import { describe, test, expect, beforeEach, vi } from 'vitest'
import { OperationTracker } from '../../src/utils/operationTracker'

// Mock uuid
vi.mock('uuid', () => ({
  v4: vi.fn(() => 'mock-uuid-123')
}))

describe('OperationTracker', () => {
  let tracker: OperationTracker

  beforeEach(() => {
    tracker = new OperationTracker()
    vi.clearAllMocks()
  })

  describe('generateOperationId', () => {
    test('generates unique operation IDs', () => {
      const id1 = tracker.generateOperationId()
      const id2 = tracker.generateOperationId()
      
      expect(id1).toBe('mock-uuid-123')
      expect(id2).toBe('mock-uuid-123') // Same because mock always returns same value
      
      // In real implementation, these would be different
      expect(id1).toBeTruthy()
      expect(id2).toBeTruthy()
    })

    test('returns string IDs', () => {
      const id = tracker.generateOperationId()
      expect(typeof id).toBe('string')
    })
  })

  describe('addOperation', () => {
    test('adds operation to tracking set', () => {
      const operationId = 'test-op-1'
      tracker.addOperation(operationId)
      
      expect(tracker.isOwnOperation(operationId)).toBe(true)
    })

    test('handles multiple operations', () => {
      tracker.addOperation('op-1')
      tracker.addOperation('op-2')
      tracker.addOperation('op-3')
      
      expect(tracker.isOwnOperation('op-1')).toBe(true)
      expect(tracker.isOwnOperation('op-2')).toBe(true)
      expect(tracker.isOwnOperation('op-3')).toBe(true)
    })

    test('handles duplicate operations gracefully', () => {
      const operationId = 'duplicate-op'
      
      tracker.addOperation(operationId)
      tracker.addOperation(operationId) // Add same ID again
      
      expect(tracker.isOwnOperation(operationId)).toBe(true)
    })
  })

  describe('removeOperation', () => {
    test('removes operation from tracking', () => {
      const operationId = 'temp-op'
      
      tracker.addOperation(operationId)
      expect(tracker.isOwnOperation(operationId)).toBe(true)
      
      tracker.removeOperation(operationId)
      expect(tracker.isOwnOperation(operationId)).toBe(false)
    })

    test('handles removing non-existent operation', () => {
      // Should not throw error
      expect(() => {
        tracker.removeOperation('non-existent')
      }).not.toThrow()
    })

    test('removes only specified operation', () => {
      tracker.addOperation('op-1')
      tracker.addOperation('op-2')
      tracker.addOperation('op-3')
      
      tracker.removeOperation('op-2')
      
      expect(tracker.isOwnOperation('op-1')).toBe(true)
      expect(tracker.isOwnOperation('op-2')).toBe(false)
      expect(tracker.isOwnOperation('op-3')).toBe(true)
    })
  })

  describe('isOwnOperation', () => {
    test('returns true for tracked operations', () => {
      const operationId = 'tracked-op'
      tracker.addOperation(operationId)
      
      expect(tracker.isOwnOperation(operationId)).toBe(true)
    })

    test('returns false for untracked operations', () => {
      expect(tracker.isOwnOperation('untracked-op')).toBe(false)
    })

    test('returns false after operation is removed', () => {
      const operationId = 'temp-op'
      
      tracker.addOperation(operationId)
      tracker.removeOperation(operationId)
      
      expect(tracker.isOwnOperation(operationId)).toBe(false)
    })
  })

  describe('clear', () => {
    test('removes all tracked operations', () => {
      tracker.addOperation('op-1')
      tracker.addOperation('op-2')
      tracker.addOperation('op-3')
      
      tracker.clear()
      
      expect(tracker.isOwnOperation('op-1')).toBe(false)
      expect(tracker.isOwnOperation('op-2')).toBe(false)
      expect(tracker.isOwnOperation('op-3')).toBe(false)
    })

    test('works with empty tracker', () => {
      expect(() => tracker.clear()).not.toThrow()
    })
  })

  describe('echo suppression scenarios', () => {
    test('prevents processing own operations', () => {
      const operationId = tracker.generateOperationId()
      tracker.addOperation(operationId)
      
      // Simulate receiving an event with our operation ID
      const event = { operationId, data: 'some data' }
      
      // Should identify as own operation (skip processing)
      if (tracker.isOwnOperation(event.operationId)) {
        // Skip processing
        expect(true).toBe(true) // Operation should be skipped
      } else {
        // Process event
        expect(false).toBe(true) // Should not reach here
      }
    })

    test('allows processing external operations', () => {
      const externalOpId = 'external-op-123'
      
      // Simulate receiving an event from another client
      const event = { operationId: externalOpId, data: 'external data' }
      
      // Should not identify as own operation
      if (!tracker.isOwnOperation(event.operationId)) {
        // Process event
        expect(true).toBe(true) // Operation should be processed
      } else {
        // Skip processing
        expect(false).toBe(true) // Should not reach here
      }
    })
  })

  describe('cleanup patterns', () => {
    test('supports operation cleanup after completion', () => {
      const operationId = tracker.generateOperationId()
      tracker.addOperation(operationId)
      
      // Simulate operation completion
      setTimeout(() => {
        tracker.removeOperation(operationId)
      }, 100)
      
      // Initially tracked
      expect(tracker.isOwnOperation(operationId)).toBe(true)
      
      // After cleanup (would be false after timeout)
      // Note: In real tests, would use fake timers or promises
    })

    test('handles batch cleanup', () => {
      const operations = ['op-1', 'op-2', 'op-3', 'op-4', 'op-5']
      
      // Add all operations
      operations.forEach(op => tracker.addOperation(op))
      
      // Remove specific operations
      tracker.removeOperation('op-2')
      tracker.removeOperation('op-4')
      
      expect(tracker.isOwnOperation('op-1')).toBe(true)
      expect(tracker.isOwnOperation('op-2')).toBe(false)
      expect(tracker.isOwnOperation('op-3')).toBe(true)
      expect(tracker.isOwnOperation('op-4')).toBe(false)
      expect(tracker.isOwnOperation('op-5')).toBe(true)
    })
  })

  describe('memory management', () => {
    test('does not accumulate unlimited operations', () => {
      // Add many operations
      for (let i = 0; i < 1000; i++) {
        tracker.addOperation(`op-${i}`)
      }
      
      // Clear to prevent memory leaks
      tracker.clear()
      
      // Verify all cleared
      expect(tracker.isOwnOperation('op-0')).toBe(false)
      expect(tracker.isOwnOperation('op-999')).toBe(false)
    })

    test('supports operation TTL pattern', () => {
      // This test demonstrates a pattern for auto-cleanup
      const operationWithTTL = (id: string, ttlMs: number) => {
        tracker.addOperation(id)
        
        setTimeout(() => {
          tracker.removeOperation(id)
        }, ttlMs)
      }
      
      const opId = 'ttl-op'
      operationWithTTL(opId, 5000) // 5 second TTL
      
      // Initially tracked
      expect(tracker.isOwnOperation(opId)).toBe(true)
      // Would be removed after TTL expires
    })
  })
})