import { describe, it, expect } from 'vitest'
import { findFailoverService } from '../src/background'
import { MonitorState, ServiceId, ServiceStatus } from '../src/types'

function makeStatus(id: ServiceId, health: ServiceStatus['health'], responseTime: number | null): ServiceStatus {
  return {
    id,
    name: id,
    url: `https://${id}.com`,
    health,
    lastChecked: Date.now(),
    responseTimeMs: responseTime,
    errorRate: 0,
    usageLimit: null,
    message: null
  }
}

describe('findFailoverService', () => {
  it('should return the fastest healthy backup', () => {
    const state: MonitorState = {
      services: {
        chatgpt: makeStatus('chatgpt', 'healthy', 100),
        claude: makeStatus('claude', 'healthy', 50),
        gemini: makeStatus('gemini', 'healthy', 200),
        grok: makeStatus('grok', 'down', null)
      },
      lastAlert: null,
      alertThreshold: 80,
      failoverEnabled: true,
      primaryService: 'chatgpt'
    }

    const result = findFailoverService(state)
    expect(result).toBe('claude')
  })

  it('should return null when no healthy backup exists', () => {
    const state: MonitorState = {
      services: {
        chatgpt: makeStatus('chatgpt', 'down', null),
        claude: makeStatus('claude', 'down', null),
        gemini: makeStatus('gemini', 'degraded', 1000),
        grok: makeStatus('grok', 'down', null)
      },
      lastAlert: null,
      alertThreshold: 80,
      failoverEnabled: true,
      primaryService: 'chatgpt'
    }

    const result = findFailoverService(state)
    expect(result).toBeNull()
  })

  it('should exclude the primary service', () => {
    const state: MonitorState = {
      services: {
        chatgpt: makeStatus('chatgpt', 'healthy', 50),
        claude: makeStatus('claude', 'healthy', 100),
        gemini: makeStatus('gemini', 'healthy', 200),
        grok: makeStatus('grok', 'healthy', 300)
      },
      lastAlert: null,
      alertThreshold: 80,
      failoverEnabled: true,
      primaryService: 'chatgpt'
    }

    const result = findFailoverService(state)
    expect(result).toBe('claude')
  })

  it('should pick gemini when claude is degraded', () => {
    const state: MonitorState = {
      services: {
        chatgpt: makeStatus('chatgpt', 'down', null),
        claude: makeStatus('claude', 'degraded', 5000),
        gemini: makeStatus('gemini', 'healthy', 150),
        grok: makeStatus('grok', 'down', null)
      },
      lastAlert: null,
      alertThreshold: 80,
      failoverEnabled: true,
      primaryService: 'chatgpt'
    }

    const result = findFailoverService(state)
    expect(result).toBe('gemini')
  })
})