using LibHac;
using Ryujinx.Common.Logging;
using Ryujinx.HLE.HOS.Font;
using Ryujinx.HLE.HOS.Kernel;
using Ryujinx.HLE.HOS.SystemState;
using Ryujinx.HLE.Loaders.Executables;
using Ryujinx.HLE.Loaders.Npdm;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Nso = Ryujinx.HLE.Loaders.Executables.Nso;

namespace Ryujinx.HLE.HOS
{
    public class Horizon : IDisposable
    {
        internal const int HidSize  = 0x40000;
        internal const int FontSize = 0x1100000;

        private Switch Device;

        private ConcurrentDictionary<int, Process> Processes;

        public SystemStateMgr State { get; private set; }

        internal KRecursiveLock CriticalSectionLock { get; private set; }

        internal KScheduler Scheduler { get; private set; }

        internal KTimeManager TimeManager { get; private set; }

        internal KAddressArbiter AddressArbiter { get; private set; }

        internal KSynchronization Synchronization { get; private set; }

        internal LinkedList<KThread> Withholders { get; private set; }

        internal KSharedMemory HidSharedMem  { get; private set; }
        internal KSharedMemory FontSharedMem { get; private set; }

        internal SharedFontManager Font { get; private set; }

        internal KEvent VsyncEvent { get; private set; }

        internal Keyset KeySet { get; private set; }

        private bool HasStarted;

        public Nacp ControlData { get; set; }

        public string CurrentTitle { get; private set; }

        public IntegrityCheckLevel FsIntegrityCheckLevel { get; set; }

        public Horizon(Switch Device)
        {
            this.Device = Device;

            Processes = new ConcurrentDictionary<int, Process>();

            State = new SystemStateMgr();

            CriticalSectionLock = new KRecursiveLock(this);

            Scheduler = new KScheduler(this);

            TimeManager = new KTimeManager();

            AddressArbiter = new KAddressArbiter(this);

            Synchronization = new KSynchronization(this);

            Withholders = new LinkedList<KThread>();

            Scheduler.StartAutoPreemptionThread();

            if (!Device.Memory.Allocator.TryAllocate(HidSize,  out long HidPA) ||
                !Device.Memory.Allocator.TryAllocate(FontSize, out long FontPA))
            {
                throw new InvalidOperationException();
            }

            HidSharedMem  = new KSharedMemory(HidPA, HidSize);
            FontSharedMem = new KSharedMemory(FontPA, FontSize);

            Font = new SharedFontManager(Device, FontSharedMem.PA);

            VsyncEvent = new KEvent(this);

            LoadKeySet();
        }

        public void LoadCart(string ExeFsDir, string RomFsFile = null)
        {
            if (RomFsFile != null)
            {
                Device.FileSystem.LoadRomFs(RomFsFile);
            }

            string NpdmFileName = Path.Combine(ExeFsDir, "main.npdm");

            Npdm MetaData = null;

            if (File.Exists(NpdmFileName))
            {
                Logger.PrintInfo(LogClass.Loader, $"Loading main.npdm...");

                using (FileStream Input = new FileStream(NpdmFileName, FileMode.Open))
                {
                    MetaData = new Npdm(Input);
                }
            }
            else
            {
                Logger.PrintWarning(LogClass.Loader, $"NPDM file not found, using default values!");
            }

            Process MainProcess = MakeProcess(MetaData);

            void LoadNso(string FileName)
            {
                foreach (string File in Directory.GetFiles(ExeFsDir, FileName))
                {
                    if (Path.GetExtension(File) != string.Empty)
                    {
                        continue;
                    }

                    Logger.PrintInfo(LogClass.Loader, $"Loading {Path.GetFileNameWithoutExtension(File)}...");

                    using (FileStream Input = new FileStream(File, FileMode.Open))
                    {
                        string Name = Path.GetFileNameWithoutExtension(File);

                        Nso Program = new Nso(Input, Name);

