/* *************************************
 *  Includes
 * *************************************/
#include "System.h"
#include "Pad.h"
#include "Menu.h"
#include "Gfx.h"
#include "MemCard.h"
#include "EndAnimation.h"
#include "Timer.h"

/* *************************************
 *  Defines
 * *************************************/
#define FILE_BUFFER_SIZE (128 << 10)    // 128 KB

#define END_STACK_PATTERN (uint32_t) 0x18022015
#define BEGIN_STACK_ADDRESS (uint32_t*) 0x801FFF00
#define STACK_SIZE (6 << 10)    // 6 KiB
#define I_MASK (*(volatile unsigned int*)0x1F801074)
#define I_STAT (*(volatile unsigned int*)0x1F801070)

/* *************************************
 *  Local Prototypes
 * *************************************/
static void SystemCheckTimer(bool* timer, uint64_t* last_timer, uint8_t step);
static void SystemSetStackPattern(void);
static void ISR_RootCounter2(void);

/* *************************************
 *  Local Variables
 * *************************************/
//Buffer to store any kind of files. It supports files up to 128 kB
static uint8_t file_buffer[FILE_BUFFER_SIZE];
//Global timer (called by interrupt)
static volatile uint64_t global_timer;
//Tells whether rand seed has been set
static bool rand_seed;
//Screen refresh flag (called by interrupt)
static volatile bool refresh_needed;
// Frames per second measurement
static volatile uint8_t fps;
static volatile uint8_t temp_fps;
//Timers
static bool one_second_timer;
static bool hundred_ms_timer;
static bool five_hundred_ms_timer;
//Emergency mode flag. Toggled on pad connected/disconnected
static bool emergency_mode;
//Critical section is entered (i.e.: when accessing fopen() or other BIOS functions
static volatile bool system_busy;
// When true, it draws a rectangle on top of all primitives with
// information for development purposes.
static bool devmenu_flag;
// Used for sine-like effect.
static unsigned char sine_counter;

/* *******************************************************************
 *
 * @name: void SystemInit(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief: Calls main intialization routines.
 *
 * @remarks: To be called before main loop.
 *
 * *******************************************************************/
void SystemInit(void)
{
    enum
    {
        RCNT2_100US_TICK_COUNTER = 0xA560
    };

    //Reset global timer
    global_timer = 0;
    //Reset 1 second timer
    one_second_timer = 0;

    //PSXSDK init
#ifdef SERIAL_INTERFACE
    // PSX_INIT_SAVESTATE | PSX_INIT_CD flags are not needed
    // when coming from OpenSend.
    PSX_InitEx(0);
#else // SERIAL_INTERFACE
    PSX_InitEx(PSX_INIT_SAVESTATE | PSX_INIT_CD);
#endif // SERIAL_INTERFACE

    // SIO init
    SerialInit();

    //Graphics init
    GsInit();
    //Clear VRAM
    GsClearMem();
    //Set Video Resolution
#ifdef _PAL_MODE_
    GsSetVideoMode(X_SCREEN_RESOLUTION, Y_SCREEN_RESOLUTION, VMODE_PAL);
#else
    GsSetVideoMode(X_SCREEN_RESOLUTION, Y_SCREEN_RESOLUTION, VMODE_NTSC);
#endif //_PAL_MODE_
    //SPU init
    SsInit();
    //Reset all user-handled timers
    TimerReset();
    //Pads init
    PadInit();
    //Set Drawing Environment
    GfxInitDrawEnv();
    //Set Display Environment
    GfxInitDispEnv();
    //Set VBlank Handler for screen refresh
    SetVBlankHandler(&ISR_SystemDefaultVBlank);
    //Set Primitive List
    GfxSetDefaultPrimitiveList();
    // Init memory card
    MemCardInit();
    //Initial value for system_busy
    system_busy = false;
    //Development menu flag
    devmenu_flag = false;
    //Emergency mode flag
    emergency_mode = false;

    GfxSetGlobalLuminance(NORMAL_LUMINANCE);

    SystemSetStackPattern();

