package service

import (
	"sort"
	"strings"
	"time"
)

// HealthInput 健康画像输入
type HealthInput struct {
	RecentRiskLevels  []string // 近 30 天巡检风险等级
	LampPositive      int
	LampTotal         int
	ConsultationCount int
	TraceCount        int
}

// ComputeHealthScore 综合健康分（0-100）与评级（优/良/中/差）
func ComputeHealthScore(in HealthInput) (float64, string) {
	score := 100.0
	for _, level := range in.RecentRiskLevels {
		switch level {
		case "red":
			score -= 25
		case "orange":
			score -= 12
		case "yellow":
			score -= 4
		}
	}
	if in.LampTotal > 0 {
		score -= float64(in.LampPositive) / float64(in.LampTotal) * 30
	}
	score -= float64(in.ConsultationCount) * 10
	score -= float64(in.TraceCount) * 8
	if score < 0 {
		score = 0
	}
	if score > 100 {
		score = 100
	}
	grade := "差"
	switch {
	case score >= 85:
		grade = "优"
	case score >= 70:
		grade = "良"
	case score >= 55:
		grade = "中"
	}
	return score, grade
}

// MonthDiseaseEntry 月度发病条目
type MonthDiseaseEntry struct {
	Month   string
	Disease string
}

// MonthStat 月度发病统计
type MonthStat struct {
	Month    string         `json:"month"`
	Total    int            `json:"total"`
	Diseases map[string]int `json:"diseases"`
}

// AggregateMonthlyStats 按月份聚合发病数与病种分布（升序）
func AggregateMonthlyStats(entries []MonthDiseaseEntry) []MonthStat {
	byMonth := make(map[string]*MonthStat)
	for _, e := range entries {
		if strings.TrimSpace(e.Month) == "" {
			continue
		}
		s, ok := byMonth[e.Month]
		if !ok {
			s = &MonthStat{Month: e.Month, Diseases: map[string]int{}}
			byMonth[e.Month] = s
		}
		s.Total++
		s.Diseases[e.Disease]++
	}
	result := make([]MonthStat, 0, len(byMonth))
	for _, s := range byMonth {
		result = append(result, *s)
	}
	sort.Slice(result, func(i, j int) bool { return result[i].Month < result[j].Month })
	return result
}

// EffectWindow 处置前后评估窗口。
type EffectWindow struct {
	BeforeStart time.Time `json:"beforeStart"`
	BeforeEnd   time.Time `json:"beforeEnd"`
	AfterStart  time.Time `json:"afterStart"`
	AfterEnd    time.Time `json:"afterEnd"`
}

// EffectMetrics 处置前后指标输入。
type EffectMetrics struct {
	RiskSamples  []float64 `json:"riskSamples"`
	LampPositive int       `json:"lampPositive"`
	LampTotal    int       `json:"lampTotal"`
	Recurrences  int       `json:"recurrences"`
	Loss         *float64  `json:"loss,omitempty"`
	Cost         *float64  `json:"cost,omitempty"`
}

// EffectReport 防控效果报告；缺失维度不按 0 当改善。
type EffectReport struct {
	EventID            string       `json:"eventId"`
	Window             EffectWindow `json:"window"`
	BeforeRiskAvg      *float64     `json:"beforeRiskAvg,omitempty"`
	AfterRiskAvg       *float64     `json:"afterRiskAvg,omitempty"`
	BeforePositiveRate *float64     `json:"beforePositiveRate,omitempty"`
	AfterPositiveRate  *float64     `json:"afterPositiveRate,omitempty"`
	Recurrences        int          `json:"recurrences"`
	Missing            []string     `json:"missing"`
	Conclusion         string       `json:"conclusion"`
}

// EvaluateControlEffect 对比指定窗口风险、阳性率和复发；缺失维度单独列出。
func EvaluateControlEffect(eventID string, window EffectWindow, before, after EffectMetrics) EffectReport {
	report := EffectReport{
		EventID:     eventID,
		Window:      window,
		Recurrences: after.Recurrences,
		Missing:     []string{},
	}
	if len(before.RiskSamples) > 0 {
		value := avg(before.RiskSamples)
		report.BeforeRiskAvg = &value
	} else {
		report.Missing = append(report.Missing, "before_risk")
	}
	if len(after.RiskSamples) > 0 {
		value := avg(after.RiskSamples)
		report.AfterRiskAvg = &value
	} else {
		report.Missing = append(report.Missing, "after_risk")
	}
	if before.LampTotal > 0 {
		value := float64(before.LampPositive) / float64(before.LampTotal)
		report.BeforePositiveRate = &value
	} else {
		report.Missing = append(report.Missing, "before_lamp")
	}
	if after.LampTotal > 0 {
		value := float64(after.LampPositive) / float64(after.LampTotal)
		report.AfterPositiveRate = &value
	} else {
		report.Missing = append(report.Missing, "after_lamp")
	}
	if before.Loss == nil {
		report.Missing = append(report.Missing, "before_loss")
	}
	if after.Loss == nil {
		report.Missing = append(report.Missing, "after_loss")
	}
	if before.Cost == nil {
		report.Missing = append(report.Missing, "before_cost")
	}
	if after.Cost == nil {
		report.Missing = append(report.Missing, "after_cost")
	}
	switch {
	case report.AfterRiskAvg == nil || report.BeforeRiskAvg == nil:
		report.Conclusion = "证据不足，无法判断效果"
	case *report.AfterRiskAvg < *report.BeforeRiskAvg && after.Recurrences == 0:
		report.Conclusion = "改善"
	case *report.AfterRiskAvg >= *report.BeforeRiskAvg:
		report.Conclusion = "未改善"
	default:
		report.Conclusion = "需人工复核"
	}
	return report
}

func avg(values []float64) float64 {
	sum := 0.0
	for _, v := range values {
		sum += v
	}
	return sum / float64(len(values))
}