import { resolve } from 'node:path';
import { config } from 'dotenv';

/**
 * Robot operating modes:
 * - 'physical': Production on Pi with I2S audio
 * - 'dev':      Test on Pi with USB audio (e.g., USB headset)
 * - 'simulator': PC dev, no real audio (future: mock services)
 */
export type RobotMode = 'physical' | 'dev' | 'simulator';

/**
 * How conversations are triggered:
 * - 'wakeword': OpenWakeWord listens for "Hey Ti-Pote" (requires Python + openwakeword)
 * - 'keyboard': Press Enter in the terminal to start a conversation
 */
export type TriggerMode = 'wakeword' | 'keyboard';

export interface RobotConfig {
  /** Operating mode */
  mode: RobotMode;

  /** How conversations are triggered */
  triggerMode: TriggerMode;

  /** Unique device identifier (generated at first setup or from env) */
  deviceId: string;

  /** JWT device token for cloud authentication */
  deviceToken: string;

  /** Cloud backend WebSocket URL */
  cloudUrl: string;

  /** Robot display name */
  robotName: string;

  /** Log level */
  logLevel: string;
}

export function loadRobotConfig(): RobotConfig {
  // Load the right .env file based on ROBOT_MODE or --env flag
  const envFile = process.env.ENV_FILE || (process.env.ROBOT_MODE === 'dev' ? '.env.dev' : '.env');
  config({ path: resolve(process.cwd(), envFile) });

  const mode = (process.env.ROBOT_MODE || 'dev') as RobotMode;

  if (!['physical', 'dev', 'simulator'].includes(mode)) {
    throw new Error(`Invalid ROBOT_MODE: ${mode}. Must be 'physical', 'dev', or 'simulator'.`);
  }

  const triggerMode = (process.env.TRIGGER_MODE || 'wakeword') as TriggerMode;
  if (!['wakeword', 'keyboard'].includes(triggerMode)) {
    throw new Error(`Invalid TRIGGER_MODE: ${triggerMode}. Must be 'wakeword' or 'keyboard'.`);
  }

  return {
    mode,
    triggerMode,
    deviceId: requireEnv('DEVICE_ID'),
    deviceToken: requireEnv('DEVICE_TOKEN'),
    cloudUrl: process.env.CLOUD_URL || 'ws://localhost:3000',
    robotName: process.env.ROBOT_NAME || 'Ti-Pote',
    logLevel: process.env.LOG_LEVEL || 'info',
  };
}

function requireEnv(key: string): string {
  const value = process.env[key];
  if (!value) {
    throw new Error(`Missing required environment variable: ${key}`);
  }
  return value;
}