                        MainProcess.LoadProgram(Program);
                    }
                }
            }

            if (!(MainProcess.MetaData?.Is64Bits ?? true))
            {
                throw new NotImplementedException("32-bit titles are unsupported!");
            }

            CurrentTitle = MainProcess.MetaData.ACI0.TitleId.ToString("x16");

            LoadNso("rtld");

            MainProcess.SetEmptyArgs();

            LoadNso("main");
            LoadNso("subsdk*");
            LoadNso("sdk");

            MainProcess.Run();
        }

        public void LoadXci(string XciFile)
        {
            FileStream File = new FileStream(XciFile, FileMode.Open, FileAccess.Read);

            Xci Xci = new Xci(KeySet, File);

            (Nca MainNca, Nca ControlNca) = GetXciGameData(Xci);

            if (MainNca == null)
            {
                Logger.PrintError(LogClass.Loader, "Unable to load XCI");

                return;
            }

            LoadNca(MainNca, ControlNca);
        }

        private (Nca Main, Nca Control) GetXciGameData(Xci Xci)
        {
            if (Xci.SecurePartition == null)
            {
                throw new InvalidDataException("Could not find XCI secure partition");
            }

            Nca MainNca    = null;
            Nca PatchNca   = null;
            Nca ControlNca = null;

            foreach (PfsFileEntry TicketEntry in Xci.SecurePartition.Files.Where(x => x.Name.EndsWith(".tik")))
            {
                Ticket ticket = new Ticket(Xci.SecurePartition.OpenFile(TicketEntry));

                if (!KeySet.TitleKeys.ContainsKey(ticket.RightsId))
                {
                    KeySet.TitleKeys.Add(ticket.RightsId, ticket.GetTitleKey(KeySet));
                }
            }

            foreach (PfsFileEntry FileEntry in Xci.SecurePartition.Files.Where(x => x.Name.EndsWith(".nca")))
            {
                Stream NcaStream = Xci.SecurePartition.OpenFile(FileEntry);

                Nca Nca = new Nca(KeySet, NcaStream, true);

                if (Nca.Header.ContentType == ContentType.Program)
                {
                    if (Nca.Sections.Any(x => x?.Type == SectionType.Romfs))
                    {
                        MainNca = Nca;
                    }
                    else if (Nca.Sections.Any(x => x?.Type == SectionType.Bktr))
                    {
                        PatchNca = Nca;
                    }
                }
                else if (Nca.Header.ContentType == ContentType.Control)
                {
                    ControlNca = Nca;
                }
            }

            if (MainNca == null)
            {
                Logger.PrintError(LogClass.Loader, "Could not find an Application NCA in the provided XCI file");
            }

            MainNca.SetBaseNca(PatchNca);

            if (ControlNca != null)
            {
                ReadControlData(ControlNca);
            }

            if (PatchNca != null)
            {
                PatchNca.SetBaseNca(MainNca);

                return (PatchNca, ControlNca);
            }

            return (MainNca, ControlNca);
        }

        public void ReadControlData(Nca ControlNca)
        {
            Romfs ControlRomfs = new Romfs(ControlNca.OpenSection(0, false, FsIntegrityCheckLevel));

            byte[] ControlFile = ControlRomfs.GetFile("/control.nacp");

            BinaryReader Reader = new BinaryReader(new MemoryStream(ControlFile));

            ControlData = new Nacp(Reader);
        }

        public void LoadNca(string NcaFile)
        {
            FileStream File = new FileStream(NcaFile, FileMode.Open, FileAccess.Read);

            Nca Nca = new Nca(KeySet, File, true);

            LoadNca(Nca, null);
        }

        public void LoadNsp(string NspFile)
        {
            FileStream File = new FileStream(NspFile, FileMode.Open, FileAccess.Read);

            Pfs Nsp = new Pfs(File);

            PfsFileEntry TicketFile = Nsp.Files.FirstOrDefault(x => x.Name.EndsWith(".tik"));

            // Load title key from the NSP's ticket in case the user doesn't have a title key file
            if (TicketFile != null)
            {
                Ticket Ticket = new Ticket(Nsp.OpenFile(TicketFile));

