package order

import (
	"time"

	"hfb_sys/backend/internal/model"
	"hfb_sys/backend/internal/modules/notification"
	"hfb_sys/backend/internal/modules/wallet"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

func (r *Repository) SubmitCheckout(userID uint64, orderID uint64, req SubmitCheckoutRequest) (*HandoffRecordDTO, error) {
	var recordID uint64
	err := r.db.Transaction(func(tx *gorm.DB) error {
		var order model.RentalOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&order, orderID).Error; err != nil {
			return err
		}
		if order.RenterID != userID {
			return ErrPermissionDenied
		}
		if (order.Status != "renting" && order.Status != "overdue") || (order.HandoffStatus != "received" && order.HandoffStatus != "return_overdue") {
			return ErrCheckoutCannotSubmit
		}
		hasOpen, err := hasOpenCheckout(tx, order.ID)
		if err != nil {
			return err
		}
		if hasOpen {
			return ErrCheckoutCannotSubmit
		}
		record := model.HandoffRecord{
			OrderID:    order.ID,
			FromUserID: order.RenterID,
			ToUserID:   order.OwnerID,
			Type:       "renter_checkout",
			Content:    req.Content,
		}
		if err := tx.Create(&record).Error; err != nil {
			return err
		}
		checkout, err := buildCheckout(order, order.RenterID, "submitted", req.Content, req.EvidenceURLS, req.ConsumableAmountCent, req.CoinConsumedM, req.OtherAmountCent, 0, false)
		if err != nil {
			return err
		}
		if err := tx.Create(&checkout).Error; err != nil {
			return err
		}
		order.Status = "pending_checkout_confirm"
		order.HandoffStatus = "pending_owner_checkout"
		order.SettlementStatus = "pending"
		orderID := order.ID
		if err := notification.Append(tx, notification.Entry{
			UserID:  order.OwnerID,
			Type:    "checkout",
			Title:   "租客已发起结账",
			Content: "请检查账号状态和消耗明细，确认无误后完成结算。",
			BizType: "order",
			BizID:   &orderID,
		}); err != nil {
			return err
		}
		if err := tx.Save(&order).Error; err != nil {
			return err
		}
		recordID = record.ID
		return nil
	})
	if err != nil {
		return nil, err
	}
	return r.findHandoffRecord(recordID)
}

func (r *Repository) ConfirmReturn(userID uint64, orderID uint64) error {
	return r.ConfirmCheckout(userID, orderID)
}

func (r *Repository) ConfirmCheckout(userID uint64, orderID uint64) error {
	var refund *refundAction
	err := r.db.Transaction(func(tx *gorm.DB) error {
		var order model.RentalOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&order, orderID).Error; err != nil {
			return err
		}
		if order.OwnerID != userID {
			return ErrPermissionDenied
		}
		if order.Status != "pending_checkout_confirm" || order.HandoffStatus != "pending_owner_checkout" {
			return ErrCheckoutCannotConfirm
		}
		var checkout model.OrderCheckout
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
			Where("order_id = ? AND status = ?", order.ID, "submitted").
			Order("id DESC").
			First(&checkout).Error; err != nil {
			return err
		}
		now := time.Now()
		if err := tx.Model(&model.HandoffRecord{}).
			Where("order_id = ? AND type = ?", order.ID, "renter_checkout").
			Update("confirmed_by_owner_at", now).Error; err != nil {
			return err
		}
		checkout.Status = "accepted"
		checkout.OwnerAdjustedAt = &now
		action, err := r.finalizeCheckout(tx, &order, &checkout, "号主已确认结账，订单完成。")
		refund = action
		return err
	})
	if err != nil {
		return err
	}
	r.startRefundBestEffort(refund)
	return nil
}

