using System.Net;
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using EnvelopeGenerator.Application.EnvelopeReceivers.Commands;
using EnvelopeGenerator.Server.Client.Models;

namespace EnvelopeGenerator.Server.Client.Services;

/// <summary>
/// Retrieves the <see cref="EnvelopeReceiverDto"/> for the authenticated receiver
/// from <c>GET /api/EnvelopeReceiver/{envelopeKey}</c>.
/// Also creates new envelopes via <c>POST /api/EnvelopeReceiver</c>.
/// </summary>
public class EnvelopeReceiverService(IHttpClientFactory httpClientFactory)
{
    private static readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);

    /// <summary>
    /// Fetches the envelope receiver data for the given envelope key from the API.
    /// Throws HttpRequestException on failure with appropriate status code.
    /// </summary>
    /// <exception cref="HttpRequestException">Thrown when the API request fails.</exception>
    public async Task<EnvelopeReceiverDto?> GetAsync(string envelopeKey, CancellationToken cancel = default)
    {
        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
        var url = $"/api/EnvelopeReceiver/{Uri.EscapeDataString(envelopeKey)}";
        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 envelope receiver data. Status: {statusCode} ({reasonPhrase})",
                null,
                response.StatusCode);
        }

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

    /// <summary>
    /// Creates a new envelope with document and receivers via <c>POST /api/EnvelopeReceiver</c>.
    /// Requires sender authentication cookie to be present in the request.
    /// </summary>
    /// <exception cref="HttpRequestException">Thrown when the API request fails.</exception>
    public async Task<CreateEnvelopeReceiverResponse?> CreateAsync(
        CreateEnvelopeReceiverCommand request,
        CancellationToken cancel = default)
    {
        using var http = httpClientFactory.CreateClient("EnvelopeGenerator.Server");
        var response   = await http.PostAsJsonAsync("/api/EnvelopeReceiver", request, _jsonOptions, cancel);

        if (!response.IsSuccessStatusCode)
        {
            var body = await response.Content.ReadAsStringAsync(cancel);
            throw new HttpRequestException(
                $"Fehler beim Erstellen des Umschlags. Status: {(int)response.StatusCode} – {body}",
                null,
                response.StatusCode);
        }

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