using System.Net.Http.Json;
using System.Text.Json;
using EnvelopeGenerator.ReceiverUI.Models;
using EnvelopeGenerator.ReceiverUI.Options;
using Microsoft.AspNetCore.WebUtilities;
using Microsoft.Extensions.Options;

namespace EnvelopeGenerator.ReceiverUI.Services;

/// <summary>
/// Retrieves <see cref="EnvelopeDto"/>s from the API.
/// </summary>
public class EnvelopeService
{
    private readonly HttpClient _http;
    private readonly ApiOptions _apiOptions;
    private static readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);

    public EnvelopeService(HttpClient http, IOptions<ApiOptions> apiOptions)
    {
        _http = http;
        _apiOptions = apiOptions.Value;
    }

    /// <summary>
    /// Fetches envelopes from the API with optional filters.
    /// </summary>
    /// <exception cref="HttpRequestException">Thrown when the API request fails.</exception>
    public async Task<IEnumerable<EnvelopeDto>?> GetAsync(
        int? id = null,
        string? uuid = null,
        bool? onlyActive = null,
        bool? onlyCompleted = null,
        CancellationToken cancel = default)
    {
        var baseUrl = $"{_apiOptions.BaseUrl}/api/Envelope";
        var queryParams = new Dictionary<string, string?>();

        if (id.HasValue)
        {
            queryParams["Id"] = id.Value.ToString();
        }
        if (!string.IsNullOrEmpty(uuid))
        {
            queryParams["Uuid"] = uuid;
        }
        if (onlyActive.HasValue)
        {
            queryParams["OnlyActive"] = onlyActive.Value.ToString();
        }
        if (onlyCompleted.HasValue)
        {
            queryParams["OnlyCompleted"] = onlyCompleted.Value.ToString();
        }

        var url = QueryHelpers.AddQueryString(baseUrl, queryParams);

        var response = await _http.GetAsync(url, cancel);

        if (!response.IsSuccessStatusCode)
        {
            var statusCode = (int)response.StatusCode;
            var reasonPhrase = response.ReasonPhrase ?? "Unknown error";
            throw new HttpRequestException(
                $"Failed to load envelopes. Status: {statusCode} ({reasonPhrase})",
                null,
                response.StatusCode);
        }

        return await response.Content.ReadFromJsonAsync<IEnumerable<EnvelopeDto>>(_jsonOptions, cancel);
    }
}