import { describe, it, expect, vi, beforeEach } from 'vitest'
import { sendMessage, testConnection } from '../utils/llmApi.js'

describe('LLM API', () => {
  beforeEach(() => {
    vi.clearAllMocks()
  })

  describe('sendMessage', () => {
    it('should throw error when endpoint is missing', async () => {
      await expect(sendMessage('', 'hello')).rejects.toThrow('API endpoint is required')
    })

    it('should send POST request and extract content from response', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({
          ok: true,
          json: () => Promise.resolve({
            choices: [{ message: { content: 'Hello there!' } }]
          })
        })
      )

      const result = await sendMessage('https://api.example.com/chat', 'Hi')

      expect(fetch).toHaveBeenCalledWith(
        'https://api.example.com/chat',
        expect.objectContaining({
          method: 'POST',
          headers: { 'Content-Type': 'application/json' }
        })
      )
      expect(result).toBe('Hello there!')
    })

    it('should throw error when response has no content', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({
          ok: true,
          json: () => Promise.resolve({ choices: [] })
        })
      )

      await expect(sendMessage('https://api.example.com/chat', 'Hi'))
        .rejects.toThrow('Invalid response format: no content found')
    })

    it('should throw error on network failure', async () => {
      global.fetch = vi.fn(() => Promise.reject(new Error('Network error')))

      await expect(sendMessage('https://api.example.com/chat', 'Hi'))
        .rejects.toThrow('Network error')
    })

    it('should include system prompt when provided', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({
          ok: true,
          json: () => Promise.resolve({
            choices: [{ message: { content: 'Response' } }]
          })
        })
      )

      await sendMessage('https://api.example.com/chat', 'Hi', [], 'You are helpful')

      const callBody = JSON.parse(global.fetch.mock.calls[0][1].body)
      expect(callBody.messages[0]).toEqual({ role: 'system', content: 'You are helpful' })
    })

    it('should include message history', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({
          ok: true,
          json: () => Promise.resolve({
            choices: [{ message: { content: 'Response' } }]
          })
        })
      )

      const history = [
        { role: 'user', content: 'Hello' },
        { role: 'assistant', content: 'Hi there!' }
      ]

      await sendMessage('https://api.example.com/chat', 'How are you?', history)

      const callBody = JSON.parse(global.fetch.mock.calls[0][1].body)
      expect(callBody.messages[0]).toEqual({ role: 'user', content: 'Hello' })
      expect(callBody.messages[1]).toEqual({ role: 'assistant', content: 'Hi there!' })
      expect(callBody.messages[2]).toEqual({ role: 'user', content: 'How are you?' })
    })
  })

  describe('testConnection', () => {
    it('should return true on successful response', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({ status: 200 })
      )

      const result = await testConnection('https://api.example.com/chat')
      expect(result).toBe(true)
    })

    it('should return true on error response (not 404)', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({ status: 401 })
      )

      const result = await testConnection('https://api.example.com/chat')
      expect(result).toBe(true)
    })

    it('should return false on 404', async () => {
      global.fetch = vi.fn(() =>
        Promise.resolve({ status: 404 })
      )

      const result = await testConnection('https://api.example.com/chat')
      expect(result).toBe(false)
    })

    it('should return false on network error', async () => {
      global.fetch = vi.fn(() => Promise.reject(new Error('Network error')))

      const result = await testConnection('https://api.example.com/chat')
      expect(result).toBe(false)
    })
  })
})