/*
 * LD7182 – AI for IoT  |  Smart Agriculture Crop Recommendation
 * Board : wokwi-esp32-devkit-v1
 *
 * ════════════════════════════════════════════════════════════════
 *  PIN MAP
 * ════════════════════════════════════════════════════════════════
 *  DHT22 data    → GPIO4  (esp:D4)
 *  LCD SDA       → GPIO21 (esp:D21)
 *  LCD SCL       → GPIO22 (esp:D22)
 *  Pot N         → GPIO36 (esp:VP)   ADC1_CH0
 *  Pot P         → GPIO39 (esp:VN)   ADC1_CH3
 *  Pot K         → GPIO34 (esp:D34)  ADC1_CH6
 *  Pot pH        → GPIO35 (esp:D35)  ADC1_CH7
 *  Pot Rainfall  → GPIO32 (esp:D32)  ADC1_CH4
 *  LED Green     → GPIO26 (esp:D26)
 *  LED Red       → GPIO27 (esp:D27)
 * ════════════════════════════════════════════════════════════════
 *
 *  ThingSpeak Fields:
 *    1=N  2=P  3=K  4=Temperature  5=Humidity  6=pH  7=Rainfall  8=CropIndex
 *
 *  HOW TO CHANGE SENSORS IN WOKWI:
 *    Temp/Humidity → Right-click the DHT22 → "Change values"
 *    Soil params   → Rotate the 5 potentiometer knobs
 */

#include <WiFi.h>
#include <WiFiClient.h>       // ← required for ESP32 HTTPClient v2
#include <HTTPClient.h>
#include <DHT.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// ── WiFi ──────────────────────────────────────────────────────────────────────
const char* WIFI_SSID     = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

// ── ThingSpeak ────────────────────────────────────────────────────────────────
const char* TS_API_KEY    = "CU98HJ3U9LDRGJ8C";
// ▲ ─────────────────────────────────────────────────── ▲

const char* TS_SERVER     = "api.thingspeak.com";       // host only, no http://
const int   TS_PORT       = 80;
const unsigned long TS_INTERVAL = 16000UL;              // 16 s (ThingSpeak min=15 s)

// ── Pins ──────────────────────────────────────────────────────────────────────
#define DHT_PIN   4
#define PIN_N     36    // VP   ADC1
#define PIN_P     39    // VN   ADC1
#define PIN_K     34    //      ADC1
#define PIN_PH    35    //      ADC1
#define PIN_RAIN  32    //      ADC1  ← was GPIO25(ADC2), now fixed
#define LCD_SDA   21
#define LCD_SCL   22
#define LCD_ADDR  0x27
#define LED_GREEN 26
#define LED_RED   27

// ── Crop labels (sklearn LabelEncoder alphabetical order) ─────────────────────
const char* CROPS[22] = {
  "Apple",      "Banana",    "Blackgram", "Chickpea",   "Coconut",
  "Coffee",     "Cotton",    "Grapes",    "Jute",       "KidneyBeans",
  "Lentil",     "Maize",     "Mango",     "MothBeans",  "MungBean",
  "Muskmelon",  "Orange",    "Papaya",    "PigeonPeas", "Pomegranate",
  "Rice",       "Watermelon"
};

DHT               dht(DHT_PIN, DHT22);
LiquidCrystal_I2C lcd(LCD_ADDR, 16, 2);
WiFiClient        wifiClient;              // persistent WiFiClient for HTTPClient

unsigned long lastUpload  = 0;
unsigned long lastSample  = 0;
int           lastCropIdx = -99;

// ── ADC helper ────────────────────────────────────────────────────────────────
float mapADC(int raw, float lo, float hi) {
  return lo + (constrain(raw, 0, 4095) / 4095.0f) * (hi - lo);
}

