package viral

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

type ViralAnalysis struct {
	HookPattern         string   `json:"hookPattern"`
	StructurePattern    string   `json:"structurePattern"`
	EmotionalTrigger    string   `json:"emotionalTrigger"`
	ReplicationStrategy string   `json:"replicationStrategy"`
	KeyTakeaways        []string `json:"keyTakeaways"`
}

type AnalyzeViralInput struct {
	PostText   string
	AuthorName string
	LikeCount  int
	ReplyCount int
	SearchTag  string
	TopicLabel string
	TopicBrief string
	Persona    string
}

func BuildAnalyzeViralSystemPrompt() string {
	return strings.TrimSpace(`你是 Threads 爆款結構分析師。拆解貼文為什麼會紅、怎麼仿寫結構，不要建議抄襲原文。

只回傳 JSON：hookPattern, structurePattern, emotionalTrigger, replicationStrategy, keyTakeaways（字串陣列 3～5 項）。繁體中文。`)
}

func BuildAnalyzeViralUserPrompt(in AnalyzeViralInput) string {
	var b strings.Builder
	b.WriteString("主題：")
	b.WriteString(strings.TrimSpace(in.TopicLabel))
	b.WriteString("\n")
	if brief := strings.TrimSpace(in.TopicBrief); brief != "" {
		b.WriteString("Brief：")
		b.WriteString(brief)
		b.WriteString("\n")
	}
	if tag := strings.TrimSpace(in.SearchTag); tag != "" {
		b.WriteString("搜尋標籤：")
		b.WriteString(tag)
		b.WriteString("\n")
	}
	author := strings.TrimSpace(in.AuthorName)
	if author == "" {
		author = "匿名"
	}
	b.WriteString(fmt.Sprintf("\n作者 @%s · %d 讚 · %d 留言\n", author, in.LikeCount, in.ReplyCount))
	b.WriteString("\n貼文：\n")
	b.WriteString(strings.TrimSpace(in.PostText))
	return b.String()
}

func ParseAnalyzeViralOutput(raw string) (ViralAnalysis, error) {
	payload, err := extractCopyMapJSON(raw)
	if err != nil {
		return ViralAnalysis{}, err
	}
	var out ViralAnalysis
	if err := json.Unmarshal(payload, &out); err != nil {
		return ViralAnalysis{}, fmt.Errorf("parse viral analysis: %w", err)
	}
	if strings.TrimSpace(out.HookPattern) == "" && strings.TrimSpace(out.StructurePattern) == "" {
		return ViralAnalysis{}, fmt.Errorf("viral analysis missing content")
	}
	return out, nil
}

func FormatAnalysisForReplicate(analysis ViralAnalysis) string {
	var b strings.Builder
	if hook := strings.TrimSpace(analysis.HookPattern); hook != "" {
		b.WriteString("Hook 模式：")
		b.WriteString(hook)
		b.WriteString("\n")
	}
	if structure := strings.TrimSpace(analysis.StructurePattern); structure != "" {
		b.WriteString("結構節奏：")
		b.WriteString(structure)
		b.WriteString("\n")
	}
	if emotion := strings.TrimSpace(analysis.EmotionalTrigger); emotion != "" {
		b.WriteString("情緒觸發：")
		b.WriteString(emotion)
		b.WriteString("\n")
	}
	if strategy := strings.TrimSpace(analysis.ReplicationStrategy); strategy != "" {
		b.WriteString("仿寫策略：")
		b.WriteString(strategy)
		b.WriteString("\n")
	}
	if len(analysis.KeyTakeaways) > 0 {
		b.WriteString("重點：")
		b.WriteString(strings.Join(analysis.KeyTakeaways, "；"))
	}
	return strings.TrimSpace(b.String())
}