package utils

import (
	"bytes"
	"encoding/json"
	"fmt"
	"regexp"
	"strings"
)

// ExamPromptQuestionType represents the structure of question type configuration passed from frontend
type ExamPromptQuestionType struct {
	Name             string `json:"name"`
	RomanNumeral     string `json:"romanNumeral"`
	QuestionCount    int    `json:"questionCount"`
	ScorePerQuestion int    `json:"scorePerQuestion"`
}

// ExamPromptRequest represents the payload required to build an exam prompt
type ExamPromptRequest struct {
	Mode          string                   `json:"mode"`
	Client        string                   `json:"client"`
	ProjectType   string                   `json:"projectType"`
	ExamTitle     string                   `json:"examTitle"`
	TotalScore    int                      `json:"totalScore"`
	QuestionTypes []ExamPromptQuestionType `json:"questionTypes"`
	PPTContent    string                   `json:"pptContent"`
}

// SingleQuestionPromptRequest represents the payload required to build a single-question prompt
type SingleQuestionPromptRequest struct {
	Client           string          `json:"client"`
	SectionType      string          `json:"sectionType"`
	QuestionIndex    int             `json:"questionIndex"`
	ProjectType      string          `json:"projectType"`
	QuestionType     string          `json:"questionType"`
	ScorePerQuestion int             `json:"scorePerQuestion"`
	CurrentQuestion  json.RawMessage `json:"currentQuestion"`
}

type questionStats struct {
	Score int
	Count int
}

// BuildExamPrompt generates the exam prompt text based on mode (ai/ppt) and client (pc/mobile)
func BuildExamPrompt(req ExamPromptRequest) (string, error) {
	mode := strings.ToLower(strings.TrimSpace(req.Mode))
	if mode == "" {
		mode = "ai"
	}

	client := strings.ToLower(strings.TrimSpace(req.Client))
	if client == "" {
		client = "pc"
	}

	switch client {
	case "mobile":
		if mode == "ppt" {
			return buildMobilePPTExamPrompt(req), nil
		}
		return buildMobileAIExamPrompt(req), nil
	default:
		if mode == "ppt" {
			return buildPcPPTExamPrompt(req), nil
		}
		return buildPcAIExamPrompt(req), nil
	}
}

// BuildSingleQuestionPrompt builds prompts for regenerating a single question
func BuildSingleQuestionPrompt(req SingleQuestionPromptRequest) (string, error) {
	client := strings.ToLower(strings.TrimSpace(req.Client))
	if client == "" {
		client = "pc"
	}
	sectionType := normalizeSectionType(req.SectionType)
	projectType := fallbackString(req.ProjectType, "工程")
	questionType := fallbackString(req.QuestionType, questionTypeFromSection(sectionType))
	scorePerQuestion := safePositive(req.ScorePerQuestion, 1)
	questionIndex := req.QuestionIndex + 1
	currentQuestion := formatCurrentQuestionJSON(req.CurrentQuestion)

	switch client {
	case "mobile":
		return buildMobileSingleQuestionPrompt(projectType, questionType, sectionType, questionIndex, scorePerQuestion, currentQuestion), nil
	default:
		return buildPcSingleQuestionPrompt(projectType, questionType, sectionType, questionIndex, scorePerQuestion, currentQuestion), nil
	}
}

func buildPcAIExamPrompt(req ExamPromptRequest) string {
	projectType := fallbackString(req.ProjectType, "工程")
	examTitle := fallbackString(req.ExamTitle, "考试试卷")
	questionConfig := buildPcQuestionConfig(req.QuestionTypes)
	jsonTemplate := buildPcJSONTemplate(req, examTitle)

	return fmt.Sprintf(`请为%[1]s工程生成一份名为"%[2]s"的考试试卷：

试卷总分：%[3]d分

题型配置：
%[4]s
请严格按照以下JSON格式返回试卷内容，不要包含任何其他文字：

%[5]s

注意：
1. 所有题目内容必须与%[1]s工程相关
2. 题目难度适中，符合考试要求
3. 严格按照JSON格式返回，不要有多余字符
4. 单选题和判断题的选项要合理
5. 多选题至少要有2个正确答案
6. 简答题要提供清晰的答题要点
7. 必须为每道题设置正确答案：
   - 单选题：selectedAnswer字段填写正确的选项(A/B/C/D)
   - 判断题：selectedAnswer字段填写"正确"或"错误"
   - 多选题：selectedAnswers数组包含所有正确答案选项
8. 简答题答案字数不超过500字
`, projectType, examTitle, safeTotalScore(req.TotalScore), questionConfig, jsonTemplate)
}