    // Configure root counter 2 so that ISR_RootCounter2
    // is executed every 100 us.
    SetRCntHandler(&ISR_RootCounter2, 2, RCNT2_100US_TICK_COUNTER);
    SystemEnableRCnt2Interrupt();
}

static volatile uint16_t u16_0_01seconds_cnt;
static volatile uint16_t u16_0_01seconds_cnt_prev;

/* *******************************************************************
 *
 * @name: void ISR_RootCounter2(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *  Executed on RCnt2 ISR every 100 us.
 *
 * *******************************************************************/
void ISR_RootCounter2(void)
{
    u16_0_01seconds_cnt++;

    if ((int16_t)(u16_0_01seconds_cnt - 1000) >= (int16_t)(u16_0_01seconds_cnt_prev))
    {
        u16_0_01seconds_cnt_prev = u16_0_01seconds_cnt;
        //~ DEBUG_PRINT_VAR(u16_0_01seconds_cnt_prev);
    }
}

/* *******************************************************************
 *
 * @name: void SystemSetRandSeed(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *  Calls srand() while avoiding multiple calls by setting internal
 *  variable rand_seed to true. Internal variable "global_timer" is
 *  used to generate the new seed.
 *
 * @remarks:
 *  It is recommended to call it once user has pressed any key.
 *
 * *******************************************************************/
void SystemSetRandSeed(void)
{
    if (rand_seed == false)
    {
        rand_seed = true;
        //Set random seed using global timer as reference
        srand((unsigned int)global_timer ^ GetRCnt(2));

        Serial_printf("Seed used: %d\n",(unsigned int)global_timer);
    }
}

/* *******************************************************************
 *
 * @name: bool SystemIsRandSeedSet(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *  Reportedly, returns whether rand seed has already been set.
 *
 * @remarks:
 *
 * @return:
 *   Reportedly, returns whether rand seed has already been set.
 *
 * *******************************************************************/
bool SystemIsRandSeedSet(void)
{
    return rand_seed;
}

/* *******************************************************************
 *
 * @name: bool SystemRefreshNeeded(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *
 * @remarks:
 *
 * @return:
 *   Returns whether VSync flag has been enabled.
 *
 * *******************************************************************/
bool SystemRefreshNeeded(void)
{
    return refresh_needed;
}

/* *******************************************************************
 *
 * @name: void ISR_SystemDefaultVBlank(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *
 * @remarks:
 *  Called from VSync interrupt. Called 50 times a second in PAL mode,
 *  60 times a second in NTSC mode.
 *
 * *******************************************************************/
void ISR_SystemDefaultVBlank(void)
{
    if (System1SecondTick())
    {
        fps = temp_fps;
        temp_fps = 0;
    }

    refresh_needed = true;
}

/* *******************************************************************
 *
 * @name: void SystemAcknowledgeFrame(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *
 * @remarks:
 *  Called by Game module in order to calculate frames per second.
 *
 * *******************************************************************/
void SystemAcknowledgeFrame(void)
{
    temp_fps++;
}

/* *******************************************************************
 *
 * @name: void SystemAcknowledgeFrame(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *  Creates a sine-like (more exactly, a sawtooth-like) effect and
 *  stores its value into a variable.
 *
 * @remarks:
 *  To be called only once, preferibly on SystemCyclic().
 *
 * *******************************************************************/
void SystemCalculateSine(void)
{
    enum
    {
        SINE_EFFECT_STEP = 24,
        SINE_EFFECT_MAX = 240
    };

    static bool sine_decrease = false;

    if (sine_decrease == false)
    {
        if (sine_counter < SINE_EFFECT_MAX)
        {
            sine_counter += SINE_EFFECT_STEP;
        }
        else
        {
            sine_decrease = true;
        }
    }
    else
    {
        if (sine_counter > SINE_EFFECT_STEP)
        {
            sine_counter -= SINE_EFFECT_STEP;
        }
        else
        {
            sine_decrease = false;
        }
    }
}