func (r *Repository) CounterCheckout(userID uint64, orderID uint64, req CounterCheckoutRequest) (*CheckoutDTO, error) {
	var checkoutID uint64
	err := r.db.Transaction(func(tx *gorm.DB) error {
		var order model.RentalOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&order, orderID).Error; err != nil {
			return err
		}
		if order.OwnerID != userID {
			return ErrPermissionDenied
		}
		if order.Status != "pending_checkout_confirm" || order.HandoffStatus != "pending_owner_checkout" {
			return ErrCheckoutCannotCounter
		}
		var checkout model.OrderCheckout
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
			Where("order_id = ? AND status = ?", order.ID, "submitted").
			Order("id DESC").
			First(&checkout).Error; err != nil {
			return err
		}
		next, err := buildCheckout(order, checkout.InitiatedBy, "countered", checkout.Content, req.EvidenceURLS, req.ConsumableAmountCent, req.CoinConsumedM, req.OtherAmountCent, req.DepositDeductAmountCent, true)
		if err != nil {
			return err
		}
		now := time.Now()
		checkout.Status = "countered"
		checkout.RentAmountCent = next.RentAmountCent
		checkout.OwnerRentAmountCent = next.OwnerRentAmountCent
		checkout.PlatformFeeCent = next.PlatformFeeCent
		checkout.DepositAmountCent = next.DepositAmountCent
		checkout.ConsumableAmountCent = next.ConsumableAmountCent
		checkout.CoinConsumedM = next.CoinConsumedM
		checkout.OtherAmountCent = next.OtherAmountCent
		checkout.DepositDeductAmountCent = next.DepositDeductAmountCent
		checkout.RenterRefundAmountCent = next.RenterRefundAmountCent
		checkout.OwnerIncomeAmountCent = next.OwnerIncomeAmountCent
		checkout.OwnerAdjustmentReason = req.Reason
		checkout.OwnerAdjustedAt = &now
		checkout.EvidenceURLS = next.EvidenceURLS
		order.Status = "pending_checkout_accept"
		order.HandoffStatus = "pending_renter_checkout"
		order.SettlementStatus = "pending"
		orderID := order.ID
		if err := notification.Append(tx, notification.Entry{
			UserID:  order.RenterID,
			Type:    "checkout",
			Title:   "号主已修改结账金额",
			Content: "请核对号主修正的消耗和结算金额。同意后订单完成；不同意可发起争议。",
			BizType: "order",
			BizID:   &orderID,
		}); err != nil {
			return err
		}
		if err := tx.Save(&order).Error; err != nil {
			return err
		}
		if err := tx.Save(&checkout).Error; err != nil {
			return err
		}
		checkoutID = checkout.ID
		return nil
	})
	if err != nil {
		return nil, err
	}
	checkout, err := r.findCheckout(checkoutID)
	if err != nil {
		return nil, err
	}
	dto := toCheckoutDTOForUser(*checkout, userID, model.RentalOrder{
		OwnerID:             userID,
		RentAmountCent:      checkout.RentAmountCent,
		OwnerRentAmountCent: checkout.OwnerRentAmountCent,
		DepositAmountCent:   checkout.DepositAmountCent,
	})
	return &dto, nil
}

func (r *Repository) AcceptCheckout(userID uint64, orderID uint64) error {
	var refund *refundAction
	err := r.db.Transaction(func(tx *gorm.DB) error {
		var order model.RentalOrder
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&order, orderID).Error; err != nil {
			return err
		}
		if order.RenterID != userID {
			return ErrPermissionDenied
		}
		if order.Status != "pending_checkout_accept" || order.HandoffStatus != "pending_renter_checkout" {
			return ErrCheckoutCannotConfirm
		}
		var checkout model.OrderCheckout
		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).
			Where("order_id = ? AND status = ?", order.ID, "countered").
			Order("id DESC").
			First(&checkout).Error; err != nil {
			return err
		}
		now := time.Now()
		checkout.Status = "accepted"
		checkout.RenterConfirmedAt = &now
		action, err := r.finalizeCheckout(tx, &order, &checkout, "租客已确认修正结账，订单完成。")
		refund = action
		return err
	})
	if err != nil {
		return err
	}
	r.startRefundBestEffort(refund)
	return nil
}