func buildPcPPTExamPrompt(req ExamPromptRequest) string {
	contentText := sanitizePPTContent(req.PPTContent)
	if contentText == "" {
		contentText = fallbackString(req.ExamTitle, "PPT内容")
	}
	examTitle := fallbackString(req.ExamTitle, "考试试卷")
	questionConfig := buildPcQuestionConfig(req.QuestionTypes)
	jsonTemplate := buildPcJSONTemplate(req, examTitle)

	return fmt.Sprintf(`请根据标题为%[1]s生成一份考试试卷：

试卷总分：%[2]d分

题型配置：
%[3]s
请严格按照以下JSON格式返回试卷内容，不要包含任何其他文字：

%[4]s

注意：
1. 所有题目内容必须基于提供的内容生成，与%[1]s工程相关
2. 题目难度适中，符合考试要求
3. 严格按照JSON格式返回，不要有多余字符
4. 单选题和判断题的选项要合理
5. 多选题至少要有2个正确答案
6. 简答题要提供清晰的答题要点
7. 必须为每道题设置正确答案：
   - 单选题：selectedAnswer字段填写正确的选项(A/B/C/D)
   - 判断题：selectedAnswer字段填写"正确"或"错误"
   - 多选题：selectedAnswers数组包含所有正确答案选项
8. 简答题答案字数不超过500字
9. 确保题目内容与提供的内容高度相关
`, contentText, safeTotalScore(req.TotalScore), questionConfig, jsonTemplate)
}

func buildMobileAIExamPrompt(req ExamPromptRequest) string {
	projectType := fallbackString(req.ProjectType, "工程")
	examTitle := fallbackString(req.ExamTitle, "考试试卷")
	questionConfig := buildMobileQuestionConfig(req.QuestionTypes)
	jsonTemplate := buildMobileJSONTemplate(req, examTitle)

	return fmt.Sprintf(`请生成一份%[1]s工程施工技术考核试卷：

试卷要求：
- 试卷名称：%[2]s
- 试卷总分：%[3]d分
- 题型配置：
%[4]s

内容要求：
1. %[1]s工程施工技术的核心知识点
2. 施工工艺流程和质量控制要点
3. 安全操作规程和事故预防措施
4. 相关法规标准和验收规范

请严格按照以下JSON格式返回试卷内容，不要包含任何其他文字：

请在questions数组中生成具体、完整的题目内容！
- 单选题需要：text题目内容、options选项数组[{"key":"A","text":"选项1"},{"key":"B","text":"选项2"},{"key":"C","text":"选项3"},{"key":"D","text":"选项4"}]、selectedAnswer正确答案
- 判断题需要：text题目内容、selectedAnswer正确答案(正确/错误)
- 多选题需要：text题目内容、options选项数组[{"key":"A","text":"选项1"},{"key":"B","text":"选项2"},{"key":"C","text":"选项3"},{"key":"D","text":"选项4"}]、selectedAnswers正确答案数组
- 简答题需要：text题目内容、outline {keyFactors:关键要点, measures:具体措施}

%[5]s`, projectType, examTitle, safeTotalScore(req.TotalScore), questionConfig, jsonTemplate)
}

func buildMobilePPTExamPrompt(req ExamPromptRequest) string {
	examTitle := fallbackString(req.ExamTitle, "考试试卷")
	pptContent := fallbackString(strings.TrimSpace(req.PPTContent), "PPT内容")
	questionConfig := buildMobileQuestionConfig(req.QuestionTypes)
	jsonTemplate := buildMobileJSONTemplate(req, examTitle+" - PPT培训考试")

