package entities

import (
	"fmt"
	"math/rand"
	"time"

	"github.com/google/uuid"
	"github.com/shopspring/decimal"
	"gorm.io/gorm"
)

// PurchaseOrderStatus 购买订单状态枚举（通用）
type PurchaseOrderStatus string

const (
	PurchaseOrderStatusCreated   PurchaseOrderStatus = "created"   // 已创建
	PurchaseOrderStatusPaid      PurchaseOrderStatus = "paid"      // 已支付
	PurchaseOrderStatusFailed    PurchaseOrderStatus = "failed"    // 支付失败
	PurchaseOrderStatusCancelled PurchaseOrderStatus = "cancelled" // 已取消
	PurchaseOrderStatusRefunded  PurchaseOrderStatus = "refunded"  // 已退款
	PurchaseOrderStatusClosed    PurchaseOrderStatus = "closed"    // 已关闭
)

// PurchaseOrder 购买订单实体（统一表 ty_purchase_orders，兼容多支付渠道）
type PurchaseOrder struct {
	// 基础标识
	ID      string  `gorm:"primaryKey;type:varchar(36)" json:"id" comment:"购买订单唯一标识"`
	UserID  string  `gorm:"type:varchar(36);not null;index" json:"user_id" comment:"购买用户ID"`
	OrderNo string  `gorm:"type:varchar(64);not null;uniqueIndex" json:"order_no" comment:"商户订单号"`
	TradeNo *string `gorm:"type:varchar(64);uniqueIndex" json:"trade_no,omitempty" comment:"第三方支付交易号"`

	// 产品信息
	ProductID   string `gorm:"type:varchar(36);not null;index" json:"product_id" comment:"产品ID"`
	ProductCode string `gorm:"type:varchar(50);not null" json:"product_code" comment:"产品编号"`
	ProductName string `gorm:"type:varchar(200);not null" json:"product_name" comment:"产品名称"`
	Category    string `gorm:"type:varchar(50)" json:"category,omitempty" comment:"产品分类"`

	// 订单信息
	Subject     string              `gorm:"type:varchar(200);not null" json:"subject" comment:"订单标题"`
	Amount      decimal.Decimal     `gorm:"type:decimal(20,8);not null" json:"amount" comment:"订单金额"`
	PayAmount   *decimal.Decimal    `gorm:"type:decimal(20,8)" json:"pay_amount,omitempty" comment:"实际支付金额"`
	Status      PurchaseOrderStatus `gorm:"type:varchar(20);not null;default:'created';index" json:"status" comment:"订单状态"`
	Platform    string              `gorm:"type:varchar(20);not null" json:"platform" comment:"下单平台：app/h5/pc/wx_h5/wx_mini等"`
	PayChannel  string              `gorm:"type:varchar(20);default:'alipay';index" json:"pay_channel" comment:"支付渠道：alipay/wechat"`
	PaymentType string              `gorm:"type:varchar(20);not null" json:"payment_type" comment:"支付类型：alipay, wechat, free"`

	// 支付渠道返回信息
	BuyerID       string          `gorm:"type:varchar(64)" json:"buyer_id,omitempty" comment:"买家ID（支付渠道方）"`
	SellerID      string          `gorm:"type:varchar(64)" json:"seller_id,omitempty" comment:"卖家ID（支付渠道方）"`
	ReceiptAmount decimal.Decimal `gorm:"type:decimal(20,8)" json:"receipt_amount,omitempty" comment:"实收金额"`

	// 回调信息
	NotifyTime *time.Time `gorm:"index" json:"notify_time,omitempty" comment:"异步通知时间"`
	ReturnTime *time.Time `gorm:"index" json:"return_time,omitempty" comment:"同步返回时间"`
	PayTime    *time.Time `gorm:"index" json:"pay_time,omitempty" comment:"支付完成时间"`

	// 文件信息
	FilePath *string `gorm:"type:varchar(500)" json:"file_path,omitempty" comment:"产品文件路径"`
	FileSize *int64  `gorm:"type:bigint" json:"file_size,omitempty" comment:"文件大小（字节）"`

	// 备注信息
	Remark string `gorm:"type:varchar(500)" json:"remark,omitempty" comment:"备注信息"`

