/**
 * Debug logging is enabled when:
 * - dev build (`import.meta.env.DEV`)
 * - env flag `VITE_ENABLE_DEBUG_LOGS` is truthy (1/true/yes)
 * - page sets `window.__VERGE_ENABLE_DEBUG_LOGS__ = true`
 * - localStorage item `VERGE_DEBUG_LOGS` is truthy (1/true/yes)
 */
let cachedDebugEnabled: boolean | undefined

const parseStringFlag = (value: unknown) => {
  const normalized = String(value ?? '')
    .trim()
    .toLowerCase()
  if (!normalized) return false
  return normalized === '1' || normalized === 'true' || normalized === 'yes'
}

const readGlobalFlag = (): boolean | null => {
  if (typeof window === 'undefined') return null
  const flag = (window as any).__VERGE_ENABLE_DEBUG_LOGS__
  return typeof flag === 'boolean' ? flag : null
}

const readStoredFlag = (): boolean | null => {
  if (typeof window === 'undefined') return null
  try {
    const stored = window.localStorage?.getItem('VERGE_DEBUG_LOGS')
    return stored ? parseStringFlag(stored) : null
  } catch {
    return null
  }
}

const computeDebugEnabled = (): boolean => {
  if (import.meta.env.DEV) return true
  if (parseStringFlag(import.meta.env.VITE_ENABLE_DEBUG_LOGS)) return true

  const globalFlag = readGlobalFlag()
  if (globalFlag !== null) return globalFlag

  const storedFlag = readStoredFlag()
  if (storedFlag !== null) return storedFlag

  return false
}

const isDebugLoggingEnabled = () =>
  cachedDebugEnabled ?? (cachedDebugEnabled = computeDebugEnabled())

/**
 * Logs to the console only when debug logging is enabled.
 * Forwards all arguments to `console.log`; does nothing otherwise.
 */
export const debugLog = (...args: any[]) => {
  if (!isDebugLoggingEnabled()) return
  console.log(...args)
}
