/*
  Simple "Hello World" for ILI9341 LCD

  https://wokwi.com/arduino/projects/308024602434470466
*/

#include "Adafruit_GFX.h"
#include "Adafruit_ILI9341.h"
#include "SPI.h"

#define TFT_DC 9
#define TFT_CS 10

#define UBUT 2
#define RBUT 3
#define DBUT 4
#define LBUT 5
#define UNKNOWN_BUT 5

#define SCREEN_HEIGHT 320
#define SCREEN_WIDTH 240

#define MENU_TXT_SIZE 3
#define MENU_LN_SPACING 10

#define PATH_TEXT_SIZE 2
#define PATH_LINE_SPACING 3
#define PATH_LINE_HEIGHT 5
#define PATH_HEIGHT PATH_TEXT_SIZE * 10 + PATH_LINE_SPACING + PATH_LINE_HEIGHT

Adafruit_ILI9341 tft = Adafruit_ILI9341(TFT_CS, TFT_DC);

byte menuDepth = 0;
byte menuCursor = 0;
byte menuPos[6] = {0, 0, 0, 0, 0, 255};

typedef struct menuEntry_s {
    char name[20];
    struct menuEntry_s *subMenus;
    byte nbSubMenu;
    void (*menuFunction)(void);
} menuEntry_t;

menuEntry_t mainSub[3] = {{"Magstripe", nullptr, 0, nullptr}, {"RFID", nullptr, 0, nullptr}, {"NFC", nullptr, 0, nullptr}};

menuEntry_t mainMenu = {"Main menu", mainSub, 3, nullptr};

void clearScreen(void) {
    tft.fillRect(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, 0);
}

void setup() {
    tft.begin();
    tft.setRotation(0);

    pinMode(LBUT, INPUT_PULLUP);
    pinMode(RBUT, INPUT_PULLUP);
    pinMode(DBUT, INPUT_PULLUP);
    pinMode(UBUT, INPUT_PULLUP);
}

byte waitButtonPress(void) {
    while (digitalRead(UBUT) == HIGH && digitalRead(RBUT) == HIGH && digitalRead(DBUT) == HIGH && digitalRead(LBUT) == HIGH)
        ;
    if (digitalRead(UBUT) == LOW)
        return UBUT;
    if (digitalRead(RBUT) == LOW)
        return RBUT;
    if (digitalRead(DBUT) == LOW)
        return DBUT;
    if (digitalRead(LBUT) == LOW)
        return LBUT;
    return UNKNOWN_BUT;
}

menuEntry_t *getCurrentMenu(void) {
    menuEntry_t *m = &mainMenu;

    for (int i = 0; i < menuDepth; ++i) {
        m = &m->subMenus[menuPos[i]];
    }
    return m;
}

void navigateButton(menuEntry_t *m, byte b) {
    if (b == UBUT) {
        if (menuCursor > 0)
            --menuCursor;
    } else if (b == RBUT) {
        if (m->nbSubMenu == 0)
            return;
        menuPos[menuDepth++] = menuCursor;
        menuCursor = 0;
    } else if (b == DBUT) {
        if (menuCursor + 1 < m->nbSubMenu)
            ++menuCursor;
    } else if (b == LBUT) {
        if (menuDepth == 0)
            return;
        menuCursor = menuPos[--menuDepth];
    } else {
        return;
    }
}

void displayText(uint16_t x, uint16_t y, uint16_t color, uint16_t backgndColor, uint8_t size, char *txt) {
    tft.setCursor(x, y);
    tft.setTextColor(color, backgndColor);
    tft.setTextSize(size);
    tft.println(txt);
}

void displayPath(menuEntry_t *m) {
    for (int i = PATH_TEXT_SIZE * 10 + PATH_LINE_SPACING; i < PATH_HEIGHT; ++i)
        tft.drawLine(0, i, SCREEN_WIDTH, i, 0x07FF);
    displayText(5, 5, 0x07FF, 0x0000, PATH_TEXT_SIZE, m->name);
}

void displayMenu(menuEntry_t *m) {
    int y = PATH_HEIGHT + MENU_LN_SPACING;

    for (int i = 0; i < 6; ++i)
        Serial.println(menuPos[i]);
    Serial.println("\r\n");
    for (int i = 0; i < m->nbSubMenu; ++i) {
        if (menuCursor == i)
            displayText(5, y, 0x0000, 0x07FF, MENU_TXT_SIZE, m->subMenus[i].name);
        else
            displayText(5, y, 0x07FF, 0x0000, MENU_TXT_SIZE, m->subMenus[i].name);
        y += MENU_LN_SPACING + MENU_TXT_SIZE * 10;
    }
}

void navigateMenus() {
    menuEntry_t *m = nullptr;

    m = getCurrentMenu();
    clearScreen();
    displayPath(m);
    displayMenu(m);
    navigateButton(m, waitButtonPress());
}

void loop() {
    navigateMenus();
}