// neato Service
// Purpose: Defines the neato Service module and the helpers/state used by this service unit.
// Scope: Keeps runtime behavior unchanged while isolating responsibilities into a clear module boundary.
const EventEmitter = require('events');
const io = require('../../globals/io');
const logger = require('../../globals/logger').child('neatoService');
const { loadConfig } = require('../../helpers/configLoader');
const { isFeatureEnabled } = require('../../helpers/features');
const { isVerified } = require('../verificationService');
const { getMode, MODES } = require('../modeManager');
const { isAdmin, isLockdownAdmin } = require('../roleService');
const { sendAlert } = require('../alertService');
const {
  homeAssistantEvents,
  getRawEntitySnapshot,
  callHomeAssistantService,
  isConnected: isHomeAssistantConnected,
  enabled: homeAssistantEnabled,
} = require('../homeAssistantService');

const events = new EventEmitter();
const config = loadConfig();
const haConfig = config.homeAssistant || {};
const neatoConfig = haConfig.neato || {};
const featureEnabled = isFeatureEnabled('neato');

function normalizeDeviceName(value) {
  const raw = String(value || '').trim().toLowerCase();
  if (!raw) return '';
  return raw.replace(/[^a-z0-9_]+/g, '_').replace(/^_+|_+$/g, '');
}

const device = normalizeDeviceName(neatoConfig.device);
const RESUME_DELAY_MS = 3000;
const ALERT_COLOR = '#a855f7';
// BrainSlug exposes these exact select values for Gen 3 robots. Keeping the
// allowlist on the server prevents arbitrary Home Assistant select options from
// being submitted by a modified browser while preserving BrainSlug's casing.
const NAVIGATION_MODES = Object.freeze(['Normal', 'Gentle', 'Deep', 'Quick']);

function entityId(domain, suffix) {
  if (!device) return '';
  return `${domain}.${device}_${suffix}`;
}

const ENTITY_IDS = {
  buttons: {
    start: entityId('button', 'house_clean'),
    resume: entityId('button', 'resume_cleaning'),
    sendHome: entityId('button', 'send_to_base'),
    locate: entityId('button', 'locate_robot'),
    clearErrors: entityId('button', 'clear_errors'),
    powerCycle: entityId('button', 'powercycle'),
  },
  sensors: {
    batteryPercent: entityId('sensor', 'fuel_percent'),
    batteryVoltage: entityId('sensor', 'battery_voltage_v'),
  },
  binarySensors: {
    chargingActive: entityId('binary_sensor', 'charging_active'),
    extPowerPresent: entityId('binary_sensor', 'ext_power_present'),
  },
  textSensors: {
    // ESPHome text_sensor entities surface in Home Assistant under the sensor domain.
    robotState: entityId('sensor', 'robot_state'),
    uiState: entityId('sensor', 'ui_state'),
    robotError: entityId('sensor', 'robot_error'),
    robotAlert: entityId('sensor', 'robot_alert'),
  },
  selects: {
    navigationMode: entityId('select', 'navigation_mode'),
  },
};

// Alert Feed coverage is intentionally limited to the raw robot lifecycle and
// issue fields requested for Neato. Battery and charger telemetry poll often and
// would create noise without representing a useful robot status transition.
const ALERT_ENTITIES = Object.freeze([
  { title: 'Neato UI state', entityId: ENTITY_IDS.textSensors.uiState },
  { title: 'Neato robot state', entityId: ENTITY_IDS.textSensors.robotState },
  { title: 'Neato robot alert', entityId: ENTITY_IDS.textSensors.robotAlert },
  { title: 'Neato robot error', entityId: ENTITY_IDS.textSensors.robotError },
  { title: 'Neato external power', entityId: ENTITY_IDS.binarySensors.extPowerPresent },
]);

// Each entity establishes its own baseline because ESPHome entities can become
// available on different snapshots. A Map also distinguishes "not observed yet"
// from a legitimate raw state string without inventing a sentinel state value.
const alertBaselines = new Map();

function readRaw(entityIdValue) {
  if (!entityIdValue) return null;
  return getRawEntitySnapshot(entityIdValue);
}

function readState(entityIdValue) {
  const raw = readRaw(entityIdValue);
  return raw?.state ?? null;
}

function parseNumber(value) {
  const next = Number(value);
  return Number.isFinite(next) ? next : null;
}

function isBinaryOn(value) {
  return String(value || '').toLowerCase() === 'on';
}

function hasEntity(entityIdValue) {
  return Boolean(readRaw(entityIdValue));
}

function isEntityAvailable(entityIdValue) {
  const raw = readRaw(entityIdValue);
  if (!raw) return false;
  const state = String(raw.state ?? '').trim().toLowerCase();
  if (!state) return false;
  return state !== 'unavailable';
}

function emitRawStateAlerts() {
  for (const { title, entityId: entityIdValue } of ALERT_ENTITIES) {
    const raw = readState(entityIdValue);
    const normalized = String(raw ?? '').trim().toLowerCase();

