#include "music.h"
#include "tables.h"
#include <msp430.h>
#include <stdint.h>

#define interrupt(x) void __attribute__((interrupt(x)))

// table size 1024 (10bit) fraction 6bit
// index = 10.6 sample = 8.8

#define RATE 8192
// #define RATE 16384

#define FTABLE_SIZE 1024
#define ETABLE_SIZE 256

#define NCHAN 4

struct channel {
  int8_t const *ftable, *etable;
  uint16_t findex, eindex;
  uint16_t fstep, estep;
  uint16_t amp;
};

struct channel chan[NCHAN];

uint16_t next_pwm = 0;
volatile uint8_t wait = 1;

int16_t ac;
uint16_t ticks;
volatile uint16_t count;
uint8_t state = 0;

int main() {
  // Disable watchdog
  WDTCTL = WDTPW | WDTHOLD;

  // Internal timer
  BCSCTL1 = CALBC1_16MHZ;
  DCOCTL = CALDCO_16MHZ;

  // TA1 on P1.2
  P1DIR = 0x04;
  P1SEL = 0x04;
  P1SEL2 = 0x00;

  TACTL = TASSEL_2 | TACLR; // SMCLK source for timer
  TACCR0 = 256;
  TACCTL0 = CCIE;
  TACCTL1 = OUTMOD_7;

  TACTL |= MC0;

  //    state = 66;

  //    while (1);

  state = 2;

  __enable_interrupt();

  int nextchan = 0, i = 0;

  state = 1;

  while (1) {
    for (i = 0; i < NCHAN; i++) {
      chan[i].ftable = 0;

      chan[i].etable = env_musicbox;
      chan[i].estep = 6;

      // chan[i].amp = 20;
    }

    int ni;
    for (ni = 0; ni < sizeof(notes); ni++) {
      uint8_t note = notes[ni];

      if (note & 0x80) {
        chan[nextchan].ftable = wave_musicbox;
        chan[nextchan].fstep = note_fstep[note & 0x7F];
        chan[nextchan].eindex = 0;

        nextchan++;
        if (nextchan == NCHAN)
          nextchan = 0;
      } else {
        uint32_t tick = note * 30;

        for (; tick; tick--) {
          ticks++;
          while (wait)
            ;

          int16_t accu = 0;

          for (i = 0; i < NCHAN; i++) {
            struct channel *c = &chan[i];

            if (!c->ftable)
              continue;

            int16_t sample = (int16_t)c->ftable[c->findex >> 6];
            sample =
                (int16_t)(sample * (int16_t)c->etable[c->eindex >> 8]) >> 8;
            sample = (int16_t)(sample * 50) >> 8;

            accu += sample;

            c->findex += c->fstep;

            if ((uint16_t)(c->eindex + c->estep) > c->eindex)
              c->eindex += c->estep;
            else
              c->ftable = 0;
          }

          ac = accu;

          next_pwm = ((accu + 0x7F) & 0xFF);

          wait = 1;
        }
      }
    }
  }

  state = 3;

  return 0;
}

interrupt(TIMER0_A0_VECTOR) timer_isr() {
  count++;
  if (count > 6) {
    TACCR1 = next_pwm;
    count = 0;
    wait = 0;
  }

  TACCTL0 &= ~CCIFG;
}