package client

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

type AGPayClient struct {
	baseURL    string
	httpClient *http.Client
}

type AGPayCreateRequest struct {
	TotalFeeFen   int64  `json:"totalFee"`
	MerchantOrder string `json:"tradeNo"`
	NotifyURL     string `json:"notifyUrl"`
}

type AGPayRequestRejectedError struct {
	StatusCode int
}

func (e *AGPayRequestRejectedError) Error() string {
	return fmt.Sprintf("AGPay rejected payment request with HTTP %d", e.StatusCode)
}

func NewAGPayClient(baseURL string) (*AGPayClient, error) {
	if baseURL == "" {
		return nil, errors.New("AGPay base URL is required")
	}
	return &AGPayClient{baseURL: strings.TrimRight(baseURL, "/"), httpClient: &http.Client{Timeout: 15 * time.Second}}, nil
}

func (c *AGPayClient) CreateWechatQRCode(req AGPayCreateRequest) ([]byte, error) {
	if req.TotalFeeFen <= 0 || req.MerchantOrder == "" || req.NotifyURL == "" {
		return nil, errors.New("invalid AGPay payment request")
	}
	body, err := json.Marshal(req)
	if err != nil {
		return nil, err
	}
	httpReq, err := http.NewRequest(http.MethodPost, c.baseURL+"/pay/wx/pay", bytes.NewReader(body))
	if err != nil {
		return nil, err
	}
	httpReq.Header.Set("Content-Type", "application/json")
	resp, err := c.httpClient.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("call AGPay: %w", err)
	}
	defer resp.Body.Close()
	response, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
	if err != nil {
		return nil, err
	}
	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
		return nil, &AGPayRequestRejectedError{StatusCode: resp.StatusCode}
	}
	return response, nil
}