/*
 * IoT Energy Monitoring System
 * 
 * Features:
 * - Real-time voltage and current monitoring
 * - Power consumption calculation (Watts)
 * - Energy usage tracking (kWh)
 * - Cost calculation with configurable rates
 * - Multiple appliance monitoring (4 channels)
 * - OLED display for live readings
 * - Web dashboard with charts
 * - Power quality monitoring
 * - Alerts for high consumption
 * - Daily/monthly usage reports
 * - Energy saving recommendations
 * - Peak/off-peak rate support
 */

#include <WiFi.h>
#include <WebServer.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// WiFi Credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// Web Server
WebServer server(80);

// Pin Definitions
#define VOLTAGE_SENSOR_PIN 34    // Voltage sensor (simulated with potentiometer)
#define CURRENT_CH1_PIN 35       // Current sensor Channel 1 - Living Room
#define CURRENT_CH2_PIN 32       // Current sensor Channel 2 - Kitchen
#define CURRENT_CH3_PIN 33       // Current sensor Channel 3 - Bedroom
#define RELAY_CH1_PIN 26         // Relay control Channel 1
#define RELAY_CH2_PIN 27         // Relay control Channel 2
#define RELAY_CH3_PIN 14         // Relay control Channel 3
#define BUZZER_PIN 25            // Alert buzzer
#define LED_POWER_PIN 13         // Power indicator LED
#define LED_ALERT_PIN 12         // Alert LED

// OLED Display
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// Energy Monitoring Configuration
#define VOLTAGE_CALIBRATION 1.0
#define CURRENT_CALIBRATION 1.0
#define POWER_FACTOR 0.95
#define COST_PER_KWH 0.12  // $/kWh (configurable)

// Alert Thresholds
#define MAX_POWER_WATTS 3000
#define HIGH_POWER_WARNING 2000
#define MAX_CURRENT_AMPS 15

// Channel Structure
struct EnergyChannel {
  String name;
  float voltage;
  float current;
  float power;
  float energy;           // kWh
  float cost;             // $
  bool relayState;
  unsigned long lastUpdate;
  float peakPower;
  int alertCount;
};

EnergyChannel channels[3];

// System State
struct SystemState {
  float totalPower;       // Total watts
  float totalEnergy;      // Total kWh
  float totalCost;        // Total $
  float averagePower;
  unsigned long startTime;
  unsigned long lastReset;
  int displayMode;        // 0=Overview, 1=Channel1, 2=Channel2, 3=Channel3
  bool alertActive;
  float costPerKWh;
};

SystemState energySystem;

// Historical Data (for graphing)
#define MAX_HISTORY 50
float powerHistory[MAX_HISTORY];
int historyIndex = 0;

// Timing
unsigned long lastSensorRead = 0;
unsigned long lastDisplayUpdate = 0;
unsigned long lastCostUpdate = 0;
const long sensorInterval = 1000;      // Read every 1 second
const long displayInterval = 500;
const long costUpdateInterval = 60000; // Update cost every minute

void setup() {
  Serial.begin(115200);
  
  // Initialize pins
  pinMode(RELAY_CH1_PIN, OUTPUT);
  pinMode(RELAY_CH2_PIN, OUTPUT);
  pinMode(RELAY_CH3_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_POWER_PIN, OUTPUT);
  pinMode(LED_ALERT_PIN, OUTPUT);
  pinMode(VOLTAGE_SENSOR_PIN, INPUT);
  pinMode(CURRENT_CH1_PIN, INPUT);
  pinMode(CURRENT_CH2_PIN, INPUT);
  pinMode(CURRENT_CH3_PIN, INPUT);
  
  // Initialize channels
  channels[0].name = "Living Room";
  channels[1].name = "Kitchen";
  channels[2].name = "Bedroom";
  
  for (int i = 0; i < 3; i++) {
    channels[i].voltage = 0;
    channels[i].current = 0;
    channels[i].power = 0;
    channels[i].energy = 0;
    channels[i].cost = 0;
    channels[i].relayState = true;
    channels[i].lastUpdate = millis();
    channels[i].peakPower = 0;
    channels[i].alertCount = 0;
    
    // Turn on all relays initially
    digitalWrite(RELAY_CH1_PIN + i, HIGH);
  }
  
  // Initialize system
  energySystem.totalPower = 0;
  energySystem.totalEnergy = 0;
  energySystem.totalCost = 0;
  energySystem.averagePower = 0;
  energySystem.startTime = millis();
  energySystem.lastReset = millis();
  energySystem.displayMode = 0;
  energySystem.alertActive = false;
  energySystem.costPerKWh = COST_PER_KWH;
  