/* *******************************************************************
 *
 * @name: unsigned char SystemGetSineValue(void)
 *
 * @author: Xavier Del Campo
 *
 * @return:
 *  Returns a value which oscillates like a sine (more exactly, like
 *  a parabola) function to be used wherever you want.
 *
 * *******************************************************************/
unsigned char SystemGetSineValue(void)
{
    return sine_counter;
}

/* *******************************************************************
 *
 * @name: void SystemIncreaseGlobalTimer(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:
 *  Increases internal variable responsible for time handling.
 *
 * @remarks:
 *  Usually called from ISR_SystemDefaultVBlank().
 *
 * *******************************************************************/
void SystemIncreaseGlobalTimer(void)
{
    global_timer++;
}

/* *******************************************************************
 *
 * @name: volatile uint64_t SystemGetGlobalTimer(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief: Returns internal global timer value.
 *
 * *******************************************************************/
volatile uint64_t SystemGetGlobalTimer(void)
{
    return global_timer;
}

/* *******************************************************************
 *
 * @name: void SystemDisableScreenRefresh(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief: Resets VBlank IRQ flag.
 *
 * *******************************************************************/
void SystemDisableScreenRefresh(void)
{
    refresh_needed = false;
}

/* *******************************************************************
 *
 * @name: bool System1SecondTick(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: bool variable with a 1-cycle-length pulse that gets
 *          set each second.
 *
 * *******************************************************************/
bool System1SecondTick(void)
{
    return one_second_timer;
}

/* *******************************************************************
 *
 * @name: bool System100msTick(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: bool variable with a 1-cycle-length pulse that gets
 *          set every 100 milliseconds.
 *
 * *******************************************************************/
bool System100msTick(void)
{
    return hundred_ms_timer;
}

/* *******************************************************************
 *
 * @name    bool System500msTick(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: bool variable with a 1-cycle-length pulse that gets
 *          set every 500 milliseconds.
 *
 * *******************************************************************/
bool System500msTick(void)
{
    return five_hundred_ms_timer;
}

/* *******************************************************************
 *
 * @name    void SystemRunTimers(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  general timer handler
 *
 * @remarks:    1 second, 500 ms and 100 ms ticks get updated here.
 *
 * *******************************************************************/
void SystemRunTimers(void)
{
    static uint64_t last_one_second_tick;
    static uint64_t last_100_ms_tick;
    static uint64_t last_500_ms_tick;

    SystemCheckTimer(&one_second_timer, &last_one_second_tick, REFRESH_FREQUENCY);

#ifdef _PAL_MODE_
    SystemCheckTimer(&hundred_ms_timer, &last_100_ms_tick, 2 /* 2 * 50 ms = 100 ms */);
    SystemCheckTimer(&five_hundred_ms_timer, &last_500_ms_tick, 10 /* 10 * 50 ms = 500 ms */);
#else // _PAL_MODE_
    SystemCheckTimer(&hundred_ms_timer, &last_100_ms_tick, 3);
#endif // _PAL_MODE_

}

/* ********************************************************************************
 *
 * @name    void SystemCheckTimer(bool* timer, uint64_t* last_timer, uint8_t step)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Checks if needed time step has been elapsed. If true, flag gets set.
 *
 * *******************************************************************************/
void SystemCheckTimer(bool* timer, uint64_t* last_timer, uint8_t step)
{
    if (*timer)
    {
        *timer = false;
    }

    if (global_timer >= (*last_timer + step) )
    {
        *timer = true;
        *last_timer = global_timer;
    }
}

/* ****************************************************************************************
 *
 * @name    bool SystemLoadFileToBuffer(char* fname, uint8_t* buffer, uint32_t szBuffer)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Given an input path, it fills a buffer pointed to by "buffer" with
 *          maximum size "szBuffer" with data from CD-ROM.
 *
 * @return: true if file has been loaded successfully, false otherwise.
 *
 * ****************************************************************************************/
bool SystemLoadFileToBuffer(const char* fname, uint8_t* buffer, uint32_t szBuffer)
{
#ifdef SERIAL_INTERFACE
    uint8_t fileSizeBuffer[sizeof (uint32_t)] = {0};
    uint32_t i;
#else // SERIAL_INTERFACE
    FILE *f;
#endif // SERIAL_INTERFACE
    int32_t size = 0;

