package unsub

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"math"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/gogf/gf/v2/database/gdb"
	"github.com/gogf/gf/v2/errors/gerror"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gtime"

	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/consts"
	unsub "git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/service/unsub"
)

const (
	agentBalanceTable  = "t_agent_balance"
	balanceDetailTable = "t_balance_detail"

	balanceAccountStatusNormal       = 0
	financeIncomeExpenseIncome       = 0
	financeTransactionTypeConsume    = 1
	financeTransactionChannelBalance = 3
	financeTransactionStatusPaid     = 1

	refundStatusRefunded = "refunded"
	refundStatusNoRefund = "no_refund"
	refundStatusSkipped  = "skipped"
)

type balanceAccountQuery struct {
	Id       int64   `orm:"id"`
	DeptId   int64   `orm:"dept_id"`
	Balance  float64 `orm:"balance"`
	Status   int     `orm:"status"`
	TenantId string  `orm:"tenant_id"`
}

type balanceDetailQuery struct {
	Id                int64   `orm:"id"`
	IncomeExpenseType int     `orm:"income_expense_type"`
	TransactionStatus int     `orm:"transaction_status"`
	Amount            float64 `orm:"amount"`
}

func unsubscribeTime(task *unsub.Task, fallback *gtime.Time) *gtime.Time {
	if task != nil && task.Batch.StartTime != nil {
		return task.Batch.StartTime
	}
	return fallback
}

func (r *Repository) lockOrdersByOrderCodes(ctx context.Context, tx gdb.TX, tenantID string, orderCounts map[string]int) (map[string]*orderQuery, error) {
	result := make(map[string]*orderQuery)
	orderCodes := sortedOrderCodes(orderCounts)
	if len(orderCodes) == 0 {
		return result, nil
	}
	var rows []*orderQuery
	model := r.applyLock(tx.Ctx(ctx).Model(orderTable)).
		WhereIn("order_sn", orderCodes).
		Fields("id", "order_sn", "customer_agent_id", "pay_type", "pay_status", "pay_order_sn", "total_amount", "paid_amount", "balance", "unrefund_amount", "tenant_id", "created_dept")
	if strings.TrimSpace(tenantID) != "" {
		model = model.Where("tenant_id", tenantID)
	}
	if err := model.Scan(&rows); err != nil {
		return nil, err
	}
	for _, row := range rows {
		if row != nil && strings.TrimSpace(row.OrderSn) != "" {
			result[strings.TrimSpace(row.OrderSn)] = row
		}
	}
	return result, nil
}

func (r *Repository) lockOrderItemsByOrderCodes(ctx context.Context, tx gdb.TX, tenantID string, orderCounts map[string]int) (map[string]*orderItemQuery, error) {
	result := make(map[string]*orderItemQuery)
	orderCodes := sortedOrderCodes(orderCounts)
	if len(orderCodes) == 0 {
		return result, nil
	}
	var rows []*orderItemQuery
	model := r.applyLock(tx.Ctx(ctx).Model(orderItemTable)).
		WhereIn("order_sn", orderCodes).
		Fields("item_id", "order_sn", "price", "quantity", "service_begin_time", "service_end_time", "extra_sku_data")
	if strings.TrimSpace(tenantID) != "" {
		model = model.Where("tenant_id", tenantID)
	}
	if err := model.Scan(&rows); err != nil {
		return nil, err
	}
	for _, row := range rows {
		if row == nil || strings.TrimSpace(row.OrderSn) == "" {
			continue
		}
		orderCode := strings.TrimSpace(row.OrderSn)
		if _, exists := result[orderCode]; !exists {
			result[orderCode] = row
		}
	}
	return result, nil
}

func (r *Repository) refundOrders(
	ctx context.Context,
	tx gdb.TX,
	task *unsub.Task,
	orderCounts map[string]int,
	bindsByIccid map[string]*bindPkgQuery,
	orders map[string]*orderQuery,
	orderItems map[string]*orderItemQuery,
	activeCounts map[string]int,
	cutoffTime, transactionTime *gtime.Time,
) (map[string]*unsub.OrderRefund, error) {
	if cutoffTime == nil {
		cutoffTime = transactionTime
	}
	if cutoffTime == nil {
		return nil, gerror.New("unsub refund cutoff time is empty")
	}
	result := make(map[string]*unsub.OrderRefund, len(orderCounts))
	orderBinds := make(map[string][]*bindPkgQuery, len(orderCounts))
	for _, detail := range task.Details {
		if detail == nil {
			continue
		}
		bind := bindsByIccid[detail.ICCID]
		if bind == nil {
			continue
		}
		orderCode := strings.TrimSpace(bind.OrderCode)
		if orderCode != "" {
			orderBinds[orderCode] = append(orderBinds[orderCode], bind)
		}
	}

