/**
 * \file main.c
 * \brief Firmware for the USB-LED-Fader.
 * \author Ronald Schaten & Thomas Stegemann
 * \version $Id: main.c,v 1.1 2006/09/26 18:18:27 rschaten Exp $
 *
 * License: See documentation.
 */

#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>

#include "usbdrv.h"
#include "oddebug.h"
#include "pwm_channels.h"
#include "usbledfader.h"
#include "channels.h"

/** Global variable, contains the state of all four LEDs. */
static fade_GlobalData fade_globalData;

/** Global variable, contains the rest-amount of data to send to the host. */
static uint8_t usbRead;

/**
 * Handler for the timer-interrupt. Determines the state of the four LEDs and
 * calls pwm_Channels_show() if something is to be changed.  This function
 * contains the logic by which the waveforms are assigned to the LEDs.
 */
static void timerInterrupt(void)
{
    uint8_t i = 0, changed = 0;
    for (i = 0; i < CHANNELS; i++) {
        fade_LedState *pLed = &(fade_globalData.led[i]);        /* fetch current LED */
        pLed->waveNextUpdate--;
        if (pLed->waveNextUpdate <= 0) {        /* time to update */
            fade_Waveform *pWave = &(pLed->wave[pLed->waveCurrentId]);  /* fetch currently active wave */
            pLed->waveCurrentPosition++;        /* go to next position */
            if (pLed->waveCurrentPosition > pWave->waveformLength) {
                pLed->waveCurrentPosition = 1;  /* restart wave */
                if (pWave->waveformRepetition == 0) {
                    /* repeat this waveform forever */
                } else {
                    /* next repetition */
                    pLed->waveCurrentRepetition++;
                    if (pLed->waveCurrentRepetition >= pWave->waveformRepetition) { /* enough of this wave */
                        pLed->waveCurrentRepetition = 0;    /* reset repetition counter */
                        switch (pLed->waveCurrentId) {     /* activate next wave */
                            case 0:
                                if (pLed->wave[1].waveformDuration > 0) { /* only activate if a wave is set */
                                    pLed->waveCurrentId = 1;
                                }
                                break;
                            case 1:
                                if (pLed->wave[0].waveformDuration > 0) { /* only activate if a wave is set */
                                    pLed->waveCurrentId = 0;
                                }
                                break;
                            case 2:
                                /* wave 2 is only to be repeated the given times,
                                 * reset and continue with wave 0 */
                                pWave->waveformId = 0;
                                pWave->waveformLength = fade_calculateWaveform(pWave->waveformId, 0);
                                pWave->waveformRepetition = 1;
                                pWave->waveformDuration = 0;
                                pWave->waveformUpdateTime = 1;
                                pLed->waveCurrentId = 0;
                                break;
                        }
                    }
                }
            }
            uint8_t newValue = fade_calculateWaveform(pLed->wave[pLed->waveCurrentId].waveformId, pLed->waveCurrentPosition); /* fetch new value */
            if (newValue != pLed->waveCurrentValue) {   /* only update if the value has changed */
                pLed->waveCurrentValue = newValue;
                changed = 1;
            }
            pLed->waveNextUpdate = pLed->wave[pLed->waveCurrentId].waveformUpdateTime; /* next update according to the wave's settings */
        }
    }
    if (changed) {              /* any value has changed, update all LEDs */
        pwm_Channels channels;
        for (i = 0; i < CHANNELS; i++) {
            channels.channel[i] = fade_globalData.led[i].waveCurrentValue;
        }
        pwm_Channels_show(channels);
    }
}

/**
 * Start displaying a certain waveform on a single LED.
 * \param ledId ID of the LED that is changed.
 * \param waveId ID of the wave that to be set: 0 and 1 are the base waves, 2 is the override wave.
 * \param waveformId ID of the Waveform that is to be assigned to the LED.
 * \param periodDuration How long should this wave stay on display? Time in seconds/10.
 * \param repetitionCount How many times should this wave be repeated while it is on display?
 */
void fade_startWaveform(uint8_t ledId, uint8_t waveId, uint8_t waveformId, uint8_t periodDuration, uint8_t repetitionCount) {
    if ((ledId < CHANNELS) && (waveId < 3)) {
        fade_LedState *pLed = &(fade_globalData.led[ledId]);
        fade_Waveform *pWave = &(pLed->wave[waveId]);
        pLed->waveCurrentId = waveId;
        pLed->waveCurrentPosition = 0;
        pLed->waveCurrentRepetition = 0;
        pLed->waveNextUpdate = 0;
        if (periodDuration > 0) {
            pWave->waveformId = waveformId;
            pWave->waveformLength = fade_calculateWaveform(waveformId, 0);
            pWave->waveformRepetition = repetitionCount;
            pWave->waveformDuration = periodDuration;
            /* waveformUpdateTime in calls of timerInterrupt().
             * periodDuration in seconds/10.
             * 12000000 cycles per second
             * 64 cycles per timer/counter (prescaler)
             * 256 timer/counter per interrupt-call
             * -> (12000000 / (256 * 64)) = 732 calls per second */
            pWave->waveformUpdateTime = ((uint32_t)periodDuration * 12000000 / 256 / 64 / 10 / pWave->waveformLength );
        } else {
            /* periodDuration = 0, reset the wave */
            pWave->waveformId = 0;
            pWave->waveformLength = fade_calculateWaveform(pWave->waveformId, 0);
            pWave->waveformRepetition = 1;
            pWave->waveformDuration = 0;
            pWave->waveformUpdateTime = 1;
        }
    }
}

