using System;
using System.Collections.Generic;

namespace ElmSharp
{
    public static class EcoreMainloop
    {
        static readonly Dictionary<int, Func<bool>> _taskMap = new Dictionary<int, Func<bool>>();
        static readonly Object _taskLock = new Object();
        static int _newTaskId = 0;


        static Interop.Ecore.EcoreTaskCallback _nativeHandler;

        static EcoreMainloop()
        {
            Interop.Ecore.ecore_init();
            Interop.Ecore.ecore_main_loop_glib_integrate();
            _nativeHandler = NativeHandler;
        }

        public static void Begin()
        {
            Interop.Ecore.ecore_main_loop_begin();
        }

        public static void Quit()
        {
            Interop.Ecore.ecore_main_loop_quit();
        }

        public static void Post(Action task)
        {
            int id = RegistHandler(() => { task(); return false; });
            Interop.Ecore.ecore_idler_add(_nativeHandler, (IntPtr)id);
        }

        public static void PostAndWakeUp(Action task)
        {
            int id = RegistHandler(() => { task(); return false; });
            Interop.Ecore.ecore_main_loop_thread_safe_call_async(_nativeHandler, (IntPtr)id);
        }

        public static void Send(Action task)
        {
            int id = RegistHandler(() => { task(); return false; });
            Interop.Ecore.ecore_main_loop_thread_safe_call_sync(_nativeHandler, (IntPtr)id);
        }

        public static IntPtr AddTimer(double interval, Func<bool> handler)
        {
            int id = RegistHandler(handler);
            return Interop.Ecore.ecore_timer_add(interval, _nativeHandler, (IntPtr)id);
        }

        public static void RemoveTimer(IntPtr id)
        {
            int taskId = (int)Interop.Ecore.ecore_timer_del(id);
            _taskMap.Remove(taskId);
        }

        static int RegistHandler(Func<bool> task)
        {
            int taskId;
            lock (_taskLock)
            {
                taskId = _newTaskId++;
            }
            _taskMap[taskId] = task;
            return taskId;
        }

        static bool NativeHandler(IntPtr user_data)
        {
            int task_id = (int)user_data;
            Func<bool> userAction = null;
            _taskMap.TryGetValue(task_id, out userAction);
            if (userAction != null)
            {
                _taskMap.Remove(task_id);
                return userAction();
            }
            return false;
        }

    }
}