#include <Wire.h>
#include <SPI.h>

// ===== Pin =====
#define CS_MATRIX  PB0                      // SPI #1: MAX7219 (chip select)
#define LATCH_595  PB1                      // SPI #2: 74HC595 (latch)
const int TOMBOL[3] = {PB12, PB13, PB14};   // tombol kandidat A, B, C

// ===== Alamat I2C =====
#define LCD_ADDR 0x27                       // I2C #1: LCD 1602
#define RTC_ADDR 0x68                       // I2C #2: RTC DS1307

// ===== Pengaturan voting =====
// RTC diset 08:00:00 saat start. Voting ditutup pukul 08:02:00 (2 menit).
const int JAM_TUTUP = 8, MENIT_TUTUP = 1;

int  suara[3] = {0, 0, 0};
bool terbuka = true;
bool sedangDitekan[3] = {false, false, false};
bool perluTampil = true;
int  detikLama = -1;
int  jam, menit, detik;

SPISettings pengaturanSPI(1000000, MSBFIRST, SPI_MODE0);

// ---------- LCD 1602 lewat PCF8574 (I2C) ----------
void tulisPCF(uint8_t d) {
  Wire.beginTransmission(LCD_ADDR);
  Wire.write(d | 0x08);                     // bit 3 = lampu latar
  Wire.endTransmission();
}
void kirimNibble(uint8_t n, uint8_t rs) {
  uint8_t d = (n << 4) | rs;
  tulisPCF(d | 0x04);                       // E = 1
  delayMicroseconds(2);
  tulisPCF(d);                              // E = 0
  delayMicroseconds(50);
}
void kirimByte(uint8_t b, uint8_t rs) {
  kirimNibble(b >> 4, rs);
  kirimNibble(b & 0x0F, rs);
}
void lcdInit() {
  delay(50);
  kirimNibble(0x03, 0); delay(5);
  kirimNibble(0x03, 0); delayMicroseconds(150);
  kirimNibble(0x03, 0);
  kirimNibble(0x02, 0);                     // mode 4-bit
  kirimByte(0x28, 0);                       // 2 baris
  kirimByte(0x0C, 0);                       // display on
  kirimByte(0x06, 0);
  kirimByte(0x01, 0); delay(3);             // hapus layar
}
void lcdBaris(uint8_t baris, const char* teks) {
  kirimByte(0x80 | (baris ? 0x40 : 0x00), 0);
  uint8_t i = 0;
  for (; i < 16 && teks[i]; i++) kirimByte(teks[i], 1);
  for (; i < 16; i++) kirimByte(' ', 1);    // sisa baris diisi spasi
}

// ---------- RTC DS1307 (I2C) ----------
uint8_t keBCD(int v)   { return ((v / 10) << 4) | (v % 10); }
int     dariBCD(int v) { return (v >> 4) * 10 + (v & 0x0F); }

void aturWaktuAwal() {                      // set 08:00:00
  Wire.beginTransmission(RTC_ADDR);
  Wire.write(0);
  Wire.write(keBCD(0));                     // detik
  Wire.write(keBCD(0));                     // menit
  Wire.write(keBCD(8));                     // jam
  Wire.write(keBCD(1));                     // hari dalam seminggu (tidak dipakai)
  Wire.write(keBCD(7));                     // tanggal
  Wire.write(keBCD(10));                    // bulan
  Wire.write(keBCD(26));                    // tahun
  Wire.endTransmission();
}
bool bacaWaktu() {
  Wire.beginTransmission(RTC_ADDR);
  Wire.write(0);
  if (Wire.endTransmission() != 0) return false;
  if (Wire.requestFrom((uint8_t)RTC_ADDR, (uint8_t)7) != 7) return false;
  detik = dariBCD(Wire.read() & 0x7F);
  menit = dariBCD(Wire.read());
  jam   = dariBCD(Wire.read() & 0x3F);
  return true;
}
bool waktuHabis() {
  return jam > JAM_TUTUP || (jam == JAM_TUTUP && menit >= MENIT_TUTUP);
}

