// RemoteRig — ESP32 + ESP8266 Unified Firmware    
// ============================================
// Compatible with both ESP32 and ESP8266 via PlatformIO build targets.
//
// ESP32:   Dual-STA — simultaneously connected to GoPro AP + travel router
// ESP8266: Time-shared STA — alternates between GoPro AP and travel router
//          (30s GoPro polling → switch to router → MQTT publish → switch back)
//
// Build:  pio run -e esp32dev     (ESP32)
//         pio run -e esp8266dev   (ESP8266 / D1 Mini)

// ────────────────────────────────────────────
// Platform-specific includes and types
// ────────────────────────────────────────────

#include <Arduino.h>

#ifdef ESP32
  #include <WiFi.h>
  #define HAS_DUAL_STA 1
#elif defined(ESP8266)
  #include <ESP8266WiFi.h>
  #define HAS_DUAL_STA 0
#else
  #error "Unsupported platform — use ESP32 or ESP8266"
#endif

#include <WiFiClient.h>
#include <HTTPClient.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>

#ifdef ESP8266
  #include <LittleFS.h>
  #define SPIFFS LittleFS
#else
  #include <SPIFFS.h>
#endif

// ────────────────────────────────────────────
// Configuration
// ────────────────────────────────────────────

struct Config {
  String wifi_ssid       = "RemoteRig";
  String wifi_password   = "";
  String camera_ssid     = "GOPRO-BP-";
  String camera_password = "goprohero";
  String camera_ip       = "10.5.5.1";
  String mqtt_broker     = "192.168.4.10";
  int    mqtt_port       = 1883;
  String camera_id       = "";
  int    poll_sec        = 30;
  int    heartbeat_sec   = 60;
  bool   dirty           = false;
} cfg;

// ────────────────────────────────────────────
// Platform-specific Wi-Fi
// ────────────────────────────────────────────

WiFiClient   goproClient;
WiFiClient   routerClient;
PubSubClient mqtt(routerClient);

unsigned long bootMs = 0;
bool cameraOnline    = false;

// ESP8266: track which network we're on
#if !HAS_DUAL_STA
enum NetState { NET_ROUTER, NET_CAMERA, NET_SWITCHING };
NetState netState = NET_ROUTER;
unsigned long lastNetSwitch = 0;
const unsigned long NET_SWITCH_DELAY = 2000; // 2s to switch networks
#endif

const int LED_PIN = 
  #ifdef ESP32
    2
  #else
    LED_BUILTIN  // ESP8266 D1 Mini = GPIO 2 (active low!)
  #endif
;

// ────────────────────────────────────────────
// SPIFFS / LittleFS Config
// ────────────────────────────────────────────

bool loadConfig() {
  #ifdef ESP8266
  if (!LittleFS.begin()) { Serial.println("LittleFS mount failed"); return false; }
  #else
  if (!SPIFFS.begin(true)) { Serial.println("SPIFFS mount failed"); return false; }
  #endif

  File f = 
    #ifdef ESP8266
    LittleFS.open("/config.json", "r");
    #else
    SPIFFS.open("/config.json", "r");
    #endif
  if (!f) { Serial.println("No config — using defaults"); return false; }

  JsonDocument doc;
  DeserializationError err = deserializeJson(doc, f);
  f.close();
  if (err) { Serial.printf("Config parse error: %s\n", err.c_str()); return false; }

  cfg.wifi_ssid       = doc["wifi_ssid"]       | cfg.wifi_ssid;
  cfg.wifi_password   = doc["wifi_password"]   | cfg.wifi_password;
  cfg.camera_ssid     = doc["camera_ssid"]     | cfg.camera_ssid;
  cfg.camera_password = doc["camera_password"] | cfg.camera_password;
  cfg.camera_ip       = doc["camera_ip"]       | cfg.camera_ip;
  cfg.mqtt_broker     = doc["mqtt_broker"]     | cfg.mqtt_broker;
  cfg.mqtt_port       = doc["mqtt_port"]       | cfg.mqtt_port;
  cfg.camera_id       = doc["camera_id"]       | cfg.camera_id;
  cfg.poll_sec        = doc["poll_interval_sec"] | cfg.poll_sec;
  cfg.heartbeat_sec   = doc["heartbeat_interval_sec"] | cfg.heartbeat_sec;

