// T-Energy-S3 MQTT Battery Monitor (Deep Sleep Edition)
// Wakes on button press, publishes voltage, then sleeps

#include <WiFi.h>
#include <WiFiClientSecure.h>
#include <PubSubClient.h>
#include "config.h"

#define BATTERY_PIN 3
#define BUTTON_PIN GPIO_NUM_0
#define PUBLISH_COUNT 3
#define PUBLISH_DELAY_MS 1000

WiFiClientSecure secureClient;
PubSubClient mqtt(secureClient);

void printMac()
{
    Serial.printf("MAC Address: %s\n", WiFi.macAddress().c_str());
}

bool connectWifi()
{
    Serial.printf("Connecting to %s...\n", WIFI_SSID);
    WiFi.mode(WIFI_STA);
    WiFi.begin(WIFI_SSID);

    int attempts = 0;
    while (WiFi.status() != WL_CONNECTED && attempts < 20)
    {
        delay(500);
        Serial.print(".");
        attempts++;
    }

    if (WiFi.status() == WL_CONNECTED)
    {
        Serial.printf("\nConnected! IP: %s\n", WiFi.localIP().toString().c_str());
        return true;
    }
    else
    {
        Serial.println("\nWiFi connection failed");
        return false;
    }
}

bool connectMqtt()
{
    Serial.printf("Connecting to MQTT %s:%d...\n", MQTT_HOST, MQTT_PORT);

    String clientId = "t-energy-" + WiFi.macAddress();

    if (mqtt.connect(clientId.c_str(), MQTT_USER, MQTT_PASS))
    {
        Serial.println("MQTT connected!");
        return true;
    }
    else
    {
        Serial.printf("MQTT failed, rc=%d\n", mqtt.state());
        return false;
    }
}

void publishVoltage()
{
    int mv = analogReadMilliVolts(BATTERY_PIN) * 2;
    Serial.printf("Battery: %d mV\n", mv);

    char payload[16];
    snprintf(payload, sizeof(payload), "%d", mv);
    if (mqtt.publish(MQTT_TOPIC, payload))
    {
        Serial.printf("Published to %s: %s\n", MQTT_TOPIC, payload);
    }
    else
    {
        Serial.println("Publish failed");
    }
    mqtt.loop();
}

void enterDeepSleep()
{
    Serial.println("Entering deep sleep... press button to wake");
    Serial.flush();

    esp_sleep_enable_ext0_wakeup(BUTTON_PIN, LOW);
    esp_deep_sleep_start();
}

void setup()
{
    Serial.begin(115200);
    delay(1000);

    Serial.println("\n=== T-Energy-S3 MQTT Monitor ===\n");

    // Check wake reason
    esp_sleep_wakeup_cause_t wakeup_reason = esp_sleep_get_wakeup_cause();
    if (wakeup_reason == ESP_SLEEP_WAKEUP_EXT0)
    {
        Serial.println("Woke up from button press!");
    }
    else
    {
        Serial.println("Initial boot");
    }

    printMac();

    pinMode(BATTERY_PIN, INPUT);
    analogReadResolution(12);
    analogSetPinAttenuation(BATTERY_PIN, ADC_11db);

    // TLS setup
    secureClient.setInsecure();
    mqtt.setServer(MQTT_HOST, MQTT_PORT);

    if (connectWifi() && connectMqtt())
    {
        for (int i = 0; i < PUBLISH_COUNT; i++)
        {
            publishVoltage();
            if (i < PUBLISH_COUNT - 1)
            {
                delay(PUBLISH_DELAY_MS);
            }
        }
    }

    // Disconnect cleanly
    mqtt.disconnect();
    WiFi.disconnect(true);

    enterDeepSleep();
}

void loop()
{
    // Never reached - we sleep in setup()
}