// Package payment 统一承载支付宝、微信和钱包支付请求及渠道回调。
package payment

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"strings"

	"git.apinb.com/heqiapp/platforms/backend/api/internal/config"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/models"
	"github.com/smartwalle/alipay/v3"
	wechatcore "github.com/wechatpay-apiv3/wechatpay-go/core"
	"github.com/wechatpay-apiv3/wechatpay-go/core/option"
	wechatapp "github.com/wechatpay-apiv3/wechatpay-go/services/payments/app"
	wechatjsapi "github.com/wechatpay-apiv3/wechatpay-go/services/payments/jsapi"
	wechatnative "github.com/wechatpay-apiv3/wechatpay-go/services/payments/native"
	"github.com/wechatpay-apiv3/wechatpay-go/utils"
)

var ErrChannelUnavailable = errors.New("payment channel is not configured")

func money(amount int64) string { return fmt.Sprintf("%d.%02d", amount/100, amount%100) }

func createChannelOrder(ctx context.Context, order models.PaymentOrder, openID string) (string, error) {
	switch order.Channel {
	case "alipay":
		return createAlipayOrder(order)
	case "wechat":
		return createWechatOrder(ctx, order, openID)
	default:
		return "", errors.New("unsupported payment channel")
	}
}

func alipayClient() (*alipay.Client, error) {
	cfg := config.Spec.Payment.Alipay
	if !cfg.Enabled || cfg.AppID == "" || cfg.PrivateKeyPath == "" {
		return nil, ErrChannelUnavailable
	}
	privateKey, err := os.ReadFile(cfg.PrivateKeyPath)
	if err != nil {
		return nil, err
	}
	client, err := alipay.New(cfg.AppID, string(privateKey), cfg.Production)
	if err != nil {
		return nil, err
	}
	if err = client.LoadAppCertPublicKeyFromFile(cfg.AppPublicCertPath); err != nil {
		return nil, err
	}
	if err = client.LoadAliPayRootCertFromFile(cfg.AlipayRootCertPath); err != nil {
		return nil, err
	}
	if err = client.LoadAlipayCertPublicKeyFromFile(cfg.AlipayPublicCertPath); err != nil {
		return nil, err
	}
	return client, nil
}

func createAlipayOrder(order models.PaymentOrder) (string, error) {
	client, err := alipayClient()
	if err != nil {
		return "", err
	}
	trade := alipay.Trade{NotifyURL: config.Spec.Payment.Alipay.NotifyURL, ReturnURL: config.Spec.Payment.Alipay.ReturnURL,
		Subject: order.Subject, OutTradeNo: order.PaymentNo, TotalAmount: money(order.Amount), TimeoutExpress: fmt.Sprintf("%dm", config.Spec.Payment.ExpireMinutes)}
	if order.PayType == "app" {
		trade.ProductCode = "QUICK_MSECURITY_PAY"
		return client.TradeAppPay(alipay.TradeAppPay{Trade: trade})
	}
	if order.PayType == "wap" {
		trade.ProductCode = "QUICK_WAP_WAY"
		value, err := client.TradeWapPay(alipay.TradeWapPay{Trade: trade})
		if err != nil {
			return "", err
		}
		return value.String(), nil
	}
	return "", errors.New("unsupported alipay product")
}

func wechatClient(ctx context.Context) (*wechatcore.Client, error) {
	cfg := config.Spec.Payment.Wechat
	if !cfg.Enabled || cfg.MerchantID == "" || cfg.MerchantPrivateKeyPath == "" || len(cfg.APIv3Key) != 32 {
		return nil, ErrChannelUnavailable
	}
	key, err := utils.LoadPrivateKeyWithPath(cfg.MerchantPrivateKeyPath)
	if err != nil {
		return nil, err
	}
	return wechatcore.NewClient(ctx, option.WithWechatPayAutoAuthCipher(cfg.MerchantID, cfg.MerchantCertificateSerial, key, cfg.APIv3Key))
}

func createWechatOrder(ctx context.Context, order models.PaymentOrder, openID string) (string, error) {
	cfg := config.Spec.Payment.Wechat
	client, err := wechatClient(ctx)
	if err != nil {
		return "", err
	}
	marshal := func(value any) (string, error) { raw, err := json.Marshal(value); return string(raw), err }
	switch order.PayType {
	case "app":
		resp, _, err := (&wechatapp.AppApiService{Client: client}).PrepayWithRequestPayment(ctx, wechatapp.PrepayRequest{
			Appid: wechatcore.String(cfg.AppAppID), Mchid: wechatcore.String(cfg.MerchantID), Description: wechatcore.String(order.Subject),
			OutTradeNo: wechatcore.String(order.PaymentNo), TimeExpire: &order.ExpiresAt, NotifyUrl: wechatcore.String(cfg.NotifyURL), Amount: &wechatapp.Amount{Total: wechatcore.Int64(order.Amount)}})
		if err != nil {
			return "", err
		}
		return marshal(resp)
	case "jsapi", "mini":
		if strings.TrimSpace(openID) == "" {
			return "", errors.New("openid is required")
		}
		appid := cfg.OfficialAccountAppID
		if order.PayType == "mini" {
			appid = cfg.MiniProgramAppID
		}
		resp, _, err := (&wechatjsapi.JsapiApiService{Client: client}).PrepayWithRequestPayment(ctx, wechatjsapi.PrepayRequest{
			Appid: wechatcore.String(appid), Mchid: wechatcore.String(cfg.MerchantID), Description: wechatcore.String(order.Subject),
			OutTradeNo: wechatcore.String(order.PaymentNo), TimeExpire: &order.ExpiresAt, NotifyUrl: wechatcore.String(cfg.NotifyURL),
			Amount: &wechatjsapi.Amount{Total: wechatcore.Int64(order.Amount)}, Payer: &wechatjsapi.Payer{Openid: wechatcore.String(openID)}})
		if err != nil {
			return "", err
		}
		return marshal(resp)
	case "native":
		resp, _, err := (&wechatnative.NativeApiService{Client: client}).Prepay(ctx, wechatnative.PrepayRequest{
			Appid: wechatcore.String(cfg.AppAppID), Mchid: wechatcore.String(cfg.MerchantID), Description: wechatcore.String(order.Subject),
			OutTradeNo: wechatcore.String(order.PaymentNo), TimeExpire: &order.ExpiresAt, NotifyUrl: wechatcore.String(cfg.NotifyURL), Amount: &wechatnative.Amount{Total: wechatcore.Int64(order.Amount)}})
		if err != nil {
			return "", err
		}
		return marshal(resp)
	}
	return "", errors.New("unsupported wechat product")
}