// ---------- MAX7219 matrix (SPI) ----------
void maxKirim(uint8_t reg, uint8_t data) {
  SPI.beginTransaction(pengaturanSPI);
  digitalWrite(CS_MATRIX, LOW);
  SPI.transfer(reg);
  SPI.transfer(data);
  digitalWrite(CS_MATRIX, HIGH);
  SPI.endTransaction();
}
void maxInit() {
  maxKirim(0x0F, 0x00);                     // test off
  maxKirim(0x0C, 0x01);                     // nyalakan chip
  maxKirim(0x09, 0x00);                     // tanpa decode
  maxKirim(0x0B, 0x07);                     // pakai 8 baris
  maxKirim(0x0A, 0x03);                     // kecerahan
}
// Kolom tiap batang: A = kiri, B = tengah, C = kanan
const uint8_t MASK[3] = {0b11000000, 0b00011000, 0b00000011};

void gambarGrafik() {
  for (int baris = 0; baris < 8; baris++) {
    uint8_t data = 0;
    for (int k = 0; k < 3; k++) {
      int tinggi = min(suara[k], 8);        // 1 suara = 1 baris, maksimum 8
      if (baris >= 8 - tinggi) data |= MASK[k];
    }
    maxKirim(baris + 1, data);
  }
}

// ---------- 74HC595 + LED (SPI) ----------
void kirimLED(uint8_t data) {
  SPI.beginTransaction(pengaturanSPI);
  SPI.transfer(data);
  SPI.endTransaction();
  digitalWrite(LATCH_595, HIGH);            // pulsa latch: data keluar ke LED
  digitalWrite(LATCH_595, LOW);
}

// ---------- Logika voting ----------
int pemimpin() {                            // 0=A, 1=B, 2=C, -1 = seri atau belum ada suara
  int maks = max(suara[0], max(suara[1], suara[2]));
  if (maks == 0) return -1;
  int jumlah = 0, idx = -1;
  for (int k = 0; k < 3; k++)
    if (suara[k] == maks) { jumlah++; idx = k; }
  return (jumlah == 1) ? idx : -1;
}

void tampilkanLCD() {
  char b[20];
  snprintf(b, sizeof(b), "A:%02d B:%02d C:%02d", suara[0], suara[1], suara[2]);
  lcdBaris(0, b);

  if (terbuka) {
    snprintf(b, sizeof(b), "%02d:%02d:%02d  BUKA", jam, menit, detik);
  } else {
    int p = pemimpin();
    if (p < 0) snprintf(b, sizeof(b), "TUTUP - SERI");
    else       snprintf(b, sizeof(b), "TUTUP Menang: %c", 'A' + p);
  }
  lcdBaris(1, b);
}

void tampilkanLED() {
  uint8_t led = 0;
  int p = pemimpin();
  if (p >= 0) led |= (1 << p);              // LED 1-3: kandidat yang memimpin
  if (terbuka) led |= (1 << 3);             // LED 4: voting sedang dibuka
  kirimLED(led);
}

// ---------- Program utama ----------
void setup() {
  Serial.begin(115200);

  for (int k = 0; k < 3; k++) pinMode(TOMBOL[k], INPUT_PULLUP);
  pinMode(CS_MATRIX, OUTPUT); digitalWrite(CS_MATRIX, HIGH);
  pinMode(LATCH_595, OUTPUT); digitalWrite(LATCH_595, LOW);

  Wire.begin();                             // I2C: PB6 (SCL), PB7 (SDA)
  SPI.begin();                              // SPI: PA5 (SCK), PA7 (MOSI)

  lcdInit();
  maxInit();
  aturWaktuAwal();

  lcdBaris(0, "VOTING DIGITAL");
  lcdBaris(1, bacaWaktu() ? "RTC OK" : "RTC ERROR");
  delay(1500);
}

void loop() {
  // 1. Baca jam dari RTC
  bacaWaktu();

  // 2. Tutup voting kalau waktu habis
  if (terbuka && waktuHabis()) {
    terbuka = false;
    perluTampil = true;
    Serial.println("Voting DITUTUP");
    Serial.print("A="); Serial.print(suara[0]);
    Serial.print(" B="); Serial.print(suara[1]);
    Serial.print(" C="); Serial.println(suara[2]);
  }

  // 3. Baca tombol: satu kali tekan = satu suara (hanya saat voting dibuka)
  for (int k = 0; k < 3; k++) {
    bool ditekan = (digitalRead(TOMBOL[k]) == LOW);
    if (ditekan && !sedangDitekan[k] && terbuka) {
      suara[k]++;
      perluTampil = true;
    }
    sedangDitekan[k] = ditekan;
  }

  // 4. Perbarui jam di LCD tiap detik saat voting dibuka
  if (terbuka && detik != detikLama) {
    detikLama = detik;
    perluTampil = true;
  }

  // 5. Perbarui semua tampilan hanya kalau ada yang berubah
  if (perluTampil) {
    perluTampil = false;
    tampilkanLCD();                         // I2C: LCD
    gambarGrafik();                         // SPI: MAX7219
    tampilkanLED();                         // SPI: 74HC595
  }

  delay(20);
}