//ESP32 charlieplexing demo 
/*
//diagram.json is generated with this js, you can run in the console and copy/paste the output

//learn about charlieplex wiring here [not affiliated] https://stkwans.blogspot.com/2012/05/designing-large-charlieplex.html

function generateDiagram() {
  
  const PINS = ['D18', 'D19', 'D21', 'D22', 'D23', 'D25', 'D26', 'D27', 'D12', 'D4'];
  const NUM_PINS = PINS.length;

  //more options maybe for larger matrices https://lastminuteengineers.com/esp32-pinout-reference/
  //const PINS = ['D18', 'D19', 'D21', 'D22', 'D23', 'D25', 'D26', 'D27', 'D12', 'D4', 'D5', 'D13', 'D14', 'D15', 'D32', 'D33', 'D2'];
  //const PINS = ['D2', 'D4', 'D5', 'D12', 'D13', 'D14', 'D15', 'D16', 'D17', 'D18', 'D19', 'D21', 'D22', 'D23', 'D25', 'D26', 'D27', 'D32', 'D33'];

 let project = {
    version: 1,
    author: "ESP32 Charlieplex Demo",
    editor: "wokwi",
    parts: [
      { type: "wokwi-esp32-devkit-v1", id: "esp", top: 0, left: 0, attrs: {} }
    ],
    connections: [
      [ "esp:TX", "$serialMonitor:RX", "", [] ],
      [ "esp:RX", "$serialMonitor:TX", "", [] ]
    ]
  };

  // Generate LED parts
  let ledIndex = 1;
  for (let i = 0; i < NUM_PINS; i++) {
    for (let j = 0; j < NUM_PINS; j++) {
      if (i !== j) {
        let top = 50 + i * 40;
        let left;
        if (j > i) {
          // Upper right triangle, shifted left
          left = 100 + (j - 1) * 40;
        } else {
          // Lower left triangle
          left = 100 + j * 40;
        }
        project.parts.push({
          type: "wokwi-led",
          id: `led${ledIndex}`,
          top: top,
          left: left,
          attrs: { color: "red" }
        });
        project.connections.push([`led${ledIndex}:A`, `esp:${PINS[i]}`, "red", ["hidden"]]);
        project.connections.push([`led${ledIndex}:C`, `esp:${PINS[j]}`, "black", ["hidden"]]);
        ledIndex++;
      }
    }
  }

  return JSON.stringify(project, null, 2);
}

console.log(generateDiagram());
*/

#define DELAY 100 // milliseconds between LED changes

// ESP32 GPIO pins
const uint8_t LEDS[] = { 18, 19, 21, 22, 23, 25, 26, 27, 12, 4 };
const uint8_t LED_COUNT = sizeof(LEDS);
const uint8_t TOTAL_LEDS = LED_COUNT * (LED_COUNT - 1);

void setup() {
  // Initialize all pins as INPUT (high impedance state)
  for (int i = 0; i < LED_COUNT; i++) {
    pinMode(LEDS[i], INPUT);
  }
}

void lightLED(int row, int col) {
  // Set all pins to input (high impedance)
  for (int i = 0; i < LED_COUNT; i++) {
    pinMode(LEDS[i], INPUT);
  }

  // Set the anode pin to HIGH (OUTPUT mode)
  pinMode(LEDS[row], OUTPUT);
  digitalWrite(LEDS[row], HIGH);

  // Set the cathode pin to LOW (OUTPUT mode)
  pinMode(LEDS[col], OUTPUT);
  digitalWrite(LEDS[col], LOW);
}

void loop() {
  for (int row = 0; row < LED_COUNT; row++) {
    for (int col = 0; col < LED_COUNT; col++) {
      if (row != col) {  // Skip when row and column are the same
        lightLED(row, col);
        delay(DELAY);
      }
    }
  }
}