#include "RowBase.h"
/*
scans the row and calls any newly pressed or released keys.
*/
void RowBase::process(const bool activeHigh)
{
    //these variables are all bitwise, one bit per key
    uint8_t rowState;                           //1 means pressed, 0 means released
    uint16_t rowEnd;                            //1 bit marks positioned after last key of row
    uint8_t debouncedChanged;                   //1 means debounced changed

    wait();
    scan(activeHigh);                           //save column-port-pin values to portState
    rowState = getRowState(rowEnd, activeHigh);
    debouncedChanged = debounce(rowState);
    pressRelease(rowEnd, debouncedChanged);
}

/* wait() delay's scan to give switches time to debounce.
This version of wait() is very simple.  More sophisticated versions can override this one.

For fastest response time, wait() should be placed before scan() or after pressRelease()
 (waiting between strobe and send would unnecessarily delay send).

A keyboard with a faster scan rate responds faster.
Follow these step to tune DELAY_MICROSECONDS for maximum scan rate for a given SAMPLE_COUNT:
Initialize DELAY_MICROSECONDS in your sketch:
    const unsigned int Row::DELAY_MICROSECONDS = 1000;
Add this to the sketch's loop() function:
    debug.print_microseconds_per_scan();
Compile and load the sketch into the microcontroller; microseconds_per_scan is printed every second.
Adjust the value of DELAY_MICROSECONDS and repeat until:
    debug.print_microseconds_per_scan() <= DEBOUNCE_TIME / SAMPLE_COUNT

DEBOUNCE_TIME can be obtained from the switch's datasheet.  Some switch bounce times are:
Cherry MX specifies 5msec bounce time http://www.cherrycorp.com/english/switches/key/mx.htm
hasu measured Cherry MX bounce times .3ms to 1.4ms http://geekhack.org/index.php?topic=42385.0
Tactile switch MJTP series bounce 10 ms http://www.apem.com/files/apem/brochures/MJTP_6MM.pdf 

Avoid sampling the switch input at a rate synchronous to events in the environment
 that might create periodic EMI. For instance, 50 and 60 Hz.

Polling I2C may slow the scan rate enough so that no additional delay is needed:
    const unsigned int Row::DELAY_MICROSECONDS = 0;

Slow-scan trick for debug messages that print too fast:
    change DELAY_MICROSECONDS to a large number like 10000
That way debug messages are printed at a managable rate.
*/
void RowBase::wait()
{
    delayMicroseconds(DELAY_MICROSECONDS);      //delay between Row scans to debounce switches
}

/*
Strobes the row and reads the columns.
Strobe is on for shortest possible time to preserve IR LED on DodoHand's optic switch.
*/
void RowBase::scan(const bool activeHigh)
{
    //strobe row on
    if (activeHigh)
    {
        refRowPort.setActivePinHigh(rowPin);
    }
    else //activeLow
    {
        refRowPort.setActivePinLow(rowPin);
    }

    //read all the column ports
    for (uint8_t i=0; i < colPortCount; i++)
    {
        ptrsColPorts[i]->read();
    }

    //strobe row off
    if (activeHigh)
    {
        refRowPort.setActivePinLow(rowPin);
    }
    else //activeLow
    {
        refRowPort.setActivePinHigh(rowPin);
    }
}

/*
Copies column pins to rowState.  Unused column pins are not copied.
Sets rowEnd and returns rowState.
rowEnd is bitwise, where 1 bit corrsiponds to place immediatly after last key of row.
rowEnd and rowMask are larger type than portMask so that they can not overflow.
*/
uint8_t RowBase::getRowState(uint16_t& rowEnd, const bool activeHigh)
{
    uint16_t rowMask = 1;           //bitwise, one col per bit, active col bit is 1
    uint8_t rowState = 0;           //bitwise, one key per bit, 1 means key is pressed

    for (uint8_t i=0; i < colPortCount; i++)    //for each col port
    {
        //bitwise colPins, 1 means pin is connected to column
        uint8_t colPins = ptrsColPorts[i]->getColPins();

        //bitwise colPortState, pin values where set in ColPort::read(), get them now
        uint8_t colPortState = ptrsColPorts[i]->getPortState();

        if (activeHigh)
        {
            colPortState = ~colPortState;
        }

        for ( uint8_t portMask = 1; portMask > 0; portMask <<= 1 ) //shift portMask until overflow
        {                                       //for each pin of col port
            if (portMask & colPins)             //if pin is connected to column
            {
                if (portMask & ~colPortState)   //if pin detected a key press
                {
                    rowState |= rowMask;        //set rowState bit for that key
                }

                rowMask <<= 1;                  //shift rowMask to next key
            }
        }
    }

    rowEnd = rowMask;

    return rowState;
}

/*
pressRelease() calls key's press() or release() function if it was pressed or released.
Both parameters are bitwise.
*/
void RowBase::pressRelease(const uint16_t rowEnd, const uint8_t debouncedChanged)
{
    uint8_t isFallingEdge;                      //1 means falling edge
    uint8_t isRisingEdge;                       //1 means rising edge
    uint8_t rowMask;                            //bitwise, active col bit is 1
    uint8_t col;                                //index for ptrsKeys[col] array

    //bit=1 if last debounced changed from 1 to 0, else bit=0
    isFallingEdge = debouncedChanged & ~debounced;

    //bit=1 if last debounced changed from 0 to 1, else bit=0
    isRisingEdge = debouncedChanged & debounced;

    for (rowMask=1, col=0; rowMask<rowEnd; rowMask<<=1, col++) //for each key in row
    {
        //release before press avoids impossible key sequence
        if (rowMask & isFallingEdge)            //if key was released
        {
            ptrsKeys[col]->release();
        }

        if (rowMask & isRisingEdge)             //if key was pressed
        {
            ptrsKeys[col]->press();
            keyWasPressed();
        }
    }
}
            
void RowBase::keyWasPressed()
{
    //empty in RowBase class.  To unstick sticky keys, override keyWasPressed() in derived class.
}