    // Wait for possible previous operation from the GPU before entering this section.
    while ( (SystemIsBusy()) || (GfxIsGPUBusy()) );

    SystemDisableRCnt2Interrupt();

    if (fname == NULL)
    {
        Serial_printf("SystemLoadFile: NULL fname!\n");
        return false;
    }

    memset(buffer,0,szBuffer);

    static char completeFileName[256];

    snprintf(completeFileName, sizeof (completeFileName), "cdrom:\\%s;1", fname);

#ifdef SERIAL_INTERFACE
    Serial_printf("#%s@", completeFileName);

    SerialRead(fileSizeBuffer, sizeof (uint32_t) );

    for (i = 0; i < sizeof (uint32_t); i++)
    {
        size |= fileSizeBuffer[i] << (i << 3); // (i << 3) == (i * 8)
    }

    SerialWrite(ACK_BYTE_STRING, 1);

    for (i = 0; i < size; i += SERIAL_DATA_PACKET_SIZE)
    {
        uint32_t bytes_to_read;

        // Read actual EXE data into proper RAM address.

        if ( (i + SERIAL_DATA_PACKET_SIZE) >= size)
        {
            bytes_to_read = size - i;
        }
        else
        {
            bytes_to_read = SERIAL_DATA_PACKET_SIZE;
        }

        SerialRead(file_buffer + i, bytes_to_read);

        SerialWrite(ACK_BYTE_STRING, sizeof (uint8_t)); // Write ACK
    }
#else // SERIAL_INTERFACE

    system_busy = true;

    SystemDisableVBlankInterrupt();

    Serial_printf("Opening %s...\n", completeFileName);

    f = fopen((char*)completeFileName, "r");

    if (f == NULL)
    {
        Serial_printf("SystemLoadFile: file could not be found!\n");
        //File couldn't be found
        return false;
    }

    fseek(f, 0, SEEK_END);

    size = ftell(f);

    if (size > szBuffer)
    {
        Serial_printf("SystemLoadFile: Exceeds file buffer size (%d bytes)\n",size);
        //Bigger than 128 kB (buffer's max size)
        return false;
    }

    fseek(f, 0, SEEK_SET); //f->pos = 0;

    fread(buffer, sizeof (char), size, f);

    fclose(f);

    SystemEnableVBlankInterrupt();
    SystemEnableRCnt2Interrupt();

    system_busy = false;

#endif // SERIAL_INTERFACE

    Serial_printf("File \"%s\" loaded successfully!\n",completeFileName);

    return true;
}

/* ****************************************************************************************
 *
 * @name    bool SystemLoadFile(char*fname)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Given an input file name, it loads its conents into internal buffer.
 *
 * @return: true if file has been loaded successfully, false otherwise.
 *
 * ****************************************************************************************/
bool SystemLoadFile(const char* fname)
{
    return SystemLoadFileToBuffer(fname,file_buffer,sizeof (file_buffer));
}

/* ******************************************************************
 *
 * @name    uint8_t* SystemGetBufferAddress(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: Reportedly, returns internal buffer initial address.
 *
 * *****************************************************************/
uint8_t* SystemGetBufferAddress(void)
{
    return file_buffer;
}

/* ******************************************************************
 *
 * @name    void SystemClearFileBuffer(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: Fills internal buffer with zeros
 *
 * *****************************************************************/
void SystemClearFileBuffer(void)
{
    memset(file_buffer, 0, sizeof (file_buffer));
}

