// Copyright (c) Umbraco.
// See LICENSE for more details.

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Umbraco.Cms.Core.Actions;
using Umbraco.Cms.Core.Configuration.Models;
using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Hosting;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Models.Entities;
using Umbraco.Cms.Core.Models.Membership;
using Umbraco.Cms.Core.Security;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Infrastructure.Services.Notifications;
using Umbraco.Extensions;

namespace Umbraco.Cms.Core.Compose
{
    // TODO: this should probably be moved to another namespace
    public sealed class UserNotificationsHandler :
        INotificationHandler<SavedNotification<IContent>>,
        INotificationHandler<SortedNotification<IContent>>,
        INotificationHandler<PublishedNotification<IContent>>,
        INotificationHandler<MovedNotification<IContent>>,
        INotificationHandler<MovedToRecycleBinNotification<IContent>>,
        INotificationHandler<CopiedNotification<IContent>>,
        INotificationHandler<RolledBackNotification<IContent>>,
        INotificationHandler<SentToPublishNotification<IContent>>,
        INotificationHandler<UnpublishedNotification<IContent>>
    {
        private readonly Notifier _notifier;
        private readonly ActionCollection _actions;
        private readonly IContentService _contentService;

        public UserNotificationsHandler(Notifier notifier, ActionCollection actions, IContentService contentService)
        {
            _notifier = notifier;
            _actions = actions;
            _contentService = contentService;
        }

        public void Handle(SavedNotification<IContent> notification)
        {
            var newEntities = new List<IContent>();
            var updatedEntities = new List<IContent>();

            //need to determine if this is updating or if it is new
            foreach (var entity in notification.SavedEntities)
            {
                var dirty = (IRememberBeingDirty)entity;
                if (dirty.WasPropertyDirty("Id"))
                {
                    //it's new
                    newEntities.Add(entity);
                }
                else
                {
                    //it's updating
                    updatedEntities.Add(entity);
                }
            }
            _notifier.Notify(_actions.GetAction<ActionNew>(), newEntities.ToArray());
            _notifier.Notify(_actions.GetAction<ActionUpdate>(), updatedEntities.ToArray());
        }

        public void Handle(SortedNotification<IContent> notification)
        {
            var parentId = notification.SortedEntities.Select(x => x.ParentId).Distinct().ToList();
            if (parentId.Count != 1)
                return; // this shouldn't happen, for sorting all entities will have the same parent id

            // in this case there's nothing to report since if the root is sorted we can't report on a fake entity.
            // this is how it was in v7, we can't report on root changes because you can't subscribe to root changes.
            if (parentId[0] <= 0)
                return;

            var parent = _contentService.GetById(parentId[0]);
            if (parent == null)
                return; // this shouldn't happen

            _notifier.Notify(_actions.GetAction<ActionSort>(), new[] { parent });
        }

        public void Handle(PublishedNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionPublish>(), notification.PublishedEntities.ToArray());

        public void Handle(MovedNotification<IContent> notification)
        {
            // notify about the move for all moved items
            _notifier.Notify(_actions.GetAction<ActionMove>(), notification.MoveInfoCollection.Select(m => m.Entity).ToArray());

            // for any items being moved from the recycle bin (restored), explicitly notify about that too
            var restoredEntities = notification.MoveInfoCollection
                .Where(m => m.OriginalPath.Contains(Constants.System.RecycleBinContentString))
                .Select(m => m.Entity)
                .ToArray();
            if (restoredEntities.Any())
            {
                _notifier.Notify(_actions.GetAction<ActionRestore>(), restoredEntities);
            }
        }

        public void Handle(MovedToRecycleBinNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionDelete>(), notification.MoveInfoCollection.Select(m => m.Entity).ToArray());

        public void Handle(CopiedNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionCopy>(), notification.Original);

        public void Handle(RolledBackNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionRollback>(), notification.Entity);

        public void Handle(SentToPublishNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionToPublish>(), notification.Entity);

        public void Handle(UnpublishedNotification<IContent> notification) => _notifier.Notify(_actions.GetAction<ActionUnpublish>(), notification.UnpublishedEntities.ToArray());