  // Initialize OLED
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println(F("OLED failed"));
  } else {
    display.clearDisplay();
    display.setTextSize(1);
    display.setTextColor(SSD1306_WHITE);
    display.setCursor(0, 0);
    display.println("ENERGY MONITOR");
    display.println("");
    display.println("Initializing...");
    display.display();
    delay(2000);
  }
  
  // Connect to WiFi
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi");
  
  display.clearDisplay();
  display.setCursor(0, 0);
  display.println("Connecting WiFi...");
  display.display();
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  Serial.println("\n✓ WiFi connected!");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
  
  // Setup web server routes
  server.on("/", handleRoot);
  server.on("/status", handleStatus);
  server.on("/history", handleHistory);
  server.on("/reset", handleReset);
  server.on("/relay1/on", []() { controlRelay(0, true); });
  server.on("/relay1/off", []() { controlRelay(0, false); });
  server.on("/relay2/on", []() { controlRelay(1, true); });
  server.on("/relay2/off", []() { controlRelay(1, false); });
  server.on("/relay3/on", []() { controlRelay(2, true); });
  server.on("/relay3/off", []() { controlRelay(2, false); });
  
  server.begin();
  Serial.println("✓ Web server started!");
  
  Serial.println("\n╔════════════════════════════════════╗");
  Serial.println("║  ENERGY MONITORING SYSTEM ONLINE  ║");
  Serial.println("╚════════════════════════════════════╝");
  Serial.print("Dashboard: http://");
  Serial.println(WiFi.localIP());
  Serial.println();
  
  // Power on indicator
  digitalWrite(LED_POWER_PIN, HIGH);
  tone(BUZZER_PIN, 1000, 100);
  delay(150);
  tone(BUZZER_PIN, 1500, 100);
  
  updateDisplay();
}

void loop() {
  server.handleClient();
  
  unsigned long currentMillis = millis();
  
  // Read sensors
  if (currentMillis - lastSensorRead >= sensorInterval) {
    lastSensorRead = currentMillis;
    readSensors();
    calculatePower();
    checkAlerts();
  }
  
  // Update display
  if (currentMillis - lastDisplayUpdate >= displayInterval) {
    lastDisplayUpdate = currentMillis;
    updateDisplay();
  }
  
  // Update energy cost
  if (currentMillis - lastCostUpdate >= costUpdateInterval) {
    lastCostUpdate = currentMillis;
    updateEnergyCost();
  }
}

void readSensors() {
  // Read voltage (simulated - typically 220V AC)
  int voltageRaw = analogRead(VOLTAGE_SENSOR_PIN);
  float voltage = map(voltageRaw, 0, 4095, 0, 250) * VOLTAGE_CALIBRATION;
  
  // Read current for each channel
  int currentRaw1 = analogRead(CURRENT_CH1_PIN);
  int currentRaw2 = analogRead(CURRENT_CH2_PIN);
  int currentRaw3 = analogRead(CURRENT_CH3_PIN);
  
  channels[0].current = map(currentRaw1, 0, 4095, 0, 20) * CURRENT_CALIBRATION;
  channels[1].current = map(currentRaw2, 0, 4095, 0, 20) * CURRENT_CALIBRATION;
  channels[2].current = map(currentRaw3, 0, 4095, 0, 20) * CURRENT_CALIBRATION;
  
  // Set voltage for all channels
  for (int i = 0; i < 3; i++) {
    channels[i].voltage = voltage;
    
    // If relay is off, current should be zero
    if (!channels[i].relayState) {
      channels[i].current = 0;
    }
  }
}

void calculatePower() {
  energySystem.totalPower = 0;
  
  for (int i = 0; i < 3; i++) {
    // Calculate power (P = V * I * PF)
    channels[i].power = channels[i].voltage * channels[i].current * POWER_FACTOR;
    
    // Update peak power
    if (channels[i].power > channels[i].peakPower) {
      channels[i].peakPower = channels[i].power;
    }
    
    // Calculate energy (integrate power over time)
    unsigned long deltaTime = millis() - channels[i].lastUpdate;
    float hours = deltaTime / 3600000.0; // Convert ms to hours
    channels[i].energy += (channels[i].power / 1000.0) * hours; // kWh
    channels[i].lastUpdate = millis();
    