/* ******************************************************************
 *
 * @name    uint32_t SystemRand(uint32_t min, uint32_t max)
 *
 * @author: Xavier Del Campo
 *
 * @return: random number between "min" and "max".
 *
 * @remarks: rand seed must be set before using this function, or
 *           you will predictable values otherwise!
 *
 * *****************************************************************/
uint32_t SystemRand(uint32_t min, uint32_t max)
{
    if (rand_seed == false)
    {
        //~ Serial_printf("Warning: calling rand() before srand()\n");
    }

    return rand() % (max - min + 1) + min;
}

/* ***********************************************************************
 *
 * @name    void SystemSetEmergencyMode(bool value)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Sets emergency mode flag.
 *
 * @remarks: emergency mode is set once that a controller is unplugged.
 *
 * ***********************************************************************/
void SystemSetEmergencyMode(bool value)
{
    emergency_mode = value;
}

/* ***********************************************************************
 *
 * @name    bool SystemGetEmergencyMode(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: returns emergency mode flag.
 *
 * ***********************************************************************/
bool SystemGetEmergencyMode(void)
{
    return emergency_mode;
}

/* ***********************************************************************
 *
 * @name    volatile bool SystemIsBusy(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: returns system busy flag.
 *
 * ***********************************************************************/
volatile bool SystemIsBusy(void)
{
    return system_busy;
}

/* ****************************************************************************
 *
 * @name    bool SystemContains_u8(uint8_t value, uint8_t* buffer, size_t sz)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  checks if a certain value is contained in a buffer with size "sz".
 *
 * @return: true if value is contained inside buffer, false otherwise.
 *
 * ****************************************************************************/
bool SystemContains_u8(const uint8_t value, const uint8_t* const buffer, const size_t sz)
{
    size_t i = 0;

    for (i = 0; i < sz; i++)
    {
        if (buffer[i] == value)
        {
            return true;
        }
    }

    return false;
}

/* ****************************************************************************
 *
 * @name    bool SystemContains_u16(uint16_t value, uint16_t* buffer, size_t sz)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  checks if a certain value is contained in a buffer with size "sz".
 *          Variant for u16 variables.
 *
 * @return: true if value is contained inside buffer, false otherwise.
 *
 * ****************************************************************************/
bool SystemContains_u16(const uint16_t value, const uint16_t* const buffer, const size_t sz)
{
    size_t i = 0;

    for (i = 0; i < sz; i++)
    {
        if (buffer[i] == value)
        {
            return true;
        }
    }

    return false;
}

/* ****************************************************************************************
 *
 * @name    bool SystemArrayCompare(unsigned short* arr1, unsigned short* arr2, size_t sz)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Reportedly, it compares two arrays "arr1" and "arr2", with size "sz".
 *
 * @return: true if they are equal, false otherwise.
 *
 * ****************************************************************************************/
bool SystemArrayCompare(const unsigned short* const arr1, const unsigned short* const arr2, const size_t sz)
{
    size_t i;

    for (i = 0; i < sz; i++)
    {
        if (arr1[i] != arr2[i])
        {
            return false;
        }
    }

    return true;
}

/* ****************************************************************************************
 *
 * @name    void SystemPrintStackPointerAddress(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Prints stack usage in percentage via dprintf calls.
 *
 * ****************************************************************************************/
void SystemPrintStackPointerAddress(void)
{
#ifdef PSXSDK_DEBUG // Used to avoid unused variable warning
    void* ptr = NULL;
    fix16_t used_bytes = fix16_from_int((int)((void*)BEGIN_STACK_ADDRESS - (void*)&ptr));
    fix16_t stackPercent = fix16_sdiv(used_bytes,fix16_from_int((int)STACK_SIZE));

    stackPercent = fix16_smul(stackPercent, fix16_from_int((int)100));

    Serial_printf("stackPercent: %d\n", stackPercent);

    Serial_printf("Stack begin pointer: 0x%08X\n"
            "Stack pointer address: 0x%08X\n"
            "Used %d%% of stack size.\n"
            "\tUsed bytes: %d\n",
            (void*)BEGIN_STACK_ADDRESS,
            (void*)&ptr,
            fix16_to_int(stackPercent),
            fix16_to_int(used_bytes)    );
#endif // PSXSDK_DEBUG

