import { useSuspenseQuery } from '@tanstack/react-query'
import { ApiResource } from '../types'
import type { ChatConfigurationResource } from '../types/resources/chat_configuration_resource'
import {
  getChatConfigurationRequestArgs,
  getChatConfigurationQueryKey,
} from '../utils/request/get_chat_configuration'
import { ONE_HOUR } from '../utils/time'
import {
  FALLBACK_ALLOWED_FILE_EXTENSIONS,
  FALLBACK_ALLOWED_MIME_TYPES,
  FALLBACK_MAX_ATTACHMENTS_PER_MESSAGE,
  FALLBACK_MAX_FILE_SIZE_IN_BYTES,
} from './attachments/fallback_chat_configuration'
import { useApiClient } from './use_api_client'

// Client-side mirror of ChatConfiguration (server is source of truth).
// Returns fallback values if the API request fails so that the attachment
// UX keeps working during transient server issues. The server still
// enforces its own limits — this hook only drives pre-upload UX.
export function useChatConfiguration() {
  const apiClient = useApiClient()
  const requestArgs = getChatConfigurationRequestArgs()

  const { data } = useSuspenseQuery({
    queryKey: getChatConfigurationQueryKey(),
    queryFn: () => {
      return apiClient.chat
        .get<ApiResource<ChatConfigurationResource>>(requestArgs)
        .catch(() => stableFallbackConfiguration)
    },
    staleTime: ONE_HOUR,
  })

  const attrs = data.data

  return {
    allowedFileExtensions: attrs.allowedFileExtensions,
    // During the server-side rollout the API may omit allowedMimeTypes.
    // The static fallback covers the same set of file kinds as the server's
    // hardcoded ALLOWED_FILE_EXTENSIONS, so the picker filter and the
    // post-pick extension validator agree. Once the server always returns
    // allowedMimeTypes, the resource type can tighten from optional to
    // required and this nullish-coalesce becomes pure defense-in-depth.
    allowedMimeTypes: attrs.allowedMimeTypes ?? FALLBACK_ALLOWED_MIME_TYPES,
    maxFileSizeInBytes: attrs.maxFileSizeInBytes,
    maxAttachmentsPerMessage: attrs.maxAttachmentsPerMessage,
  }
}

// Shape matches what consumers see after transform_response flattens
// attributes and camelCases keys.
const stableFallbackConfiguration: ApiResource<ChatConfigurationResource> = {
  data: {
    type: 'ChatConfiguration',
    id: 'current',
    allowedFileExtensions: FALLBACK_ALLOWED_FILE_EXTENSIONS,
    allowedMimeTypes: FALLBACK_ALLOWED_MIME_TYPES,
    maxFileSizeInBytes: FALLBACK_MAX_FILE_SIZE_IN_BYTES,
    maxAttachmentsPerMessage: FALLBACK_MAX_ATTACHMENTS_PER_MESSAGE,
  },
  links: {},
  meta: {},
}