package ai

import (
	"time"

	"gorm.io/gorm"

	"eai_agentplatform/backend/internal/model"
	"eai_agentplatform/backend/internal/store"
)

// ──────────────────────────────────────────────
// 按用户算力点计费
// ──────────────────────────────────────────────

// AI 能力常量
const (
	CapabilityAIChat     = "ai_chat"     // PathCoach 对话（每轮扣 1 点）
	CapabilityTextGen    = "text_gen"    // 快捷动作（情景演练/查佣金/产品对比，扣 1 点）
	CapabilityImageGen   = "image_gen"   // 文生图（按次扣点）
	CapabilityEmbed      = "embed"       // 知识检索内部 embedding（不扣点，仅审计）
	CapabilityEssayGrade = "essay_grade" // 简答题 LLM 评分（系统自动，不扣点，仅审计）
)

// CapabilityCredits 各能力扣点成本
var CapabilityCredits = map[string]int{
	CapabilityAIChat:     1,
	CapabilityTextGen:    1,
	CapabilityImageGen:   1,
	CapabilityEmbed:      0,
	CapabilityEssayGrade: 0,
}

// ComputeCredits 扣点决策：仅「成功」才扣点；失败不扣。
func ComputeCredits(capability string, success bool) int {
	if !success {
		return 0
	}
	return CapabilityCredits[capability]
}

// LogEntry 一次 AI 调用的审计入参
type LogEntry struct {
	UserID     uint
	Capability string
	// SpecialistKey 本次调用以哪个专员的身份进行；空 = 通用助手
	SpecialistKey string
	Provider      string
	AIRouteID     string
	Model         string
	TokensInput   int
	TokensOutput  int
	Success       bool
	ErrorMessage  string
	LatencyMs     int
}

// LogCall 写 ai_call_log；成功且需扣点时从用户余额扣点。审计写入失败不阻断主流程。
func LogCall(e LogEntry) {
	credits := ComputeCredits(e.Capability, e.Success)
	status := "success"
	if !e.Success {
		status = "failed"
	}
	rec := model.AiCallLog{
		UserID:         e.UserID,
		Capability:     e.Capability,
		SpecialistKey:  e.SpecialistKey,
		Provider:       e.Provider,
		AIRouteID:      e.AIRouteID,
		Model:          e.Model,
		TokensInput:    e.TokensInput,
		TokensOutput:   e.TokensOutput,
		CreditsCharged: credits,
		Status:         status,
		ErrorMessage:   e.ErrorMessage,
		LatencyMs:      e.LatencyMs,
		CreatedAt:      time.Now(),
	}
	if err := store.DB.Create(&rec).Error; err != nil {
		return
	}
	if credits > 0 {
		store.DB.Model(&model.User{}).Where("id = ?", e.UserID).
			UpdateColumn("ai_points", gorm.Expr("ai_points - ?", credits))
	}
}