}

/* ****************************************************************************************
 *
 * @name    void SystemCheckStack(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Compares stack top with expected byte pattern. If does not match, a stack
 *          overflow has been caused, and application returns to a safe state.
 *
 * ****************************************************************************************/
void SystemCheckStack(void)
{
    const uint32_t* const ptrStack = BEGIN_STACK_ADDRESS - STACK_SIZE;
    const uint32_t data = *ptrStack;

    if (data != END_STACK_PATTERN)
    {
        Serial_printf("Stack overflow?\n");

        while (1);
    }
}


/* ****************************************************************************************
 *
 * @name    void SystemSetStackPattern(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Sets a determined byte pattern on stack top to detect possible stack
 *          overflow during execution.
 *
 * ****************************************************************************************/
void SystemSetStackPattern(void)
{
    uint32_t* const ptrStack = BEGIN_STACK_ADDRESS - STACK_SIZE;

    *ptrStack = END_STACK_PATTERN;
}

/* ****************************************************************************************
 *
 * @name    int32_t SystemIndexOfStringArray(char* str, char** array)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Finds string "str" inside an array of strings "array".
 *
 * @return  Index for a string "str" inside "array". -1 if it could not be found.
 *
 * ****************************************************************************************/
int32_t SystemIndexOfStringArray(const char* str, const char* const* array)
{
    int32_t i;

    for (i = 0; array[i] != NULL; i++)
    {
        Serial_printf("String to find: %s\nEntry: %s\n", str, array[i]);

        if (strcmp(str, array[i]) == 0)
        {
            Serial_printf("Match! Returning index %d...\n", i);
            return i;
        }
    }

    return -1;
}

/* ****************************************************************************************
 *
 * @name    int32_t SystemIndexOf_U16(uint16_t value, uint16_t* array, uint32_t sz)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  For a uint16_t array, it returns index of a variable "value" inside an array.
 *
 * @return  Index for a variable "value" inside "array". -1 if it could not be found.
 *
 * ****************************************************************************************/
int32_t SystemIndexOf_U16(const uint16_t value, const uint16_t* const array, const uint32_t sz)
{
    int32_t i;

    for (i = 0; i < sz; i++)
    {
        if (value == array[i])
        {
            return i;
        }
    }

    return -1;
}

/* ****************************************************************************************
 *
 * @name    int32_t SystemIndexOf_U8(uint8_t value, uint8_t* array, uint32_t from, uint32_t sz)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  For a uint8_t array, it returns index of a variable "value" inside an array.
 *          "from" and "size_t" can be used to determine initial/ending positions.
 *
 * @return  Index for a variable "value" inside "array". -1 if it could not be found.
 *
 * ****************************************************************************************/

int32_t SystemIndexOf_U8(const uint8_t value, const uint8_t* const array, const uint32_t from, const uint32_t sz)
{
    int32_t i;

    for (i = from; i < sz; i++)
    {
        if (value == array[i])
        {
            return i;
        }
    }

    return -1;
}

/* ****************************************************************************************
 *
 * @name    volatile uint8_t SystemGetFPS(void)
 *
 * @author: Xavier Del Campo
 *
 * @return: Frames per second
 *
 * ****************************************************************************************/
volatile uint8_t SystemGetFPS(void)
{
    return fps;
}

/* ****************************************************************************************
 *
 * @name    void SystemCyclicHandler(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  It calls system handlers once an execution cycle has finished.
 *
 *
 * ****************************************************************************************/
void SystemCyclicHandler(void)
{
    UpdatePads();

    SystemIncreaseGlobalTimer();

    SystemRunTimers();

    TimerHandler();

    SystemDisableScreenRefresh();

    MemCardHandler();

    SystemCalculateSine();

    SystemCheckStack();
}

/* ****************************************************************************************
 *
 * @name    void SystemDisableVBlankInterrupt(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Reportedly, this routine enables VBLANK interrupt flag.
 *
 * @remark: Used when critical timing is needed or GPU activity is not desired
 *          e.g.: when reading files from CD-ROM.
 *
 * ****************************************************************************************/
void SystemDisableVBlankInterrupt(void)
{
    I_MASK &= ~1;
}