  Serial.println("Config loaded");
  return true;
}

bool saveConfig() {
  File f = 
    #ifdef ESP8266
    LittleFS.open("/config.json", "w");
    #else
    SPIFFS.open("/config.json", "w");
    #endif
  if (!f) return false;

  JsonDocument doc;
  doc["wifi_ssid"]       = cfg.wifi_ssid;
  doc["wifi_password"]   = cfg.wifi_password;
  doc["camera_ssid"]     = cfg.camera_ssid;
  doc["camera_password"] = cfg.camera_password;
  doc["camera_ip"]       = cfg.camera_ip;
  doc["mqtt_broker"]     = cfg.mqtt_broker;
  doc["mqtt_port"]       = cfg.mqtt_port;
  doc["camera_id"]       = cfg.camera_id;
  doc["poll_interval_sec"]   = cfg.poll_sec;
  doc["heartbeat_interval_sec"] = cfg.heartbeat_sec;
  serializeJson(doc, f);
  f.close();
  return true;
}

// ────────────────────────────────────────────
// Wi-Fi Connection
// ────────────────────────────────────────────

#if HAS_DUAL_STA
// ESP32: connect to both simultaneously
bool connectBoth() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(cfg.wifi_ssid.c_str(), cfg.wifi_password.c_str());
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 40) {
    delay(500); Serial.print("."); attempts++;
  }
  if (WiFi.status() != WL_CONNECTED) return false;
  
  Serial.printf("\nRouter: %s\n", WiFi.localIP().toString().c_str());
  
  // GoPro connection handled per-poll (just HTTP to camera IP)
  // Camera is assumed always reachable at camera_ip via the GoPro AP
  return true;
}
#else
// ESP8266: connect to one network at a time
bool connectTo(const String& ssid, const String& pass) {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid.c_str(), pass.c_str());
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 30) {
    delay(500); Serial.print("."); attempts++;
  }
  return WiFi.status() == WL_CONNECTED;
}

void switchToRouter() {
  if (netState == NET_ROUTER) return;
  netState = NET_SWITCHING;
  WiFi.disconnect();
  delay(500);
  connectTo(cfg.wifi_ssid, cfg.wifi_password);
  netState = NET_ROUTER;
  lastNetSwitch = millis();
  Serial.printf("Switched to router: %s\n", WiFi.localIP().toString().c_str());
}

void switchToCamera() {
  if (netState == NET_CAMERA) return;
  netState = NET_SWITCHING;
  WiFi.disconnect();
  delay(500);
  connectTo(cfg.camera_ssid, cfg.camera_password);
  netState = NET_CAMERA;
  lastNetSwitch = millis();
  Serial.printf("Switched to camera AP: %s\n", WiFi.localIP().toString().c_str());
}
#endif

// ────────────────────────────────────────────
// GoPro / Camera HTTP API
// ────────────────────────────────────────────

struct CamStatus {
  bool   valid = false;
  int    video_remaining_sec = 0;
  bool   recording = false;
  int    battery_raw = 0;
};

CamStatus fetchCameraStatus() {
  CamStatus s;
  
  String url = "http://" + cfg.camera_ip +
               "/bacpac/SH?t=" + cfg.camera_password + "&p=%01";
  
  HTTPClient http;
  http.useHTTP10(true);
  http.begin(goproClient, url);
  http.setTimeout(5000);
  int code = http.GET();

  if (code != 200) { http.end(); return s; }

  String raw = http.getString();
  http.end();

  if (raw.length() < 58) return s;

  const uint8_t* buf = (const uint8_t*)raw.c_str();
  s.valid = true;
  s.video_remaining_sec = buf[25] | (buf[26] << 8);
  s.recording = (buf[29] == 1);
  s.battery_raw = buf[57];

  return s;
}

bool sendCameraCommand(const String& cmd) {
  String param = (cmd == "start_recording") ? "%01" : "%00";
  String url = "http://" + cfg.camera_ip +
               "/bacpac/SH?t=" + cfg.camera_password + "&p=" + param;
  
