package employeecollection

import (
	"context"

	"github.com/bytedance/sonic"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"

	employeecollectiondomain "github.com/break/junhong_cmp_fiber/internal/domain/employeecollection"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// BillAudit 描述员工代收款账单事实的实际变化。
type BillAudit struct {
	// EventID 是审计事件稳定标识，同一业务事实重复重放时保持相同值。
	EventID string
	// ActionCode 是已注册的账单审计动作码。
	ActionCode string
	// Summary 是给人工阅读的中文摘要。
	Summary string
	// Bill 是本次动作后的账单事实。
	Bill *model.EmployeeCollectionBill
	// BeforeData 与 AfterData 是脱敏前后的字段快照。
	BeforeData map[string]any
	AfterData  map[string]any
	// CorrelationID 是来源业务链路标识。
	CorrelationID string
}

// BillAuditWriter 在员工代收款业务事务内追加统一 Audit Event。
type BillAuditWriter interface {
	WriteEmployeeCollectionBill(ctx context.Context, tx *gorm.DB, change BillAudit) error
}

// BillCreationService 在来源成功事务内按来源唯一键幂等创建员工代收款账单。
// 建账只由来源成功事务携带的来源主键触发，不存在扫描历史订单或充值补建的路径。
type BillCreationService struct {
	audit BillAuditWriter
}

// NewBillCreationService 创建员工代收款建账用例。
func NewBillCreationService(audit BillAuditWriter) *BillCreationService {
	return &BillCreationService{audit: audit}
}

// CreateFromOrderInTx 在后台线下套餐订单激活事务内建账。
// 判据见 employeecollectiondomain.ShouldCreateBillForOrder；不满足判据时返回 (nil, nil)。
// 重复订单事务、重放或重试都命中 source_key 唯一约束并返回既有账单，不使订单事务失败。
func (s *BillCreationService) CreateFromOrderInTx(
	ctx context.Context,
	tx *gorm.DB,
	order *model.Order,
	hasGiftPackage bool,
) (*model.EmployeeCollectionBill, error) {
	if s == nil || tx == nil || s.audit == nil {
		return nil, errors.New(errors.CodeInternalError, "员工代收款建账用例未完整配置")
	}
	if order == nil || order.ID == 0 {
		return nil, errors.New(errors.CodeInvalidParam, "员工代收款建账缺少来源订单")
	}
	if !employeecollectiondomain.ShouldCreateBillForOrder(
		employeecollectiondomain.OrderBillSubjectFromOrder(order, hasGiftPackage)) {
		return nil, nil
	}
	if order.OperatorAccountID == nil || *order.OperatorAccountID == 0 {
		return nil, errors.New(errors.CodeInternalError, "线下套餐订单缺少欠款人账号")
	}
	debtorAccountID := *order.OperatorAccountID
	debtorSnapshot, err := marshalSnapshot(map[string]any{
		"account_id": debtorAccountID, "account_name": order.OperatorAccountName,
		"account_type": order.OperatorAccountType,
	})
	if err != nil {
		return nil, err
	}
	// shop_id 与 seller_shop_id 同时写入：店铺筛选统一读 shop_id，seller_shop_id 保留兼容口径。
	customerSnapshot, err := marshalSnapshot(map[string]any{
		"buyer_type": order.BuyerType, "buyer_id": order.BuyerID,
		"buyer_nickname": order.BuyerNickname,
		"shop_id":        order.SellerShopID, "seller_shop_id": order.SellerShopID,
		"asset_identifier": order.AssetIdentifier,
	})
	if err != nil {
		return nil, err
	}
	sourceKey := employeecollectiondomain.OrderSourceKey(order.ID)
	bill := &model.EmployeeCollectionBill{
		SourceType:       constants.EmployeeCollectionSourceTypeOrder,
		SourceID:         order.ID,
		SourceKey:        sourceKey,
		SourceNo:         order.OrderNo,
		DebtorAccountID:  debtorAccountID,
		DebtorSnapshot:   debtorSnapshot,
		CustomerSnapshot: customerSnapshot,
		ReceivableAmount: *order.ActualPaidAmount,
		Status:           constants.EmployeeCollectionBillStatusPending,
		Creator:          debtorAccountID,
		Updater:          debtorAccountID,
	}
	return s.persistInTx(ctx, tx, bill,
		[]string{"employee_collection", "bill", "order", uintText(order.ID), "create"},
		"后台线下套餐订单创建员工代收款账单", order.OrderNo)
}

