/*
    Copyright 2016-2023 melonDS team

    This file is part of melonDS.

    melonDS is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with melonDS. If not, see http://www.gnu.org/licenses/.
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <string>
#include <QCoreApplication>
#include <QStandardPaths>
#include <QString>
#include <QDateTime>
#include <QDir>
#include <QThread>
#include <QSemaphore>
#include <QMutex>
#include <QOpenGLContext>
#include <QSharedMemory>
#include <QTemporaryFile>
#include <SDL_loadso.h>

#include "Platform.h"
#include "Config.h"
#include "ROMManager.h"
#include "CameraManager.h"
#include "LAN_Socket.h"
#include "LAN_PCap.h"
#include "LocalMP.h"
#include "SPI_Firmware.h"

#ifdef __WIN32__
#define fseek _fseeki64
#define ftell _ftelli64
#endif // __WIN32__

std::string EmuDirectory;

extern CameraManager* camManager[2];

void emuStop();

// TEMP
//#include "main.h"
//extern MainWindow* mainWindow;


namespace melonDS::Platform
{

void PathInit(int argc, char** argv)
{
    // First, check for the portable directory next to the executable.
    QString appdirpath = QCoreApplication::applicationDirPath();
    QString portablepath = appdirpath + QDir::separator() + "portable";

#if defined(__APPLE__)
    // On Apple platforms we may need to navigate outside an app bundle.
    // The executable directory would be "melonDS.app/Contents/MacOS", so we need to go a total of three steps up.
    QDir bundledir(appdirpath);
    if (bundledir.cd("..") && bundledir.cd("..") && bundledir.dirName().endsWith(".app") && bundledir.cd(".."))
    {
        portablepath = bundledir.absolutePath() + QDir::separator() + "portable";
    }
#endif

    QDir portabledir(portablepath);
    if (portabledir.exists())
    {
        EmuDirectory = portabledir.absolutePath().toStdString();
    }
    else
    {
        // If no overrides are specified, use the default path.
#if defined(__WIN32__) && defined(WIN32_PORTABLE)
        EmuDirectory = appdirpath.toStdString();
#else
        QString confdir;
        QDir config(QStandardPaths::writableLocation(QStandardPaths::ConfigLocation));
        config.mkdir("melonDS");
        confdir = config.absolutePath() + QDir::separator() + "melonDS";
        EmuDirectory = confdir.toStdString();
#endif
    }
}

QSharedMemory* IPCBuffer = nullptr;
int IPCInstanceID;

void IPCInit()
{
    IPCInstanceID = 0;

    IPCBuffer = new QSharedMemory("melonIPC");

#if !defined(Q_OS_WINDOWS)
    // QSharedMemory instances can be left over from crashed processes on UNIX platforms.
    // To prevent melonDS thinking there's another instance, we attach and then immediately detach from the
    // shared memory. If no other process was actually using it, it'll be destroyed and we'll have a clean
    // shared memory buffer after creating it again below.
    if (IPCBuffer->attach())
    {
        IPCBuffer->detach();
        delete IPCBuffer;
        IPCBuffer = new QSharedMemory("melonIPC");
    }
#endif

    if (!IPCBuffer->attach())
    {
        Log(LogLevel::Info, "IPC sharedmem doesn't exist. creating\n");
        if (!IPCBuffer->create(1024))
        {
            Log(LogLevel::Error, "IPC sharedmem create failed: %s\n", IPCBuffer->errorString().toStdString().c_str());
            delete IPCBuffer;
            IPCBuffer = nullptr;
            return;
        }

        IPCBuffer->lock();
        memset(IPCBuffer->data(), 0, IPCBuffer->size());
        IPCBuffer->unlock();
    }

    IPCBuffer->lock();
    u8* data = (u8*)IPCBuffer->data();
    u16 mask = *(u16*)&data[0];
    for (int i = 0; i < 16; i++)
    {
        if (!(mask & (1<<i)))
        {
            IPCInstanceID = i;
            *(u16*)&data[0] |= (1<<i);
            break;
        }
    }
    IPCBuffer->unlock();

    Log(LogLevel::Info, "IPC: instance ID %d\n", IPCInstanceID);
}

void IPCDeInit()
{
    if (IPCBuffer)
    {
        IPCBuffer->lock();
        u8* data = (u8*)IPCBuffer->data();
        *(u16*)&data[0] &= ~(1<<IPCInstanceID);
        IPCBuffer->unlock();

