package service

import (
	"encoding/json"
	"fmt"
)

// ExtractPaperIDFromTaskContent 从任务 content JSON 中解析试卷 ID（支持 exam_id/paper_id/examId/paperId，含数字）
func ExtractPaperIDFromTaskContent(content json.RawMessage) string {
	if len(content) == 0 {
		return ""
	}
	var m map[string]interface{}
	if err := json.Unmarshal(content, &m); err != nil {
		return ""
	}
	paperID := stringFromMap(m, "exam_id", "paper_id", "examId", "paperId")
	if paperID != "" {
		return paperID
	}
	if obj, ok := m["objective"].(map[string]interface{}); ok {
		paperID = stringFromMap(obj, "exam_id", "paper_id", "examId", "paperId")
	}
	return paperID
}

func stringFromMap(m map[string]interface{}, keys ...string) string {
	for _, k := range keys {
		v, ok := m[k]
		if !ok || v == nil {
			continue
		}
		switch val := v.(type) {
		case string:
			if val != "" {
				return val
			}
		case float64:
			if val == float64(int64(val)) {
				return fmt.Sprintf("%d", int64(val))
			}
			return fmt.Sprintf("%.0f", val)
		case int:
			return fmt.Sprintf("%d", val)
		case int64:
			return fmt.Sprintf("%d", val)
		}
	}
	return ""
}