using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Newtonsoft.Json;

public class HttpClientHelper
{
    // 单例实例
    private static readonly Lazy<HttpClientHelper> _instance = new Lazy<HttpClientHelper>(() => new HttpClientHelper());

    // 全局访问属性
    public static HttpClientHelper Instance => _instance.Value;

    // 内部使用的 HttpClient
    private readonly HttpClient _httpClient;

    // 私有构造函数，防止外部实例化
    private HttpClientHelper()
    {
        _httpClient = new HttpClient();
    }

    // 定义内容类型枚举
    public enum ContentType
    {
        Json,
        FormData,
        Text,
        Xml,
        Plain,
        x_www_form
    }


    public void SetBaseAddress(string baseAddress)
    {
        _httpClient.BaseAddress = new Uri(baseAddress);
    }

    // 发送请求的方法（保持原有逻辑不变）
    public async Task<ApiResponse<string>> SendRequestAsync(
        HttpMethod method,
        string requestUri,
        object body = null,
        Dictionary<string, string> headers = null,
        ContentType contentType = ContentType.Json)
    {
        var request = new HttpRequestMessage
        {
            Method = method,
            RequestUri = new Uri(_httpClient.BaseAddress, requestUri)
        };

        if (headers != null)
        {
            foreach (var header in headers)
            {
                request.Headers.Add(header.Key, header.Value);
            }
        }

        if (body != null)
        {
            switch (contentType)
            {
                case ContentType.Json:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "application/json");
                    break;

                case ContentType.FormData:
                    if (body is Dictionary<string, string> formData)
                    {
                        var multipartContent = new MultipartFormDataContent();

                        foreach (var pair in formData)
                        {
                            multipartContent.Add(new StringContent(pair.Value, Encoding.UTF8),
                                                 $"\"{pair.Key}\""); // 注意 Key 要加引号
                        }

                        request.Content = multipartContent;

                    }
                    else
                    {
                        return ApiResponse<string>.Failure("FormData body must be Dictionary<string, string>", 400);
                    }
                    break;

                case ContentType.Text:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "text/plain");
                    break;

                case ContentType.Xml:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "application/xml");
                    break;

                case ContentType.Plain:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "text/plain");
                    break;
                case ContentType.x_www_form:
                    if (body is Dictionary<string, string> xformData)
                    {
                        var formContent = new FormUrlEncodedContent(xformData);
                        request.Content = formContent;
                    }
                    else
                    {
                        return ApiResponse<string>.Failure("FormData body must be Dictionary<string, string>", 400);
                    }
                    break;
                default:
                    return ApiResponse<string>.Failure("Unsupported content type", 400);
            }
        }

        HttpResponseMessage response;

        try
        {
            response = await _httpClient.SendAsync(request);
        }
        catch (Exception ex)
        {
            return ApiResponse<string>.Failure($"Network error: {ex.Message}", 503);
        }

        var responseBody = await response.Content.ReadAsStringAsync();

        if (response.IsSuccessStatusCode)
        {
            return ApiResponse<string>.Success(responseBody, (int)response.StatusCode);
        }
        else
        {
            return ApiResponse<string>.Failure(responseBody, (int)response.StatusCode);
        }
    }

    public ApiResponse<string> SendRequest(
    HttpMethod method,
    string requestUri,
    object body = null,
    Dictionary<string, string> headers = null,
    ContentType contentType = ContentType.Json)
    {
        var request = new HttpRequestMessage
        {
            Method = method,
            RequestUri = new Uri(_httpClient.BaseAddress, requestUri)
        };

        if (headers != null)
        {
            foreach (var header in headers)
            {
                request.Headers.Add(header.Key, header.Value);
            }
        }

        if (body != null)
        {
            switch (contentType)
            {
                case ContentType.Json:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "application/json");
                    break;

                case ContentType.FormData:
                    if (body is Dictionary<string, string> formData)
                    {
                        var multipartContent = new MultipartFormDataContent();

                        foreach (var pair in formData)
                        {
                            multipartContent.Add(
                                new StringContent(pair.Value, Encoding.UTF8),
                                $"\"{pair.Key}\""); // 注意 key 加引号
                        }

                        request.Content = multipartContent;
                    }
                    else
                    {
                        return ApiResponse<string>.Failure("FormData body must be Dictionary<string, string>", 400);
                    }
                    break;

                case ContentType.x_www_form:
                    if (body is Dictionary<string, string> xformData)
                    {
                        request.Content = new FormUrlEncodedContent(xformData);
                    }
                    else
                    {
                        return ApiResponse<string>.Failure("FormData body must be Dictionary<string, string>", 400);
                    }
                    break;

                case ContentType.Text:
                case ContentType.Plain:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "text/plain");
                    break;

                case ContentType.Xml:
                    request.Content = new StringContent(
                        body.ToString(),
                        Encoding.UTF8,
                        "application/xml");
                    break;

                default:
                    return ApiResponse<string>.Failure("Unsupported content type", 400);
            }
        }

        HttpResponseMessage response;

        try
        {
            // ✅ 使用 SendAsync().Result 模拟同步发送
            response = _httpClient.SendAsync(request, HttpCompletionOption.ResponseContentRead).Result;
        }
        catch (Exception ex)
        {
            return ApiResponse<string>.Failure($"Network error: {ex.Message}", 503);
        }

        var responseBody = response.Content.ReadAsStringAsync().Result;

        if (response.IsSuccessStatusCode)
        {
            return ApiResponse<string>.Success(responseBody, (int)response.StatusCode);
        }
        else
        {
            return ApiResponse<string>.Failure(responseBody, (int)response.StatusCode);
        }
    }

    public class ApiResponse<T>
    {
        public bool IsSuccess { get; set; }
        public int StatusCode { get; set; }
        public string ErrorMessage { get; set; }
        public T Result { get; set; }

        public static ApiResponse<T> Success(T result, int statusCode)
        {
            return new ApiResponse<T> { IsSuccess = true, StatusCode = statusCode, Result = result };
        }

        public static ApiResponse<T> Failure(string message, int statusCode)
        {
            return new ApiResponse<T> { IsSuccess = false, StatusCode = statusCode, ErrorMessage = message };
        }
    }
}