        IPCBuffer->detach();
        delete IPCBuffer;
    }
    IPCBuffer = nullptr;
}


void Init(int argc, char** argv)
{
    PathInit(argc, argv);
    IPCInit();
}

void DeInit()
{
    IPCDeInit();
}

void SignalStop(StopReason reason)
{
    emuStop();
    switch (reason)
    {
        case StopReason::GBAModeNotSupported:
            Log(LogLevel::Error, "!! GBA MODE NOT SUPPORTED\n");
            //mainWindow->osdAddMessage(0xFFA0A0, "GBA mode not supported.");
            break;
        case StopReason::BadExceptionRegion:
            //mainWindow->osdAddMessage(0xFFA0A0, "Internal error.");
            break;
        case StopReason::PowerOff:
        case StopReason::External:
            //mainWindow->osdAddMessage(0xFFC040, "Shutdown");
        default:
            break;
    }
}


int InstanceID()
{
    return IPCInstanceID;
}

std::string InstanceFileSuffix()
{
    int inst = IPCInstanceID;
    if (inst == 0) return "";

    char suffix[16] = {0};
    snprintf(suffix, 15, ".%d", inst+1);
    return suffix;
}

constexpr char AccessMode(FileMode mode, bool file_exists)
{

    if (mode & FileMode::Append)
        return  'a';

    if (!(mode & FileMode::Write))
        // If we're only opening the file for reading...
        return 'r';

    if (mode & (FileMode::NoCreate))
        // If we're not allowed to create a new file...
        return 'r'; // Open in "r+" mode (IsExtended will add the "+")

    if ((mode & FileMode::Preserve) && file_exists)
        // If we're not allowed to overwrite a file that already exists...
        return 'r'; // Open in "r+" mode (IsExtended will add the "+")

    return 'w';
}

constexpr bool IsExtended(FileMode mode)
{
    // fopen's "+" flag always opens the file for read/write
    return (mode & FileMode::ReadWrite) == FileMode::ReadWrite;
}

static std::string GetModeString(FileMode mode, bool file_exists)
{
    std::string modeString;

    modeString += AccessMode(mode, file_exists);

    if (IsExtended(mode))
        modeString += '+';

    if (!(mode & FileMode::Text))
        modeString += 'b';

    return modeString;
}

FileHandle* OpenFile(const std::string& path, FileMode mode)
{
    if ((mode & (FileMode::ReadWrite | FileMode::Append)) == FileMode::None)
    { // If we aren't reading or writing, then we can't open the file
        Log(LogLevel::Error, "Attempted to open \"%s\" in neither read nor write mode (FileMode 0x%x)\n", path.c_str(), mode);
        return nullptr;
    }

    bool file_exists = QFile::exists(QString::fromStdString(path));
    std::string modeString = GetModeString(mode, file_exists);

    FILE* file = fopen(path.c_str(), modeString.c_str());
    if (file)
    {
        Log(LogLevel::Debug, "Opened \"%s\" with FileMode 0x%x (effective mode \"%s\")\n", path.c_str(), mode, modeString.c_str());
        return reinterpret_cast<FileHandle *>(file);
    }
    else
    {
        Log(LogLevel::Warn, "Failed to open \"%s\" with FileMode 0x%x (effective mode \"%s\")\n", path.c_str(), mode, modeString.c_str());
        return nullptr;
    }
}

FileHandle* OpenLocalFile(const std::string& path, FileMode mode)
{
    QString qpath = QString::fromStdString(path);
    QDir dir(qpath);
    QString fullpath;

    if (dir.isAbsolute())
    {
        // If it's an absolute path, just open that.
        fullpath = qpath;
    }
    else
    {
        fullpath = QString::fromStdString(EmuDirectory) + QDir::separator() + qpath;
    }

    return OpenFile(fullpath.toStdString(), mode);
}

bool CloseFile(FileHandle* file)
{
    return fclose(reinterpret_cast<FILE *>(file)) == 0;
}

bool IsEndOfFile(FileHandle* file)
{
    return feof(reinterpret_cast<FILE *>(file)) != 0;
}

bool FileReadLine(char* str, int count, FileHandle* file)
{
    return fgets(str, count, reinterpret_cast<FILE *>(file)) != nullptr;
}

bool FileExists(const std::string& name)
{
    FileHandle* f = OpenFile(name, FileMode::Read);
    if (!f) return false;
    CloseFile(f);
    return true;
}

bool LocalFileExists(const std::string& name)
{
    FileHandle* f = OpenLocalFile(name, FileMode::Read);
    if (!f) return false;
    CloseFile(f);
    return true;
}

bool CheckFileWritable(const std::string& filepath)
{
    FileHandle* file = Platform::OpenFile(filepath.c_str(), FileMode::Read);

