// =======================================================
//  Unified ESP32 Greenhouse Controller (Potentiometer & Water Alarm)
//  Features: Web Control, NTP Time, Precise Stepper, Servo Watering, Water Alarm
// =======================================================

// ================= 庫與定義 =================
#include <WiFi.h>
#include "time.h"
#include <WebServer.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHTesp.h>

// ---------------- WiFi + NTP ----------------
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* ntpServer = "pool.ntp.org";
const long gmtOffset_sec = 8 * 3600;
const int daylightOffset_sec = 0;

// ---------------- 引腳定義 ----------------
#define DHT_PIN 15
#define US_TRIG 5
#define US_ECHO 18
#define WATER_ALARM_PIN 13 // 缺水警報 LED
#define SOIL_PIN 34        // **連接可變電阻 (Potentiometer) 模擬土壤濕度**
#define SERVO_PIN 4
#define STEP_PIN 19
#define DIR_PIN 23
#define EN_PIN 17
#define BUTTON_PIN 2

// LED Bar (8 LEDs)
const int ledPins[8] = {32, 33, 25, 26, 27, 14, 12, 16};
const int TOTAL_LEDS = 8;

// ---------------- Stepper 參數 ----------------
const int STEPS_PER_REV = 200;
const int MICROSTEPS = 16;
const float FAN_RPM = 120.0;
const bool FAN_DIR_CW = true;

// ---------------- 狀態與數據 ----------------
float tempC = NAN;
float humidity = NAN;
float waterDistance = 0;
float waterLevelPercent = 0;
int soilMoisturePercent = 0; // 0% 極乾 (Pot. 撥到 4095), 100% 極濕 (Pot. 撥到 0)

bool manualOverride = false;
bool fanEnabled = false;
bool waterAlarm = false;
bool wateringState = false;
int stableButtonState = HIGH;

// ---------------- 計時器與閾值 ----------------
uint32_t lastDHT = 0;
uint32_t lastDisplay = 0;
uint32_t lastButtonChange = 0;
uint32_t lastStepUs = 0;
uint32_t DHT_INTERVAL = 2000;
uint32_t DISP_INTERVAL = 500;
uint32_t BUTTON_DEBOUNCE = 50;
uint32_t stepIntervalUs = 0;
bool stepLevel = LOW;

const int servoFreq = 50;
const int servoRes = 16;
const int TEMP_THRESHOLD_ON = 25.0;
const int TEMP_THRESHOLD_OFF = 24.0;
const float LOW_WATER_THRESHOLD_CM = 15.0;
const int DRY_SOIL_THRESHOLD = 30; // 濕度低於 30% 觸發澆水

// ================= 函數原型聲明 =================
void updateStepInterval();
void stepperEnable(bool en);
void stepperDir(bool cw);
void stepperTick();
void updateFanAuto();
void setServoAngle(int angle);
void readButton();
void sampleDHT();
void checkWaterLevelAndAlarm();
void updateOutputs();
void updateLedBar();
void updateLCD();
void connectWiFiAndTime();
String NTP_Time_String();
void handleRoot();
void handleFanOn();
void handleFanOff();

// ================= 步進馬達控制函數 =================
void updateStepInterval() {
    float stepsPerSec = FAN_RPM * (STEPS_PER_REV * MICROSTEPS) / 60.0;
    if (stepsPerSec < 1) stepsPerSec = 1;
    stepIntervalUs = (uint32_t)(1e6 / stepsPerSec / 2);
}
void stepperEnable(bool en) {
    digitalWrite(EN_PIN, en ? LOW : HIGH);
}
void stepperDir(bool cw) {
    digitalWrite(DIR_PIN, cw ? HIGH : LOW);
}
void stepperTick() {
    if (!fanEnabled) {
        digitalWrite(STEP_PIN, LOW);
        stepLevel = LOW;
        return;
    }
    uint32_t now = micros();
    if (now - lastStepUs >= stepIntervalUs) {
        lastStepUs = now;
        stepLevel = !stepLevel;
        digitalWrite(STEP_PIN, stepLevel);
    }
}
void updateFanAuto() {
    if (manualOverride) {
        fanEnabled = true;
        return;
    }
    if (!isnan(tempC)) {
        if (!fanEnabled && tempC >= TEMP_THRESHOLD_ON) {
            fanEnabled = true;
        } else if (fanEnabled && tempC <= TEMP_THRESHOLD_OFF) {
            fanEnabled = false;
        }
    }
}

