#include <avr/io.h>
#include <util/delay.h>
#include <base.h>
#include <spi.h>
#include <reg.h>

typedef struct HD44780 {
    shift_register_t reg;
    gpio_t register_select;
    gpio_t enable;
} hd44780_t;

void strobe_line(gpio_t *line) {
    set_line(line);
    _delay_ms(1);
    clear_line(line);
    _delay_ms(1);
}

void hd44780_init(hd44780_t *disp) {
    spi_initialize(disp);
    set_line_direction(&disp->register_select, LINE_OUT);
    set_line_direction(&disp->enable, LINE_OUT);
    send_msb(&disp->reg, 0b00111100);
}

void hd44780_clear(hd44780_t *disp) {
    clear_line(&disp->register_select);
    send_msb(&disp->reg, 0b00000001);
    _delay_ms(1);
    strobe_line(&disp->enable);

    send_msb(&disp->reg, 0b00000010);
    _delay_ms(1);
    strobe_line(&disp->enable);
}

void hd44780_display(hd44780_t *disp) {
    clear_line(&disp->register_select);
    send_msb(&disp->reg, 0b00001110);
    _delay_ms(1);
    strobe_line(&disp->enable);
}

void hd44780_write_char(hd44780_t *disp, uint8_t bitcode) {
    set_line(&disp->register_select);
    send_msb(&disp->reg, bitcode);
    strobe_line(&disp->enable);
}

void hd44780_write(hd44780_t *disp) {
    set_line(&disp->register_select);

    hd44780_write_char(disp, 0b01001000);
    hd44780_write_char(disp, 0b01000101);
    hd44780_write_char(disp, 0b01001100);
    hd44780_write_char(disp, 0b01001100);
    hd44780_write_char(disp, 0b01001111);
    hd44780_write_char(disp, 0b00101100);

    hd44780_write_char(disp, 0b00100000);

    hd44780_write_char(disp, 0b01001101);
    hd44780_write_char(disp, 0b01011001);

    hd44780_write_char(disp, 0b00100000);

    hd44780_write_char(disp, 0b01000010);
    hd44780_write_char(disp, 0b01000001);
    hd44780_write_char(disp, 0b01010100);
}

int main(void) {
    hd44780_t display = {
        .reg = {
            .output         = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 5 },
            .latch_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 6 },
            .shift_clock    = { .ddr = &DDRB, .port = &PORTB, .pin = &PINB, .addr = 7 },
        },
        .register_select    = { .ddr = &DDRF, .port = &PORTF, .pin = &PINF, .addr = 1 },
        .enable             = { .ddr = &DDRF, .port = &PORTF, .pin = &PINF, .addr = 0 },
    };

    gpio_t light = { .ddr = &DDRC, .port = &PORTC, .pin = &PINC, .addr = 7 };
    set_line_direction(&light, LINE_OUT);
    clear_line(&light);

    hd44780_init(&display);

    hd44780_clear(&display);
    _delay_ms(500);

    hd44780_write(&display);
    hd44780_display(&display);

    set_line(&light);

    while(1) { _delay_ms(1); }
}