import type { OperationCategory } from '../types.js'
/**
 * Category inference for route contracts.
 * Pure functions, no side effects.
 * Optimized: direct string comparison over Set for hot path.
 */
// Fast path: direct string comparison for most common utility paths
const isUtilityPath = (path: string): boolean => {
  // Check exact matches first (fastest)
  if (
    path === '/reset' ||
    path === '/health' ||
    path === '/ping' ||
    path === '/login' ||
    path === '/logout' ||
    path === '/auth' ||
    path === '/callback' ||
    path === '/purge' ||
    path === '/clear' ||
    path === '/initialize' ||
    path === '/setup' ||
    path === '/webhook'
  ) {
    return true
  }
  // Check trailing slash variants
  const last = path.charCodeAt(path.length - 1)
  if (last === 47) {
    const base = path.slice(0, -1)
    return (
      base === '/reset' ||
      base === '/health' ||
      base === '/ping' ||
      base === '/login' ||
      base === '/logout' ||
      base === '/auth' ||
      base === '/callback' ||
      base === '/purge' ||
      base === '/clear' ||
      base === '/initialize' ||
      base === '/setup' ||
      base === '/webhook'
    )
  }
  return false
}
// Fast path: check last 7 chars for common suffixes
const isObserverSuffix = (path: string): boolean => {
  const len = path.length
  if (len >= 7) {
    const end = path.slice(-7)
    if (end === '/search') return true
  }
  if (len >= 6) {
    const end = path.slice(-6)
    if (end === '/count' || end === '/stats') return true
  }
  if (len >= 7) {
    const end = path.slice(-7)
    if (end === '/status') return true
  }
  return false
}
const isCollectionPath = (path: string): boolean => {
  const len = path.length
  let i = len - 1
  // Skip trailing slash
  while (i > 0 && path.charCodeAt(i) === 47) i--
  // Find last segment
  const lastSlash = path.lastIndexOf('/', i)
  const segment = path.slice(lastSlash + 1, i + 1)
  return segment.length > 0 && segment.charCodeAt(0) !== 58 // ':'.charCodeAt(0) === 58
}
const hasPathParam = (path: string): boolean => path.includes(':')
export const inferCategory = (
  path: string,
  method: string,
  override: string | undefined
): OperationCategory => {
  if (override !== undefined && override !== '') {
    return override as OperationCategory
  }
  if (isUtilityPath(path)) {
    return 'utility'
  }
  const upperMethod = method.toUpperCase()
  if (upperMethod === 'GET' || isObserverSuffix(path)) {
    return 'observer'
  }
  if (upperMethod === 'POST' && isCollectionPath(path)) {
    return 'constructor'
  }
  if (upperMethod === 'PUT' || upperMethod === 'PATCH' || upperMethod === 'DELETE' || (upperMethod === 'POST' && hasPathParam(path))) {
    return 'mutator'
  }
  return 'observer'
}