/* ****************************************************************************************
 *
 * @name    void SystemEnableVBlankInterrupt(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Reportedly, this routine enables VBLANK interrupt flag.
 *
 *
 * ****************************************************************************************/
void SystemEnableVBlankInterrupt(void)
{
    I_MASK |= 1;
}

/* ****************************************************************************************
 *
 * @name    void SystemReturnToLoader(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Deinitializes PSXSDK library and returns to OpenSend loader,
 *          located at memory address 0x801A0000
 *
 * ****************************************************************************************/
void SystemReturnToLoader(void)
{
    Serial_printf("Returning to loader...\n");

    EndAnimation();

    PSX_DeInit();

    __asm__("j 0x801A0000");
}

/* ****************************************************************************************
 *
 * @name    void SystemDevMenuToggle(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  It toggles a flag called "devmenu_flag" which, if true, shows information on
 *          top of all drawn primitives for debugging/development purposes.
 *
 * ****************************************************************************************/
void SystemDevMenuToggle(void)
{
    devmenu_flag = devmenu_flag? false: true;
}

/* ****************************************************************************************
 *
 * @name    void SystemEnableRCnt2Interrupt(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Enables bit 6 from I_MASK (0x1F801074)/IRQ6 RCNT2 (System clock / 8)
 *
 * ****************************************************************************************/
void SystemEnableRCnt2Interrupt(void)
{
    I_MASK |= 1<<6;
}


/* ****************************************************************************************
 *
 * @name    void SystemDisableRCnt2Interrupt(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Disables bit 6 from I_MASK (0x1F801074)/IRQ6 RCNT2 (System clock / 8)
 *
 * ****************************************************************************************/
void SystemDisableRCnt2Interrupt(void)
{
    I_MASK &= ~(1 << 6);
}

/* ****************************************************************************************
 *
 * @name    void SystemDevMenu(void)
 *
 * @author: Xavier Del Campo
 *
 * @brief:  Shows information on top of all drawn primitives for debugging/development purposes.
 *
 * ****************************************************************************************/
void SystemDevMenu(void)
{
    enum
    {
        DEVMENU_BG_W = 256,
        DEVMENU_BG_X = (X_SCREEN_RESOLUTION >> 1) - (DEVMENU_BG_W >> 1),
        DEVMENU_BG_Y = 32,
        DEVMENU_BG_H = 128,

        DEVMENU_BG_R = 0,
        DEVMENU_BG_G = 128,
        DEVMENU_BG_B = 32,
    };

    enum
    {
        DEVMENU_TEXT_GAP = 8,

        DEVMENU_PAD1_STATUS_TEXT_X = DEVMENU_BG_X + DEVMENU_TEXT_GAP,
        DEVMENU_PAD1_STATUS_TEXT_Y = DEVMENU_BG_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD1_TYPE_TEXT_X = DEVMENU_PAD1_STATUS_TEXT_X,
        DEVMENU_PAD1_TYPE_TEXT_Y = DEVMENU_PAD1_STATUS_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD1_ID_TEXT_X = DEVMENU_PAD1_STATUS_TEXT_X,
        DEVMENU_PAD1_ID_TEXT_Y = DEVMENU_PAD1_TYPE_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD1_RAW_DATA_TEXT_X = DEVMENU_PAD1_ID_TEXT_X,
        DEVMENU_PAD1_RAW_DATA_TEXT_Y = DEVMENU_PAD1_ID_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD2_STATUS_TEXT_X = DEVMENU_PAD1_RAW_DATA_TEXT_X,
        DEVMENU_PAD2_STATUS_TEXT_Y = DEVMENU_PAD1_RAW_DATA_TEXT_Y + (DEVMENU_TEXT_GAP << 1), // Leave a bigger gap here

