export type AppRuntimeConfig = {
  title: string;
  userModelId: string;
  userDataDirectoryName: string;
  iconPathOverride?: string;
  nodecgPort: string;
  bundleName: string;
  mainDashboardRoute: string;
  loadingDashboardRoute: string;
  loadDelayMs: number;
  startupTimeoutMs: number;
  nodecgKillTimeoutMs: number;
};

const MIN_TCP_PORT = 1;
const MAX_TCP_PORT = 65535;

export function getRuntimeConfig(): AppRuntimeConfig {
  // Centralized defaults keep local development and packaged builds consistent.
  return {
    title: getEnv("SCOREKO_APP_TITLE", "Scoreko"),
    userModelId: getEnv("SCOREKO_APP_USER_MODEL_ID", "com.scoreko.desktop"),
    userDataDirectoryName: getEnv("SCOREKO_APP_USER_DATA_DIRECTORY", "scoreko"),
    iconPathOverride: getOptionalEnv("SCOREKO_APP_ICON_PATH"),
    nodecgPort: parseEnvPort("NODECG_PORT", "9090"),
    bundleName: getEnv("NODECG_BUNDLE_NAME", "scoreko-dev"),
    mainDashboardRoute: getEnv("SCOREKO_DASHBOARD_ROUTE", "dashboard/scoreko-dev/main.html?standalone=true"),
    loadingDashboardRoute: getEnv("SCOREKO_LOADING_ROUTE", "dashboard/loading/main.html?standalone=true"),
    loadDelayMs: parseEnvIntInRange("ELECTRON_LOAD_DELAY_MS", 10000, 0, 600000),
    startupTimeoutMs: parseEnvIntInRange("NODECG_STARTUP_TIMEOUT_MS", 30000, 1000, 600000),
    nodecgKillTimeoutMs: parseEnvIntInRange("NODECG_KILL_TIMEOUT_MS", 2500, 0, 120000),
  };
}

export function getOptionalEnv(name: string): string | undefined {
  const value = process.env[name]?.trim();
  return value && value.length > 0 ? value : undefined;
}

export function getEnv(name: string, fallback: string): string {
  return getOptionalEnv(name) ?? fallback;
}

export function parseEnvInt(name: string, fallback: number): number {
  const rawValue = process.env[name];
  if (!rawValue) {
    return fallback;
  }

  const parsedValue = Number.parseInt(rawValue, 10);
  return Number.isFinite(parsedValue) ? parsedValue : fallback;
}

export function parseEnvIntInRange(name: string, fallback: number, min: number, max: number): number {
  // We throw here instead of silently coercing to avoid hidden misconfiguration in production.
  const rawValue = process.env[name];
  if (!rawValue) {
    return fallback;
  }

  const parsedValue = Number.parseInt(rawValue, 10);
  if (!Number.isFinite(parsedValue) || parsedValue < min || parsedValue > max) {
    throw new Error(`The ${name} variable must be an integer between ${min} and ${max}. Received value: '${rawValue}'.`);
  }

  return parsedValue;
}

export function parseEnvPort(name: string, fallback: string): string {
  const rawValue = getEnv(name, fallback);
  const parsedValue = Number.parseInt(rawValue, 10);

  if (!Number.isFinite(parsedValue) || parsedValue < MIN_TCP_PORT || parsedValue > MAX_TCP_PORT) {
    throw new Error(
      `The ${name} variable must be a valid TCP port (${MIN_TCP_PORT}-${MAX_TCP_PORT}). Received value: '${rawValue}'.`,
    );
  }

  return String(parsedValue);
}