#include "inputs.h"
#include "hardware/gpio.h"
#include "pico/time.h"

static const uint8_t ROWS[3] = {2, 3, 5};
static const uint8_t COLS[4] = {6, 7, 8, 9};
static const uint8_t SWITCHES[3] = {13, 14, 12};   /* IN_SEED, IN_RUN, IN_PUSH */
#define DEBOUNCE_MS 10   /* a change must hold this long to count */
#define LOCKOUT_MS  40   /* then the input ignores further changes this long (worn switches chatter) */

/* (1,1) KICK (1,2) KICK 2 (1,3) SNARE (1,4) none; (2,1) HAT (2,2) HAT 16 (2,3) PERC (2,4) GHOST;
   (3,1) BASS (3,2) MEL A (3,3) MEL B (3,4) PAD */
const int8_t INPUT_KEY_TRACK[12] = { 0, 1, 2, -1,   4, 5, 6, 3,   7, 8, 9, 10 };

static uint32_t state;
static uint8_t count[IN_COUNT], lockout[IN_COUNT];

static void input_pullup(uint pin){ gpio_init(pin); gpio_set_dir(pin, GPIO_IN); gpio_pull_up(pin); }

void inputs_init(void){
  int i;
  for(i = 0; i < 3; i++) input_pullup(ROWS[i]);
  for(i = 0; i < 4; i++){ input_pullup(COLS[i]); gpio_put(COLS[i], 0); }   /* idle: Hi-Z with pull-up (E9) */
  for(i = 0; i < 3; i++) input_pullup(SWITCHES[i]);
}

static uint32_t raw_read(void){
  uint32_t raw = 0;
  int r, c;
  for(c = 0; c < 4; c++){
    gpio_set_dir(COLS[c], GPIO_OUT);   /* output latch is already 0: drive low */
    busy_wait_us(5);                   /* settle */
    for(r = 0; r < 3; r++) if(!gpio_get(ROWS[r])) raw |= 1u << (r * 4 + c);
    gpio_set_dir(COLS[c], GPIO_IN);    /* back to Hi-Z, pull-up holds it high */
  }
  for(r = 0; r < 3; r++) if(!gpio_get(SWITCHES[r])) raw |= 1u << (IN_SEED + r);
  return raw;
}

uint32_t inputs_scan(void){
  uint32_t raw = raw_read();
  int i;
  for(i = 0; i < IN_COUNT; i++){
    uint32_t bit = 1u << i;
    if(lockout[i]){ lockout[i]--; count[i] = 0; continue; }
    if((raw & bit) != (state & bit)){ if(++count[i] >= DEBOUNCE_MS){ state ^= bit; count[i] = 0; lockout[i] = LOCKOUT_MS; } }
    else count[i] = 0;
  }
  return state;
}