func (r *Repository) finalizeCheckout(tx *gorm.DB, order *model.RentalOrder, checkout *model.OrderCheckout, renterContent string) (*refundAction, error) {
	var listing model.RentalListing
	if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&listing, order.ListingID).Error; err != nil {
		return nil, err
	}
	var account model.GameAccount
	if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).First(&account, order.AccountID).Error; err != nil {
		return nil, err
	}
	now := time.Now()
	order.Status = "completed"
	order.HandoffStatus = "returned"
	order.SettlementStatus = "settled"
	order.SettledAt = &now
	order.OwnerSettledAt = &now
	archiveListingAfterCheckout(&listing, &account)
	orderID := order.ID
	settlement := buildCheckoutSettlement(*order, checkout)

	// 卖家收入进入站内钱包；租客资金不进入站内钱包。
	var ownerEntries []wallet.Entry
	if settlement.OwnerRentIncomeCent > 0 {
		ownerEntries = append(ownerEntries, wallet.Entry{
			UserID:      order.OwnerID,
			OrderID:     &orderID,
			Direction:   "in",
			AmountCent:  settlement.OwnerRentIncomeCent,
			BalanceType: "available",
			BizType:     "owner_income",
			BizNo:       order.OrderNo,
			Remark:      "订单结账租金收入",
		})
	}
	if settlement.DepositCompensationCent > 0 {
		ownerEntries = append(ownerEntries, wallet.Entry{
			UserID:      order.OwnerID,
			OrderID:     &orderID,
			Direction:   "in",
			AmountCent:  settlement.DepositCompensationCent,
			BalanceType: "available",
			BizType:     "deposit_compensation",
			BizNo:       order.OrderNo,
			Remark:      "订单结账押金赔付",
		})
	}
	if len(ownerEntries) > 0 {
		if err := wallet.AppendEntries(tx, ownerEntries...); err != nil {
			return nil, err
		}
	}

	var refund *refundAction
	renterRefundTotalCent := settlement.RentRefundCent + settlement.DepositRefundCent
	if renterRefundTotalCent > 0 {
		action, err := r.prepareRefund(order, renterRefundTotalCent, "checkout_refund", "结账退款原路退还")
		if err != nil {
			return nil, err
		}
		refund = action
	}

	checkout.RentAmountCent = settlement.ActualRentAmountCent
	checkout.OwnerRentAmountCent = settlement.OwnerRentIncomeCent
	checkout.PlatformFeeCent = settlement.PlatformFeeCent
	checkout.RenterRefundAmountCent = settlement.RenterRefundCent
	checkout.OwnerIncomeAmountCent = settlement.OwnerIncomeCent
	if err := notification.Append(tx,
		notification.Entry{
			UserID:  order.RenterID,
			Type:    "settlement",
			Title:   "订单已完成",
			Content: renterContent,
			BizType: "order",
			BizID:   &orderID,
		},
		notification.Entry{
			UserID:  order.OwnerID,
			Type:    "settlement",
			Title:   "订单已完成",
			Content: "订单已完成，结账金额已入账。",
			BizType: "order",
			BizID:   &orderID,
		},
	); err != nil {
		return nil, err
	}
	if err := tx.Save(order).Error; err != nil {
		return nil, err
	}
	if err := tx.Save(checkout).Error; err != nil {
		return nil, err
	}
	if err := tx.Save(&listing).Error; err != nil {
		return nil, err
	}
	if err := tx.Save(&account).Error; err != nil {
		return nil, err
	}
	return refund, nil
}

// 完成后的账号先下架，避免已完成订单对应的账号重新出现在公开首页。
func archiveListingAfterCheckout(listing *model.RentalListing, account *model.GameAccount) {
	listing.Status = "offline"
	listing.InTransaction = false
	listing.PublishedAt = nil
	account.Status = "offline"
}

func hasOpenCheckout(tx *gorm.DB, orderID uint64) (bool, error) {
	var count int64
	err := tx.Model(&model.OrderCheckout{}).
		Where("order_id = ? AND status IN ?", orderID, []string{"submitted", "countered", "accepted", "disputed"}).
		Count(&count).Error
	return count > 0, err
}