#define ALPH_LEN 26
#define UNIT 100

#include "nrf_delay.h"

void morse(char ch, int led)
{
        /* even numbers represent a code of a letter
		 * e.g.: -... -> 0111 -> 1110 -> 0xe
         * odd numbers represent the length of a character
         */
        static char code[ALPH_LEN*2] = {
                0x1,2, 0xe,4, 0xa,4, 0x6,3, 0x1,1, 0xb,4, 0x4,3, 0xf,4, 0x3,2, 0x1,4,
                0x2,3, 0xd,4, 0x0,2, 0x2,2, 0x0,3, 0x9,4, 0x4,4, 0x5,3, 0x7,3, 0x0,1,
                0x3,3, 0x7,4, 0x1,3, 0x6,4, 0x2,4, 0xc,4
        };

        if (ch == ' ') {
                nrf_delay_ms(UNIT*4);
                return;
        }
        if (ch < 'a' || ch > 'z') return;

        char letter = code[2*(ch - 'a')];
        char count = code[2*(ch - 'a') + 1];
        char signal;
        for (char i = 0; i < count; ++i) {
                signal = letter & 1;

                bsp_board_led_invert(led);
                nrf_delay_ms(UNIT * (signal ? 1 : 3));
                bsp_board_led_invert(led);

                letter >>= 1;
                nrf_delay_ms(UNIT);
        }
        nrf_delay_ms(UNIT*3);
}

#undef UNIT
#undef ALPH_LEN