package model

import (
	"context"

	"gorm.io/gorm"
)

// AIUsageRecordInsert 插入AI使用记录
func AIUsageRecordInsert(ctx context.Context, db *gorm.DB, record *AIUsageRecord) (int64, error) {
	result := db.WithContext(ctx).Create(record)
	if result.Error != nil {
		return 0, result.Error
	}
	return record.Id, nil
}

// AIUsageRecordFindByUser 根据用户ID查询使用记录（分页，按创建时间倒序）
func AIUsageRecordFindByUser(ctx context.Context, db *gorm.DB, userId int64, page, pageSize int64) ([]AIUsageRecord, int64, error) {
	var records []AIUsageRecord
	var total int64

	query := db.WithContext(ctx).Model(&AIUsageRecord{}).Where("user_id = ?", userId)

	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	offset := (page - 1) * pageSize
	if offset < 0 {
		offset = 0
	}
	err := query.Order("created_at DESC").Offset(int(offset)).Limit(int(pageSize)).Find(&records).Error
	if err != nil {
		return nil, 0, err
	}

	return records, total, nil
}

// AIUsageRecordFindList 查询使用记录（支持过滤，admin/user通用）
func AIUsageRecordFindList(ctx context.Context, db *gorm.DB, userId int64, modelId, status string, page, pageSize int64) ([]AIUsageRecord, int64, error) {
	var records []AIUsageRecord
	var total int64

	query := db.WithContext(ctx).Model(&AIUsageRecord{})
	if userId > 0 {
		query = query.Where("user_id = ?", userId)
	}
	if modelId != "" {
		query = query.Where("model_id = ?", modelId)
	}
	if status != "" {
		query = query.Where("status = ?", status)
	}

	if err := query.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	offset := (page - 1) * pageSize
	if offset < 0 {
		offset = 0
	}
	err := query.Order("created_at DESC").Offset(int(offset)).Limit(int(pageSize)).Find(&records).Error
	return records, total, err
}

// AIUsageRecordModelStats 按模型分组统计（指定天数内）
type ModelStatResult struct {
	ModelId      string  `json:"modelId"`
	Calls        int64   `json:"calls"`
	InputTokens  int64   `json:"inputTokens"`
	OutputTokens int64   `json:"outputTokens"`
	TotalCost    float64 `json:"totalCost"`
}

func AIUsageRecordModelStats(ctx context.Context, db *gorm.DB, days int) ([]ModelStatResult, error) {
	var results []ModelStatResult
	err := db.WithContext(ctx).Model(&AIUsageRecord{}).
		Select("model_id, COUNT(*) as calls, SUM(input_tokens) as input_tokens, SUM(output_tokens) as output_tokens, SUM(cost) as total_cost").
		Where("created_at >= DATE_SUB(NOW(), INTERVAL ? DAY)", days).
		Group("model_id").
		Order("total_cost DESC").
		Find(&results).Error
	return results, err
}

// AIUsageRecordDailyStats 按日统计（指定天数内）
type DailyStatResult struct {
	Date        string  `json:"date"`
	Calls       int64   `json:"calls"`
	TotalTokens int64   `json:"totalTokens"`
	TotalCost   float64 `json:"totalCost"`
}

func AIUsageRecordDailyStats(ctx context.Context, db *gorm.DB, days int) ([]DailyStatResult, error) {
	var results []DailyStatResult
	err := db.WithContext(ctx).Model(&AIUsageRecord{}).
		Select("DATE(created_at) as date, COUNT(*) as calls, SUM(input_tokens + output_tokens) as total_tokens, SUM(cost) as total_cost").
		Where("created_at >= DATE_SUB(NOW(), INTERVAL ? DAY)", days).
		Group("DATE(created_at)").
		Order("date ASC").
		Find(&results).Error
	return results, err
}

// AIUsageRecordTotalStats 总体统计（指定天数内）
type TotalStatResult struct {
	TotalCalls  int64   `json:"totalCalls"`
	TotalTokens int64   `json:"totalTokens"`
	TotalCost   float64 `json:"totalCost"`
	TotalUsers  int64   `json:"totalUsers"`
}

func AIUsageRecordTotalStats(ctx context.Context, db *gorm.DB, days int) (*TotalStatResult, error) {
	var result TotalStatResult
	err := db.WithContext(ctx).Model(&AIUsageRecord{}).
		Select("COUNT(*) as total_calls, COALESCE(SUM(input_tokens + output_tokens), 0) as total_tokens, COALESCE(SUM(cost), 0) as total_cost, COUNT(DISTINCT user_id) as total_users").
		Where("created_at >= DATE_SUB(NOW(), INTERVAL ? DAY)", days).
		Find(&result).Error
	return &result, err
}