/*Projeto de Ian Périgo aluno de TSI da UERN e FIC Embarcatech IFRN
https://www.linkedin.com/in/ianperigo/
https://github.com/IanPerigoUERN
https://github.com/IanPerigoVianna
Bibliotecas do SSD1306, ws2818b e código do teste do display retirados do repositório
Oficial BitDogLab: https://github.com/BitDogLab/BitDogLab-C/blob/main/display_oled/display_oled.c
*/
/*166- https://www.ti.com/lit/ds/symlink/sn74hc166.pdf*/

/*https://docs.wokwi.com/pt-BR/parts/wokwi-74hc165*/
/*Datasheet https://www.ti.com/lit/ds/symlink/sn74hc165-ep.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1748975820690&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fsn74hc165-ep */

#include <stdio.h>
#include "pico/stdlib.h"
#include "ssd1306.h"
#include "hardware/gpio.h"

#define I2C_SDA 14
#define I2C_SCL 15

#define BTN_B_PIN 6

// Define Shift Register pins based on your initial comment
// For a parallel-in serial-out shift register like 74HC165:
// - Load pin (PL on 74HC165) is connected to PICO_LOAD_PIN
// - Clock pin (CP on 74HC165) is connected to PICO_CLK_PIN
// - Serial Data Output (Q7 or QH on 74HC165) is connected to PICO_DATA_IN_PIN
#define PICO_LOAD_PIN         28 // GP28 - Parallel Load (PL)
#define PICO_CLK_PIN          17 // GP17 - Clock (CLK)
#define PICO_DATA_IN_PIN      16 // GP16 - Serial Data Input (Data from Shift Register)

#define NUM_DIP_SWITCHES 8   // We are reading 8 bits from the DIP switch

uint8_t ssd[ssd1306_buffer_length];

struct render_area frame_area = {
    start_column : 0,
    end_column : ssd1306_width - 1,
    start_page : 0,
    end_page : ssd1306_n_pages - 1
};

void setup_gpios() {
    gpio_init(BTN_B_PIN);
    gpio_set_dir(BTN_B_PIN, GPIO_IN);
    gpio_pull_up(BTN_B_PIN);

    i2c_init(i2c1, ssd1306_i2c_clock * 1000);
    gpio_set_function(I2C_SDA, GPIO_FUNC_I2C);
    gpio_set_function(I2C_SCL, GPIO_FUNC_I2C);
    gpio_pull_up(I2C_SDA);
    gpio_pull_up(I2C_SCL);

    ssd1306_init();
    calculate_render_area_buffer_length(&frame_area);

    // Initialize Shift Register control pins
    gpio_init(PICO_LOAD_PIN);
    gpio_set_dir(PICO_LOAD_PIN, GPIO_OUT);
    gpio_put(PICO_LOAD_PIN, 1); // PL is often active low, so keep it high initially

    gpio_init(PICO_CLK_PIN);
    gpio_set_dir(PICO_CLK_PIN, GPIO_OUT);
    gpio_put(PICO_CLK_PIN, 0); // Clock initially low

    gpio_init(PICO_DATA_IN_PIN);
    gpio_set_dir(PICO_DATA_IN_PIN, GPIO_IN);
    // No pull-up/down needed here as it's driven by the shift register
}

// Function to read the state of the DIP switches from the shift register
uint8_t read_dip_switches() {
    uint8_t dip_data = 0;

    gpio_put(PICO_LOAD_PIN, 0);
    sleep_us(5); // Small delay to ensure the load pulse is registered

    gpio_put(PICO_CLK_PIN, 1);
    sleep_us(2);
    gpio_put(PICO_CLK_PIN, 0);
    sleep_us(2);

    gpio_put(PICO_LOAD_PIN, 1);
    sleep_us(5);

    for (int i = 0; i < NUM_DIP_SWITCHES; i++) {
        // Shift current data one bit to the left to make space for the new bit
        dip_data = dip_data << 1;

        // Read the current bit from the shift register's serial output
        // Ensure clock is low before reading if register changes output on rising edge
        gpio_put(PICO_CLK_PIN, 0); // Not strictly necessary if clock cycle starts low
        sleep_us(2); // Allow data line to settle

        if (gpio_get(PICO_DATA_IN_PIN)) {
            dip_data |= 0x01; // Set the LSB if the input is high
        }

        gpio_put(PICO_CLK_PIN, 1);
        sleep_us(2);
        gpio_put(PICO_CLK_PIN, 0);
        sleep_us(2);
    }
    return dip_data;
}

int main() {
    stdio_init_all();
    setup_gpios();

    ssd1306_draw_string(ssd, 8, 8, "VALz ");
    render_on_display(ssd, &frame_area);

    uint8_t previous_dip_state = 0; // To detect changes
    while (1) {
        uint8_t current_dip_state = read_dip_switches(); // está constantemente lendo

        if (gpio_get(BTN_B_PIN) == 0) { // só imprime na tela quando aperto o botão

            printf("DIP Switch State: ");
            for (int i = 7; i >= 0; i--) { // esse for é pra mostrar o DIP em binário
                printf("%d", (current_dip_state >> i) & 1);
            }
            printf(" Decimal: %d\n", current_dip_state);

            char buffer[1];
            sprintf(buffer, "%d", current_dip_state);
            ssd1306_draw_string(ssd, 48, 8, buffer);
            render_on_display(ssd, &frame_area);

            previous_dip_state = current_dip_state;
        }
        sleep_ms(100); // Read DIP switches every 100ms
    }

    return 0; // Should not be reached
}