import { useApolloClient, useSubscription } from '@vue/apollo-composable'
import { graphql } from '~/lib/common/generated/gql'
import { WorkspaceProjectsUpdatedMessageType } from '~/lib/common/generated/gql/graphql'
import { getCacheId, modifyObjectField } from '~/lib/common/helpers/graphql'
import { ToastNotificationType, useGlobalToast } from '~/lib/common/composables/toast'
import { projectRoute } from '~/lib/common/helpers/route'
import { useLock } from '~/lib/common/composables/singleton'

export function useWorkspaceProjectsUpdatedTracking(
  workspaceSlug: ComputedRef<string>
) {
  const apollo = useApolloClient().client
  const { triggerNotification } = useGlobalToast()
  const { hasLock } = useLock(
    computed(() => `useWorkspaceProjectsUpdatedTracking-${workspaceSlug.value}`)
  )
  const isEnabled = computed(() => hasLock.value)

  const { onResult: onWorkspaceProjectsUpdate } = useSubscription(
    graphql(`
      subscription OnWorkspaceProjectsUpdate($slug: String!) {
        workspaceProjectsUpdated(workspaceId: null, workspaceSlug: $slug) {
          projectId
          workspaceId
          type
          project {
            ...ProjectDashboardItem
          }
        }
      }
    `),
    () => ({ slug: workspaceSlug.value }),
    { enabled: isEnabled }
  )

  onWorkspaceProjectsUpdate((res) => {
    if (!hasLock.value) return
    const event = res.data?.workspaceProjectsUpdated
    if (!event) return

    const cache = apollo.cache
    const isNewProject = event.type === WorkspaceProjectsUpdatedMessageType.Added
    const incomingProject = event.project
    const workspaceId = event.workspaceId
    const projectId = event.projectId

    if (isNewProject && incomingProject) {
      // Add to workspace.projects
      modifyObjectField(
        cache,
        getCacheId('Workspace', workspaceId),
        'projects',
        ({ helpers: { ref, createUpdatedValue } }) =>
          createUpdatedValue(({ update }) => {
            update('items', (items) => [
              ref('Project', incomingProject.id),
              ...(items || [])
            ])
            update('totalCount', (count) => count + 1)
          }),
        { autoEvictFiltered: true }
      )
    } else if (!isNewProject) {
      // Being removed, remove from workspace.projects specifically
      // (the project may still exist, but in a different workspace)
      modifyObjectField(
        cache,
        getCacheId('Workspace', workspaceId),
        'projects',
        ({ helpers: { createUpdatedValue, readField } }) =>
          createUpdatedValue(({ update }) => {
            update('items', (items) =>
              items.filter((item) => readField(item, 'id') !== projectId)
            )
            update('totalCount', (count) => count - 1)
          }),
        { autoEvictFiltered: true }
      )
    }

    // Emit toast notification
    triggerNotification({
      type: ToastNotificationType.Info,
      title: isNewProject ? 'New project added' : 'A project has been removed',
      cta:
        isNewProject && incomingProject
          ? {
              url: projectRoute(incomingProject.id),
              title: 'View project'
            }
          : undefined
    })
  })
}