// ================= 閥門與按鈕控制函數 =================
void setServoAngle(int angle) {
    if (angle < 0) angle = 0;
    if (angle > 180) angle = 180;
    long pulseWidthUs = map(angle, 0, 180, 500, 2500);
    long duty = (pulseWidthUs * 65536) / 20000;
    ledcWrite(SERVO_PIN, duty);
}
void readButton() {
    int raw = digitalRead(BUTTON_PIN);
    uint32_t now = millis();
    if (raw != stableButtonState) {
        lastButtonChange = now;
    }
    if (now - lastButtonChange >= BUTTON_DEBOUNCE) {
        if (stableButtonState != raw) {
            stableButtonState = raw;
            if (raw == LOW) {
                manualOverride = !manualOverride;
            }
        }
    }
}

// ================= 傳感器與警報函數 =================
void sampleDHT() {
    if (millis() - lastDHT >= DHT_INTERVAL) {
        lastDHT = millis();
        TempAndHumidity data = dht.getTempAndHumidity();
        if (!isnan(data.temperature)) {
            tempC = data.temperature;
            humidity = data.humidity;
        }
        // 讀取可變電阻 (Pot.)
        int rawSoil = analogRead(SOIL_PIN);
        // 模擬：0 (Pot. 撥到底) => 100% 濕潤, 4095 (Pot. 撥到底) => 0% 乾燥
        soilMoisturePercent = map(rawSoil, 0, 4095, 100, 0); 
    }
}

void checkWaterLevelAndAlarm() {
    digitalWrite(US_TRIG, LOW); delayMicroseconds(2);
    digitalWrite(US_TRIG, HIGH); delayMicroseconds(10);
    digitalWrite(US_TRIG, LOW);
    long duration = pulseIn(US_ECHO, HIGH, 30000);
    float distance = duration * 0.034 / 2;

    waterDistance = distance;
    waterLevelPercent = map(waterDistance, 20, 2, 0, 100);
    waterLevelPercent = constrain(waterLevelPercent, 0, 100);

    // 缺水警報邏輯
    if (waterDistance > LOW_WATER_THRESHOLD_CM) {
        waterAlarm = true;
    } else {
        waterAlarm = false;
    }
}

// ================= 輸出設備控制函數 =================
void updateOutputs() {
    // --- LED Bar (顯示溫度) ---
    int ledCount = round(tempC / (50.0 / TOTAL_LEDS));
    if (ledCount < 0) ledCount = 0;
    if (ledCount > TOTAL_LEDS) ledCount = TOTAL_LEDS;

    for (int i = 0; i < TOTAL_LEDS; i++) {
        digitalWrite(ledPins[i], (i < ledCount) ? HIGH : LOW);
    }

    // --- 缺水警報 LED (GPIO 13) ---
    digitalWrite(WATER_ALARM_PIN, waterAlarm ? HIGH : LOW);

    // --- 澆水閥門 (Servo) 自動控制 ---
    // 條件：土壤乾燥 (<30%) 且 無缺水警報
    if (soilMoisturePercent < DRY_SOIL_THRESHOLD && !waterAlarm) {
        if (!wateringState) {
            setServoAngle(90);
            wateringState = true;
        }
    } else {
        if (wateringState) {
            setServoAngle(0);
            wateringState = false;
        }
    }
}

// ================= LCD 顯示函數 (集成 NTP 時間與警報) =================
void updateLCD() {
    if (millis() - lastDisplay < DISP_INTERVAL) return;
    lastDisplay = millis();

    struct tm timeinfo;
    getLocalTime(&timeinfo);
    char timeStr[9];
    strftime(timeStr, sizeof(timeStr), "%H:%M:%S", &timeinfo);

    lcd.setCursor(0, 0);
    if (waterAlarm) {
        lcd.print("!!! LOW WATER !!!");
    } else {
        lcd.print("Time: ");
        lcd.print(timeStr);
    }

    lcd.setCursor(0, 1);
    lcd.printf("T:%.1f H:%.0f%% S:%02d%%", tempC, humidity, soilMoisturePercent);
    lcd.setCursor(15, 1);
    lcd.print(manualOverride ? "M" : "A");
}

