using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Xamarin.Forms;

namespace LibTVRefCommonPortable.Utils
{
    /// <summary>
    /// A class provides application controlling functions
    /// </summary>
    public sealed class ApplicationManagerUtils
    {
        /// <summary>
        /// A instance of platform specific application manager port.
        /// </summary>
        private static IApplicationManagerAPIs applicationManagerAPIs;

        /// <summary>
        /// A instance of ApplicationManagerUtils
        /// </summary>
        private static readonly ApplicationManagerUtils instance = new ApplicationManagerUtils();

        /// <summary>
        /// A getter of ApplicationManagerUtils instance
        /// </summary>
        public static ApplicationManagerUtils Instance
        {
            get
            {
                return instance;
            }
        }

        /// <summary>
        /// A unit testing stub of IApplicationManagerAPIs.
        /// </summary>
        private class TestingStub : IApplicationManagerAPIs
        {
            public void DeleteAllRecentApplication()
            {
                throw new NotImplementedException();
            }

            public void DeleteRecentApplication(string appId)
            {
                throw new NotImplementedException();
            }

            public Task<Dictionary<string, string[]>> GetAllInstalledApplication()
            {
                throw new NotImplementedException();
            }

            public Task<string> GetAppIDbyAppLabel(string appLabel)
            {
                throw new NotImplementedException();
            }

            public bool GetAppInfoRemovable(string appID)
            {
                throw new NotImplementedException();
            }

            public Dictionary<string, string> GetInstalledApplication(string applicationId)
            {
                throw new NotImplementedException();
            }

            public IEnumerable<RecentApp> GetRecentApplications()
            {
                IList<RecentApp> testData = new List<RecentApp>();

                testData.Add(new RecentApp
                {
                    InstanceID = "recentapp1",
                    InstanceLabel = "recentapp1",
                    AppID = "org.tizen.recentapp1",
                    Applabel = "recentapp1",
                    IconPath = "/test/recentapp1",
                    LaunchedTime = new DateTime(2014, 11, 12),
                    Uri = "uri/recentapp1",
                    ScreenShot = "screenshot/recentapp1",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "recentapp2.noscreenshot",
                    InstanceLabel = "recentapp2.noscreenshot",
                    AppID = "org.tizen.recentapp2.noscreenshot",
                    Applabel = "recentapp2.noscreenshot",
                    IconPath = "/test/recentapp2",
                    LaunchedTime = new DateTime(2014, 11, 12),
                    Uri = "uri/recentapp2",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "invalid.recentapp3.nolabel",
                    AppID = "invalid.org.tizen.recentapp3.nolabel",
                    IconPath = "/test/recentapp3",
                    LaunchedTime = new DateTime(2014, 11, 12),
                    Uri = "uri/recentapp3",
                    ScreenShot = "screenshot/recentapp3",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "invalid.recentapp4.notime",
                    AppID = "invalid.org.tizen.recentapp4.notime",
                    Applabel = "recentapp4.notime",
                    IconPath = "/test/recentapp4",
                    Uri = "uri/recentapp4",
                    ScreenShot = "screenshot/recentapp4",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "recentapp5",
                    InstanceLabel = "recentapp5",
                    AppID = "org.tizen.recentapp5",
                    Applabel = "recentapp5",
                    IconPath = "/test/recentapp5",
                    LaunchedTime = new DateTime(2017, 05, 02),
                    Uri = "uri/recentapp5",
                    ScreenShot = "screenshot/recentapp5",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "recentapp6",
                    InstanceLabel = "recentapp6",
                    AppID = "org.tizen.recentapp6",
                    Applabel = "recentapp6",
                    IconPath = "/test/recentapp6",
                    LaunchedTime = new DateTime(2017, 02, 26),
                    Uri = "uri/recentapp6",
                    ScreenShot = "screenshot/recentapp6",
                });
                testData.Add(new RecentApp
                {
                    InstanceID = "recentapp7",
                    InstanceLabel = "recentapp7",
                    AppID = "org.tizen.recentapp7",
                    Applabel = "recentapp7",
                    IconPath = "/test/recentapp7",
                    LaunchedTime = new DateTime(2016, 04, 25),
                    Uri = "uri/recentapp7",
                    ScreenShot = "screenshot/recentapp7",
                });

                return testData;
            }
        }

        /// <summary>
        /// A constructor
        /// </summary>
        private ApplicationManagerUtils()
        {
            applicationManagerAPIs = new TestingStub();

            try
            {
                if (DependencyService.Get<IApplicationManagerAPIs>() != null)
                {
                    applicationManagerAPIs = DependencyService.Get<IApplicationManagerAPIs>();
                }
            }
            catch (InvalidOperationException e)
            {
                DebuggingUtils.Err(e.Message);
            }
        }

        /// <summary>
        /// A method for removing all recent applications
        /// </summary>
        public void DeleteAllRecentApplication()
        {
            applicationManagerAPIs.DeleteAllRecentApplication();
        }

        /// <summary>
        /// A method for removing the specified recent application
        /// </summary>
        /// <param name="appId">An application ID</param>
        public void DeleteRecentApplication(string appId)
        {
            applicationManagerAPIs.DeleteRecentApplication(appId);
        }


        /// <summary>
        /// Gets the information of the recent applications
        /// </summary>
        /// <returns>The list of the recent applications</returns>
        public IEnumerable<RecentApp> GetRecentApplications()
        {
            return applicationManagerAPIs.GetRecentApplications();
        }

        /// <summary>
        /// Gets the information of the specified application with the app ID
        /// </summary>
        /// <param name="appID">The app Id to get</param>
        /// <returns>The information of the installed application</returns>
        public Dictionary<string, string> GetInstalledApplication(string appID)
        {
            return applicationManagerAPIs.GetInstalledApplication(appID);
        }

        /// <summary>
        /// Gets the information of the installed applications asynchronously
        /// </summary>
        /// <returns>The list of the installed applications</returns>
        public Task<Dictionary<string, string[]>> GetAllInstalledApplication()
        {
            return applicationManagerAPIs.GetAllInstalledApplication();
        }

        /// <summary>
        /// Checks whether application is removable
        /// </summary>
        /// <param name="appID">The app ID to get</param>
        /// <returns>If the application is removable, true; otherwise, false</returns>
        public bool GetAppInfoRemovable(string appID)
        {
            return applicationManagerAPIs.GetAppInfoRemovable(appID);
        }

        /// <summary>
        /// Gets the app ID by the app label
        /// </summary>
        /// <param name="appLabel">the app label to get</param>
        /// <returns>the app ID of the app label</returns>
        public Task<string> GetAppIDbyAppLabel(string appLabel)
        {
            return applicationManagerAPIs.GetAppIDbyAppLabel(appLabel);
        }
    }
}