// Copyright (c) 2026 Lark Technologies Pte. Ltd.
// SPDX-License-Identifier: MIT

package credential

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/larksuite/cli/internal/core"
)

type userInfo struct {
	OpenID string
	Name   string
}

// fetchUserInfo calls /open-apis/authen/v1/user_info with a UAT to get the user's identity.
func fetchUserInfo(ctx context.Context, httpClient *http.Client, brand core.LarkBrand, uat string) (*userInfo, error) {
	ep := core.ResolveEndpoints(brand)
	url := ep.Open + "/open-apis/authen/v1/user_info"

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("Authorization", "Bearer "+uat)

	resp, err := httpClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("user_info API returned HTTP %d", resp.StatusCode)
	}

	var result struct {
		Code int    `json:"code"`
		Msg  string `json:"msg"`
		Data struct {
			OpenID string `json:"open_id"`
			Name   string `json:"name"`
		} `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return nil, err
	}
	if result.Code != 0 {
		return nil, fmt.Errorf("user_info API error: [%d] %s", result.Code, result.Msg)
	}
	return &userInfo{OpenID: result.Data.OpenID, Name: result.Data.Name}, nil
}