        DEVMENU_PAD2_TYPE_TEXT_X = DEVMENU_PAD2_STATUS_TEXT_X,
        DEVMENU_PAD2_TYPE_TEXT_Y = DEVMENU_PAD2_STATUS_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD2_ID_TEXT_X = DEVMENU_PAD2_TYPE_TEXT_X,
        DEVMENU_PAD2_ID_TEXT_Y = DEVMENU_PAD2_TYPE_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_PAD2_RAW_DATA_TEXT_X = DEVMENU_PAD2_ID_TEXT_X,
        DEVMENU_PAD2_RAW_DATA_TEXT_Y = DEVMENU_PAD2_ID_TEXT_Y + DEVMENU_TEXT_GAP,

        DEVMENU_ROOTCNT2_TEXT_X = DEVMENU_PAD2_RAW_DATA_TEXT_X,
        DEVMENU_ROOTCNT2_TEXT_Y = DEVMENU_PAD2_RAW_DATA_TEXT_Y + DEVMENU_TEXT_GAP,
    };

    if (devmenu_flag)
    {
        static const GsRectangle devMenuBg =
        {
            .x = DEVMENU_BG_X,
            .y = DEVMENU_BG_Y,
            .w = DEVMENU_BG_W,
            .h = DEVMENU_BG_H,
            .r = DEVMENU_BG_R,
            .g = DEVMENU_BG_G,
            .b = DEVMENU_BG_B,
            .attribute = ENABLE_TRANS | TRANS_MODE(0)
        };

        GsSortRectangle((GsRectangle*)&devMenuBg);

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD1_STATUS_TEXT_X,
                        DEVMENU_PAD1_STATUS_TEXT_Y,
                        "Pad1 connected = %d",
                        PadOneConnected()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD1_TYPE_TEXT_X,
                        DEVMENU_PAD1_TYPE_TEXT_Y,
                        "Pad1 type = 0x%02X",
                        PadOneGetType()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD1_ID_TEXT_X,
                        DEVMENU_PAD1_ID_TEXT_Y,
                        "Pad1 ID = 0x%02X",
                        PadOneGetID()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD1_RAW_DATA_TEXT_X,
                        DEVMENU_PAD1_RAW_DATA_TEXT_Y,
                        "Pad1 raw data = 0x%04X",
                        PadOneGetRawData()   );

         FontPrintText( &SmallFont,
                        DEVMENU_PAD2_STATUS_TEXT_X,
                        DEVMENU_PAD2_STATUS_TEXT_Y,
                        "Pad2 connected = %d",
                        PadTwoConnected()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD2_TYPE_TEXT_X,
                        DEVMENU_PAD2_TYPE_TEXT_Y,
                        "Pad2 type = 0x%02X",
                        PadTwoGetType()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD2_ID_TEXT_X,
                        DEVMENU_PAD2_ID_TEXT_Y,
                        "Pad2 ID = 0x%02X",
                        PadTwoGetID()   );

        FontPrintText(  &SmallFont,
                        DEVMENU_PAD2_RAW_DATA_TEXT_X,
                        DEVMENU_PAD2_RAW_DATA_TEXT_Y,
                        "Pad2 raw data = 0x%04X",
                        PadTwoGetRawData()   );

        /*FontPrintText(  &SmallFont,
                        DEVMENU_ROOTCNT2_TEXT_X,
                        DEVMENU_ROOTCNT2_TEXT_Y,
                        "Timer2 = 0x%04X",
                        GetRCnt(2) );*/

        FontPrintText(  &SmallFont,
                        DEVMENU_ROOTCNT2_TEXT_X,
                        DEVMENU_ROOTCNT2_TEXT_Y,
                        "Timer2 = 0x%04X, timer2 = 0x%04X",
                        u16_0_01seconds_cnt, GetRCnt(2) );
    }
}

void SystemGetFileBasename(const char* fileName, char* str, const size_t sz)
{
    size_t i;
    size_t j = 0;
    const size_t len = strlen(fileName);

    memset(str, 0, sz);

    for (i = (len - 1); fileName[i] != '\\'; i--);

    i++; // Skip '\\' character.

    for (; fileName[i]; i++)
    {
        str[j++] = fileName[i];
    }
}