    // Missing and unavailable values commonly occur while Home Assistant or the
    // ESPHome device reconnects. Ignoring them preserves the last real baseline
    // and prevents connection churn from becoming misleading Neato activity.
    if (!normalized || normalized === 'unavailable' || normalized === 'unknown') continue;

    const rawMessage = String(raw);
    if (!alertBaselines.has(entityIdValue)) {
      // The first real value is startup state, not a transition caused while the
      // service was watching, so record it without creating an Alert Feed toast.
      alertBaselines.set(entityIdValue, rawMessage);
      continue;
    }
    if (alertBaselines.get(entityIdValue) === rawMessage) continue;

    alertBaselines.set(entityIdValue, rawMessage);
    // The title provides field context, while the message remains exactly the
    // new Home Assistant state with no friendly translation or previous value.
    sendAlert({ color: ALERT_COLOR, title, message: rawMessage });
  }
}

function requiredEntityIds() {
  return [
    ENTITY_IDS.buttons.start,
    ENTITY_IDS.buttons.resume,
    ENTITY_IDS.buttons.sendHome,
    ENTITY_IDS.buttons.locate,
    ENTITY_IDS.buttons.clearErrors,
    ENTITY_IDS.buttons.powerCycle,
    ENTITY_IDS.sensors.batteryPercent,
    ENTITY_IDS.sensors.batteryVoltage,
    ENTITY_IDS.binarySensors.chargingActive,
    ENTITY_IDS.binarySensors.extPowerPresent,
    ENTITY_IDS.textSensors.robotState,
    ENTITY_IDS.textSensors.uiState,
    ENTITY_IDS.textSensors.robotError,
    ENTITY_IDS.textSensors.robotAlert,
  ].filter(Boolean);
}

function buildState() {
  const configured = Boolean(device);
  const haConnected = isHomeAssistantConnected();
  const requiredIds = requiredEntityIds();
  const entitiesAvailable = requiredIds.length > 0 && requiredIds.every((id) => isEntityAvailable(id));
  const connected = Boolean(haConnected && entitiesAvailable);
  const enabled = Boolean(featureEnabled && homeAssistantEnabled && configured);

  const controls = {
    start: {
      entityId: ENTITY_IDS.buttons.start,
      available: hasEntity(ENTITY_IDS.buttons.start),
    },
    resume: {
      entityId: ENTITY_IDS.buttons.resume,
      available: hasEntity(ENTITY_IDS.buttons.resume),
    },
    sendHome: {
      entityId: ENTITY_IDS.buttons.sendHome,
      available: hasEntity(ENTITY_IDS.buttons.sendHome),
    },
    locate: {
      entityId: ENTITY_IDS.buttons.locate,
      available: hasEntity(ENTITY_IDS.buttons.locate),
    },
    clearErrors: {
      entityId: ENTITY_IDS.buttons.clearErrors,
      available: hasEntity(ENTITY_IDS.buttons.clearErrors),
    },
    powerCycle: {
      entityId: ENTITY_IDS.buttons.powerCycle,
      available: hasEntity(ENTITY_IDS.buttons.powerCycle),
    },
    navigationMode: {
      entityId: ENTITY_IDS.selects.navigationMode,
      available: isEntityAvailable(ENTITY_IDS.selects.navigationMode),
      value: readState(ENTITY_IDS.selects.navigationMode),
      // The browser receives the supported choices through the session contract
      // instead of duplicating BrainSlug-specific values in the presentation layer.
      options: NAVIGATION_MODES,
    },
  };

  const batteryPercentValue = parseNumber(readState(ENTITY_IDS.sensors.batteryPercent));
  const batteryPercent =
    batteryPercentValue == null ? null : Math.max(0, Math.min(100, Math.round(batteryPercentValue)));
  const batteryVoltage = parseNumber(readState(ENTITY_IDS.sensors.batteryVoltage));
  const robotState = readState(ENTITY_IDS.textSensors.robotState);
  const uiState = readState(ENTITY_IDS.textSensors.uiState);
  const robotError = readState(ENTITY_IDS.textSensors.robotError);
  const robotAlert = readState(ENTITY_IDS.textSensors.robotAlert);
  const chargingActive = isBinaryOn(readState(ENTITY_IDS.binarySensors.chargingActive));
  const extPowerPresent = isBinaryOn(readState(ENTITY_IDS.binarySensors.extPowerPresent));

  return {
    enabled,
    configured,
    connected,
    device,
    entityPrefix: device ? `${device}_` : '',
    controls,
    telemetry: {
      batteryPercent,
      batteryVoltage,
      chargingActive,
      extPowerPresent,
      robotState,
      uiState,
      robotError,
      robotAlert,
    },
    entities: ENTITY_IDS,
  };
}

let cachedState = buildState();

