using System.Net;
using System.Net.Http.Headers;

using collAnon.Client.Services;

using decePubClient.Extensions;
using decePubClient.Models;
using decePubClient.Models.Mastodon;

using PrivaPub.ClientModels;

namespace decePubClient.Services
{
	/// <summary>Uploads a picked file to PrivaPub (/api/v2/media, multipart) before the post that uses it.</summary>
	public class MediaService(IHttpService httpService, CoalescingStringLocalizer localizer)
	{
		/// <summary>The uploaded attachment as Data; its id goes in the post's media_ids.</summary>
		public async Task<WebResult> Upload(UploadMedia media, CancellationToken cancellationToken = default)
		{
			using var response = await httpService.Post(APIs.Mastodon.POST_Media, (Func<HttpContent>)(() =>
			{
				var file = new ByteArrayContent(media.Blob);
				file.Headers.ContentType = MediaTypeHeaderValue.Parse(media.ContentType);
				var content = new MultipartFormDataContent { { file, "file", media.FileName } };
				if (media.AltText is { Length: > 0 } description)
					content.Add(new StringContent(description), "description");
				return content;
			}), cancellationToken: cancellationToken);
			if (!response.IsSuccessStatusCode)
				return await response.Content.ReadWebResult(response.StatusCode, localizer, cancellationToken);

			var attachment = await response.MastodonReadFromJsonAsync<MediaAttachment>(cancellationToken);
			return attachment?.Id is null
				? new WebResult().Invalidate(localizer["The server sent an invalid response."], (int)HttpStatusCode.BadGateway)
				: new WebResult { Data = attachment };
		}
	}
}