using System.Net;
using System.Net.Http;
using Microsoft.Extensions.Options;
using EnvelopeGenerator.ReceiverUI.Options;

namespace EnvelopeGenerator.ReceiverUI.Services;

public class DocumentService(HttpClient http, IOptions<ApiOptions> apiOptions)
{
    private readonly ApiOptions _api = apiOptions.Value;

    /// <summary>
    /// Fetches the PDF bytes 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<byte[]?> GetDocumentAsync(string envelopeKey, CancellationToken cancel = default)
    {
        var response = await http.GetAsync($"{_api.BaseUrl}/api/Document/{Uri.EscapeDataString(envelopeKey)}", cancel);

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

        var bytes = await response.Content.ReadAsByteArrayAsync(cancel);
        return bytes;
    }
}