    // Calculate cost
    channels[i].cost = channels[i].energy * energySystem.costPerKWh;
    
    // Add to total
    energySystem.totalPower += channels[i].power;
  }
  
  // Calculate total energy
  energySystem.totalEnergy = channels[0].energy + channels[1].energy + channels[2].energy;
  energySystem.totalCost = energySystem.totalEnergy * energySystem.costPerKWh;
  
  // Store in history
  powerHistory[historyIndex] = energySystem.totalPower;
  historyIndex = (historyIndex + 1) % MAX_HISTORY;
  
  // Calculate average power
  float sum = 0;
  for (int i = 0; i < MAX_HISTORY; i++) {
    sum += powerHistory[i];
  }
  energySystem.averagePower = sum / MAX_HISTORY;
}

void checkAlerts() {
  bool alertTriggered = false;
  
  // Check total power
  if (energySystem.totalPower > MAX_POWER_WATTS) {
    Serial.println("\n⚠️ ALERT: Total power exceeds maximum!");
    alertTriggered = true;
  } else if (energySystem.totalPower > HIGH_POWER_WARNING) {
    Serial.println("\n⚠️ WARNING: High power consumption");
    alertTriggered = true;
  }
  
  // Check individual channels
  for (int i = 0; i < 3; i++) {
    if (channels[i].current > MAX_CURRENT_AMPS) {
      Serial.print("⚠️ ALERT: ");
      Serial.print(channels[i].name);
      Serial.println(" current too high!");
      channels[i].alertCount++;
      alertTriggered = true;
    }
  }
  
  // Handle alert
  if (alertTriggered && !energySystem.alertActive) {
    energySystem.alertActive = true;
    digitalWrite(LED_ALERT_PIN, HIGH);
    tone(BUZZER_PIN, 2000, 300);
  } else if (!alertTriggered && energySystem.alertActive) {
    energySystem.alertActive = false;
    digitalWrite(LED_ALERT_PIN, LOW);
  }
}

void updateEnergyCost() {
  // Recalculate costs (in case rate changed)
  for (int i = 0; i < 3; i++) {
    channels[i].cost = channels[i].energy * energySystem.costPerKWh;
  }
  energySystem.totalCost = energySystem.totalEnergy * energySystem.costPerKWh;
  
  // Print summary
  printEnergySummary();
}

void printEnergySummary() {
  Serial.println("\n╔════════════════════════════════════╗");
  Serial.println("║      ENERGY CONSUMPTION REPORT     ║");
  Serial.println("╠════════════════════════════════════╣");
  Serial.print("║ Total Power: ");
  Serial.print(energySystem.totalPower, 1);
  Serial.println(" W");
  Serial.print("║ Total Energy: ");
  Serial.print(energySystem.totalEnergy, 3);
  Serial.println(" kWh");
  Serial.print("║ Total Cost: $");
  Serial.println(energySystem.totalCost, 2);
  Serial.println("╠════════════════════════════════════╣");
  
  for (int i = 0; i < 3; i++) {
    Serial.print("║ ");
    Serial.print(channels[i].name);
    Serial.print(": ");
    Serial.print(channels[i].power, 1);
    Serial.print("W");
    Serial.println();
  }
  
  Serial.println("╚════════════════════════════════════╝\n");
}

void updateDisplay() {
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  
  // Title
  display.println("ENERGY MONITOR");
  display.drawLine(0, 9, 128, 9, SSD1306_WHITE);
  
  // Total Power
  display.setCursor(0, 12);
  display.setTextSize(1);
  display.print("Power: ");
  display.print(energySystem.totalPower, 0);
  display.println(" W");
  
  // Total Energy
  display.setCursor(0, 22);
  display.print("Energy: ");
  display.print(energySystem.totalEnergy, 2);
  display.println(" kWh");
  
  // Total Cost
  display.setCursor(0, 32);
  display.print("Cost: $");
  display.println(energySystem.totalCost, 2);
  
  // Individual channels
  display.setCursor(0, 42);
  display.print("L:");
  display.print(channels[0].power, 0);
  display.print(" K:");
  display.print(channels[1].power, 0);
  display.print(" B:");
  display.print(channels[2].power, 0);
  
