool.markAccountFailed('pac-1', error)
      }

      const status = pool.getAccountStatus('pac-1')
      expect(status?.isHealthy).toBe(false)
      expect(status?.consecutiveFailures).toBe(3)
    })

    test('should recover accounts on success after failures', () => {
      const error = new Error('Temporary failure')

      pool.markAccountFailed('pac-1', error)
      pool.markAccountSuccess('pac-1')

      const status = pool.getAccountStatus('pac-1')
      expect(status?.isHealthy).toBe(true)
      expect(status?.consecutiveFailures).toBe(0)
    })
  })

  describe('Pool Status and Monitoring', () => {
    test('should provide pool status for platform', () => {
      const status = pool.getPoolStatus(Platform.PACIFICA)

      expect(status).toBeDefined()
      expect(status.platform).toBe(Platform.PACIFICA)
      expect(status.totalAccounts).toBe(3)
      expect(status.activeAccounts).toBeGreaterThan(0)
      expect(status.isEnabled).toBe(true)
    })

    test('should show disabled platforms correctly', () => {
      const status = pool.getPoolStatus(Platform.BINANCE)

      expect(status.isEnabled).toBe(false)
      expect(status.activeAccounts).toBe(0)
    })

    test('should provide comprehensive pool statistics', () => {
      const stats = pool.getPoolStatistics()

      expect(stats).toBeDefined()
      expect(stats.totalAccounts).toBeGreaterThan(0)
      expect(stats.enabledPlatforms).toContain(Platform.PACIFICA)
      expect(stats.enabledPlatforms).toContain(Platform.ASTER)
      expect(stats.enabledPlatforms).not.toContain(Platform.BINANCE)
    })
  })

  describe('Cross-Platform Balancing', () => {
    test('should balance load across platforms when enabled', async () => {
      const accounts = await pool.selectAccountsAcrossPlatforms(
        [Platform.PACIFICA, Platform.ASTER],
        4
      )

      expect(accounts.length).toBeLessThanOrEqual(4)

      const pacificaAccounts = accounts.filter(a => a.platform === Platform.PACIFICA)
      const asterAccounts = accounts.filter(a => a.platform === Platform.ASTER)

      // Should have accounts from both platforms
      expect(pacificaAccounts.length).toBeGreaterThan(0)
      expect(asterAccounts.length).toBeGreaterThan(0)
    })

    test('should respect platform capabilities', async () => {
      const accounts = await pool.selectAccountsAcrossPlatforms(
        [Platform.PACIFICA, Platform.BINANCE], // BINANCE is disabled
        2
      )

      // Should only return Pacifica accounts since Binance is disabled
      expect(accounts.every(a => a.platform === Platform.PACIFICA)).toBe(true)
    })
  })

  describe('Performance Requirements', () => {
    test('should select accounts within performance limits', async () => {
      const startTime = Date.now()

      for (let i = 0; i < 100; i++) {
        await pool.selectAccount(Platform.PACIFICA)
      }

      const duration = Date.now() - startTime

      // Should handle 100 selections within 50ms
      expect(duration).toBeLessThan(50)
    })

    test('should handle concurrent account selections efficiently', async () => {
      const startTime = Date.now()

      const promises = Array.from({ length: 50 }, () =>
        pool.selectAccount(Platform.PACIFICA)
      )

      const results = await Promise.all(promises)
      const duration = Date.now() - startTime

      expect(results).toHaveLength(50)
      expect(duration).toBeLessThan(100)
    })
  })

  describe('Load Balance Strategies', () => {
    test('should implement round-robin strategy', async () => {
      const pacificaPool = new HedgingAccountPool({
        platforms: {
          [Platform.PACIFICA]: {
            enabled: true,
            primaryAccounts: ['pac-1', 'pac-2'],
            backupAccounts: [],
            loadBalanceStrategy: LoadBalanceStrategy.ROUND_ROBIN,
            healthCheckInterval: 30000,
            failoverThreshold: 3
          }
        },
        hedging: {
          enableCrossplatformBalancing: false,
          maxAccountsPerPlatform: 10,
          reservationTimeoutMs: 60000
        }
      })

      const selections = []
      for (let i = 0; i < 4; i++) {
        const selection = await pacificaPool.selectAccount(Platform.PACIFICA)
        selections.push(selection.accountId)
      }