        /// <summary>
        /// This class is used to send the notifications
        /// </summary>
        public sealed class Notifier
        {
            private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;
            private readonly IHostingEnvironment _hostingEnvironment;
            private readonly INotificationService _notificationService;
            private readonly IUserService _userService;
            private readonly ILocalizedTextService _textService;
            private readonly GlobalSettings _globalSettings;
            private readonly ILogger<Notifier> _logger;

            /// <summary>
            /// Initializes a new instance of the <see cref="Notifier"/> class.
            /// </summary>
            public Notifier(
                IBackOfficeSecurityAccessor backOfficeSecurityAccessor,
                IHostingEnvironment hostingEnvironment,
                INotificationService notificationService,
                IUserService userService,
                ILocalizedTextService textService,
                IOptions<GlobalSettings> globalSettings,
                ILogger<Notifier> logger)
            {
                _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
                _hostingEnvironment = hostingEnvironment;
                _notificationService = notificationService;
                _userService = userService;
                _textService = textService;
                _globalSettings = globalSettings.Value;
                _logger = logger;
            }

            public void Notify(IAction action, params IContent[] entities)
            {
                var user = _backOfficeSecurityAccessor?.BackOfficeSecurity?.CurrentUser;

                //if there is no current user, then use the admin
                if (user == null)
                {
                    _logger.LogDebug("There is no current Umbraco user logged in, the notifications will be sent from the administrator");
                    user = _userService.GetUserById(Constants.Security.SuperUserId);
                    if (user == null)
                    {
                        _logger.LogWarning("Notifications can not be sent, no admin user with id {SuperUserId} could be resolved", Constants.Security.SuperUserId);
                        return;
                    }
                }

                SendNotification(user, entities, action, _hostingEnvironment.ApplicationMainUrl);
            }

            private void SendNotification(IUser sender, IEnumerable<IContent> entities, IAction action, Uri siteUri)
            {
                if (sender == null)
                    throw new ArgumentNullException(nameof(sender));
                if (siteUri == null)
                {
                    _logger.LogWarning("Notifications can not be sent, no site URL is set (might be during boot process?)");
                    return;
                }

                //group by the content type variation since the emails will be different
                foreach (var contentVariantGroup in entities.GroupBy(x => x.ContentType.Variations))
                {
                    _notificationService.SendNotifications(
                        sender,
                        contentVariantGroup,
                        action.Letter.ToString(CultureInfo.InvariantCulture),
                        _textService.Localize("actions", action.Alias),
                        siteUri,
                        ((IUser user, NotificationEmailSubjectParams subject) x)
                            => _textService.Localize(
                                "notifications/mailSubject",
                                x.user.GetUserCulture(_textService, _globalSettings),
                                new[] { x.subject.SiteUrl, x.subject.Action, x.subject.ItemName }),
                        ((IUser user, NotificationEmailBodyParams body, bool isHtml) x)
                            => _textService.Localize(
                                x.isHtml ? "notifications/mailBodyHtml" : "notifications/mailBody",
                                x.user.GetUserCulture(_textService, _globalSettings),
                                new[]
                                {
                                    x.body.RecipientName,
                                    x.body.Action,
                                    x.body.ItemName,
                                    x.body.EditedUser,
                                    x.body.SiteUrl,
                                    x.body.ItemId,
                                    //format the summary depending on if it's variant or not
                                    contentVariantGroup.Key == ContentVariation.Culture
                                        ? (x.isHtml ? _textService.Localize("notifications/mailBodyVariantHtmlSummary", new[]{ x.body.Summary }) : _textService.Localize("notifications/mailBodyVariantSummary", new []{ x.body.Summary }))
                                        : x.body.Summary,
                                    x.body.ItemUrl
                                }));
                }
            }

        }
    }
}