package qrcode

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"time"

	"lone-services/pkg/utils"
	"lone-services/pkg/wechat/auth"
)

// 小程序码（有数量限制）：https://developers.weixin.qq.com/miniprogram/dev/OpenApiDoc/qrcode-link/qr-code/getQRCode.html
const wxaCodeURL = "https://api.weixin.qq.com/wxa/getwxacode"

// BuildPath 拼小程序 path，如 pagesB/userLogin/index?session_id=xxx
func BuildPath(page string, params map[string]string) string {
	if len(params) == 0 {
		return page
	}
	query := url.Values{}
	for k, v := range params {
		query.Add(k, v)
	}
	return page + "?" + query.Encode()
}

// GetWxaCode 使用已有 access_token 生成有限小程序码，成功返回图片二进制。
func (c *Client) GetWxaCode(accessToken string, req *WxaCodeRequest) ([]byte, error) {
	if accessToken == utils.StringEmpty {
		return nil, fmt.Errorf("wechat access_token empty")
	}
	if req == nil || req.Path == utils.StringEmpty {
		return nil, fmt.Errorf("wechat qrcode path empty")
	}

	payload, err := json.Marshal(req)
	if err != nil {
		return nil, err
	}

	apiURL := fmt.Sprintf("%s?access_token=%s", wxaCodeURL, accessToken)
	httpClient := &http.Client{Timeout: 15 * time.Second}
	resp, err := httpClient.Post(apiURL, "application/json", bytes.NewReader(payload))
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("wechat qrcode http status %d", resp.StatusCode)
	}

	if err := parseImageOrError(body); err != nil {
		return nil, err
	}
	return body, nil
}

// CreateWxaCode 通过 auth 拉取 access_token 后生成有限小程序码。
func (c *Client) CreateWxaCode(ctx context.Context, req *WxaCodeRequest) ([]byte, error) {
	token, err := auth.NewClient(c.AppID, c.Secret).AccessToken(ctx)
	if err != nil {
		return nil, err
	}
	return c.GetWxaCode(token.AccessToken, req)
}