package qrcode

import (
	"bytes"
	"context"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

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

const unlimitedURL = "https://api.weixin.qq.com/wxa/getwxacodeunlimit"

func (c *Client) GetUnlimited(accessToken string, req *UnlimitedRequest) ([]byte, error) {
	if accessToken == utils.StringEmpty {
		return nil, fmt.Errorf("wechat access_token empty")
	}
	if req == nil || req.Scene == utils.StringEmpty {
		return nil, fmt.Errorf("wechat qrcode scene empty")
	}

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

	url := fmt.Sprintf("%s?access_token=%s", unlimitedURL, accessToken)
	httpClient := &http.Client{Timeout: 15 * time.Second}
	resp, err := httpClient.Post(url, "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
}

func (c *Client) CreateUnlimited(ctx context.Context, req *UnlimitedRequest) ([]byte, error) {
	token, err := auth.NewClient(c.AppID, c.Secret).AccessToken(ctx)
	if err != nil {
		return nil, err
	}
	return c.GetUnlimited(token.AccessToken, req)
}

func (c *Client) CreateUnlimitedBase64(ctx context.Context, req *UnlimitedRequest) (string, error) {
	img, err := c.CreateUnlimited(ctx, req)
	if err != nil {
		return "", err
	}
	return base64.StdEncoding.EncodeToString(img), nil
}

func parseImageOrError(body []byte) error {
	trim := bytes.TrimSpace(body)
	if len(trim) == 0 {
		return fmt.Errorf("wechat qrcode empty response")
	}
	if trim[0] == '{' || strings.HasPrefix(string(trim), "{\"errcode\"") {
		var errBody apiErrorBody
		if err := json.Unmarshal(trim, &errBody); err != nil {
			return fmt.Errorf("wechat qrcode invalid error body: %w", err)
		}
		if errBody.ErrCode != utils.NumberZero {
			return errors.New(errBody.ErrMsg)
		}
		return fmt.Errorf("wechat qrcode unexpected json response")
	}
	return nil
}