  HTTPClient http;
  http.useHTTP10(true);
  http.begin(goproClient, url);
  http.setTimeout(5000);
  int code = http.GET();
  http.end();
  return (code == 200);
}

// ────────────────────────────────────────────
// MQTT
// ────────────────────────────────────────────

String clientID() {
  uint8_t mac[6];
  WiFi.macAddress(mac);
  char buf[32];
  snprintf(buf, sizeof(buf), "rig-%02x%02x%02x", mac[3], mac[4], mac[5]);
  return String(buf);
}

String top(const char* t) { 
  return "remoterig/cameras/" + cfg.camera_id + "/" + t; 
}

void mqttCallback(char* topic, byte* payload, unsigned int len) {
  char buf[256];
  unsigned int n = len < 255 ? len : 255;
  memcpy(buf, payload, n); buf[n] = 0;

  JsonDocument doc;
  if (deserializeJson(doc, buf)) return;

  String cmd = doc["command"] | "";
  if (cmd == "start_recording" || cmd == "stop_recording") {
    sendCameraCommand(cmd);
  } else if (cmd == "reboot") {
    ESP.restart();
  } else if (cmd == "registered") {
    String id = doc["camera_id"] | "";
    if (id.length() > 0 && id != cfg.camera_id) {
      cfg.camera_id = id;
      cfg.dirty = true;
      mqtt.unsubscribe(top("command").c_str());
      mqtt.subscribe(top("command").c_str(), 2);
      Serial.printf("Registered as %s\n", id.c_str());
    }
  }
}

bool connectMQTT() {
  mqtt.setServer(cfg.mqtt_broker.c_str(), cfg.mqtt_port);
  mqtt.setCallback(mqttCallback);
  mqtt.setKeepAlive(60);

  if (!mqtt.connect(clientID().c_str())) {
    Serial.printf("MQTT fail (state=%d)\n", mqtt.state());
    return false;
  }

  mqtt.subscribe(top("command").c_str(), 2);

  if (cfg.camera_id.length() == 0) {
    // Announce as new camera
    JsonDocument doc;
    doc["mac_address"]      = WiFi.macAddress();
    doc["firmware_version"] = 
      #ifdef ESP32
      "0.2.0-esp32"
      #else
      "0.2.0-esp8266"
      #endif
    ;
    doc["friendly_name"] = "Cam-" + clientID();
    JsonArray caps = doc["capabilities"].to<JsonArray>();
    caps.add("start_stop"); caps.add("status");
    String payload; serializeJson(doc, payload);
    mqtt.publish("remoterig/cameras/announce-" + clientID(), payload.c_str(), true);
    Serial.println("Announced for registration");
  }

  return true;
}

void publishStatus(const CamStatus& s) {
  if (cfg.camera_id.length() == 0) return;

  JsonDocument doc;
  doc["camera_id"]   = cfg.camera_id;
  doc["timestamp"]   = millis();
  doc["battery_raw"] = s.battery_raw;
  doc["video_remaining_sec"] = s.video_remaining_sec;
  doc["recording"]   = s.recording;
  doc["online"]      = cameraOnline;

  String payload; serializeJson(doc, payload);
  mqtt.publish(top("status").c_str(), payload.c_str(), true);
}

// ────────────────────────────────────────────
// Setup
// ────────────────────────────────────────────

void setup() {
  Serial.begin(115200);
  delay(500);
  Serial.printf("\n\nRemoteRig v0.2.0 [%s]\n", 
    #ifdef ESP32
    "ESP32"
    #else
    "ESP8266"
    #endif
  );
  bootMs = millis();
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, 
    #ifdef ESP8266
    HIGH  // ESP8266 LED is active-low
    #else
    LOW
    #endif
  );

  loadConfig();

  #if HAS_DUAL_STA
  connectBoth();
  #else
  connectTo(cfg.wifi_ssid, cfg.wifi_password);
  netState = NET_ROUTER;
  #endif

  connectMQTT();
}

// ────────────────────────────────────────────
// Main Loop
// ────────────────────────────────────────────

void loop() {
  unsigned long now = millis();
  static unsigned long lastPoll = 0, lastBeat = 0, lastRecon = 0;
  static int reconDelay = 1;

