using System.Net;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using Contracts;
using Contracts.Menu;
using Contracts.Orders;
using Contracts.Requests;
using Contracts.Responses;
using Domain.Entities;

namespace ApiClient.Http;

public sealed class HttpSmsClient : ISmsClient, IDisposable
{
    private readonly HttpClient _httpClient;

    public HttpSmsClient(HttpSmsClientOptions options)
    {
        _httpClient = new HttpClient { BaseAddress = new Uri(options.BaseUrl) };

        var credentials = Convert.ToBase64String(Encoding.UTF8.GetBytes($"{options.Username}:{options.Password}"));
        _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", credentials);
    }

    public async Task<GetMenuApiResponse> GetMenuAsync(bool withPrice = true, CancellationToken cancellationToken = default)
    {
        var request = new GetMenuApiRequest
        {
            CommandParameters = new GetMenuParameters(withPrice),
        };

        var response = await SendAsync(request, cancellationToken);
        return ToGetMenuResponse(response);
    }

    public async Task<SendOrderApiResponse> SendOrderAsync(Order order, CancellationToken cancellationToken = default)
    {
        var request = new SendOrderApiRequest
        {
            CommandParameters = new SendOrderParameters
            {
                OrderId = order.Id.ToString(),
                MenuItems = order.Items.ToList(),
            },
        };

        var response = await SendAsync(request, cancellationToken);
        return ToSendOrderResponse(response);
    }

    public void Dispose() => _httpClient.Dispose();

    private async Task<ApiResponse> SendAsync(ApiRequest request, CancellationToken cancellationToken)
    {
        var json = JsonSerializer.Serialize(request, request.GetType(), ApiJsonOptions.Instance);
        using var content = new StringContent(json, Encoding.UTF8, "application/json");
        using var httpResponse = await _httpClient.PostAsync("/", content, cancellationToken);

        if (httpResponse.StatusCode == HttpStatusCode.Unauthorized)
        {
            return new ApiResponse
            {
                Command = request.Command,
                Success = false,
                ErrorMessage = "Требуется аутентификация.",
            };
        }

        var responseJson = await httpResponse.Content.ReadAsStringAsync(cancellationToken);

        if (string.IsNullOrWhiteSpace(responseJson))
        {
            return new ApiResponse
            {
                Command = request.Command,
                Success = false,
                ErrorMessage = $"Пустой ответ сервера (HTTP {(int)httpResponse.StatusCode}).",
            };
        }

        try
        {
            return ApiResponseDeserializer.Deserialize(responseJson);
        }
        catch (JsonException)
        {
            return new ApiResponse
            {
                Command = request.Command,
                Success = false,
                ErrorMessage = $"Некорректный JSON в ответе (HTTP {(int)httpResponse.StatusCode}): {responseJson}",
            };
        }
    }

    private static GetMenuApiResponse ToGetMenuResponse(ApiResponse response) =>
        response as GetMenuApiResponse ?? new GetMenuApiResponse
        {
            Command = Commands.GetMenu,
            Success = false,
            ErrorMessage = response.ErrorMessage,
        };

    private static SendOrderApiResponse ToSendOrderResponse(ApiResponse response) =>
        response as SendOrderApiResponse ?? new SendOrderApiResponse
        {
            Command = Commands.SendOrder,
            Success = false,
            ErrorMessage = response.ErrorMessage,
        };
}