// CreateFromRechargeInTx 在代理线下充值入账事务内建账。
// 判据见 employeecollectiondomain.ShouldCreateBillForRecharge；欠款人为发起充值的后台账号。
// 覆盖企业微信终审通过入账与后台人工确认入账两条入口，重复入账不重复建账。
func (s *BillCreationService) CreateFromRechargeInTx(
	ctx context.Context,
	tx *gorm.DB,
	record *model.AgentRechargeRecord,
) (*model.EmployeeCollectionBill, error) {
	if s == nil || tx == nil || s.audit == nil {
		return nil, errors.New(errors.CodeInternalError, "员工代收款建账用例未完整配置")
	}
	if record == nil || record.ID == 0 {
		return nil, errors.New(errors.CodeInvalidParam, "员工代收款建账缺少来源充值记录")
	}
	if !employeecollectiondomain.ShouldCreateBillForRecharge(employeecollectiondomain.RechargeBillSubject{
		PaymentMethod: record.PaymentMethod, Amount: record.Amount,
	}) {
		return nil, nil
	}
	if record.UserID == 0 {
		return nil, errors.New(errors.CodeInternalError, "线下充值记录缺少发起账号")
	}
	debtorName, err := rechargeAccountName(ctx, tx, record.UserID)
	if err != nil {
		return nil, err
	}
	debtorSnapshot, err := marshalSnapshot(map[string]any{
		"account_id": record.UserID, "account_name": debtorName,
		"account_type": model.OperatorAccountTypePlatform,
	})
	if err != nil {
		return nil, err
	}
	customerSnapshot, err := marshalSnapshot(map[string]any{
		"shop_id": record.ShopID, "agent_wallet_id": record.AgentWalletID,
		"payment_method": record.PaymentMethod, "recharge_no": record.RechargeNo,
	})
	if err != nil {
		return nil, err
	}
	sourceKey := employeecollectiondomain.RechargeSourceKey(record.ID)
	bill := &model.EmployeeCollectionBill{
		SourceType:       constants.EmployeeCollectionSourceTypeRecharge,
		SourceID:         record.ID,
		SourceKey:        sourceKey,
		SourceNo:         record.RechargeNo,
		DebtorAccountID:  record.UserID,
		DebtorSnapshot:   debtorSnapshot,
		CustomerSnapshot: customerSnapshot,
		ReceivableAmount: record.Amount,
		Status:           constants.EmployeeCollectionBillStatusPending,
		Creator:          record.UserID,
		Updater:          record.UserID,
	}
	return s.persistInTx(ctx, tx, bill,
		[]string{"employee_collection", "bill", "recharge", uintText(record.ID), "create"},
		"代理线下充值入账创建员工代收款账单", record.RechargeNo)
}

// persistInTx 以来源唯一键幂等写入账单：已存在同一来源账单时返回既有事实且不重复审计。
func (s *BillCreationService) persistInTx(
	ctx context.Context,
	tx *gorm.DB,
	bill *model.EmployeeCollectionBill,
	eventIDParts []string,
	summary string,
	correlationID string,
) (*model.EmployeeCollectionBill, error) {
	eventID, err := composeAuditEventID(eventIDParts...)
	if err != nil {
		return nil, err
	}
	result := tx.WithContext(ctx).Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "source_key"}},
		DoNothing: true,
	}).Create(bill)
	if result.Error != nil {
		return nil, errors.Wrap(errors.CodeDatabaseError, result.Error, "创建员工代收款账单失败")
	}
	if result.RowsAffected == 0 {
		var existing model.EmployeeCollectionBill
		if err := tx.WithContext(ctx).Where("source_key = ?", bill.SourceKey).First(&existing).Error; err != nil {
			return nil, errors.Wrap(errors.CodeDatabaseError, err, "读取既有员工代收款账单失败")
		}
		return &existing, nil
	}
	if err := s.audit.WriteEmployeeCollectionBill(ctx, tx, BillAudit{
		EventID: eventID, ActionCode: constants.AuditActionEmployeeCollectionBillCreated, Summary: summary,
		Bill: bill, AfterData: billAuditSnapshot(bill), CorrelationID: correlationID,
	}); err != nil {
		return nil, err
	}
	return bill, nil
}

// marshalSnapshot 将只读业务快照序列化为 jsonb，快照不得包含付款凭证或外部交易敏感内容。
func marshalSnapshot(snapshot map[string]any) ([]byte, error) {
	payload, err := sonic.Marshal(snapshot)
	if err != nil {
		return nil, errors.Wrap(errors.CodeInternalError, err, "序列化员工代收款账单快照失败")
	}
	return payload, nil
}

// rechargeAccountName 读取充值发起账号名称用于欠款人快照；账号已被删除时留空名称。
func rechargeAccountName(ctx context.Context, tx *gorm.DB, accountID uint) (string, error) {
	var account model.Account
	if err := tx.WithContext(ctx).Unscoped().First(&account, accountID).Error; err != nil {
		if err == gorm.ErrRecordNotFound {
			return "", nil
		}
		return "", errors.Wrap(errors.CodeDatabaseError, err, "查询线下充值发起账号失败")
	}
	return account.Username, nil
}

// billAuditSnapshot 生成账单审计快照，只包含 ID、来源、金额与状态，不含凭证内容。
func billAuditSnapshot(bill *model.EmployeeCollectionBill) map[string]any {
	return map[string]any{
		"id": bill.ID, "source_type": bill.SourceType, "source_id": bill.SourceID,
		"source_key": bill.SourceKey, "source_no": bill.SourceNo,
		"debtor_account_id": bill.DebtorAccountID, "receivable_amount": bill.ReceivableAmount,
		"received_amount": bill.ReceivedAmount, "reserved_amount": bill.ReservedAmount,
		"status": bill.Status,
	}
}