using MediaBrowser.Model.Tasks;
using Microsoft.Extensions.Logging;
using MediaBrowser.Controller;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.Collections;
using MediaBrowser.Controller.Providers;
using MediaBrowser.Model.IO;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Entities.Movies;
using Jellyfin.Data.Entities;

using Jellyfin.Plugin.SmartPlaylist.Lisp;
using Jellyfin.Plugin.SmartPlaylist.Lisp.Compiler;

namespace Jellyfin.Plugin.SmartPlaylist.ScheduledTasks {
    public class GenerateCollection: Common, IScheduledTask {

        private readonly ILibraryManager _libraryManager;
        private readonly IUserManager _userManager;
        private readonly IProviderManager _providerManager;
        private readonly IFileSystem _fileSystem;
        private readonly ICollectionManager _collectionManager;

        private readonly IStore _store;

        public GenerateCollection(
            ILogger<Plugin> logger,
            ILibraryManager libraryManager,
            IUserManager userManager,
            IProviderManager providerManager,
            IFileSystem fileSystem,
            ICollectionManager collectionManager,
            IServerApplicationPaths serverApplicationPaths
        ) : base(logger) {
            _libraryManager = libraryManager;
            _userManager = userManager;
            _providerManager = providerManager;
            _fileSystem = fileSystem;
            _collectionManager = collectionManager;

            _store = new Store(new SmartFileSystem(serverApplicationPaths));
        }

        public string Category => "Library";
        public string Name => "(re)generate Smart Collections";
        public string Description => "Generate or regenerate all Smart Collections";
        public string Key => nameof(GenerateCollection);

        public IEnumerable<TaskTriggerInfo> GetDefaultTriggers() {
            return new[] {
                new TaskTriggerInfo {
                    IntervalTicks = TimeSpan.FromHours(24).Ticks,
                    Type = TaskTriggerInfo.TriggerInterval,
                }
            };
        }

        private async Task<CollectionId> CreateNewCollection(string name) {
            _logger.LogDebug("Creating collection '{0}'", name);
            return (await _collectionManager.CreateCollectionAsync(
                new CollectionCreationOptions {
                    Name = name,
                }
            )).Id;
        }

        public IEnumerable<Guid> FilterCollectionItems(IEnumerable<BaseItem> items, User? user, string name, string program, string sortProgram) {
            List<BaseItem> results = new List<BaseItem>();
            Expression expression = new Parser(StringTokenStream.generate(program)).parse(); // parse here, so that we don't repeat the work for each item
            Executor executor = SetupExecutor();

            executor.environment.Set("*user*", Lisp.Object.FromBase(user));
            foreach (var i in items) {
                executor.environment.Set("*item*", Lisp.Object.FromBase(i));
                var r = executor.eval(expression);
                _logger.LogTrace("Item {0} evaluated to {1}", i, r.ToString());
                if ((r is not Lisp.Boolean r_bool) || (r_bool.Value())) {
                    _logger.LogDebug("Added '{0}' to Smart Collection {1}", i, name);
                    results.Add(i);
                }
            }
            executor = SetupExecutor();
            executor.environment.Set("*user*", Lisp.Object.FromBase(user));
            executor.environment.Set("*items*", Lisp.Object.FromBase(results));
            results = new List<BaseItem>();
            var sort_result = executor.eval(sortProgram);
            if (sort_result is Cons sorted_items) {
                foreach (var i in sorted_items.ToList()) {
                    if (i is Lisp.Object iObject && iObject.Value() is BaseItem iBaseItem) {
                        results.Add(iBaseItem);
                        continue;
                    }
                    throw new ApplicationException($"Returned sorted list does contain unexpected items, got {i}");
                }
            } else if (sort_result == Lisp.Boolean.FALSE) {
            } else {
                throw new ApplicationException($"Did not return a list of items, returned {sort_result}");
            }
            return results.Select(x => x.Id);
        }

        private IEnumerable<BaseItem> GetAllMedia() {
            var req = new InternalItemsQuery() {
                IncludeItemTypes = AvailableFilterItems,
                Recursive = true,
            };
            return _libraryManager.GetItemsResult(req).Items;
        }

        public async Task ExecuteAsync(IProgress<double> progress, CancellationToken cancellationToken) {
            _logger.LogInformation("Started regenerate Smart Collections");
            _logger.LogDebug("Loaded Assemblies:");
            foreach (var asm in AppDomain.CurrentDomain.GetAssemblies()) {
                _logger.LogDebug("- {0}", asm);
            }
            var i = 0;
            var smartCollections = await _store.GetAllSmartCollectionsAsync();
            foreach (SmartCollectionDto dto in smartCollections) {
                if (!dto.Enabled) {
                    progress.Report(100 * ((double)i)/smartCollections.Count());
                    i += 1;
                    continue;
                }
                if (dto.CollectionId == Guid.Empty) {
                    dto.CollectionId = await CreateNewCollection(dto.Name);
                    _store.DeleteSmartCollection(dto); // delete in case the file was not the canonical one.
                    await _store.SaveSmartCollectionAsync(dto);
                }
                var insertItems = FilterCollectionItems(GetAllMedia(), null, dto.Name, dto.Program, dto.SortProgram).ToArray();
                await ClearCollection(dto.CollectionId);
                await _collectionManager.AddToCollectionAsync(dto.CollectionId, insertItems);
                i += 1;
                progress.Report(100 * ((double)i)/smartCollections.Count());
            }
        }

        private async Task ClearCollection(CollectionId collectionId) {
            // fuck if I know
            if (_libraryManager.GetItemById(collectionId) is not BoxSet collection) {
                throw new ArgumentException("");
            }
            var existingItems = collection.LinkedChildren.Select(x => x.ItemId).Where(x => x != null).Select(x => x.Value);
            await _collectionManager.RemoveFromCollectionAsync(collectionId, existingItems);
        }
    }
}