import type { UserFile } from '@/executor/types'

export type UserFileLike = Pick<UserFile, 'id' | 'name' | 'url' | 'key'> &
  Partial<Pick<UserFile, 'size' | 'type' | 'context' | 'base64'>>

/**
 * Fields exposed for UserFile objects in UI (tag dropdown) and logs.
 * Internal fields like 'key' and 'context' are not exposed.
 */
export const USER_FILE_DISPLAY_FIELDS = ['id', 'name', 'url', 'size', 'type', 'base64'] as const

export type UserFileDisplayField = (typeof USER_FILE_DISPLAY_FIELDS)[number]

/**
 * Checks if a value matches the minimal UserFile shape.
 */
export function isUserFile(value: unknown): value is UserFileLike {
  if (!value || typeof value !== 'object') {
    return false
  }

  const candidate = value as Record<string, unknown>

  return (
    typeof candidate.id === 'string' &&
    typeof candidate.key === 'string' &&
    typeof candidate.url === 'string' &&
    typeof candidate.name === 'string'
  )
}

/**
 * Checks if a value matches the full UserFile metadata shape.
 */
export function isUserFileWithMetadata(value: unknown): value is UserFile {
  if (!isUserFile(value)) {
    return false
  }

  const candidate = value as Record<string, unknown>

  return typeof candidate.size === 'number' && typeof candidate.type === 'string'
}

/**
 * Finds storage keys for UserFile objects embedded in a value.
 */
export function collectUserFileKeys(value: unknown): string[] {
  const keys = new Set<string>()
  collectUserFileKeysInto(value, keys, new WeakSet<object>())
  return Array.from(keys)
}

function collectUserFileKeysInto(value: unknown, keys: Set<string>, seen: WeakSet<object>): void {
  if (!value || typeof value !== 'object') {
    return
  }

  if (seen.has(value)) {
    return
  }
  seen.add(value)

  if (isUserFileWithMetadata(value)) {
    keys.add(value.key)
    return
  }

  if (Array.isArray(value)) {
    for (const item of value) {
      collectUserFileKeysInto(item, keys, seen)
    }
    return
  }

  for (const item of Object.values(value)) {
    collectUserFileKeysInto(item, keys, seen)
  }
}

/**
 * Checks if a value matches the display-safe UserFile metadata shape after internal fields are stripped.
 */
export function isUserFileDisplayMetadata(value: unknown): value is Record<string, unknown> {
  if (!value || typeof value !== 'object' || Array.isArray(value)) {
    return false
  }

  const candidate = value as Record<string, unknown>
  const url = typeof candidate.url === 'string' ? candidate.url : ''

  return (
    typeof candidate.id === 'string' &&
    typeof candidate.name === 'string' &&
    url.length > 0 &&
    typeof candidate.size === 'number' &&
    typeof candidate.type === 'string' &&
    (candidate.id.startsWith('file_') || url.includes('/api/files/serve/'))
  )
}

/**
 * Filters a UserFile object to only include display fields.
 * Used for both UI display and log sanitization.
 */
export function filterUserFileForDisplay(data: Record<string, unknown>): Record<string, unknown> {
  const filtered: Record<string, unknown> = {}
  for (const field of USER_FILE_DISPLAY_FIELDS) {
    if (field in data) {
      filtered[field] = data[field]
    }
  }
  return filtered
}

/**
 * Extracts base64 content from either a raw base64 string or a UserFile object.
 * Useful for tools that accept file input in either format.
 * @returns The base64 string, or undefined if not found
 */
export function extractBase64FromFileInput(
  input: string | UserFileLike | null | undefined
): string | undefined {
  if (typeof input === 'string') {
    return input
  }
  if (input?.base64) {
    return input.base64
  }
  return undefined
}