#include <Arduino.h>

#define CLK 13
#define DIN 11
#define CS 10
#define XS 8     // X Segments (8 wide)
#define YS 8     // Y Segments (8 high)
#define NUMS (XS * YS) // 64 total segments
#define BORDER 1
#define MAX_X (XS * 8) // 64 pixels wide
#define MAX_Y (YS * 8) // 64 pixels high
#define BALLS 120 // Increased number of balls

// Frame buffer is now 8 rows * 64 segments = 512 bytes
byte fb[8 * NUMS];
int bx[BALLS], by[BALLS], vx[BALLS], vy[BALLS], sz[BALLS];

// Combined Shift function for initialization
void sh(byte a, byte d) {
  digitalWrite(CS, LOW);
  // Send command to all 64 segments
  for (int i = 0; i < NUMS; i++) {
    shiftOut(DIN, CLK, MSBFIRST, a);
    shiftOut(DIN, CLK, MSBFIRST, d);
  }
  digitalWrite(CS, HIGH);
}

// Set/Clear Pixel
void p(uint8_t x, uint8_t y, uint8_t m) {
  byte *a = &fb[x / 8 + y * XS];
  byte mask = 128 >> (x % 8);
  if (m == 0) *a &= ~mask; else *a |= mask;
}

// Clear Framebuffer
void c() { for (byte i = 0; i < 8 * NUMS; i++) fb[i] = 0; }

void setup() {
  pinMode(CLK, OUTPUT); pinMode(DIN, OUTPUT); pinMode(CS, OUTPUT);
  // Initialize all 64 MAX7219 chips
  sh(0x0f, 0x00); sh(0x0b, 0x07); 
  sh(0x0c, 0x01); sh(0x0a, 0x0f); 
  sh(0x09, 0x00);
  c(); // Clear display
  randomSeed(analogRead(A0));
  for (int i = 0; i < BALLS; i++) {
    bx[i] = random(BORDER, MAX_X - BORDER - 2);
    by[i] = random(BORDER, MAX_Y - BORDER - 2);
    vx[i] = random(-1, 2); 
    vy[i] = random(-1, 2);
    sz[i] = random(1, 4); 
  }
}

void loop() {
  // Move and Redraw Balls (Logic is unchanged, relies on new MAX_X/Y)
  for (int i = 0; i < BALLS; i++) {
    int s = sz[i];
    // Erase
    for (int dx = 0; dx < s; dx++)
      for (int dy = 0; dy < s; dy++)
        p(bx[i] + dx, by[i] + dy, 0);

    // Update Position and Check Collision
    bx[i] += vx[i]; by[i] += vy[i];
    if (bx[i] >= MAX_X - BORDER - s || bx[i] < BORDER) vx[i] = -vx[i];
    if (by[i] >= MAX_Y - BORDER - s || by[i] < BORDER) vy[i] = -vy[i];

    // Draw
    for (int dx = 0; dx < s; dx++)
      for (int dy = 0; dy < s; dy++)
        p(bx[i] + dx, by[i] + dy, 1);
  }
  
  // Show/Display Frame Buffer (Optimized for 8x8 segments)
  for (byte r = 0; r < 8; r++) { // Iterate through the 8 rows
    digitalWrite(CS, LOW);
    // Loop through all 64 segments in reverse order
    for (byte s = NUMS - 1; s < NUMS; s--) { 
      byte x = s % XS;
      byte y_start = s / XS * 8; // Row address start (0, 8, 16, 24, 32, 40, 48, 56)
      byte addr = (r + y_start) * XS; // Base address in fb

      // Logic for zig-zag/alternatingly wired segments (critical for display)
      if (s / XS % 2 == 0) { // Even segment rows (0, 2, 4, 6)
        shiftOut(DIN, CLK, MSBFIRST, 1 + r); // MAX7219 row address (1-8)
        shiftOut(DIN, CLK, MSBFIRST, fb[addr + x]); // Data for segment
      } else { // Odd segment rows (1, 3, 5, 7) - Rotated 180 degrees
        shiftOut(DIN, CLK, MSBFIRST, 8 - r); // MAX7219 row address (8-1)
        shiftOut(DIN, CLK, LSBFIRST, fb[addr + x]); // Data for segment (LSBFIRST flip)
      }
    }
    digitalWrite(CS, HIGH);
  }
  delay(1); // Small delay to control animation speed
}