    if (file)
    {
        // if the file exists, check if it can be opened for writing.
        Platform::CloseFile(file);
        file = Platform::OpenFile(filepath.c_str(), FileMode::Append);
        if (file)
        {
            Platform::CloseFile(file);
            return true;
        }
        else return false;
    }
    else
    {
        // if the file does not exist, create a temporary file to check, to avoid creating an empty file.
        if (QTemporaryFile(filepath.c_str()).open())
        {
            return true;
        }
        else return false;
    }
}

bool CheckLocalFileWritable(const std::string& name)
{
    FileHandle* file = Platform::OpenLocalFile(name.c_str(), FileMode::Append);
    if (file)
    {
        Platform::CloseFile(file);
        return true;
    }
    else return false;
}

bool FileSeek(FileHandle* file, s64 offset, FileSeekOrigin origin)
{
    int stdorigin;
    switch (origin)
    {
        case FileSeekOrigin::Start: stdorigin = SEEK_SET; break;
        case FileSeekOrigin::Current: stdorigin = SEEK_CUR; break;
        case FileSeekOrigin::End: stdorigin = SEEK_END; break;
    }

    return fseek(reinterpret_cast<FILE *>(file), offset, stdorigin) == 0;
}

void FileRewind(FileHandle* file)
{
    rewind(reinterpret_cast<FILE *>(file));
}

u64 FileRead(void* data, u64 size, u64 count, FileHandle* file)
{
    return fread(data, size, count, reinterpret_cast<FILE *>(file));
}

bool FileFlush(FileHandle* file)
{
    return fflush(reinterpret_cast<FILE *>(file)) == 0;
}

u64 FileWrite(const void* data, u64 size, u64 count, FileHandle* file)
{
    return fwrite(data, size, count, reinterpret_cast<FILE *>(file));
}

u64 FileWriteFormatted(FileHandle* file, const char* fmt, ...)
{
    if (fmt == nullptr)
        return 0;

    va_list args;
    va_start(args, fmt);
    u64 ret = vfprintf(reinterpret_cast<FILE *>(file), fmt, args);
    va_end(args);
    return ret;
}

u64 FileLength(FileHandle* file)
{
    FILE* stdfile = reinterpret_cast<FILE *>(file);
    long pos = ftell(stdfile);
    fseek(stdfile, 0, SEEK_END);
    long len = ftell(stdfile);
    fseek(stdfile, pos, SEEK_SET);
    return len;
}

void Log(LogLevel level, const char* fmt, ...)
{
    if (fmt == nullptr)
        return;

    va_list args;
    va_start(args, fmt);
    vprintf(fmt, args);
    va_end(args);
}

Thread* Thread_Create(std::function<void()> func)
{
    QThread* t = QThread::create(func);
    t->start();
    return (Thread*) t;
}

void Thread_Free(Thread* thread)
{
    QThread* t = (QThread*) thread;
    t->terminate();
    delete t;
}

void Thread_Wait(Thread* thread)
{
    ((QThread*) thread)->wait();
}

Semaphore* Semaphore_Create()
{
    return (Semaphore*)new QSemaphore();
}

void Semaphore_Free(Semaphore* sema)
{
    delete (QSemaphore*) sema;
}

void Semaphore_Reset(Semaphore* sema)
{
    QSemaphore* s = (QSemaphore*) sema;

    s->acquire(s->available());
}

void Semaphore_Wait(Semaphore* sema)
{
    ((QSemaphore*) sema)->acquire();
}

void Semaphore_Post(Semaphore* sema, int count)
{
    ((QSemaphore*) sema)->release(count);
}

Mutex* Mutex_Create()
{
    return (Mutex*)new QMutex();
}

void Mutex_Free(Mutex* mutex)
{
    delete (QMutex*) mutex;
}

void Mutex_Lock(Mutex* mutex)
{
    ((QMutex*) mutex)->lock();
}

void Mutex_Unlock(Mutex* mutex)
{
    ((QMutex*) mutex)->unlock();
}

bool Mutex_TryLock(Mutex* mutex)
{
    return ((QMutex*) mutex)->try_lock();
}

void Sleep(u64 usecs)
{
    QThread::usleep(usecs);
}


void WriteNDSSave(const u8* savedata, u32 savelen, u32 writeoffset, u32 writelen)
{
    if (ROMManager::NDSSave)
        ROMManager::NDSSave->RequestFlush(savedata, savelen, writeoffset, writelen);
}

void WriteGBASave(const u8* savedata, u32 savelen, u32 writeoffset, u32 writelen)
{
    if (ROMManager::GBASave)
        ROMManager::GBASave->RequestFlush(savedata, savelen, writeoffset, writelen);
}