                KeySet.TitleKeys[Ticket.RightsId] = Ticket.GetTitleKey(KeySet);
            }

            Nca MainNca    = null;
            Nca ControlNca = null;

            foreach (PfsFileEntry NcaFile in Nsp.Files.Where(x => x.Name.EndsWith(".nca")))
            {
                Nca Nca = new Nca(KeySet, Nsp.OpenFile(NcaFile), true);

                if (Nca.Header.ContentType == ContentType.Program)
                {
                    MainNca = Nca;
                }
                else if (Nca.Header.ContentType == ContentType.Control)
                {
                    ControlNca = Nca;
                }
            }

            if (MainNca != null)
            {
                LoadNca(MainNca, ControlNca);

                return;
            }

            Logger.PrintError(LogClass.Loader, "Could not find an Application NCA in the provided NSP file");
        }

        public void LoadNca(Nca MainNca, Nca ControlNca)
        {
            if (MainNca.Header.ContentType != ContentType.Program)
            {
                Logger.PrintError(LogClass.Loader, "Selected NCA is not a \"Program\" NCA");

                return;
            }

            Stream RomfsStream = MainNca.OpenSection(ProgramPartitionType.Data, false, FsIntegrityCheckLevel);
            Stream ExefsStream = MainNca.OpenSection(ProgramPartitionType.Code, false, FsIntegrityCheckLevel);

            if (ExefsStream == null)
            {
                Logger.PrintError(LogClass.Loader, "No ExeFS found in NCA");

                return;
            }

            if (RomfsStream == null)
            {
                Logger.PrintWarning(LogClass.Loader, "No RomFS found in NCA");
            }
            else
            {
                Device.FileSystem.SetRomFs(RomfsStream);
            }
            
            Pfs Exefs = new Pfs(ExefsStream);

            Npdm MetaData = null;

            if (Exefs.FileExists("main.npdm"))
            {
                Logger.PrintInfo(LogClass.Loader, "Loading main.npdm...");

                MetaData = new Npdm(Exefs.OpenFile("main.npdm"));
            }
            else
            {
                Logger.PrintWarning(LogClass.Loader, $"NPDM file not found, using default values!");
            }

            Process MainProcess = MakeProcess(MetaData);

            void LoadNso(string Filename)
            {
                foreach (PfsFileEntry File in Exefs.Files.Where(x => x.Name.StartsWith(Filename)))
                {
                    if (Path.GetExtension(File.Name) != string.Empty)
                    {
                        continue;
                    }

                    Logger.PrintInfo(LogClass.Loader, $"Loading {Filename}...");

                    string Name = Path.GetFileNameWithoutExtension(File.Name);

                    Nso Program = new Nso(Exefs.OpenFile(File), Name);

                    MainProcess.LoadProgram(Program);
                }
            }

            Nacp ReadControlData()
            {
                Romfs ControlRomfs = new Romfs(ControlNca.OpenSection(0, false, FsIntegrityCheckLevel));

                byte[] ControlFile = ControlRomfs.GetFile("/control.nacp");

                BinaryReader Reader = new BinaryReader(new MemoryStream(ControlFile));

                Nacp ControlData = new Nacp(Reader);

                CurrentTitle = ControlData.Languages[(int)State.DesiredTitleLanguage].Title;

                if (string.IsNullOrWhiteSpace(CurrentTitle))
                {
                    CurrentTitle = ControlData.Languages.ToList().Find(x => !string.IsNullOrWhiteSpace(x.Title)).Title;
                }

                return ControlData;
            }

            if (ControlNca != null)
            {
                MainProcess.ControlData = ReadControlData();
            }
            else
            {
                CurrentTitle = MainProcess.MetaData.ACI0.TitleId.ToString("x16");
            }

            if (!MainProcess.MetaData.Is64Bits)
            {
                throw new NotImplementedException("32-bit titles are unsupported!");
            }

            LoadNso("rtld");

            MainProcess.SetEmptyArgs();

            LoadNso("main");
            LoadNso("subsdk");
            LoadNso("sdk");

