// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using System.Collections.Generic;
using System.Linq;
using Squidex.Domain.Apps.Core.Comments;
using Squidex.Domain.Apps.Events.Comments;
using Squidex.Infrastructure;
using Squidex.Infrastructure.EventSourcing;

namespace Squidex.Domain.Apps.Entities.Comments
{
    public sealed class CommentsResult
    {
        public List<Comment> CreatedComments { get; set; } = new List<Comment>();

        public List<Comment> UpdatedComments { get; set; } = new List<Comment>();

        public List<DomainId> DeletedComments { get; set; } = new List<DomainId>();

        public long Version { get; set; }

        public static CommentsResult FromEvents(IEnumerable<Envelope<CommentsEvent>> events, long currentVersion, int lastVersion)
        {
            var result = new CommentsResult { Version = currentVersion };

            foreach (var @event in events.Skip(lastVersion < 0 ? 0 : lastVersion + 1))
            {
                switch (@event.Payload)
                {
                    case CommentDeleted deleted:
                        {
                            var id = deleted.CommentId;

                            if (result.CreatedComments.Any(x => x.Id == id))
                            {
                                result.CreatedComments.RemoveAll(x => x.Id == id);
                            }
                            else if (result.UpdatedComments.Any(x => x.Id == id))
                            {
                                result.UpdatedComments.RemoveAll(x => x.Id == id);
                                result.DeletedComments.Add(id);
                            }
                            else
                            {
                                result.DeletedComments.Add(id);
                            }

                            break;
                        }

                    case CommentCreated created:
                        {
                            var comment = new Comment(
                                created.CommentId,
                                @event.Headers.Timestamp(),
                                @event.Payload.Actor,
                                created.Text,
                                created.Url);

                            result.CreatedComments.Add(comment);
                            break;
                        }

                    case CommentUpdated updated:
                        {
                            var id = updated.CommentId;

                            var comment = new Comment(
                                id,
                                @event.Headers.Timestamp(),
                                @event.Payload.Actor,
                                updated.Text,
                                null);

                            if (result.CreatedComments.Any(x => x.Id == id))
                            {
                                result.CreatedComments.RemoveAll(x => x.Id == id);
                                result.CreatedComments.Add(comment);
                            }
                            else
                            {
                                result.UpdatedComments.Add(comment);
                            }

                            break;
                        }
                }
            }

            return result;
        }
    }
}