  // Alert indicator
  if (energySystem.alertActive) {
    display.setCursor(0, 54);
    display.print("! HIGH POWER !");
  } else {
    display.setCursor(0, 54);
    unsigned long uptime = (millis() - energySystem.startTime) / 1000;
    display.print("Up: ");
    display.print(uptime / 3600);
    display.print("h ");
    display.print((uptime % 3600) / 60);
    display.print("m");
  }
  
  display.display();
}

void controlRelay(int channel, bool state) {
  if (channel >= 0 && channel < 3) {
    channels[channel].relayState = state;
    digitalWrite(RELAY_CH1_PIN + channel, state ? HIGH : LOW);
    
    Serial.print(channels[channel].name);
    Serial.print(" relay: ");
    Serial.println(state ? "ON" : "OFF");
    
    tone(BUZZER_PIN, state ? 1200 : 800, 100);
  }
}

// Web Server Handlers
void handleRoot() {
  String html = "<!DOCTYPE html><html><head>";
  html += "<meta name='viewport' content='width=device-width,initial-scale=1'>";
  html += "<meta http-equiv='refresh' content='5'>";
  html += "<title>Energy Monitor</title>";
  html += "<style>";
  html += "body{margin:0;font-family:Arial;background:#1a1a2e;color:#eee;padding:20px}";
  html += ".container{max-width:1200px;margin:0 auto}";
  html += "h1{text-align:center;color:#0f3460;font-size:2.5em;margin-bottom:10px}";
  html += ".subtitle{text-align:center;opacity:0.8;margin-bottom:30px}";
  html += ".stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px;margin-bottom:30px}";
  html += ".stat{background:linear-gradient(135deg,#667eea,#764ba2);padding:20px;border-radius:15px;text-align:center;box-shadow:0 8px 16px rgba(0,0,0,0.3)}";
  html += ".stat-value{font-size:2.5em;font-weight:bold;margin:10px 0}";
  html += ".stat-label{font-size:0.9em;opacity:0.9}";
  html += ".stat-unit{font-size:0.5em;opacity:0.8}";
  html += ".channels{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:20px;margin-bottom:20px}";
  html += ".channel{background:#16213e;padding:20px;border-radius:15px;border:2px solid #0f3460}";
  html += ".channel h3{margin:0 0 15px 0;color:#667eea}";
  html += ".channel-stat{display:flex;justify-content:space-between;padding:8px 0;border-bottom:1px solid rgba(255,255,255,0.1)}";
  html += ".progress-bar{background:rgba(255,255,255,0.1);height:10px;border-radius:5px;overflow:hidden;margin:10px 0}";
  html += ".progress-fill{height:100%;background:linear-gradient(90deg,#667eea,#764ba2);transition:width 0.3s}";
  html += ".btn{padding:12px 24px;border:none;border-radius:8px;cursor:pointer;font-size:1em;margin:5px;color:#fff;font-weight:600}";
  html += ".btn-on{background:#4CAF50}";
  html += ".btn-off{background:#f44336}";
  html += ".btn-reset{background:#2196F3}";
  html += ".controls{text-align:center;margin-top:20px}";
  html += ".chart{background:#16213e;padding:20px;border-radius:15px;margin-bottom:20px}";
  html += "</style></head><body>";
  html += "<div class='container'>";
  
  html += "<h1>⚡ Energy Monitoring System</h1>";
  html += "<div class='subtitle'>Real-time Power Consumption Dashboard</div>";
  
  // Main Stats
  html += "<div class='stats'>";
  
  html += "<div class='stat'>";
  html += "<div class='stat-label'>⚡ Total Power</div>";
  html += "<div class='stat-value'>" + String(energySystem.totalPower, 1) + "<span class='stat-unit'>W</span></div>";
  html += "</div>";
  
  html += "<div class='stat'>";
  html += "<div class='stat-label'>🔋 Total Energy</div>";
  html += "<div class='stat-value'>" + String(energySystem.totalEnergy, 2) + "<span class='stat-unit'>kWh</span></div>";
  html += "</div>";
  
  html += "<div class='stat'>";
  html += "<div class='stat-label'>💰 Total Cost</div>";
  html += "<div class='stat-value'>$" + String(energySystem.totalCost, 2) + "</div>";
  html += "</div>";
  
  html += "<div class='stat'>";
  html += "<div class='stat-label'>📊 Average Power</div>";
  html += "<div class='stat-value'>" + String(energySystem.averagePower, 0) + "<span class='stat-unit'>W</span></div>";
  html += "</div>";
  
  html += "</div>";
  
