using Firebird2D.EventPipelines;
using SFML.System;
using SFML.Window;
using System.Runtime.CompilerServices;
using System.Text.Json;


namespace Firebird2D.KeyMapping
{
    public class KeyMapper
    {
        private EventBus eventBus;

        private Dictionary<string, Delegate> inputEvents = [];

        private Dictionary<string, Type> eventTypes = [];

        private Dictionary<string, FirebirdEvent> inputMapping = [];

        private Dictionary<FirebirdEvent, I_Pipeline> cachedPipelines = [];

        public KeyMapper(EventBus eventBus)
        {
            if (eventBus == null) throw new NullReferenceException(nameof(eventBus));
            this.eventBus = eventBus;
        }

        public void RegisterEvent<T>(string EventName, EventHandler<T> handler, FirebirdEvent eventNumber) where T : EventArgs
        {
            if (inputEvents.ContainsKey(EventName)) throw new ArgumentException($"Event {EventName} exist Already.");
            inputEvents.Add(EventName, handler);

            eventTypes.Add(EventName, typeof(T));

            Map(EventName, eventNumber);
        }

        public void Map(string EventName, FirebirdEvent eventNumber)
        {
            if (inputMapping.ContainsKey(EventName))
            {
                RemoveMapping(EventName);
                inputMapping[EventName] = eventNumber;
                AjustPipeline(EventName, eventNumber);
            }
            else
            {
                inputMapping.Add(EventName, eventNumber);
                AjustPipeline(EventName, eventNumber);
            }
        }

        private void RemoveMapping(string EventName)
        {
            if (!inputMapping.TryGetValue(EventName, out var firebirdEvent)) return;
            if (!eventTypes.TryGetValue(EventName, out var type)) return;

            I_Pipeline? pipeline = eventBus.GetPipeline(firebirdEvent, type);

            if (pipeline != null)
            {
                pipeline.Unsubscribe(inputEvents[EventName]);
                if (pipeline.IsEventEmpty)
                {
                    eventBus.DestroyPipeline(firebirdEvent, this);
                    cachedPipelines.Remove(firebirdEvent);
                }
            }
            inputMapping.Remove(EventName);
        }

        private void AjustPipeline(string EventName, FirebirdEvent eventNumber)
        {
            if (!eventTypes.TryGetValue(EventName, out var type)) return;

            I_Pipeline pipeline = eventBus.GetOrBuildPipeline(eventNumber, type, this);
            pipeline.Subscribe(inputEvents[EventName]);
        }

        public void SaveMapping(string Path)
        {
            string json = JsonSerializer.Serialize(inputMapping);
            File.WriteAllText(Path, json);
        }

        public void LoadMapping(string Path)
        {
            string json = File.ReadAllText(Path);
            Dictionary<string, FirebirdEvent>? keyValuePairs = JsonSerializer.Deserialize<Dictionary<string, FirebirdEvent>>(json);
            if (keyValuePairs == null) throw new FileLoadException("Unable to deserialize Inputmapping");

            cachedPipelines.Clear();

            foreach (var kvp in inputMapping)
            {
                RemoveMapping(kvp.Key);
            }
            
            inputMapping = keyValuePairs;

            foreach (var kvp in inputMapping)
            {
                if (inputEvents.ContainsKey(kvp.Key))
                {
                    AjustPipeline(kvp.Key, kvp.Value);
                }
            }
        }

        public void InvalidatePipelineCache(FirebirdEvent fbEvent)
        {
            cachedPipelines.Remove(fbEvent);
        }


        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private Pipeline<T>? GetOrCachePipeline<T>(FirebirdEvent fbEvent) where T : EventArgs
        {
            if (cachedPipelines.TryGetValue(fbEvent, out var pipelineObj) && pipelineObj is Pipeline<T> cached)
                return cached;

            var pipeline = eventBus?.GetPipeline(fbEvent, typeof(T)) as Pipeline<T>;

            if (pipeline != null)
                cachedPipelines[fbEvent] = pipeline;

            return pipeline;
        }


        public void HandleKeyboardInput(KeyEvent key)
        {
            var pipeline = GetOrCachePipeline<KeyEventArgs>((FirebirdEvent)key.Code);
            pipeline?.SendEvent(this, new KeyEventArgs(key));
        }

        public void HandleMouseInput(MouseButtonEvent button)
        {
            var pipeline = GetOrCachePipeline<MouseButtonEventArgs>((FirebirdEvent)(button.Button + 101));
            pipeline?.SendEvent(this, new MouseButtonEventArgs(button));
        }

        public void HandleJoystickButtonInput(JoystickButtonEvent joystickButton)
        {
            var pipeline = GetOrCachePipeline<JoystickButtonEventArgs>(FirebirdEvent.JoystickButton);
            pipeline?.SendEvent(this, new JoystickButtonEventArgs(joystickButton));
        }

        public void HandleMouseMovement(MouseMoveEvent mouseMove)
        {
            var pipeline = GetOrCachePipeline<MouseMoveEventArgs>(FirebirdEvent.MouseMove);
            pipeline?.SendEvent(this, new MouseMoveEventArgs(mouseMove));
        }

        public void HandleJoytickMove(JoystickMoveEvent joystickMove)
        {
            var pipeline = GetOrCachePipeline<JoystickMoveEventArgs>(FirebirdEvent.JoystickMove);
            pipeline?.SendEvent(this, new JoystickMoveEventArgs(joystickMove));
        }
    }
}