import { describe, it, expect, vi, beforeEach } from 'vitest'
import { 
  listSupportedBackends, 
  getBackendDir, 
  getBackendExePath, 
  isBackendInstalled,
  downloadBackend 
} from '../backend'

// Mock the global fetch function
global.fetch = vi.fn()

describe('Backend functions', () => {
  beforeEach(() => {
    vi.clearAllMocks()
  })

  describe('listSupportedBackends', () => {
    it('should return supported backends for Windows x64', async () => {
      // Mock system info
      window.core.api.getSystemInfo = vi.fn().mockResolvedValue({
        os_type: 'windows',
        cpu: {
          arch: 'x86_64',
          extensions: ['avx', 'avx2']
        },
        gpus: []
      })

      // Mock GitHub releases
      const mockReleases = [
        {
          tag_name: 'v1.0.0',
          assets: [
            { name: 'llama-v1.0.0-bin-win-avx2-x64.tar.gz' },
            { name: 'llama-v1.0.0-bin-win-avx-x64.tar.gz' }
          ]
        }
      ]

      global.fetch = vi.fn().mockResolvedValue({
        ok: true,
        json: () => Promise.resolve(mockReleases)
      })

      const result = await listSupportedBackends()
      
      expect(result).toEqual([
        { version: 'v1.0.0', backend: 'win-avx2-x64' },
        { version: 'v1.0.0', backend: 'win-avx-x64' }
      ])
    })

    it('should return supported backends for macOS arm64', async () => {
      window.core.api.getSystemInfo = vi.fn().mockResolvedValue({
        os_type: 'macos',
        cpu: {
          arch: 'aarch64',
          extensions: []
        },
        gpus: []
      })

      const mockReleases = [
        {
          tag_name: 'v1.0.0',
          assets: [
            { name: 'llama-v1.0.0-bin-macos-arm64.tar.gz' }
          ]
        }
      ]

      global.fetch = vi.fn().mockResolvedValue({
        ok: true,
        json: () => Promise.resolve(mockReleases)
      })

      const result = await listSupportedBackends()
      
      expect(result).toEqual([
        { version: 'v1.0.0', backend: 'macos-arm64' }
      ])
    })
  })

  describe('getBackendDir', () => {
    it('should return correct backend directory path', async () => {
      const { getJanDataFolderPath, joinPath } = await import('@janhq/core')
      
      vi.mocked(getJanDataFolderPath).mockResolvedValue('/path/to/jan')
      vi.mocked(joinPath).mockResolvedValue('/path/to/jan/llamacpp/backends/v1.0.0/win-avx2-x64')

      const result = await getBackendDir('win-avx2-x64', 'v1.0.0')
      
      expect(result).toBe('/path/to/jan/llamacpp/backends/v1.0.0/win-avx2-x64')
      expect(joinPath).toHaveBeenCalledWith(['/path/to/jan', 'llamacpp', 'backends', 'v1.0.0', 'win-avx2-x64'])
    })
  })

  describe('getBackendExePath', () => {
    it('should return correct exe path for Windows', async () => {
      window.core.api.getSystemInfo = vi.fn().mockResolvedValue({
        os_type: 'windows'
      })

      const { getJanDataFolderPath, joinPath } = await import('@janhq/core')
      
      vi.mocked(getJanDataFolderPath).mockResolvedValue('/path/to/jan')
      vi.mocked(joinPath)
        .mockResolvedValueOnce('/path/to/jan/llamacpp/backends/v1.0.0/win-avx2-x64')
        .mockResolvedValueOnce('/path/to/jan/llamacpp/backends/v1.0.0/win-avx2-x64/build/bin/llama-server.exe')

      const result = await getBackendExePath('win-avx2-x64', 'v1.0.0')
      
      expect(result).toBe('/path/to/jan/llamacpp/backends/v1.0.0/win-avx2-x64/build/bin/llama-server.exe')
    })

    it('should return correct exe path for Linux/macOS', async () => {
      window.core.api.getSystemInfo = vi.fn().mockResolvedValue({
        os_type: 'linux'
      })

      const { getJanDataFolderPath, joinPath } = await import('@janhq/core')
      
      vi.mocked(getJanDataFolderPath).mockResolvedValue('/path/to/jan')
      vi.mocked(joinPath)
        .mockResolvedValueOnce('/path/to/jan/llamacpp/backends/v1.0.0/linux-avx2-x64')
        .mockResolvedValueOnce('/path/to/jan/llamacpp/backends/v1.0.0/linux-avx2-x64/build/bin/llama-server')

      const result = await getBackendExePath('linux-avx2-x64', 'v1.0.0')
      
      expect(result).toBe('/path/to/jan/llamacpp/backends/v1.0.0/linux-avx2-x64/build/bin/llama-server')
    })
  })

  describe('isBackendInstalled', () => {
    it('should return true when backend is installed', async () => {
      const { fs } = await import('@janhq/core')
      
      vi.mocked(fs.existsSync).mockResolvedValue(true)

      const result = await isBackendInstalled('win-avx2-x64', 'v1.0.0')
      
      expect(result).toBe(true)
    })

    it('should return false when backend is not installed', async () => {
      const { fs } = await import('@janhq/core')
      
      vi.mocked(fs.existsSync).mockResolvedValue(false)

      const result = await isBackendInstalled('win-avx2-x64', 'v1.0.0')
      
      expect(result).toBe(false)
    })
  })

  describe('downloadBackend', () => {
    it('should download backend successfully', async () => {
      const mockDownloadManager = {
        downloadFiles: vi.fn().mockImplementation((items, taskId, onProgress) => {
          // Simulate successful download
          onProgress(100, 100)
          return Promise.resolve()
        })
      }

      window.core.extensionManager.getByName = vi.fn().mockReturnValue(mockDownloadManager)

      const { getJanDataFolderPath, joinPath, fs, events } = await import('@janhq/core')
      const { invoke } = await import('@tauri-apps/api/core')
      
      vi.mocked(getJanDataFolderPath).mockResolvedValue('/path/to/jan')
      vi.mocked(joinPath).mockImplementation((paths) => Promise.resolve(paths.join('/')))
      vi.mocked(fs.rm).mockResolvedValue(undefined)
      vi.mocked(invoke).mockResolvedValue(undefined)

      await downloadBackend('win-avx2-x64', 'v1.0.0')

      expect(mockDownloadManager.downloadFiles).toHaveBeenCalled()
      expect(events.emit).toHaveBeenCalledWith('onFileDownloadSuccess', {
        modelId: 'llamacpp-v1-0-0-win-avx2-x64',
        downloadType: 'Engine'
      })
    })

    it('should handle download errors', async () => {
      const mockDownloadManager = {
        downloadFiles: vi.fn().mockRejectedValue(new Error('Download failed'))
      }

      window.core.extensionManager.getByName = vi.fn().mockReturnValue(mockDownloadManager)

      const { events } = await import('@janhq/core')

      await expect(downloadBackend('win-avx2-x64', 'v1.0.0')).rejects.toThrow('Download failed')
      
      expect(events.emit).toHaveBeenCalledWith('onFileDownloadError', {
        modelId: 'llamacpp-v1-0-0-win-avx2-x64',
        downloadType: 'Engine'
      })
    })
  })
})