import { describe, it, expect, beforeEach, vi } from 'vitest'
import { ReviewService } from '../reviewService'

describe('ReviewService', () => {
  describe('transformToExtendedFlashcard', () => {
    it('應該正確轉換基礎 Flashcard 為 ExtendedFlashcard', () => {
      const basicFlashcard = {
        id: 'test-1',
        word: 'hello',
        translation: '你好',
        definition: 'greeting',
        partOfSpeech: 'interjection',
        pronunciation: '/həˈloʊ/',
        example: 'Hello world',
        masteryLevel: 1,
        timesReviewed: 3,
        isFavorite: false,
        nextReviewDate: '2025-10-03T00:00:00Z',
        cefr: 'A1',
        createdAt: '2024-01-01T00:00:00Z',
        updatedAt: '2024-01-01T00:00:00Z',
        exampleImages: [],
        hasExampleImage: false
      }

      const extended = ReviewService.transformToExtendedFlashcard(basicFlashcard)

      // 基礎欄位保持不變
      expect(extended.id).toBe('test-1')
      expect(extended.word).toBe('hello')
      expect(extended.nextReviewDate).toBe('2025-10-03T00:00:00Z')

      // 新增的擴展欄位有預設值
      expect(extended.synonyms).toEqual([])
      expect(extended.reviewCount).toBe(3) // 來自 timesReviewed
      expect(extended.successRate).toBe(0)
      expect(extended.currentInterval).toBe(0)
      expect(extended.isOverdue).toBe(false)
    })

    it('應該處理缺少可選欄位的情況', () => {
      const minimalFlashcard = {
        id: 'minimal',
        word: 'test',
        translation: '測試',
        definition: 'test definition',
        partOfSpeech: 'noun',
        pronunciation: '/test/',
        example: 'This is a test',
        masteryLevel: 0,
        timesReviewed: 0,
        isFavorite: false,
        nextReviewDate: '2025-10-03T00:00:00Z',
        cefr: 'A1',
        createdAt: '2024-01-01T00:00:00Z',
        exampleImages: [],
        hasExampleImage: false
        // 缺少 updatedAt, primaryImageUrl 等
      }

      const extended = ReviewService.transformToExtendedFlashcard(minimalFlashcard)

      expect(extended.synonyms).toEqual([])
      expect(extended.exampleImage).toBeUndefined()
      expect(extended.reviewCount).toBe(0)
      expect(extended.lastReviewDate).toBeUndefined()
    })

    it('應該為缺少 nextReviewDate 的數據提供預設值', () => {
      const flashcardWithoutDate = {
        id: 'no-date',
        word: 'test',
        // nextReviewDate 缺失
        masteryLevel: 0,
        timesReviewed: 0
      }

      const extended = ReviewService.transformToExtendedFlashcard(flashcardWithoutDate)

      expect(extended.nextReviewDate).toBeDefined()
      expect(new Date(extended.nextReviewDate!)).toBeInstanceOf(Date)
    })
  })

  describe('calculateStats', () => {
    it('應該正確計算學習統計', () => {
      const testItems = [
        { id: '1', isCompleted: true },
        { id: '2', isCompleted: false },
        { id: '3', isCompleted: true },
        { id: '4', isCompleted: false }
      ]

      const score = { correct: 3, total: 4 }

      const stats = ReviewService.calculateStats(testItems as any, score)

      expect(stats.completed).toBe(2)
      expect(stats.total).toBe(4)
      expect(stats.remaining).toBe(2)
      expect(stats.progressPercentage).toBe(50) // 2/4 = 50%
      expect(stats.accuracyPercentage).toBe(75) // 3/4 = 75%
      expect(stats.estimatedTimeRemaining).toBe(60) // 2 * 30秒
    })

    it('應該處理空數據的情況', () => {
      const testItems: any[] = []
      const score = { correct: 0, total: 0 }

      const stats = ReviewService.calculateStats(testItems, score)

      expect(stats.completed).toBe(0)
      expect(stats.total).toBe(0)
      expect(stats.remaining).toBe(0)
      expect(stats.progressPercentage).toBe(0)
      expect(stats.accuracyPercentage).toBe(0)
      expect(stats.estimatedTimeRemaining).toBe(0)
    })
  })

  describe('validateSession', () => {
    it('應該驗證有效的學習會話', () => {
      const cards = [
        { id: 'card1', word: 'hello' },
        { id: 'card2', word: 'world' }
      ]

      const testItems = [
        { cardId: 'card1', id: 'test1' },
        { cardId: 'card2', id: 'test2' }
      ]

      const validation = ReviewService.validateSession(cards as any, testItems as any)

      expect(validation.isValid).toBe(true)
      expect(validation.errors).toEqual([])
    })

    it('應該檢測無效的學習會話', () => {
      const cards: any[] = []
      const testItems = [
        { cardId: 'non-existent', id: 'test1' }
      ]

      const validation = ReviewService.validateSession(cards, testItems as any)

      expect(validation.isValid).toBe(false)
      expect(validation.errors).toContain('沒有可用的詞卡')
      expect(validation.errors).toContain('測驗項目引用了不存在的詞卡: non-existent')
    })
  })
})