#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>

#include <cx/chlcd.h>
#include <cx/chlcd/__helper.h>


static chlcd_error_t __chlcd_hd44780_shift_register_set_byte(
    chlcd_hd44780_shift_register_connector_t *self,
    uint8_t content
) {
    self->last_state = content; 
    
    for (uint8_t count = 0; count < 8; ++count) {
        bool current = (content & 0b1) != 0x00;
        content = content >> 1;

        __R(chlcd_pin_write(self->register_data, current));
        __R(chlcd_pin_write(self->register_clock, true));
        __R(chlcd_sleep_us(200));
        __R(chlcd_pin_write(self->register_clock, false));
        __R(chlcd_sleep_us(200));
    }

    __R(chlcd_pin_write(self->register_latch, true));
    __R(chlcd_sleep_us(200));
    __R(chlcd_pin_write(self->register_latch, false));

    return CHLCD_SUCCESS;
}

chlcd_error_t chlcd_hd44780_shift_register_init(void *self_pointer) {
    chlcd_hd44780_shift_register_connector_t *self 
    = (chlcd_hd44780_shift_register_connector_t *) self_pointer;

    __R(chlcd_pin_set_output(self->register_latch));
    __R(chlcd_pin_set_output(self->register_clock));
    __R(chlcd_pin_set_output(self->register_data));
    
    __R(chlcd_pin_write(self->register_data, false));
    __R(chlcd_pin_write(self->register_clock, false));
    __R(chlcd_pin_write(self->register_latch, false));

    __R(chlcd_sleep_us(200));

    __R(__chlcd_hd44780_shift_register_set_byte(self, 0x00));

    return CHLCD_SUCCESS;
}

chlcd_error_t __chlcd_hd44780_shift_register_send_half_byte(
    chlcd_hd44780_shift_register_connector_t *self,
    uint8_t content,
    bool is_command
) {
    uint8_t d7 = (content & 0b10000000) ? 0b1 : 0b0;
    uint8_t d6 = (content & 0b01000000) ? 0b1 : 0b0;
    uint8_t d5 = (content & 0b00100000) ? 0b1 : 0b0;
    uint8_t d4 = (content & 0b00010000) ? 0b1 : 0b0;
    uint8_t rs = is_command ? 0b0 : 0b1;
    uint8_t e_mask = 0b1 << self->e;

    uint8_t target = 0x00;
    target |= (d7 << self->d7);
    target |= (d6 << self->d6);
    target |= (d5 << self->d5);
    target |= (d4 << self->d4);
    target |= (rs << self->rs);
    target |= e_mask;

    __R(__chlcd_hd44780_shift_register_set_byte(self, target));
    __R(chlcd_sleep_us(2000));

    target &= ~e_mask;

    __R(__chlcd_hd44780_shift_register_set_byte(self, target));
    __R(chlcd_sleep_us(2000));

    return CHLCD_SUCCESS;
}

chlcd_error_t chlcd_hd44780_shift_register_sender(
    void *self_pointer,
    chlcd_data_t content,
    bool is_command,
    bool is_half_word
) {
    chlcd_hd44780_shift_register_connector_t *self
    = (chlcd_hd44780_shift_register_connector_t *) self_pointer;

    if (!is_half_word) {
        __R(__chlcd_hd44780_shift_register_send_half_byte(
            self, 
            content, 
            is_command
        ));
    }

    content = content << 4;

    __R(__chlcd_hd44780_shift_register_send_half_byte(
        self, 
        content, 
        is_command
    ));
    
    return CHLCD_SUCCESS;
}