	return fmt.Sprintf(`请基于以下PPT培训内容生成考试试卷：

培训主题：%[1]s
PPT内容：%[2]s

请生成一份包含以下题型的考试试卷：
%[3]s

试卷总分：%[4]d分

要求：
1. 重点考查PPT中的核心知识点
2. 涵盖主要概念、工艺流程、操作规程等关键内容
3. 题目难度适中，具有实际应用价值
4. 确保答案准确性和专业性

请严格按照以下JSON格式返回试卷内容，不要包含任何其他文字：

请在questions数组中生成具体、完整的题目内容！
- 单选题需要：text题目内容、options选项数组[{"key":"A","text":"选项1"},{"key":"B","text":"选项2"},{"key":"C","text":"选项3"},{"key":"D","text":"选项4"}]、selectedAnswer正确答案
- 判断题需要：text题目内容、selectedAnswer正确答案(正确/错误)
- 多选题需要：text题目内容、options选项数组[{"key":"A","text":"选项1"},{"key":"B","text":"选项2"},{"key":"C","text":"选项3"},{"key":"D","text":"选项4"}]、selectedAnswers正确答案数组
- 简答题需要：text题目内容、outline {keyFactors:关键要点, measures:具体措施}

%[5]s`, examTitle, pptContent, questionConfig, safeTotalScore(req.TotalScore), jsonTemplate)
}

func buildPcQuestionConfig(questionTypes []ExamPromptQuestionType) string {
	if len(questionTypes) == 0 {
		return "暂无题型配置\n"
	}

	var builder strings.Builder
	for _, qt := range questionTypes {
		roman := strings.TrimSpace(qt.RomanNumeral)
		if roman == "" {
			roman = "•"
		}
		score := safePositive(qt.ScorePerQuestion, 1)
		count := safePositive(qt.QuestionCount, 1)
		builder.WriteString(fmt.Sprintf("%s、%s：%d题，每题%d分，共%d分\n", roman, qt.Name, count, score, count*score))
	}
	return builder.String()
}

func buildMobileQuestionConfig(questionTypes []ExamPromptQuestionType) string {
	if len(questionTypes) == 0 {
		return "暂无题型配置\n"
	}

	var builder strings.Builder
	for _, qt := range questionTypes {
		score := safePositive(qt.ScorePerQuestion, 1)
		count := safePositive(qt.QuestionCount, 1)
		builder.WriteString(fmt.Sprintf("%s：%d题，每题%d分，共%d分\n", qt.Name, count, score, count*score))
	}
	return builder.String()
}

func buildPcJSONTemplate(req ExamPromptRequest, title string) string {
	totalQuestions := sumQuestionCount(req.QuestionTypes)
	single := statsByName(req.QuestionTypes, "单选题", 2, 15)
	judge := statsByName(req.QuestionTypes, "判断题", 2, 10)
	multiple := statsByName(req.QuestionTypes, "多选题", 3, 10)
	short := statsByName(req.QuestionTypes, "简答题", 10, 2)

	return fmt.Sprintf(`{
  "title": "%[1]s",
  "totalScore": %[2]d,
  "totalQuestions": %[3]d,
  "singleChoice": {
    "scorePerQuestion": %[4]d,
    "totalScore": %[5]d,
    "count": %[6]d,
    "questions": [
      {
        "text": "题目内容",
        "options": [
          {"key": "A", "text": "选项A内容"},
          {"key": "B", "text": "选项B内容"},
          {"key": "C", "text": "选项C内容"},
          {"key": "D", "text": "选项D内容"}
        ],
        "selectedAnswer": "正确答案选项(A/B/C/D)"
      }
    ]
  },
  "judge": {
    "scorePerQuestion": %[7]d,
    "totalScore": %[8]d,
    "count": %[9]d,
    "questions": [
      {
        "text": "题目内容",
        "selectedAnswer": "正确答案(正确/错误)"
      }
    ]
  },
  "multiple": {
    "scorePerQuestion": %[10]d,
    "totalScore": %[11]d,
    "count": %[12]d,
    "questions": [
      {
        "text": "题目内容",
        "options": [
          {"key": "A", "text": "选项A内容"},
          {"key": "B", "text": "选项B内容"},
          {"key": "C", "text": "选项C内容"},
          {"key": "D", "text": "选项D内容"}
        ],
        "selectedAnswers": ["正确答案选项1", "正确答案选项2"]
      }
    ]
  },
  "short": {
    "scorePerQuestion": %[13]d,
    "totalScore": %[14]d,
    "count": %[15]d,
    "questions": [
      {
        "text": "题目内容",
        "outline": {
          "keyFactors": "答题要点、关键因素、示例答案"
        }
      }
    ]
  }
}`, title, safeTotalScore(req.TotalScore), totalQuestions,
		single.Score, single.Score*single.Count, single.Count,
		judge.Score, judge.Score*judge.Count, judge.Count,
		multiple.Score, multiple.Score*multiple.Count, multiple.Count,
		short.Score, short.Score*short.Count, short.Count)
}

