package dialoguectx

import (
	"crypto/sha256"
	"encoding/hex"
	"strings"
	"unicode/utf8"

	"chat-agent-system/internal/replyexport"
)

// cleanResult is the outcome of cleaning a raw message.
type cleanResult struct {
	Include bool
	Content string
	Noise   bool
	Private bool
	NoAccess bool
}

// cleanMessage applies visibility, export-policy, noise, and R13 neutralization.
func cleanMessage(role, content, contentKind, exportPolicy, stageKey, allowedStageKey string, metadata map[string]any) cleanResult {
	trimmed := strings.TrimSpace(content)
	if trimmed == "" {
		return cleanResult{Noise: true}
	}
	if strings.HasPrefix(trimmed, "[private]") || strings.HasPrefix(trimmed, "[draft]") {
		return cleanResult{Private: true}
	}
	if vis, _ := metadata["visibility"].(string); vis == "private" {
		return cleanResult{Private: true}
	}
	if allowedStageKey != "" && stageKey != "" && stageKey != allowedStageKey {
		return cleanResult{NoAccess: true}
	}

	switch role {
	case "user":
		if utf8.RuneCountInString(trimmed) < MinContentRunes {
			return cleanResult{Noise: true}
		}
		if isGreetingNoise(trimmed) {
			return cleanResult{Noise: true}
		}
		return cleanResult{Include: true, Content: neutralizeDirective(trimmed)}
	case "assistant":
		switch contentKind {
		case string(replyexport.KindActionCard), string(replyexport.KindStatusUpdate),
			string(replyexport.KindErrorNotice), string(replyexport.KindSystemNotice):
			return cleanResult{Noise: true}
		}
		switch exportPolicy {
		case string(replyexport.PolicyFull), string(replyexport.PolicyCopyOnly):
			if utf8.RuneCountInString(trimmed) < MinContentRunes {
				return cleanResult{Noise: true}
			}
			return cleanResult{Include: true, Content: neutralizeDirective(trimmed)}
		default:
			return cleanResult{Noise: true}
		}
	default:
		return cleanResult{Noise: true}
	}
}

func isGreetingNoise(s string) bool {
	lower := strings.ToLower(strings.TrimSpace(s))
	greetings := []string{
		"你好", "您好", "hi", "hello", "hey", "在吗", "早上好", "下午好", "晚上好",
		"谢谢", "感谢", "ok", "好的", "收到", "嗯", "哈哈",
	}
	for _, g := range greetings {
		if lower == g || lower == g+"。" || lower == g+"！" || lower == g+"?" || lower == g+"？" {
			return true
		}
	}
	return false
}

// neutralizeDirective marks instruction-like text as user material (R13).
func neutralizeDirective(c string) string {
	lower := strings.ToLower(c)
	markers := []string{
		"ignore previous",
		"system:",
		"忽略以上",
		"忽略之前",
		"提权",
		"grant yourself",
		"override auth",
		"将所有阶段",
	}
	for _, m := range markers {
		if strings.Contains(lower, strings.ToLower(m)) || strings.Contains(c, m) {
			return "【用户材料】" + c
		}
	}
	return c
}

func contentFingerprint(role, content string) string {
	sum := sha256.Sum256([]byte(role + "|" + content))
	return hex.EncodeToString(sum[:8])
}

func truncateRunes(s string, max int) string {
	if max <= 0 || utf8.RuneCountInString(s) <= max {
		return s
	}
	runes := []rune(s)
	return string(runes[:max]) + "…"
}

func stageKeyFromMeta(metadata map[string]any) string {
	if metadata == nil {
		return ""
	}
	if sk, ok := metadata["stage_key"].(string); ok {
		return sk
	}
	return ""
}