	// 错误信息
	ErrorCode    string `gorm:"type:varchar(64)" json:"error_code,omitempty" comment:"错误码"`
	ErrorMessage string `gorm:"type:text" json:"error_message,omitempty" comment:"错误信息"`

	// 时间戳字段
	CreatedAt time.Time      `gorm:"autoCreateTime" json:"created_at" comment:"创建时间"`
	UpdatedAt time.Time      `gorm:"autoUpdateTime" json:"updated_at" comment:"更新时间"`
	DeletedAt gorm.DeletedAt `gorm:"index" json:"-" comment:"软删除时间"`
}

// TableName 指定数据库表名
func (PurchaseOrder) TableName() string {
	return "ty_purchase_orders"
}

// BeforeCreate GORM钩子：创建前自动生成UUID和订单号
func (p *PurchaseOrder) BeforeCreate(tx *gorm.DB) error {
	if p.ID == "" {
		p.ID = uuid.New().String()
	}
	if p.OrderNo == "" {
		p.OrderNo = generatePurchaseOrderNo()
	}
	return nil
}

// generatePurchaseOrderNo 生成购买订单号
func generatePurchaseOrderNo() string {
	// 使用时间戳+随机数生成唯一订单号，例如：PO202312200001
	timestamp := time.Now().Format("20060102")
	random := fmt.Sprintf("%04d", rand.Intn(9999))
	return fmt.Sprintf("PO%s%s", timestamp, random)
}

// IsCreated 检查是否为已创建状态
func (p *PurchaseOrder) IsCreated() bool {
	return p.Status == PurchaseOrderStatusCreated
}

// IsPaid 检查是否为已支付状态
func (p *PurchaseOrder) IsPaid() bool {
	return p.Status == PurchaseOrderStatusPaid
}

// IsFailed 检查是否为支付失败状态
func (p *PurchaseOrder) IsFailed() bool {
	return p.Status == PurchaseOrderStatusFailed
}

// IsCancelled 检查是否为已取消状态
func (p *PurchaseOrder) IsCancelled() bool {
	return p.Status == PurchaseOrderStatusCancelled
}

// IsRefunded 检查是否为已退款状态
func (p *PurchaseOrder) IsRefunded() bool {
	return p.Status == PurchaseOrderStatusRefunded
}

// IsClosed 检查是否为已关闭状态
func (p *PurchaseOrder) IsClosed() bool {
	return p.Status == PurchaseOrderStatusClosed
}

// MarkPaid 标记为已支付
func (p *PurchaseOrder) MarkPaid(tradeNo, buyerID, sellerID string, payAmount, receiptAmount decimal.Decimal) {
	p.Status = PurchaseOrderStatusPaid
	p.TradeNo = &tradeNo
	p.BuyerID = buyerID
	p.SellerID = sellerID
	p.PayAmount = &payAmount
	p.ReceiptAmount = receiptAmount
	now := time.Now()
	p.PayTime = &now
	p.NotifyTime = &now
}

// MarkFailed 标记为支付失败
func (p *PurchaseOrder) MarkFailed(errorCode, errorMessage string) {
	p.Status = PurchaseOrderStatusFailed
	p.ErrorCode = errorCode
	p.ErrorMessage = errorMessage
}

// MarkCancelled 标记为已取消
func (p *PurchaseOrder) MarkCancelled() {
	p.Status = PurchaseOrderStatusCancelled
}

// MarkRefunded 标记为已退款
func (p *PurchaseOrder) MarkRefunded() {
	p.Status = PurchaseOrderStatusRefunded
}

// MarkClosed 标记为已关闭
func (p *PurchaseOrder) MarkClosed() {
	p.Status = PurchaseOrderStatusClosed
}

// NewPurchaseOrder 通用工厂方法 - 创建购买订单（支持多支付渠道）
func NewPurchaseOrder(userID, productID, productCode, productName, subject string, amount decimal.Decimal, platform, payChannel, paymentType string) *PurchaseOrder {
	return &PurchaseOrder{
		ID:          uuid.New().String(),
		UserID:      userID,
		OrderNo:     generatePurchaseOrderNo(),
		ProductID:   productID,
		ProductCode: productCode,
		ProductName: productName,
		Subject:     subject,
		Amount:      amount,
		Status:      PurchaseOrderStatusCreated,
		Platform:    platform,
		PayChannel:  payChannel,
		PaymentType: paymentType,
	}
}