	for _, orderCode := range sortedOrderCodes(orderCounts) {
		refund := &unsub.OrderRefund{Status: refundStatusNoRefund}
		result[orderCode] = refund
		order := orders[orderCode]
		if order == nil {
			refund.Status = refundStatusSkipped
			refund.Reason = "order not found"
			g.Log().Warningf(ctx, "unsub balance refund skipped, order not found, batchNo=%s orderNo=%s", task.Batch.BatchNo, orderCode)
			continue
		}
		if order.PayType != consts.PayTypeBalance {
			refund.Status = refundStatusSkipped
			refund.Reason = "order is not paid by balance"
			g.Log().Warningf(ctx, "unsub balance refund skipped, order is not paid by balance, batchNo=%s orderNo=%s payType=%d", task.Batch.BatchNo, orderCode, order.PayType)
			continue
		}
		if order.PayStatus != 0 && order.PayStatus != consts.PayStatusPaid {
			refund.Status = refundStatusSkipped
			refund.Reason = "order is not paid"
			g.Log().Warningf(ctx, "unsub balance refund skipped, order is not paid, batchNo=%s orderNo=%s payStatus=%d", task.Batch.BatchNo, orderCode, order.PayStatus)
			continue
		}

		binds := orderBinds[orderCode]
		if len(binds) == 0 {
			continue
		}
		item := orderItems[orderCode]
		totalQuantity := resolveOrderQuantity(order, item, activeCounts[orderCode])
		if totalQuantity <= 0 {
			return nil, gerror.Newf("order %s lacks a valid subscription quantity for refund", orderCode)
		}
		paidAmount := orderPaidAmount(order, item, totalQuantity)
		if paidAmount <= 0 {
			refund.Reason = "order paid amount is zero"
			continue
		}
		unitPaidAmount := paidAmount / float64(totalQuantity)
		refundAmount := 0.0
		for _, bind := range binds {
			if bind == nil {
				continue
			}
			if bind.EffectiveTime == nil || bind.DurationMonths <= 0 {
				return nil, gerror.Newf("order %s has an invalid paid subscription period", orderCode)
			}
			refundAmount += unitPaidAmount * calculateRefundRatio(bind.EffectiveTime.Time, cutoffTime.Time, bind.DurationMonths)
		}
		refund.Amount = roundUnsubAmount(refundAmount)
		if refund.Amount <= 0 {
			refund.Reason = "paid subscription period has been fully used"
			continue
		}

		refund.SerialNo = unsubscribeRefundSerialNo(task.Batch.BatchNo, orderCode)
		existing, err := r.lockRefundDetail(ctx, tx, task.Batch.TenantID, refund.SerialNo)
		if err != nil {
			return nil, gerror.Wrap(err, "query existing unsub refund detail")
		}
		if existing.Id != 0 {
			if existing.IncomeExpenseType != financeIncomeExpenseIncome || existing.TransactionStatus != financeTransactionStatusPaid {
				return nil, gerror.Newf("existing unsub refund detail is invalid, order %s", orderCode)
			}
			refund.Amount = roundUnsubAmount(existing.Amount)
			refund.Status = refundStatusRefunded
			refund.Reason = "refund detail already exists"
			continue
		}

		payerDeptID := refundPayerDeptID(order, binds)
		if payerDeptID <= 0 {
			return nil, gerror.Newf("order %s lacks a balance payer department", orderCode)
		}
		tenantID := strings.TrimSpace(order.TenantId)
		if tenantID == "" {
			tenantID = strings.TrimSpace(task.Batch.TenantID)
		}
		if tenantID == "" {
			return nil, gerror.Newf("order %s lacks a tenant id for refund", orderCode)
		}
		var account balanceAccountQuery
		accountModel := r.applyLock(tx.Ctx(ctx).Model(agentBalanceTable)).
			Where("dept_id", payerDeptID).
			Where("tenant_id", tenantID).
			Fields("id", "dept_id", "balance", "status", "tenant_id")
		if err := accountModel.Scan(&account); err != nil && !errors.Is(err, sql.ErrNoRows) {
			return nil, gerror.Wrap(err, "query balance account for unsub refund")
		}
		if account.Id == 0 {
			return nil, gerror.Newf("balance account for order %s does not exist", orderCode)
		}
		if account.Status != balanceAccountStatusNormal {
			return nil, gerror.Newf("balance account for order %s is not available", orderCode)
		}
		before := roundUnsubAmount(account.Balance)
		after := roundUnsubAmount(before + refund.Amount)
		accountUpdate, err := tx.Ctx(ctx).Model(agentBalanceTable).
			Where("id", account.Id).
			Data(g.Map{
				"balance":    after,
				"updated_by": task.Batch.CreatedBy,
				"updated_at": transactionTime,
			}).Update()
		if err != nil {
			return nil, gerror.Wrap(err, "update balance account for unsub refund")
		}
		if affected, err := accountUpdate.RowsAffected(); err != nil {
			return nil, gerror.Wrap(err, "read balance account update result")
		} else if affected != 1 {
			return nil, gerror.Newf("balance account for order %s changed during refund", orderCode)
		}

