/**
 * TemperatureViz — DataNet example
 *
 * Subscribes to a temperature channel on DataNet and draws a real-time
 * scrolling line graph. Each incoming message is expected to have the shape:
 *
 *   { "value": 22.4 }
 *
 * Replace API_KEY and CHANNEL with your own values before running.
 *
 * Dependencies:
 *   - DataNet library  (see README.md for installation)
 *   - Java-WebSocket jar in the library's code/ folder
 */

import datanet.*;

// ── Configuration ─────────────────────────────────────────────────────────
final String API_KEY = "ak_your_api_key_here";
final String CHANNEL = "project.your_project_id.temperature";

// ── Graph parameters ───────────────────────────────────────────────────────
final int    HISTORY    = 120;     // number of readings shown at once
final float  TEMP_MIN   = 0.0;    // y-axis lower bound (°C)
final float  TEMP_MAX   = 50.0;   // y-axis upper bound (°C)
final int    GRAPH_PAD  = 60;     // pixels of padding around graph area
final color  LINE_COL   = #FF6B35;
final color  DOT_COL    = #FFD166;
final color  GRID_COL   = #2A2A3A;
final color  BG_COL     = #1A1A2E;
final color  TEXT_COL   = #E0E0E0;

// ── State ──────────────────────────────────────────────────────────────────
DataNet dn;
float[] readings = new float[HISTORY];  // circular buffer of temperature values
int     head     = 0;                   // index of oldest reading
int     count    = 0;                   // how many readings received so far
float   lastTemp = Float.NaN;
String  status   = "Connecting…";
long    lastMsgAt = 0;

// ── Setup ──────────────────────────────────────────────────────────────────
void setup() {
  size(900, 500);
  smooth(4);
  textFont(createFont("Monospaced", 12));

  // Initialise the DataNet client.
  dn = new DataNet(this, API_KEY);

  dn.onConnect(() -> {
    status = "Connected — waiting for data";
    // Subscribe to the temperature channel.
    dn.subscribe(CHANNEL, (ch, data, from, ts) -> {
      float val = data.getFloat("value");
      pushReading(val);
    });
  });

  dn.onDisconnect(() -> {
    status = "Disconnected — reconnecting…";
  });

  dn.onError((e) -> {
    status = "Error: " + e.getMessage();
    println("[DataNet] " + e.getMessage());
  });

  dn.connect();
}

// ── Draw ───────────────────────────────────────────────────────────────────
void draw() {
  background(BG_COL);

  drawGrid();
  drawGraph();
  drawOverlay();
}

// ── Graph helpers ──────────────────────────────────────────────────────────

/** Push a new reading into the circular buffer. */
void pushReading(float val) {
  readings[head % HISTORY] = val;
  head++;
  if (count < HISTORY) count++;
  lastTemp = val;
  lastMsgAt = millis();
}

/** Map a temperature value to a y pixel coordinate. */
float tempToY(float temp) {
  int graphH = height - 2 * GRAPH_PAD;
  return map(temp, TEMP_MIN, TEMP_MAX, height - GRAPH_PAD, GRAPH_PAD);
}

/** Map a reading index (0 = oldest) to an x pixel coordinate. */
float indexToX(int i) {
  int graphW = width - 2 * GRAPH_PAD;
  return GRAPH_PAD + map(i, 0, HISTORY - 1, 0, graphW);
}

/** Draw horizontal grid lines and y-axis labels. */
void drawGrid() {
  stroke(GRID_COL);
  strokeWeight(1);
  textAlign(RIGHT, CENTER);
  fill(TEXT_COL, 140);
  textSize(10);

  int steps = 5;
  for (int i = 0; i <= steps; i++) {
    float temp = map(i, 0, steps, TEMP_MIN, TEMP_MAX);
    float y = tempToY(temp);
    line(GRAPH_PAD - 5, y, width - GRAPH_PAD, y);
    text(nf(temp, 1, 1) + "°", GRAPH_PAD - 8, y);
  }
}

/** Draw the scrolling temperature line and animated dots. */
void drawGraph() {
  if (count == 0) return;

  // Draw filled area under the line.
  noStroke();
  fill(LINE_COL, 40);
  beginShape();
  vertex(indexToX(0), height - GRAPH_PAD);
  for (int i = 0; i < count; i++) {
    int bufIdx = (head - count + i + HISTORY) % HISTORY;
    float x = indexToX(i + (HISTORY - count));
    float y = tempToY(readings[bufIdx]);
    vertex(x, y);
  }
  vertex(indexToX(HISTORY - 1), height - GRAPH_PAD);
  endShape(CLOSE);

  // Draw the line itself.
  stroke(LINE_COL);
  strokeWeight(2);
  noFill();
  beginShape();
  for (int i = 0; i < count; i++) {
    int bufIdx = (head - count + i + HISTORY) % HISTORY;
    float x = indexToX(i + (HISTORY - count));
    float y = tempToY(readings[bufIdx]);
    curveVertex(x, y);
  }
  endShape();

  // Animated pulsing dot at the latest reading.
  if (count > 0) {
    int latestBuf = (head - 1 + HISTORY) % HISTORY;
    float lx = indexToX(HISTORY - 1);
    float ly = tempToY(readings[latestBuf]);

    float pulse = 0.5 + 0.5 * sin(millis() * 0.006);
    noStroke();
    fill(DOT_COL, 60 * pulse);
    ellipse(lx, ly, 20 + 12 * pulse, 20 + 12 * pulse);
    fill(DOT_COL);
    ellipse(lx, ly, 8, 8);
  }
}

/** Draw status text, channel name, current value, and time since last message. */
void drawOverlay() {
  // Title bar.
  fill(TEXT_COL);
  textAlign(LEFT, TOP);
  textSize(14);
  text("DataNet — Temperature Monitor", GRAPH_PAD, 12);

  textAlign(RIGHT, TOP);
  textSize(11);
  fill(TEXT_COL, 160);
  text(CHANNEL, width - GRAPH_PAD, 12);

  // Current value — large display.
  if (!Float.isNaN(lastTemp)) {
    textAlign(LEFT, TOP);
    textSize(36);
    fill(DOT_COL);
    text(nf(lastTemp, 1, 2) + " °C", GRAPH_PAD, 30);

    // Time since last message.
    long ago = (millis() - lastMsgAt) / 1000;
    textSize(11);
    fill(TEXT_COL, 120);
    text(ago + "s ago", GRAPH_PAD, 72);
  }

  // Status bar at bottom.
  textAlign(LEFT, BOTTOM);
  textSize(11);
  fill(TEXT_COL, 160);
  text(status, GRAPH_PAD, height - 8);

  // Message count.
  textAlign(RIGHT, BOTTOM);
  fill(TEXT_COL, 100);
  text("msgs: " + (head), width - GRAPH_PAD, height - 8);
}

// ── Keyboard shortcuts ─────────────────────────────────────────────────────
void keyPressed() {
  if (key == 'd' || key == 'D') {
    dn.disconnect();
    status = "Disconnected";
  }
  if (key == 'r' || key == 'R') {
    dn.connect();
  }
}