  #if HAS_DUAL_STA
  // ESP32: simple loop — everything concurrent
  if (WiFi.status() != WL_CONNECTED) {
    if (now - lastRecon > 5000) { lastRecon = now; WiFi.reconnect(); }
    delay(100); return;
  }
  if (!mqtt.connected()) {
    if (now - lastRecon > (unsigned long)(reconDelay * 1000)) {
      lastRecon = now;
      if (connectMQTT()) reconDelay = 1;
      else reconDelay = min(reconDelay * 2, 30);
    }
    mqtt.loop(); delay(100); return;
  }
  mqtt.loop();

  // Poll camera every poll_sec
  if (now - lastPoll > (unsigned long)(cfg.poll_sec * 1000)) {
    lastPoll = now;
    CamStatus s = fetchCameraStatus();
    cameraOnline = s.valid;
    publishStatus(s);
  }

  // Heartbeat every heartbeat_sec
  if (now - lastBeat > (unsigned long)(cfg.heartbeat_sec * 1000)) {
    lastBeat = now;
    if (cfg.camera_id.length() > 0) {
      JsonDocument doc;
      doc["camera_id"] = cfg.camera_id;
      doc["timestamp"] = millis();
      doc["uptime_sec"] = (now - bootMs) / 1000;
      doc["free_heap"] = 
        #ifdef ESP32
        ESP.getFreeHeap()
        #else
        ESP.getFreeHeap()
        #endif
      ;
      String p; serializeJson(doc, p);
      mqtt.publish(top("heartbeat").c_str(), p.c_str(), false);
    }
  }

  #else  // ESP8266: time-shared loop
  // Ensure we're on the right network for the current phase
  static bool polledThisCycle = false;
  
  if (now - lastPoll > (unsigned long)(cfg.poll_sec * 1000) && !polledThisCycle) {
    // Phase 1: Switch to camera AP, poll status
    switchToCamera();
    delay(500);
    
    CamStatus s = fetchCameraStatus();
    cameraOnline = s.valid;
    
    // Phase 2: Switch to router, publish MQTT
    switchToRouter();
    delay(500);
    
    // Reconnect MQTT if needed (router may have new IP)
    if (!mqtt.connected()) {
      if (now - lastRecon > (unsigned long)(reconDelay * 1000)) {
        lastRecon = now;
        if (connectMQTT()) reconDelay = 1;
        else reconDelay = min(reconDelay * 2, 30);
      }
    }
    mqtt.loop();
    
    publishStatus(s);
    lastPoll = now;
    polledThisCycle = true;
  }
  
  if (now - lastBeat > (unsigned long)(cfg.heartbeat_sec * 1000)) {
    // Already on router from poll — just publish heartbeat
    if (!mqtt.connected()) { 
      connectMQTT(); 
    }
    mqtt.loop();
    
    if (cfg.camera_id.length() > 0) {
      JsonDocument doc;
      doc["camera_id"] = cfg.camera_id;
      doc["timestamp"] = millis();
      doc["uptime_sec"] = (now - bootMs) / 1000;
      doc["free_heap"] = ESP.getFreeHeap();
      String p; serializeJson(doc, p);
      mqtt.publish(top("heartbeat").c_str(), p.c_str(), false);
    }
    lastBeat = now;
  }
  
  // Reset poll cycle flag
  if (now - lastPoll > 2000) polledThisCycle = false;
  
  // Stay on router for MQTT command reception
  mqtt.loop();
  #endif

  // Save config
  if (cfg.dirty) { cfg.dirty = false; saveConfig(); }

  // LED heartbeat
  static unsigned long lastLed = 0;
  int interval = cameraOnline ? 1000 : 200;
  if (now - lastLed > interval) {
    lastLed = now;
    #ifdef ESP8266
    digitalWrite(LED_PIN, !digitalRead(LED_PIN)); // toggle (active-low handled)
    #else
    digitalWrite(LED_PIN, !digitalRead(LED_PIN));
    #endif
  }

  delay(50);
}