            MainProcess.Run();
        }

        public void LoadProgram(string FilePath)
        {
            bool IsNro = Path.GetExtension(FilePath).ToLower() == ".nro";

            string Name = Path.GetFileNameWithoutExtension(FilePath);
            string SwitchFilePath = Device.FileSystem.SystemPathToSwitchPath(FilePath);

            if (IsNro && (SwitchFilePath == null || !SwitchFilePath.StartsWith("sdmc:/")))
            {
                string SwitchPath = $"sdmc:/switch/{Name}{Homebrew.TemporaryNroSuffix}";
                string TempPath = Device.FileSystem.SwitchPathToSystemPath(SwitchPath);

                string SwitchDir = Path.GetDirectoryName(TempPath);

                if (!Directory.Exists(SwitchDir))
                {
                    Directory.CreateDirectory(SwitchDir);
                }

                File.Copy(FilePath, TempPath, true);

                FilePath = TempPath;
            }

            Process MainProcess = MakeProcess();

            using (FileStream Input = new FileStream(FilePath, FileMode.Open))
            {
                MainProcess.LoadProgram(IsNro
                    ? (IExecutable)new Nro(Input, FilePath)
                    : (IExecutable)new Nso(Input, FilePath));
            }

            MainProcess.SetEmptyArgs();
            MainProcess.Run(IsNro);
        }

        public void LoadKeySet()
        {
            string KeyFile        = null;
            string TitleKeyFile   = null;
            string ConsoleKeyFile = null;

            string Home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);

            LoadSetAtPath(Path.Combine(Home, ".switch"));
            LoadSetAtPath(Device.FileSystem.GetSystemPath());

            KeySet = ExternalKeys.ReadKeyFile(KeyFile, TitleKeyFile, ConsoleKeyFile);

            void LoadSetAtPath(string BasePath)
            {
                string LocalKeyFile        = Path.Combine(BasePath,    "prod.keys");
                string LocalTitleKeyFile   = Path.Combine(BasePath,   "title.keys");
                string LocalConsoleKeyFile = Path.Combine(BasePath, "console.keys");

                if (File.Exists(LocalKeyFile))
                {
                    KeyFile = LocalKeyFile;
                }

                if (File.Exists(LocalTitleKeyFile))
                {
                    TitleKeyFile = LocalTitleKeyFile;
                }

                if (File.Exists(LocalConsoleKeyFile))
                {
                    ConsoleKeyFile = LocalConsoleKeyFile;
                }
            }
        }

        public void SignalVsync()
        {
            VsyncEvent.ReadableEvent.Signal();
        }

        private Process MakeProcess(Npdm MetaData = null)
        {
            HasStarted = true;

            Process Process;

            lock (Processes)
            {
                int ProcessId = 0;

                while (Processes.ContainsKey(ProcessId))
                {
                    ProcessId++;
                }

                Process = new Process(Device, ProcessId, MetaData);

                Processes.TryAdd(ProcessId, Process);
            }

            InitializeProcess(Process);

            return Process;
        }

        private void InitializeProcess(Process Process)
        {
            Process.AppletState.SetFocus(true);
        }

        internal void ExitProcess(int ProcessId)
        {
            if (Processes.TryRemove(ProcessId, out Process Process))
            {
                Process.Dispose();

                if (Processes.Count == 0)
                {
                    Scheduler.Dispose();

                    TimeManager.Dispose();

                    Device.Unload();
                }
            }
        }

        public void EnableMultiCoreScheduling()
        {
            if (!HasStarted)
            {
                Scheduler.MultiCoreScheduling = true;
            }
        }

        public void DisableMultiCoreScheduling()
        {
            if (!HasStarted)
            {
                Scheduler.MultiCoreScheduling = false;
            }
        }

        public void Dispose()
        {
            Dispose(true);
        }

        protected virtual void Dispose(bool Disposing)
        {
            if (Disposing)
            {
                foreach (Process Process in Processes.Values)
                {
                    Process.Dispose();
                }
            }
        }
    }
}