// ================= SETUP, Web Handlers, LOOP =================
String NTP_Time_String() {
  struct tm timeinfo;
  if (!getLocalTime(&timeinfo)) return "N/A";
  char output[30];
  strftime(output, 30, "%Y-%m-%d %H:%M:%S", &timeinfo);
  return String(output);
}

void connectWiFiAndTime() {
    Serial.print("Connecting WiFi");
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(200); Serial.print(".");
    }
    Serial.println(" OK!");
    configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
    struct tm timeinfo;
    while (!getLocalTime(&timeinfo)) {
        delay(200); Serial.print("/");
    }
    Serial.println(" Time Synced.");
}

void handleRoot() {
    String html = "<html><body style='font-family:sans-serif; text-align:center; padding:20px;'>";
    html += "<h1>ESP32 Greenhouse Monitor</h1>";
    html += String("<p>Time: ") + NTP_Time_String() + "</p>";
    html += String("<h3>Temp: ") + String(tempC, 1) + " C | Hum: " + String(humidity, 0) + " %</h3>";
    html += String("<p>Soil Moist: ") + String(soilMoisturePercent) + "% | Water Lvl: " + String(waterLevelPercent, 0) + "%</p>";
    html += String("<p style='color:") + (waterAlarm ? "red" : "green") + ";'>Water Alarm: " + (waterAlarm ? "**ACTIVE**" : "Normal") + "</p>";
    html += String("<p>Fan Status: ") + (manualOverride ? "MANUAL ON" : "AUTO") + "</p>";
    html += "<p><a href='/fan/on'><button style='font-size:18px;padding:10px;background:green;color:white;'>Fan ON</button></a>";
    html += "&nbsp;<a href='/fan/off'><button style='font-size:18px;padding:10px;background:red;color:white;'>Fan Auto</button></a></p>";
    html += String("<p>Valve: ") + (wateringState ? "OPEN" : "CLOSED") + "</p>";
    html += "</body></html>";
    server.send(200, "text/html", html);
}

void handleFanOn() { manualOverride = true; server.sendHeader("Location", "/"); server.send(303); }
void handleFanOff() { manualOverride = false; server.sendHeader("Location", "/"); server.send(303); }

void setup() {
    Serial.begin(115200);
    dht.setup(DHT_PIN, DHTesp::DHT22);
    lcd.init();
    lcd.backlight();

    for (int i = 0; i < TOTAL_LEDS; i++) pinMode(ledPins[i], OUTPUT);
    pinMode(US_TRIG, OUTPUT);
    pinMode(US_ECHO, INPUT);
    pinMode(WATER_ALARM_PIN, OUTPUT);
    pinMode(SOIL_PIN, INPUT);
    pinMode(STEP_PIN, OUTPUT);
    pinMode(DIR_PIN, OUTPUT);
    pinMode(EN_PIN, OUTPUT);
    pinMode(BUTTON_PIN, INPUT_PULLUP);

    stepperDir(FAN_DIR_CW);
    updateStepInterval();
    stepperEnable(false);

    ledcAttach(SERVO_PIN, servoFreq, servoRes);
    setServoAngle(0);

    lcd.setCursor(0, 0); lcd.print("Connecting...");
    connectWiFiAndTime();
    lcd.clear();

    server.on("/", handleRoot);
    server.on("/fan/on", handleFanOn);
    server.on("/fan/off", handleFanOff);
    server.begin();
}

void loop() {
    sampleDHT();
    readButton();
    updateFanAuto();
    stepperEnable(fanEnabled);
    stepperTick();

    checkWaterLevelAndAlarm();
    updateOutputs();
    updateLCD();
    server.handleClient();

    delay(1);
}