#include "midi_uart.h"
#include "hardware/gpio.h"
#include "hardware/uart.h"

#define PIN_OUT_KIT     0   /* UART0 TX */
#define PIN_IN        1   /* UART0 RX, 6N137 output with a 1 kΩ pull-up on the board */
#define PIN_OUT_SYNTH 4   /* UART1 TX */
#define MIDI_BAUD     31250

static uart_inst_t *const PORTS[2] = { uart0, uart1 };

void midi_init(void){
  uart_init(uart0, MIDI_BAUD);
  uart_init(uart1, MIDI_BAUD);
  uart_set_format(uart0, 8, 1, UART_PARITY_NONE);
  uart_set_format(uart1, 8, 1, UART_PARITY_NONE);
  gpio_set_function(PIN_OUT_KIT, GPIO_FUNC_UART);
  gpio_set_function(PIN_IN, GPIO_FUNC_UART);
  gpio_set_function(PIN_OUT_SYNTH, GPIO_FUNC_UART);   /* GP5 (UART1 RX) stays a matrix row */
  gpio_pull_up(PIN_IN);
  /* each MIDI current loop draws 6–8 mA, above the 4 mA default */
  gpio_set_drive_strength(PIN_OUT_KIT, GPIO_DRIVE_STRENGTH_12MA);
  gpio_set_drive_strength(PIN_OUT_SYNTH, GPIO_DRIVE_STRENGTH_12MA);
}

void midi_send(int port, const uint8_t *bytes, int n){ uart_write_blocking(PORTS[port], bytes, (size_t)n); }

void midi_note_on(int port, int ch, int note, int vel){
  uint8_t m[3] = { (uint8_t)(0x90 | (ch & 15)), (uint8_t)(note & 127), (uint8_t)(vel & 127) };
  midi_send(port, m, 3);
}
void midi_note_off(int port, int ch, int note){
  uint8_t m[3] = { (uint8_t)(0x80 | (ch & 15)), (uint8_t)(note & 127), 0 };
  midi_send(port, m, 3);
}

int midi_in_read(void){ return uart_is_readable(uart0) ? uart_getc(uart0) : -1; }