function emitUpdate() {
  const next = buildState();
  const changed = JSON.stringify(next) !== JSON.stringify(cachedState);
  cachedState = next;
  if (changed) {
    events.emit('update', next);
  }
}

if (featureEnabled) {
  /*
    Neato telemetry is derived from Home Assistant entities. Disabled installs
    should keep the exported API inert instead of tracking HA snapshots for a
    robot vacuum feature that does not exist on that server.
  */
  homeAssistantEvents.on('snapshot', () => {
    emitUpdate();
    emitRawStateAlerts();
  });

  homeAssistantEvents.on('status', () => {
    emitUpdate();
  });
}

function assertConfiguredAndConnected() {
  if (!featureEnabled) {
    throw new Error('Neato is disabled');
  }
  if (!device) {
    throw new Error('Neato not configured');
  }
  if (!homeAssistantEnabled) {
    throw new Error('Home Assistant not configured');
  }
  if (!isHomeAssistantConnected()) {
    throw new Error('Home Assistant not connected');
  }
}

async function pressButton(entityIdValue, actionLabel) {
  assertConfiguredAndConnected();
  if (!entityIdValue) {
    throw new Error(`Neato ${actionLabel} entity missing`);
  }
  if (!hasEntity(entityIdValue)) {
    throw new Error(`Neato action unavailable: ${actionLabel}`);
  }
  await callHomeAssistantService('button', 'press', { entity_id: entityIdValue });
  logger.info('Issued Neato action', { action: actionLabel, entityId: entityIdValue });
}

async function startCleaning() {
  await pressButton(ENTITY_IDS.buttons.start, 'start');
  await new Promise((resolve) => setTimeout(resolve, RESUME_DELAY_MS));
  await pressButton(ENTITY_IDS.buttons.resume, 'resume_cleaning');
}

async function sendHome() {
  await pressButton(ENTITY_IDS.buttons.sendHome, 'send_home');
}

async function locateRobot() {
  await pressButton(ENTITY_IDS.buttons.locate, 'locate');
}

async function clearErrors() {
  await pressButton(ENTITY_IDS.buttons.clearErrors, 'clear_errors');
}

async function powerCycle() {
  await pressButton(ENTITY_IDS.buttons.powerCycle, 'powercucle');
}

async function setNavigationMode(mode) {
  assertConfiguredAndConnected();
  const normalizedMode = String(mode || '').trim();
  if (!NAVIGATION_MODES.includes(normalizedMode)) {
    throw new Error('Invalid Neato navigation mode');
  }
  if (!isEntityAvailable(ENTITY_IDS.selects.navigationMode)) {
    throw new Error('Neato action unavailable: navigation_mode');
  }

  // ESPHome implements Navigation Mode as a Home Assistant select entity, so
  // select_option is the native service call and avoids sending raw UART commands.
  await callHomeAssistantService('select', 'select_option', {
    entity_id: ENTITY_IDS.selects.navigationMode,
    option: normalizedMode,
  });
  logger.info('Issued Neato action', {
    action: 'set_navigation_mode',
    entityId: ENTITY_IDS.selects.navigationMode,
    option: normalizedMode,
  });
}

function getState() {
  cachedState = buildState();
  return cachedState;
}

function hasVerifiedSockets() {
  for (const socket of io.sockets.sockets.values()) {
    if (isVerified(socket)) return true;
  }
  return false;
}

if (featureEnabled) {
  io.on('connection', (socket) => {
  function assertFeatureAccess() {
    const mode = getMode();
    // Neato shares the same public-activity policy as lift: everyone may use
    // it in open/turns modes, admin mode requires an admin, and lockdown
    // requires a lockdown admin. This service-level gate protects every socket
    // action even if a future client bypasses the current UI presentation.
    if (mode === MODES.ADMIN && !isAdmin(socket)) throw new Error('Admin mode: admins only');
    if (mode === MODES.LOCKDOWN && !isLockdownAdmin(socket)) throw new Error('Server in lockdown');
  }

  socket.on('neato:start', async (_, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await startCleaning();
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });

  socket.on('neato:sendHome', async (_, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await sendHome();
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });

  socket.on('neato:locate', async (_, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await locateRobot();
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });

  socket.on('neato:clearErrors', async (_, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await clearErrors();
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });

  socket.on('neato:powerCycle', async (_, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await powerCycle();
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });

  socket.on('neato:setNavigationMode', async ({ mode } = {}, cb = () => {}) => {
    try {
      assertFeatureAccess();
      await setNavigationMode(mode);
      cb({ success: true });
    } catch (err) {
      cb({ error: err.message });
    }
  });
  });
} else {
  logger.info('Neato disabled by config');
}

emitUpdate();

module.exports = {
  getState,
  startCleaning,
  sendHome,
  locateRobot,
  clearErrors,
  powerCycle,
  setNavigationMode,
  neatoEvents: events,
};