		createdDept := order.CreatedDept
		if createdDept <= 0 {
			createdDept = payerDeptID
		}
		if _, err := tx.Ctx(ctx).Model(balanceDetailTable).Data(g.Map{
			"dept_id":             payerDeptID,
			"serial_no":           refund.SerialNo,
			"transaction_time":    transactionTime,
			"income_expense_type": financeIncomeExpenseIncome,
			"transaction_type":    financeTransactionTypeConsume,
			"transaction_channel": financeTransactionChannelBalance,
			"transaction_status":  financeTransactionStatusPaid,
			"amount":              refund.Amount,
			"before_balance":      before,
			"balance_after":       after,
			"order_sn":            orderCode,
			"remark":              fmt.Sprintf("SIM card unsubscribe balance refund, batchNo=%s, orderNo=%s", task.Batch.BatchNo, orderCode),
			"tenant_id":           tenantID,
			"created_dept":        createdDept,
			"created_by":          task.Batch.CreatedBy,
			"created_at":          transactionTime,
		}).Insert(); err != nil {
			return nil, gerror.Wrap(err, "insert unsub refund detail")
		}
		refund.Status = refundStatusRefunded
	}
	return result, nil
}

func (r *Repository) lockRefundDetail(ctx context.Context, tx gdb.TX, tenantID, serialNo string) (*balanceDetailQuery, error) {
	var row balanceDetailQuery
	model := r.applyLock(tx.Ctx(ctx).Model(balanceDetailTable)).
		Where("tenant_id", tenantID).
		Where("serial_no", serialNo).
		Fields("id", "income_expense_type", "transaction_status", "amount")
	if err := model.Scan(&row); err != nil && !errors.Is(err, sql.ErrNoRows) {
		return nil, err
	}
	return &row, nil
}

func sortedOrderCodes(orderCounts map[string]int) []string {
	orderCodes := make([]string, 0, len(orderCounts))
	for orderCode := range orderCounts {
		if strings.TrimSpace(orderCode) != "" {
			orderCodes = append(orderCodes, orderCode)
		}
	}
	sort.Strings(orderCodes)
	return orderCodes
}

func resolveOrderQuantity(order *orderQuery, item *orderItemQuery, activeCount int) int {
	if item != nil && item.Quantity > 0 {
		return item.Quantity
	}
	paidAmount := orderPaidAmount(order, nil, 0)
	if item != nil && item.Price > 0 && paidAmount > 0 {
		quantity := int(math.Round(paidAmount / item.Price))
		if quantity > 0 {
			return quantity
		}
	}
	return activeCount
}

func orderPaidAmount(order *orderQuery, item *orderItemQuery, quantity int) float64 {
	if order != nil {
		if order.Balance > 0 {
			return order.Balance
		}
		if order.PaidAmount > 0 {
			return order.PaidAmount
		}
		if order.TotalAmount > 0 {
			return order.TotalAmount
		}
	}
	if item != nil && item.Price > 0 && quantity > 0 {
		return item.Price * float64(quantity)
	}
	return 0
}

func refundPayerDeptID(order *orderQuery, binds []*bindPkgQuery) int64 {
	if order != nil && order.CustomerAgentId > 0 {
		return order.CustomerAgentId
	}
	for _, bind := range binds {
		if bind == nil {
			continue
		}
		if deptID, err := strconv.ParseInt(strings.TrimSpace(bind.DeptId), 10, 64); err == nil && deptID > 0 {
			return deptID
		}
	}
	if order != nil && order.CreatedDept > 0 {
		return order.CreatedDept
	}
	return 0
}

func unsubscribeRefundSerialNo(batchNo, orderCode string) string {
	return fmt.Sprintf("UNSUBREFUND-%s-%s", strings.TrimSpace(batchNo), strings.TrimSpace(orderCode))
}

func roundUnsubAmount(value float64) float64 {
	if value <= 0 {
		return 0
	}
	return math.Round(value*100) / 100
}

func calculateRefundRatio(effectiveAt, cutoffAt time.Time, durationMonths int) float64 {
	if effectiveAt.IsZero() || cutoffAt.IsZero() || durationMonths <= 0 {
		return 0
	}
	paidEndAt := addRefundMonths(effectiveAt, durationMonths)
	if !cutoffAt.After(effectiveAt) {
		return 1
	}
	if !cutoffAt.Before(paidEndAt) {
		return 0
	}
	totalSeconds := paidEndAt.Sub(effectiveAt).Seconds()
	remainingSeconds := paidEndAt.Sub(cutoffAt).Seconds()
	if totalSeconds <= 0 || remainingSeconds <= 0 {
		return 0
	}
	ratio := remainingSeconds / totalSeconds
	if ratio < 0 {
		return 0
	}
	if ratio > 1 {
		return 1
	}
	return ratio
}

func addRefundMonths(value time.Time, months int) time.Time {
	if months <= 0 {
		return value
	}
	targetMonth := time.Date(value.Year(), value.Month()+time.Month(months), 1, value.Hour(), value.Minute(), value.Second(), value.Nanosecond(), value.Location())
	day := value.Day()
	lastDay := time.Date(targetMonth.Year(), targetMonth.Month()+1, 0, value.Hour(), value.Minute(), value.Second(), value.Nanosecond(), value.Location()).Day()
	if day > lastDay {
		day = lastDay
	}
	return time.Date(targetMonth.Year(), targetMonth.Month(), day, value.Hour(), value.Minute(), value.Second(), value.Nanosecond(), value.Location())
}