const dgram = require('dgram');

const {
  addHexColor,
  createFrame,
  fadeFrame,
  frameToPayload,
  hexToRgb,
  samplePalette,
  toIndex,
} = require('./shared-frame-utils');

const DEFAULT_PORT = 4210;
const DEFAULT_WIDTH = 16;
const DEFAULT_HEIGHT = 16;
const DEFAULT_INTERVAL_MS = 50;
const PATH_FADE = 0.85;
const PULSE_LENGTH = 6;

const paletteStops = [
  { stop: 0.0, color: hexToRgb('020209') },
  { stop: 0.3, color: hexToRgb('023047') },
  { stop: 0.6, color: hexToRgb('115173') },
  { stop: 0.8, color: hexToRgb('1ca78f') },
  { stop: 1.0, color: hexToRgb('94fdf3') },
];

const accentColors = ['14f5ff', 'a7ff4d', 'ffcc3f'];

const host = process.argv[2];
const port = parseInt(process.argv[3] || String(DEFAULT_PORT), 10);
const width = parseInt(process.argv[4] || String(DEFAULT_WIDTH), 10);
const height = parseInt(process.argv[5] || String(DEFAULT_HEIGHT), 10);
const intervalMs = parseInt(process.argv[6] || String(DEFAULT_INTERVAL_MS), 10);

if (!host) {
  console.error('Usage: node circuit-pulse.js <device-ip> [port] [width] [height] [interval-ms]');
  process.exit(1);
}

if (Number.isNaN(port) || Number.isNaN(width) || Number.isNaN(height) || Number.isNaN(intervalMs)) {
  console.error('Invalid numeric argument. Expected integers for port, width, height, and interval-ms.');
  process.exit(1);
}

if (width <= 0 || height <= 0) {
  console.error('Matrix dimensions must be positive integers.');
  process.exit(1);
}

const socket = dgram.createSocket('udp4');
const isBroadcast = host === '255.255.255.255' || host.endsWith('.255');
const frame = createFrame(width, height);
const paths = createPaths(width, height);
const pulses = createPulses(paths.length);
const frameTimeSeconds = intervalMs / 1000;

if (isBroadcast) {
  socket.bind(() => {
    socket.setBroadcast(true);
  });
}

socket.on('error', (error) => {
  console.error('Socket error:', error.message);
});

function createPaths(matrixWidth, matrixHeight) {
  const horizontalStep = Math.max(2, Math.floor(matrixHeight / 4));
  const verticalStep = Math.max(2, Math.floor(matrixWidth / 4));
  const generatedPaths = [];

  for (let y = 1; y < matrixHeight; y += horizontalStep) {
    const path = [];
    for (let x = 0; x < matrixWidth; ++x) {
      path.push({ x, y });
    }
    generatedPaths.push(path);
  }

  for (let x = 2; x < matrixWidth; x += verticalStep) {
    const path = [];
    for (let y = 0; y < matrixHeight; ++y) {
      path.push({ x, y });
    }
    generatedPaths.push(path);
  }

  return generatedPaths;
}

function createPulses(count) {
  const pulseList = [];
  for (let index = 0; index < count; ++index) {
    pulseList.push(spawnPulse(index));
  }
  return pulseList;
}

function spawnPulse(pathIndex) {
  const color = accentColors[pathIndex % accentColors.length];
  return {
    pathIndex,
    position: 0,
    speed: 3 + Math.random() * 2,
    color,
  };
}

function updatePulse(pulse, deltaSeconds) {
  pulse.position += pulse.speed * deltaSeconds;
  const path = paths[pulse.pathIndex];

  if (!path || path.length === 0) {
    return;
  }

  if (pulse.position >= path.length + PULSE_LENGTH) {
    Object.assign(pulse, spawnPulse(pulse.pathIndex));
    pulse.position = 0;
  }
}

function renderPulse(pulse) {
  const path = paths[pulse.pathIndex];
  if (!path) {
    return;
  }

  for (let offset = 0; offset < PULSE_LENGTH; ++offset) {
    const index = Math.floor(pulse.position) - offset;
    if (index < 0 || index >= path.length) {
      continue;
    }

    const { x, y } = path[index];
    const intensity = Math.max(0, 1 - offset / PULSE_LENGTH);
    const baseColor = samplePalette(paletteStops, intensity);
    frame[toIndex(x, y, width)] = baseColor;
    addHexColor(frame, toIndex(x, y, width), pulse.color, intensity * 1.4);
  }
}

function generateFrame() {
  fadeFrame(frame, PATH_FADE);

  pulses.forEach((pulse) => {
    updatePulse(pulse, frameTimeSeconds);
    renderPulse(pulse);
  });

  return frameToPayload(frame);
}

function sendFrame() {
  const payload = generateFrame();
  const message = Buffer.from(payload, 'utf8');
  socket.send(message, port, host);
}

setInterval(sendFrame, intervalMs);

console.log(
  `Streaming circuit pulse to ${host}:${port} (${width}x${height}, interval=${intervalMs}ms, paths=${paths.length})`
);