// ── Decision Tree (sklearn max_depth=12) ─────────────────────────────────────
int predictCrop(float N, float P, float K,
                float temp, float hum, float ph, float rain) {
  if (rain <= 30.3935f) return 15; // Muskmelon
  if (hum  <= 27.6851f) return (K <= 50.0f) ? 9 : 3;
  if (P    >  107.5f)   return (hum <= 87.0046f) ? 7 : 0;
  if (hum  <= 70.8150f) {
    if (N <= 59.5f) {
      if (rain <= 82.1035f) {
        if (hum  <= 60.016f)  return 13;
        if (rain <= 57.6786f) {
          if (P <= 52.0f) return 13;
          return (temp <= 30.1687f) ? 10 : 13;
        }
        if (P <= 53.5f) return 13;
        return (ph <= 8.5957f) ? 2 : 13;
      }
      return (P <= 47.5f) ? 12 : 18;
    }
    if (rain <= 112.454f) return (temp <= 29.0062f) ? 11 : 2;
    return 5;
  }
  if (P <= 32.5f) {
    if (rain <= 79.9668f)  return 21;
    if (rain <= 125.3923f) return (K <= 25.0f) ? 16 : 19;
    return 4;
  }
  if (hum > 90.0174f) return 17;
  if (P <= 65.0f) {
    if (N <= 50.0f) return 14;
    if (N <= 99.5f) {
      if (rain <= 199.9623f) return (K <= 29.5f) ? 11 : (ph <= 6.0012f ? 20 : 8);
      return 20;
    }
    return (K <= 30.5f) ? 6 : 8;
  }
  return 1;
}

// ═════════════════════════════════════════════════════════════════════════════
//  ThingSpeak upload — uses raw TCP via WiFiClient (most reliable on ESP32)
//  Pattern: HTTP GET over port 80 using WiFiClient directly
//  This avoids the HTTPClient.begin(String) bug on ESP32 Arduino core v2+
// ═════════════════════════════════════════════════════════════════════════════
bool uploadThingSpeak(float N, float P, float K, float temp,
                      float hum, float ph, float rain, int idx) {

  if (WiFi.status() != WL_CONNECTED) {
    Serial.println("[TS] No WiFi — skip upload");
    return false;
  }

  // Build the GET request path
  char path[256];
  snprintf(path, sizeof(path),
    "/update?api_key=%s"
    "&field1=%.1f&field2=%.1f&field3=%.1f"
    "&field4=%.2f&field5=%.2f&field6=%.3f"
    "&field7=%.1f&field8=%d",
    TS_API_KEY, N, P, K, temp, hum, ph, rain, idx);

  Serial.printf("[TS] Connecting to %s:%d\n", TS_SERVER, TS_PORT);

  // Connect TCP
  if (!wifiClient.connect(TS_SERVER, TS_PORT)) {
    Serial.println("[TS] TCP connect FAILED");
    return false;
  }

  // Send HTTP GET
  wifiClient.print(String("GET ") + path + " HTTP/1.1\r\n");
  wifiClient.print(String("Host: ") + TS_SERVER + "\r\n");
  wifiClient.print("Connection: close\r\n\r\n");

  Serial.printf("[TS] Sent GET %s\n", path);

  // Wait for response (up to 5 s)
  unsigned long t0 = millis();
  while (!wifiClient.available() && millis() - t0 < 5000) delay(10);

  // Read status line  e.g. "HTTP/1.1 200 OK"
  String statusLine = wifiClient.readStringUntil('\n');
  Serial.printf("[TS] Response: %s\n", statusLine.c_str());

  // Drain remaining response
  while (wifiClient.available()) wifiClient.read();
  wifiClient.stop();

  // ThingSpeak returns the entry ID (a positive integer) in the body on success
  // Status line contains "200" on success
  return statusLine.indexOf("200") >= 0;
}

// ── LCD helpers ───────────────────────────────────────────────────────────────
void lcdDraw(int idx, float temp, float hum) {
  lcd.setCursor(0, 0);
  lcd.print("Crop:          ");
  lcd.setCursor(5, 0);
  char name[12]; strncpy(name, CROPS[idx], 11); name[11] = '\0';
  lcd.print(name);

  lcd.setCursor(0, 1);
  lcd.print("T:");
  lcd.print(temp, 1);
  lcd.write(223);   // ° — direct write, always correct
  lcd.print("C H:");
  lcd.print((int)hum);
  lcd.print("%   ");
}

void lcdMsg(const char* r0, const char* r1) {
  lcd.clear();
  lcd.setCursor(0, 0); lcd.print(r0);
  lcd.setCursor(0, 1); lcd.print(r1);
}