func buildMobileJSONTemplate(req ExamPromptRequest, title string) string {
	totalQuestions := sumQuestionCount(req.QuestionTypes)
	q0 := statsByIndex(req.QuestionTypes, 0, 2, 8)
	q1 := statsByIndex(req.QuestionTypes, 1, 2, 5)
	q2 := statsByIndex(req.QuestionTypes, 2, 3, 5)
	q3 := statsByIndex(req.QuestionTypes, 3, 10, 2)

	return fmt.Sprintf(`{
  "title": "%[1]s",
  "totalScore": %[2]d,
  "totalQuestions": %[3]d,
  "singleChoice": {
    "scorePerQuestion": %[4]d,
    "totalScore": %[5]d,
    "count": %[6]d,
    "questions": []
  },
  "judge": {
    "scorePerQuestion": %[7]d,
    "totalScore": %[8]d,
    "count": %[9]d,
    "questions": []
  },
  "multiple": {
    "scorePerQuestion": %[10]d,
    "totalScore": %[11]d,
    "count": %[12]d,
    "questions": []
  },
  "short": {
    "scorePerQuestion": %[13]d,
    "totalScore": %[14]d,
    "count": %[15]d,
    "questions": []
  }
}`, title, safeTotalScore(req.TotalScore), totalQuestions,
		q0.Score, q0.Score*q0.Count, q0.Count,
		q1.Score, q1.Score*q1.Count, q1.Count,
		q2.Score, q2.Score*q2.Count, q2.Count,
		q3.Score, q3.Score*q3.Count, q3.Count)
}

func statsByName(questionTypes []ExamPromptQuestionType, name string, defaultScore, defaultCount int) questionStats {
	for _, qt := range questionTypes {
		if strings.TrimSpace(qt.Name) == name {
			return questionStats{
				Score: safePositive(qt.ScorePerQuestion, defaultScore),
				Count: safePositive(qt.QuestionCount, defaultCount),
			}
		}
	}
	return questionStats{Score: defaultScore, Count: defaultCount}
}

func statsByIndex(questionTypes []ExamPromptQuestionType, index int, defaultScore, defaultCount int) questionStats {
	if index >= 0 && index < len(questionTypes) {
		qt := questionTypes[index]
		return questionStats{
			Score: safePositive(qt.ScorePerQuestion, defaultScore),
			Count: safePositive(qt.QuestionCount, defaultCount),
		}
	}
	return questionStats{Score: defaultScore, Count: defaultCount}
}

func sumQuestionCount(questionTypes []ExamPromptQuestionType) int {
	total := 0
	for _, qt := range questionTypes {
		total += safePositive(qt.QuestionCount, 0)
	}
	return total
}

func buildPcSingleQuestionPrompt(projectType, questionType, sectionType string, questionIndex, score int, currentQuestion string) string {
	format := buildPcSingleQuestionFormat(sectionType)
	return fmt.Sprintf(`请基于以下%[1]s工程的%[2]s题目，重新生成一道相似主题的题目，要求如下：

当前题目参考：
%[3]s

题目类型：%[2]s
每题分值：%[4]d分
题目序号：第%[5]d题

请严格按照以下JSON格式返回，不要包含任何其他文字：

%[6]s

注意：
1. 新题目必须与当前题目保持相似的主题和难度
2. 题目内容必须与%[1]s工程相关
3. 题目难度适中，符合考试要求
4. 严格按照JSON格式返回，不要有多余字符
5. 单选题和判断题的选项要合理
6. 多选题至少要有2个正确答案
7. 简答题要提供清晰的答题要点
8. 必须为每道题设置正确答案：
   - 单选题：selectedAnswer字段填写正确的选项(A/B/C/D)
   - 判断题：selectedAnswer字段填写"正确"或"错误"
   - 多选题：selectedAnswers数组包含所有正确答案选项
9. 简答题答案字数不超过500字
10. 新题目应该是当前题目的变体，保持主题一致性但内容要有所变化`, projectType, questionType, currentQuestion, score, questionIndex, format)
}

func buildMobileSingleQuestionPrompt(projectType, questionType, sectionType string, questionIndex, score int, currentQuestion string) string {
	format := buildMobileSingleQuestionFormat(sectionType)
	return fmt.Sprintf(`请基于以下%[1]s工程的%[2]s题目，重新生成一道相似主题的题目：

