// 织忆 MemoryWeave — 被动验证器 (PassiveValidator) P1/P2/P3 三层匹配
package selfoptimize

import (
	"strings"
	"sync"
	"time"
)

// ─── 被动验证器 ──────────────────────────────────────────

// ValidationLevel 验证层级
type ValidationLevel int

const (
	P1_ExactMatch   ValidationLevel = 1 // 精确匹配：牧尘再次提到同一事实
	P2_PartialMatch ValidationLevel = 2 // 部分匹配：子串/同义词
	P3_ImpliedMatch ValidationLevel = 3 // 隐含验证：牧尘基于该记忆做出的决策成功
)

// ValidationRecord 单条验证记录
type ValidationRecord struct {
	MemoryID   string          `json:"memory_id"`
	Level      ValidationLevel `json:"level"`
	MatchedBy  string          `json:"matched_by"`  // 匹配到的内容片段
	Confidence float64         `json:"confidence"`   // 当前信任度
	LastSeen   time.Time       `json:"last_seen"`
	PassiveHits int            `json:"passive_hits"` // 被动匹配次数
}

// PassiveValidator 被动验证引擎
type PassiveValidator struct {
	mu        sync.RWMutex
	records   map[string]*ValidationRecord // memory_id → record
	boostP1   float64                      // P1 信任度提升 (default 0.1)
	boostP2   float64                      // P2 信任度提升 (default 0.05)
	boostP3   float64                      // P3 信任度提升 (default 0.15)
	maxConf   float64                      // 最大信任度 (default 0.99)
}

var Validator = NewPassiveValidator()

func NewPassiveValidator() *PassiveValidator {
	return &PassiveValidator{
		records: make(map[string]*ValidationRecord),
		boostP1: 0.10,
		boostP2: 0.05,
		boostP3: 0.15,
		maxConf: 0.99,
	}
}

// Validate 牧尘的新输入到达时，检查是否验证了已有记忆
func (pv *PassiveValidator) Validate(userInput string, existingMemories []MemoryForValidation) []*ValidationRecord {
	pv.mu.Lock()
	defer pv.mu.Unlock()

	var validated []*ValidationRecord

	for _, mem := range existingMemories {
		level := pv.checkMatch(userInput, mem.Content)
		if level == 0 {
			continue
		}

		record, exists := pv.records[mem.ID]
		if !exists {
			record = &ValidationRecord{
				MemoryID:    mem.ID,
				Confidence:  mem.QualityScore,
				PassiveHits: 0,
			}
			pv.records[mem.ID] = record
		}

		record.Level = level
		record.MatchedBy = extractMatchFragment(userInput, mem.Content)
		record.LastSeen = time.Now()
		record.PassiveHits++

		// 按层级提升信任度
		switch level {
		case P1_ExactMatch:
			record.Confidence = minConf(record.Confidence+pv.boostP1, pv.maxConf)
		case P2_PartialMatch:
			record.Confidence = minConf(record.Confidence+pv.boostP2, pv.maxConf)
		case P3_ImpliedMatch:
			record.Confidence = minConf(record.Confidence+pv.boostP3, pv.maxConf)
		}

		validated = append(validated, record)
	}
	return validated
}

// checkMatch 三层匹配检测
func (pv *PassiveValidator) checkMatch(userInput, memoryContent string) ValidationLevel {
	// P1: 精确匹配 — memoryContent 是 userInput 的子串（或相反）
	if strings.Contains(userInput, memoryContent) || strings.Contains(memoryContent, userInput) {
		return P1_ExactMatch
	}

	// P2: 部分匹配 — 关键词重叠 > 60%
	overlap := keywordOverlap(userInput, memoryContent)
	if overlap > 0.6 {
		return P2_PartialMatch
	}

	// P3: 隐含匹配 — 共享实体引用
	entities1 := extractEntities(userInput)
	entities2 := extractEntities(memoryContent)
	if sharedEntities(entities1, entities2) {
		return P3_ImpliedMatch
	}

	return 0 // 无匹配
}

// GetConfidence 获取某条记忆的被动验证信任度
func (pv *PassiveValidator) GetConfidence(memoryID string) float64 {
	pv.mu.RLock()
	defer pv.mu.RUnlock()
	if record, ok := pv.records[memoryID]; ok {
		return record.Confidence
	}
	return 0
}

// GetRecords 获取所有验证记录（按 confidence 降序）
func (pv *PassiveValidator) GetRecords() []*ValidationRecord {
	pv.mu.RLock()
	defer pv.mu.RUnlock()
	var records []*ValidationRecord
	for _, r := range pv.records {
		records = append(records, r)
	}
	if records == nil {
		return []*ValidationRecord{}
	}
	return records
}

// ─── 辅助函数 ──────────────────────────────────────────

type MemoryForValidation struct {
	ID           string
	Content      string
	QualityScore float64
}

func keywordOverlap(a, b string) float64 {
	wordsA := strings.Fields(strings.ToLower(a))
	wordsB := strings.Fields(strings.ToLower(b))
	setA := make(map[string]bool, len(wordsA))
	for _, w := range wordsA {
		setA[w] = true
	}
	overlap := 0
	for _, w := range wordsB {
		if setA[w] {
			overlap++
		}
	}
	if len(wordsA) == 0 || len(wordsB) == 0 {
		return 0
	}
	return float64(overlap) / float64(maxInt(len(wordsA), len(wordsB)))
}

func extractEntities(text string) []string {
	// 简单启发式：提取大写开头的词和中文专有名词
	words := strings.Fields(text)
	var entities []string
	for _, w := range words {
		if len(w) > 1 && (w[0] >= 'A' && w[0] <= 'Z') {
			entities = append(entities, w)
		}
	}
	return entities
}

func sharedEntities(a, b []string) bool {
	set := make(map[string]bool, len(a))
	for _, e := range a {
		set[e] = true
	}
	for _, e := range b {
		if set[e] {
			return true
		}
	}
	return false
}

func extractMatchFragment(userInput, memoryContent string) string {
	// 返回重叠部分
	if idx := strings.Index(userInput, memoryContent); idx >= 0 {
		return memoryContent
	}
	// 返回共享关键实体
	entities := extractEntities(memoryContent)
	if len(entities) > 0 {
		return strings.Join(entities, ", ")
	}
	return memoryContent[:minInt(50, len(memoryContent))]
}

func minConf(a, b float64) float64 {
	if a < b { return a }
	return b
}

func maxInt(a, b int) int {
	if a > b { return a }
	return b
}

func minInt(a, b int) int {
	if a < b { return a }
	return b
}