void WriteFirmware(const Firmware& firmware, u32 writeoffset, u32 writelen)
{
    if (!ROMManager::FirmwareSave)
        return;

    if (firmware.GetHeader().Identifier != GENERATED_FIRMWARE_IDENTIFIER)
    { // If this is not the default built-in firmware...
        // ...then write the whole thing back.
        ROMManager::FirmwareSave->RequestFlush(firmware.Buffer(), firmware.Length(), writeoffset, writelen);
    }
    else
    {
        u32 eapstart = firmware.GetExtendedAccessPointOffset();
        u32 eapend = eapstart + sizeof(firmware.GetExtendedAccessPoints());

        u32 apstart = firmware.GetWifiAccessPointOffset();
        u32 apend = apstart + sizeof(firmware.GetAccessPoints());

        // assert that the extended access points come just before the regular ones
        assert(eapend == apstart);

        if (eapstart <= writeoffset && writeoffset < apend)
        { // If we're writing to the access points...
            const u8* buffer = firmware.GetExtendedAccessPointPosition();
            u32 length = sizeof(firmware.GetExtendedAccessPoints()) + sizeof(firmware.GetAccessPoints());
            ROMManager::FirmwareSave->RequestFlush(buffer, length, writeoffset - eapstart, writelen);
        }
    }

}

void WriteDateTime(int year, int month, int day, int hour, int minute, int second)
{
    QDateTime hosttime = QDateTime::currentDateTime();
    QDateTime time = QDateTime(QDate(year, month, day), QTime(hour, minute, second));

    Config::RTCOffset = hosttime.secsTo(time);
    Config::Save();
}

bool MP_Init()
{
    return LocalMP::Init();
}

void MP_DeInit()
{
    return LocalMP::DeInit();
}

void MP_Begin()
{
    return LocalMP::Begin();
}

void MP_End()
{
    return LocalMP::End();
}

int MP_SendPacket(u8* data, int len, u64 timestamp)
{
    return LocalMP::SendPacket(data, len, timestamp);
}

int MP_RecvPacket(u8* data, u64* timestamp)
{
    return LocalMP::RecvPacket(data, timestamp);
}

int MP_SendCmd(u8* data, int len, u64 timestamp)
{
    return LocalMP::SendCmd(data, len, timestamp);
}

int MP_SendReply(u8* data, int len, u64 timestamp, u16 aid)
{
    return LocalMP::SendReply(data, len, timestamp, aid);
}

int MP_SendAck(u8* data, int len, u64 timestamp)
{
    return LocalMP::SendAck(data, len, timestamp);
}

int MP_RecvHostPacket(u8* data, u64* timestamp)
{
    return LocalMP::RecvHostPacket(data, timestamp);
}

u16 MP_RecvReplies(u8* data, u64 timestamp, u16 aidmask)
{
    return LocalMP::RecvReplies(data, timestamp, aidmask);
}

bool LAN_Init()
{
    if (Config::DirectLAN)
    {
        if (!LAN_PCap::Init(true))
            return false;
    }
    else
    {
        if (!LAN_Socket::Init())
            return false;
    }

    return true;
}

void LAN_DeInit()
{
    // checkme. blarg
    //if (Config::DirectLAN)
    //    LAN_PCap::DeInit();
    //else
    //    LAN_Socket::DeInit();
    LAN_PCap::DeInit();
    LAN_Socket::DeInit();
}

int LAN_SendPacket(u8* data, int len)
{
    if (Config::DirectLAN)
        return LAN_PCap::SendPacket(data, len);
    else
        return LAN_Socket::SendPacket(data, len);
}

int LAN_RecvPacket(u8* data)
{
    if (Config::DirectLAN)
        return LAN_PCap::RecvPacket(data);
    else
        return LAN_Socket::RecvPacket(data);
}


void Camera_Start(int num)
{
    return camManager[num]->start();
}

void Camera_Stop(int num)
{
    return camManager[num]->stop();
}

void Camera_CaptureFrame(int num, u32* frame, int width, int height, bool yuv)
{
    return camManager[num]->captureFrame(frame, width, height, yuv);
}

DynamicLibrary* DynamicLibrary_Load(const char* lib)
{
    return (DynamicLibrary*) SDL_LoadObject(lib);
}

void DynamicLibrary_Unload(DynamicLibrary* lib)
{
    SDL_UnloadObject(lib);
}

void* DynamicLibrary_LoadFunction(DynamicLibrary* lib, const char* name)
{
    return SDL_LoadFunction(lib, name);
}

}