当前题目参考：
%[3]s

题目类型：%[2]s
每题分值：%[4]d分
题目序号：第%[5]d题

请严格按照以下JSON格式返回，不要包含任何其他文字：

%[6]s`, projectType, questionType, currentQuestion, score, questionIndex, format)
}

func buildPcSingleQuestionFormat(sectionType string) string {
	switch sectionType {
	case "single":
		return `{
  "text": "题目内容",
  "options": [
    {"key": "A", "text": "选项A内容"},
    {"key": "B", "text": "选项B内容"},
    {"key": "C", "text": "选项C内容"},
    {"key": "D", "text": "选项D内容"}
  ],
  "selectedAnswer": "正确答案选项(A/B/C/D)"
}`
	case "judge":
		return `{
  "text": "题目内容",
  "selectedAnswer": "正确答案(正确/错误)"
}`
	case "multiple":
		return `{
  "text": "题目内容",
  "options": [
    {"key": "A", "text": "选项A内容"},
    {"key": "B", "text": "选项B内容"},
    {"key": "C", "text": "选项C内容"},
    {"key": "D", "text": "选项D内容"}
  ],
  "selectedAnswers": ["正确答案选项1", "正确答案选项2"]
}`
	case "short":
		return `{
  "text": "题目内容",
  "outline": {
    "keyFactors": "答题要点、关键因素、示例答案"
  }
}`
	default:
		return `{
  "text": "题目内容"
}`
	}
}

func buildMobileSingleQuestionFormat(sectionType string) string {
	switch sectionType {
	case "single":
		return `{
  "text": "题目内容",
  "options": [
    {"key": "A", "text": "选项A"},
    {"key": "B", "text": "选项B"},
    {"key": "C", "text": "选项C"},
    {"key": "D", "text": "选项D"}
  ],
  "selectedAnswer": "A"
}`
	case "judge":
		return `{
  "text": "题目内容",
  "selectedAnswer": "正确"
}`
	case "multiple":
		return `{
  "text": "题目内容",
  "options": [
    {"key": "A", "text": "选项A"},
    {"key": "B", "text": "选项B"},
    {"key": "C", "text": "选项C"},
    {"key": "D", "text": "选项D"}
  ],
  "selectedAnswers": ["A", "B"]
}`
	case "short":
		return `{
  "text": "题目内容",
  "outline": {
    "keyFactors": "关键要点内容",
    "measures": "具体措施内容"
  }
}`
	default:
		return `{
  "text": "题目内容"
}`
	}
}

func formatCurrentQuestionJSON(raw json.RawMessage) string {
	if len(raw) == 0 {
		return "无"
	}
	var buf bytes.Buffer
	if err := json.Indent(&buf, raw, "", "  "); err != nil {
		return string(raw)
	}
	return buf.String()
}

func questionTypeFromSection(sectionType string) string {
	switch sectionType {
	case "single":
		return "单选题"
	case "judge":
		return "判断题"
	case "multiple":
		return "多选题"
	case "short":
		return "简答题"
	default:
		return "题目"
	}
}

func normalizeSectionType(sectionType string) string {
	switch strings.ToLower(strings.TrimSpace(sectionType)) {
	case "single", "judge", "multiple", "short":
		return strings.ToLower(strings.TrimSpace(sectionType))
	default: 
		return "single"
	}
}

func sanitizePPTContent(content string) string {
	text := strings.TrimSpace(content)
	if text == "" {
		return ""
	}
	if strings.Contains(text, "PPT文件信息") {
		re := regexp.MustCompile(`(?s)提取的文本内容：\n(.*?)(\n\n|$)`)
		if matches := re.FindStringSubmatch(text); len(matches) > 1 {
			text = strings.TrimSpace(matches[1])
		}
	}
	return text
}

func fallbackString(value string, fallback string) string {
	if strings.TrimSpace(value) == "" {
		return fallback
	}
	return value
}

func safePositive(value int, fallback int) int {
	if value <= 0 {
		return fallback
	}
	return value
}

func safeTotalScore(score int) int {
	if score <= 0 {
		return 100
	}
	return score
}