/**
 * Fills fade_globalData. The state of all LEDs is initialized to off. One
 * signal is displayed on all LEDs to ensure they're working.
 */
void fade_globalData_init(void) {
    int i = 0, j = 0;
    for (i = 0; i < CHANNELS; i++) {
        fade_globalData.led[i].waveCurrentId = 0;
        fade_globalData.led[i].waveCurrentPosition = 0;
        fade_globalData.led[i].waveCurrentRepetition = 0;
        fade_globalData.led[i].waveNextUpdate = 0;
        for (j = 0; j < 3; j++) {
            fade_globalData.led[i].wave[j].waveformId = 0;
            fade_globalData.led[i].wave[j].waveformLength =
                fade_calculateWaveform(fade_globalData.led[i].wave[j].
                                       waveformId, 0);
            fade_globalData.led[i].wave[j].waveformRepetition = 1;
            fade_globalData.led[i].wave[j].waveformDuration = 0;
            fade_globalData.led[i].wave[j].waveformUpdateTime = 1;
        }
    }
    /* show that we are ready */
    for (i = 0; i < CHANNELS; i++) {
        fade_startWaveform(i, 2, 36, 10, 1);
    }
}

/**
 * USB-Data-Handler (device -> host). Handles data that is to be sent to the
 * host via USB-Interface. In our case the data contains the current settings
 * for the LEDs. This function is called until the returned length is shorter
 * than the buffer (typically 8 bytes).
 * \param data Buffer for the data.
 * \param len Length of the buffer.
 * \return Length of the returned buffer.
 */
uchar usbFunctionRead(uchar *data, uchar len) {
    uint8_t i = 0;
    uint8_t *p_fade_globalData = (uint8_t*)&fade_globalData;
    while ((i < len) && (usbRead < sizeof(fade_GlobalData))) {
        data[i] = p_fade_globalData[usbRead];
        usbRead++;
        i++;
    }
    return i;
}

/**
 * USB-Data-Handler (host -> device). Handles data that is received from the
 * USB-Interface. In our case the data contains settings for the LEDs.
 * \param data The received data, up to 8 bytes.
 * \param len Length of the received data.
 * \return 1 if we have received the entire payload successfully, 0 if we expect more data. We don't, so we always return 1.
 */
uchar usbFunctionWrite(uchar *data, uchar len) {
    /* parameters:
     * data[0]: command (0: echo, 1: read status, 2: set status, 3: clear)
     * data[1]: ledId
     * data[2]: waveId
     * data[3]: waveformId
     * data[4]: periodDuration
     * data[5]: repetitionCount
     */
    fade_startWaveform(data[1], data[2], data[3], data[4], data[5]);
    return 1;
}

/**
 * USB-Setup-Handler. Handles setup-calls that are received from the
 * USB-Interface.
 * \param data Eight bytes of data.
 * \return The number of returned bytes (in replyBuffer[]).
 */
uchar usbFunctionSetup(uchar data[8]) {
    int i;
    static uchar replyBuffer[8];
    uchar replyLength;

    replyBuffer[0] = msgOK;
    switch (data[1]) {
    case CMD_ECHO:                    /* echo */
        replyBuffer[0] = data[2];
        replyBuffer[1] = data[3];
        replyLength = 2;
        break;
    case CMD_GET:                    /* read status */
        usbRead = 0;
        replyLength = 0xff; /* special value, indicates that usbFunctionRead() has to be called */
        break;
    case CMD_SET:                    /* set status */
        replyLength = 0xff; /* special value, indicates that usbFunctionWrite() has to be called */
        break;
    case CMD_CLEAR:                  /* clear one LED */
        for (i = 0; i <= 2; i++) {
            /* clear all three waves on this LED */
            fade_startWaveform(data[2], i, 0, 0, 0);
        }
        replyLength = 1;
        break;
    case CMD_RESET:                  /* reset the device */
        fade_globalData_init();
        replyLength = 1;
        break;
    default:                         /* WTF? */
        replyBuffer[0] = msgErr;
        replyLength = 1;
        break;
    }
    usbMsgPtr = replyBuffer;
    return replyLength;
}

/**
 * Main-function. Initializes the hardware and starts the main loop of the
 * application.
 * \return An integer. Whatever... :-)
 */
int main(void) {
    uchar i, j;
    odDebugInit();
    DDRB = ~0;                  /* output SE0 for USB reset */
    PORTB = 0x00;               /* no pullups on USB pins */
    DDRC = 0xff;                /* all outputs */
    PORTC = 0x00;
    DDRD = 0x00;                /* all inputs */
    PORTD = 0x00;

    j = 0;
    while (--j) {               /* USB Reset by device only required on Watchdog Reset */
        i = 0;
        while (--i);            /* delay >10ms for USB reset */
    }
    DDRB = ~USBMASK;            /* all outputs except USB data */
    TCCR0 = 3;                  /* set prescaler to 1/64 */
    usbInit();
    sei();

    pwm_Channels_init();
    fade_globalData_init();

    while (1) {                 /* main event loop */
        usbPoll();
        if (TIFR & (1 << TOV0)) {
            TIFR |= 1 << TOV0;  /* clear pending flag */
            timerInterrupt();
        }
    }
    return 0;
}