// ── WiFi connect ──────────────────────────────────────────────────────────────
void connectWiFi() {
  lcdMsg("Connecting WiFi", WIFI_SSID);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("[WiFi] Connecting");
  for (int i = 0; i < 30 && WiFi.status() != WL_CONNECTED; i++) {
    delay(500); Serial.print(".");
  }
  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("\n[WiFi] Connected: " + WiFi.localIP().toString());
    digitalWrite(LED_GREEN, HIGH);
    digitalWrite(LED_RED,   LOW);
    lcdMsg("WiFi Connected!", WiFi.localIP().toString().c_str());
  } else {
    Serial.println("\n[WiFi] FAILED");
    digitalWrite(LED_GREEN, LOW);
    digitalWrite(LED_RED,   HIGH);
    lcdMsg("WiFi Failed!", "Offline Mode");
  }
  delay(2000);
}

// ── Setup ─────────────────────────────────────────────────────────────────────
void setup() {
  Serial.begin(115200);
  delay(500);

  pinMode(LED_GREEN, OUTPUT); digitalWrite(LED_GREEN, LOW);
  pinMode(LED_RED,   OUTPUT); digitalWrite(LED_RED,   HIGH);

  analogReadResolution(12);
  analogSetAttenuation(ADC_11db);

  Wire.begin(LCD_SDA, LCD_SCL);
  delay(100);
  lcd.init();
  lcd.backlight();
  lcdMsg("Smart Agri AI", "LD7182 IoT");
  delay(2000);

  dht.begin();
  delay(500);

  connectWiFi();

  Serial.println();
  Serial.println("╔══════════════════════════════════════════════╗");
  Serial.println("║  Smart Agriculture – LD7182                  ║");
  Serial.println("║  ThingSpeak upload: WiFiClient TCP (fixed)   ║");
  Serial.println("║  Upload interval  : 16 seconds               ║");
  Serial.println("╚══════════════════════════════════════════════╝");
  Serial.println();
}

// ── Loop ──────────────────────────────────────────────────────────────────────
void loop() {
  unsigned long now = millis();

  if (now - lastSample >= 1000) {
    lastSample = now;

    // DHT22
    float temp = dht.readTemperature();
    float hum  = dht.readHumidity();
    if (isnan(temp) || isnan(hum)) {
      Serial.println("[WARN] DHT22 read failed — using 25.0C / 70%");
      temp = 25.0f; hum = 70.0f;
    }

    // Potentiometers (all ADC1)
    int rN    = analogRead(PIN_N);
    int rP    = analogRead(PIN_P);
    int rK    = analogRead(PIN_K);
    int rPH   = analogRead(PIN_PH);
    int rRAIN = analogRead(PIN_RAIN);

    float N    = mapADC(rN,     0.0f,  140.0f);
    float P    = mapADC(rP,     5.0f,  145.0f);
    float K    = mapADC(rK,     5.0f,  205.0f);
    float ph   = mapADC(rPH,    3.5f,   9.94f);
    float rain = mapADC(rRAIN, 20.0f,  300.0f);

    int cropIdx = predictCrop(N, P, K, temp, hum, ph, rain);

    // Serial log
    Serial.println("─────────────────────────────────────────────");
    Serial.printf("  Temp=%.1f°C  Hum=%.1f%%\n", temp, hum);
    Serial.printf("  N=%.1f  P=%.1f  K=%.1f  pH=%.2f  Rain=%.1fmm\n",
                   N, P, K, ph, rain);
    Serial.printf("  RAW: VP=%d VN=%d D34=%d D35=%d D32=%d\n",
                   rN, rP, rK, rPH, rRAIN);
    Serial.printf("  CROP → %s (idx=%d)\n", CROPS[cropIdx], cropIdx);

    // LCD
    lcdDraw(cropIdx, temp, hum);
    lastCropIdx = cropIdx;

    // LEDs
    bool online = (WiFi.status() == WL_CONNECTED);
    digitalWrite(LED_GREEN, online ? HIGH : LOW);
    digitalWrite(LED_RED,   online ? LOW  : HIGH);

    // ThingSpeak — every 16 s
    if (now - lastUpload >= TS_INTERVAL) {
      lastUpload = now;
      Serial.println("  [TS] Starting upload...");
      bool ok = uploadThingSpeak(N, P, K, temp, hum, ph, rain, cropIdx);
      Serial.println(ok ? "  [TS] ✓ Upload OK!" : "  [TS] ✗ Upload FAILED");
      if (!ok && !online) connectWiFi();
      lcdMsg("ThingSpeak", ok ? "Upload OK!" : "Upload FAIL");
      delay(1500);
      lcdDraw(cropIdx, temp, hum);
    }
  }
}