      // Should alternate between accounts
      expect(selections[0]).toBe('pac-1')
      expect(selections[1]).toBe('pac-2')
      expect(selections[2]).toBe('pac-1')
      expect(selections[3]).toBe('pac-2')
    })

    test('should implement weighted strategy', async () => {
      const asterPool = new HedgingAccountPool({
        platforms: {
          [Platform.ASTER]: {
            enabled: true,
            primaryAccounts: ['ast-1', 'ast-2'],
            backupAccounts: [],
            loadBalanceStrategy: LoadBalanceStrategy.WEIGHTED,
            healthCheckInterval: 30000,
            failoverThreshold: 3
          }
        },
        hedging: {
          enableCrossplatformBalancing: false,
          maxAccountsPerPlatform: 10,
          reservationTimeoutMs: 60000
        }
      })

      const selections = []
      for (let i = 0; i < 10; i++) {
        const selection = await asterPool.selectAccount(Platform.ASTER)
        selections.push(selection.accountId)
      }

      // With weighted strategy, distribution might not be perfectly even
      // but should include both accounts
      const uniqueAccounts = new Set(selections)
      expect(uniqueAccounts.size).toBeGreaterThan(1)
    })
  })

  describe('Account Reservation', () => {
    test('should reserve accounts for trading operations', async () => {
      const result = await pool.reserveAccounts(['pac-1', 'pac-2'], 30000)

      expect(result.success).toBe(true)
      expect(result.reservedAccounts).toContain('pac-1')
      expect(result.reservedAccounts).toContain('pac-2')
    })

    test('should prevent selection of reserved accounts', async () => {
      await pool.reserveAccounts(['pac-1'], 30000)

      // Should not select reserved account
      const selection = await pool.selectAccount(Platform.PACIFICA)
      expect(selection.accountId).not.toBe('pac-1')
    })

    test('should auto-release expired reservations', async () => {
      await pool.reserveAccounts(['pac-1'], 1) // 1ms reservation

      // Wait for expiration
      await new Promise(resolve => setTimeout(resolve, 10))

      // Should be able to select previously reserved account
      const selection = await pool.selectAccount(Platform.PACIFICA)
      // pac-1 might be selected again since reservation expired
    })

    test('should release accounts manually', async () => {
      await pool.reserveAccounts(['pac-1'], 30000)
      const released = await pool.releaseAccounts(['pac-1'])

      expect(released.success).toBe(true)
      expect(released.releasedAccounts).toContain('pac-1')
    })
  })

  describe('Error Handling', () => {
    test('should handle invalid platform gracefully', async () => {
      await expect(pool.selectAccount('INVALID' as Platform))
        .rejects.toThrow('Platform INVALID is not supported')
    })

    test('should handle empty account pools', async () => {
      const emptyPool = new HedgingAccountPool({
        platforms: {
          [Platform.PACIFICA]: {
            enabled: true,
            primaryAccounts: [],
            backupAccounts: [],
            loadBalanceStrategy: LoadBalanceStrategy.ROUND_ROBIN,
            healthCheckInterval: 30000,
            failoverThreshold: 3
          }
        },
        hedging: {
          enableCrossplatformBalancing: false,
          maxAccountsPerPlatform: 10,
          reservationTimeoutMs: 60000
        }
      })

      await expect(emptyPool.selectAccount(Platform.PACIFICA))
        .rejects.toThrow('No available accounts for platform PACIFICA')
    })

    test('should provide meaningful error messages', async () => {
      try {
        await pool.selectAccount(Platform.BINANCE)
      } catch (error) {
        expect(error).toBeInstanceOf(Error)
        expect((error as Error).message).toContain('BINANCE')
      }
    })
  })
})