// 云账单同步引擎 — 从云账号 AK 拉取日账单写入本地 // Logan.Li
package billingsync

import (
	"fmt"
	"time"

	"ezops/cloud"
	"ezops/model"

	"gorm.io/gorm"
)

// Result 同步结果
type Result struct {
	BillingDate string   `json:"billing_date"`
	Accounts    int      `json:"accounts"`
	Created     int      `json:"created"`
	Updated     int      `json:"updated"`
	Skipped     int      `json:"skipped"`
	Errors      []string `json:"errors"`
}

// Yesterday 昨日日期 YYYY-MM-DD
func Yesterday() string {
	return billingYesterdayAt(time.Now())
}

// billingYesterdayAt 按平台业务时区计算昨日，避免服务器 UTC 时区造成日期偏差。 // Logan.Li
func billingYesterdayAt(now time.Time) string {
	location, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		location = time.FixedZone("CST", 8*60*60)
	}
	return now.In(location).AddDate(0, 0, -1).Format("2006-01-02")
}

// SyncDate 同步指定日期账单（全部或单个活跃云账号）
func SyncDate(db *gorm.DB, billingDate string, accountID *uint) Result {
	result := Result{
		BillingDate: billingDate,
		Errors:      []string{},
	}

	var accounts []model.CloudAccount
	q := db.Where("status = ?", "active")
	if accountID != nil {
		q = q.Where("id = ?", *accountID)
	} else {
		// 批量同步只选择已接入账单 API 的厂商，避免无效失败。 // Logan.Li
		q = q.Where("provider IN ?", cloud.SupportedBillingProviders)
	}
	q.Find(&accounts)
	result.Accounts = len(accounts)

	if len(accounts) == 0 {
		result.Errors = append(result.Errors, "没有可同步的活跃云账号")
		return result
	}

	for _, account := range accounts {
		created, updated, skipped, err := syncAccount(db, account, billingDate)
		result.Created += created
		result.Updated += updated
		result.Skipped += skipped
		if err != nil {
			result.Errors = append(result.Errors, fmt.Sprintf("%s(%s): %s", account.Name, account.Provider, err.Error()))
		}
	}
	return result
}

// SummaryMessage 生成执行摘要文案
func SummaryMessage(r Result) string {
	msg := fmt.Sprintf("%s 新增 %d 条，更新 %d 条", r.BillingDate, r.Created, r.Updated)
	if len(r.Errors) > 0 {
		msg += fmt.Sprintf("；%d 个账号异常", len(r.Errors))
	}
	return msg
}

func syncAccount(db *gorm.DB, account model.CloudAccount, billingDate string) (created, updated, skipped int, err error) {
	fetcher := cloud.NewBillingFetcher(account.Provider, account.AccessKey, account.SecretKey)
	if fetcher == nil {
		return 0, 0, 0, fmt.Errorf("暂不支持该云厂商账单同步")
	}

	records, err := fetcher.FetchDailyBill(billingDate)
	if err != nil {
		return 0, 0, 0, err
	}
	if len(records) == 0 {
		return 0, 0, 1, fmt.Errorf("该日期暂无账单数据（可能尚未出账）")
	}

	accountID := account.ID
	accountName := account.Name
	billingCurrency := records[0].Currency
	if billingCurrency == "" {
		billingCurrency = "CNY"
	}

	for _, rec := range records {
		if rec.Currency == "" {
			rec.Currency = billingCurrency
		}
		var existing model.CloudBilling
		findErr := db.Where(
			"cloud_account_id = ? AND billing_date = ? AND provider = ? AND service = ? AND region = ?",
			accountID, billingDate, rec.Provider, rec.Service, rec.Region,
		).Take(&existing).Error

		if findErr == gorm.ErrRecordNotFound {
			row := model.CloudBilling{
				CloudAccountID: &accountID,
				AccountName:    accountName,
				Provider:       rec.Provider,
				BillingDate:    billingDate,
				Cost:           rec.Cost,
				Currency:       rec.Currency,
				Service:        rec.Service,
				Region:         rec.Region,
				Description:    rec.Description,
			}
			if row.Currency == "" {
				row.Currency = "CNY"
			}
			if db.Create(&row).Error == nil {
				created++
			} else {
				skipped++
			}
			continue
		}
		if findErr != nil {
			skipped++
			continue
		}

		if db.Model(&existing).Updates(map[string]interface{}{
			"cost":         rec.Cost,
			"currency":     rec.Currency,
			"description":  rec.Description,
			"account_name": accountName,
		}).Error == nil {
			updated++
		} else {
			skipped++
		}
	}

	monthStart := billingDate[:7] + "-01"
	var monthCost float64
	db.Model(&model.CloudBilling{}).
		Where("cloud_account_id = ? AND billing_date >= ? AND currency = ?", accountID, monthStart, billingCurrency).
		Select("COALESCE(SUM(cost), 0)").Scan(&monthCost)
	db.Model(&account).Updates(map[string]interface{}{
		"monthly_cost":     monthCost,
		"billing_currency": billingCurrency,
	})

	return created, updated, skipped, nil
}