package apple

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"

	"bet24.com/log"
)

// Receipt is information returned by Apple
//
// Documentation: https://developer.apple.com/library/ios/releasenotes/General/ValidateAppStoreReceipt/Chapters/ReceiptFields.html#//apple_ref/doc/uid/TP40010573-CH106-SW10
type Receipt struct {
	OriginalPurchaseDatePst   string `json:"original_purchase_date_pst"`
	UniqueIdentifier          string `json:"unique_identifier"`
	OriginalTransactionId     string `json:"original_transaction_id"`
	Bvrs                      string `json:"bvrs"`
	AppItemId                 string `json:"app_item_id"`
	TransactionId             string `json:"transaction_id"`
	Quantity                  string `json:"quantity"`
	UniqueVendorIdentifier    string `json:"unique_vendor_identifier"`
	ProductId                 string `json:"product_id"`
	ItemId                    string `json:"item_id"`
	VersionExternalIdentifier string `json:"version_external_identifier"`
	Bid                       string `json:"bid"`
	IsInIntroOfferPeriod      string `json:"is_in_intro_offer_period"`
	PurchaseDateMs            string `json:"purchase_date_ms"`
	PurchaseDate              string `json:"purchase_date"`
	IsTrialPeriod             string `json:"is_trial_period"`
	PurchaseDatePst           string `json:"purchase_date_pst"`
	OriginalPurchaseDate      string `json:"original_purchase_date"`
	OriginalPurchaseDateMs    string `json:"original_purchase_date_ms"`
}

type receiptRequestData struct {
	Receiptdata string `json:"receipt-data"`
}

const (
	appleSandboxURL    string = "https://sandbox.itunes.apple.com/verifyReceipt"
	appleProductionURL string = "https://buy.itunes.apple.com/verifyReceipt"
)

// Simple interface to get the original error code from the error object
type ErrorWithCode interface {
	Code() float64
}

type Error struct {
	error
	errCode float64
}

// Simple method to get the original error code from the error object
func (e *Error) Code() float64 {
	return e.errCode
}

// Given receiptData (base64 encoded) it tries to connect to either the sandbox (useSandbox true) or
// apples ordinary service (useSandbox false) to validate the receipt. Returns either a receipt struct or an error.
func VerifyReceipt(receiptData string, useSandbox bool) (*Receipt, error, string) {
	return sendReceiptToApple(receiptData, verificationURL(useSandbox))
}

// Selects the proper url to use when talking to apple based on if we should use the sandbox environment or not
func verificationURL(useSandbox bool) string {

	if useSandbox {
		return appleSandboxURL
	}
	return appleProductionURL
}

// Sends the receipt to apple, returns the receipt or an error upon completion
func sendReceiptToApple(receiptData, url string) (*Receipt, error, string) {
	requestData, err := json.Marshal(receiptRequestData{receiptData})
	if err != nil {
		return nil, err, ""
	}

	toSend := bytes.NewBuffer(requestData)
	resp, err := http.Post(url, "application/json", toSend)
	if err != nil {
		log.Error("apple.sendReceiptToApple post fail %v ==> receiptData=%s", err, receiptData)
		return nil, err, ""
	}

	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	//log.Debug("sendReceiptToApple body ==> %s", body)

	var responseData struct {
		Status         float64  `json:"status"`
		ReceiptContent *Receipt `json:"receipt"`
	}

	responseData.ReceiptContent = new(Receipt)

	err = json.Unmarshal(body, &responseData)

	if err != nil {
		return nil, err, ""
	}

	if responseData.Status != 0 {
		return nil, verificationError(responseData.Status), string(body)
	}

	return responseData.ReceiptContent, nil, string(body)
}

// Error codes as they returned by the App Store
const (
	UnreadableJSON       = 21000 //App Store无法读取您提供的JSON对象。
	MalformedData        = 21002 //该receipt-data属性中的数据格式错误或丢失。
	AuthenticationError  = 21003 //收据无法认证。
	UnmatchedSecret      = 21004 //您提供的共享密码与您帐户的文件共享密码不匹配。
	ServerUnavailable    = 21005 //收据服务器当前不可用。
	SubscriptionExpired  = 21006 //该收据有效，但订阅已过期。当此状态代码返回到您的服务器时，收据数据也会被解码并作为响应的一部分返回。仅针对自动续订的iOS 6样式交易收据返回。
	SandboxReceiptOnProd = 21007 //该收据来自测试环境，但已发送到生产环境以进行验证。而是将其发送到测试环境。
	ProdReceiptOnSandbox = 21008 //该收据来自生产环境，但是已发送到测试环境以进行验证。而是将其发送到生产环境。
	ErrorReceiptNoAuth   = 21010 //此收据无法授权。就像从未进行过购买一样对待。
	ErrorInternalMin     = 21100 //21100~21199 内部数据访问错误。
	ErrorInternalMax     = 21199 //21100~21199 内部数据访问错误。
)

// Generates the correct error based on a status error code
func verificationError(errCode float64) error {
	var errorMessage string

	switch errCode {
	case UnreadableJSON:
		errorMessage = "The App Store could not read the JSON object you provided."
	case MalformedData:
		errorMessage = "The data in the receipt-data property was malformed."
	case AuthenticationError:
		errorMessage = "The receipt could not be authenticated."
	case UnmatchedSecret:
		errorMessage = "The shared secret you provided does not match the shared secret on file for your account."
	case ServerUnavailable:
		errorMessage = "The receipt server is not currently available."
	case SubscriptionExpired:
		errorMessage = "This receipt is valid but the subscription has expired. When this status code is returned to your server, " +
			"the receipt data is also decoded and returned as part of the response."
	case SandboxReceiptOnProd:
		errorMessage = "This receipt is a sandbox receipt, but it was sent to the production service for verification."
	case ProdReceiptOnSandbox:
		errorMessage = "This receipt is a production receipt, but it was sent to the sandbox service for verification."
	default:
		errorMessage = "An unknown error ocurred"
	}

	errorMessage = fmt.Sprintf("Code：%.f  %s", errCode, errorMessage)
	return &Error{errors.New(errorMessage), errCode}
}