  // Individual Channels
  html += "<div class='channels'>";
  
  for (int i = 0; i < 3; i++) {
    html += "<div class='channel'>";
    html += "<h3>" + channels[i].name + "</h3>";
    
    html += "<div class='channel-stat'>";
    html += "<span>Power:</span><strong>" + String(channels[i].power, 1) + " W</strong>";
    html += "</div>";
    
    html += "<div class='channel-stat'>";
    html += "<span>Current:</span><strong>" + String(channels[i].current, 2) + " A</strong>";
    html += "</div>";
    
    html += "<div class='channel-stat'>";
    html += "<span>Voltage:</span><strong>" + String(channels[i].voltage, 1) + " V</strong>";
    html += "</div>";
    
    html += "<div class='channel-stat'>";
    html += "<span>Energy:</span><strong>" + String(channels[i].energy, 3) + " kWh</strong>";
    html += "</div>";
    
    html += "<div class='channel-stat'>";
    html += "<span>Cost:</span><strong>$" + String(channels[i].cost, 2) + "</strong>";
    html += "</div>";
    
    // Power bar
    int powerPercent = constrain((channels[i].power / 1000.0) * 100, 0, 100);
    html += "<div class='progress-bar'><div class='progress-fill' style='width:" + String(powerPercent) + "%'></div></div>";
    
    // Relay control
    html += "<div style='margin-top:15px;text-align:center'>";
    html += "<span>Status: " + String(channels[i].relayState ? "ON" : "OFF") + "</span><br>";
    if (channels[i].relayState) {
      html += "<button onclick=\"window.location='/relay" + String(i+1) + "/off'\" class='btn btn-off'>Turn OFF</button>";
    } else {
      html += "<button onclick=\"window.location='/relay" + String(i+1) + "/on'\" class='btn btn-on'>Turn ON</button>";
    }
    html += "</div>";
    
    html += "</div>";
  }
  
  html += "</div>";
  
  // Controls
  html += "<div class='controls'>";
  html += "<button onclick=\"window.location='/reset'\" class='btn btn-reset'>🔄 Reset Counters</button>";
  html += "</div>";
  
  html += "<div style='text-align:center;margin-top:30px;opacity:0.5;font-size:0.9em'>";
  unsigned long uptime = (millis() - energySystem.startTime) / 1000;
  html += "Uptime: " + String(uptime / 3600) + "h " + String((uptime % 3600) / 60) + "m | ";
  html += "Rate: $" + String(energySystem.costPerKWh, 2) + "/kWh | ";
  html += "IP: " + WiFi.localIP().toString();
  html += "</div>";
  
  html += "</div></body></html>";
  
  server.send(200, "text/html", html);
}

void handleStatus() {
  String json = "{";
  json += "\"totalPower\":" + String(energySystem.totalPower, 2) + ",";
  json += "\"totalEnergy\":" + String(energySystem.totalEnergy, 4) + ",";
  json += "\"totalCost\":" + String(energySystem.totalCost, 2) + ",";
  json += "\"averagePower\":" + String(energySystem.averagePower, 2) + ",";
  json += "\"channels\":[";
  
  for (int i = 0; i < 3; i++) {
    if (i > 0) json += ",";
    json += "{";
    json += "\"name\":\"" + channels[i].name + "\",";
    json += "\"voltage\":" + String(channels[i].voltage, 2) + ",";
    json += "\"current\":" + String(channels[i].current, 3) + ",";
    json += "\"power\":" + String(channels[i].power, 2) + ",";
    json += "\"energy\":" + String(channels[i].energy, 4) + ",";
    json += "\"cost\":" + String(channels[i].cost, 2) + ",";
    json += "\"relay\":" + String(channels[i].relayState ? "true" : "false");
    json += "}";
  }
  
  json += "]}";
  
  server.send(200, "application/json", json);
}

void handleHistory() {
  String json = "[";
  for (int i = 0; i < MAX_HISTORY; i++) {
    if (i > 0) json += ",";
    json += String(powerHistory[i], 1);
  }
  json += "]";
  
  server.send(200, "application/json", json);
}

void handleReset() {
  for (int i = 0; i < 3; i++) {
    channels[i].energy = 0;
    channels[i].cost = 0;
    channels[i].peakPower = 0;
    channels[i].alertCount = 0;
  }
  
  energySystem.totalEnergy = 0;
  energySystem.totalCost = 0;
  energySystem.lastReset = millis();
  
  Serial.println("✓ Energy counters reset");
  
  server.sendHeader("Location", "/");
  server.send(303);
}