import dotenv from "dotenv";

dotenv.config();

/** Configuration derived from .env and app constants. */
function parseNum(envVar: string, defaultVal: number): number {
  const val = Number(process.env[envVar] ?? defaultVal);
  if (!Number.isFinite(val)) {
    throw new Error(`Invalid value for ${envVar}: "${process.env[envVar]}" is not a number`);
  }
  return val;
}

export const config = {
  openai: {
    apiKey: process.env.OPENAI_API_KEY,
  },
  porcupine: {
    accessKey: process.env.PORCUPINE_ACCESS_KEY,
    keywordPath: process.env.PORCUPINE_KEYWORD_PATH,
    builtinKeyword: (process.env.PORCUPINE_BUILTIN_KEYWORD ?? "jarvis").toLowerCase(),
    sensitivity: parseNum("PORCUPINE_SENSITIVITY", 0.65),
  },
  gate: {
    /** How many ms after wake word to stream mic audio into the API. */
    windowMs: parseNum("WAKE_WINDOW_MS", 8000),
    /** Close gate if there is silence longer than this (ms). */
    silenceMs: parseNum("GATE_SILENCE_MS", 1200),
    /** RMS threshold for "speech present" (local VAD). */
    minRms: parseNum("MIN_RMS", 200),
    /** Debounce: ignore repeated wake words for this many ms. */
    debounceMs: parseNum("WAKE_DEBOUNCE_MS", 1500),
  },
  beep: {
    durationMs: parseNum("BEEP_DURATION_MS", 150),
    freqHz: parseNum("BEEP_FREQ", 880),
  },
  audio: {
    /** Output sample rate (assistant replies) — 24 kHz for OpenAI. */
    outputSampleRate: 24000,
    /** Input sample rate (mic, Porcupine). */
    inputSampleRate: 16000,
    channels: 1,
  },
  /** Input device on Linux (arecord -D) / macOS (AUDIODEV). */
  audioDevice: process.env.AUDIO_DEVICE,
  /** Output device on Linux: pw-play target — see pw-play --list-targets. */
  audioOutputDevice: process.env.AUDIO_OUTPUT_DEVICE,
} as const;

export function requireEnv(name: string, value: string | undefined): string {
  if (!value?.trim()) {
    throw new Error(`Set ${name} in .env`);
  }
  return value;
}