import { useCallback, useState } from 'react'

/**
 * Optional click handler used by every viewer-backed attachment.
 *
 * Return `false` to cancel the default open behavior — useful for
 * route-based viewers or confirmation modals. Any other return value
 * (including `void`/`undefined`) lets the built-in viewer open as
 * normal. The `index` argument identifies the row in stacked
 * attachments and is `0` for the single-attachment shape.
 */
export type ViewerClickHandler = (index: number) => boolean | void

export interface UseViewerResult {
  viewerOpen: boolean
  viewerIndex: number
  /**
   * Open the viewer at the given index. Forwards to the caller's
   * `onClick` first so analytics + intercept logic can fire before
   * the viewer mounts; if `onClick` returns `false` the open is
   * skipped entirely.
   */
  handleActivate: (index: number) => void
  closeViewer: () => void
}

/**
 * Tiny piece of state shared by every `MessageAttachment` that opens
 * a fullscreen viewer (`Image`, `Video`, `Pdf`). Tracks the open flag
 * + the active index, and threads the caller's `onClick` callback
 * through `handleActivate` so consumers can intercept the open
 * (e.g. analytics) or cancel it (return `false` to swap in a
 * route-based viewer / confirmation modal).
 */
export const useViewer = (onClick?: ViewerClickHandler): UseViewerResult => {
  const [viewerOpen, setViewerOpen] = useState(false)
  const [viewerIndex, setViewerIndex] = useState(0)

  const handleActivate = useCallback(
    (index: number) => {
      if (onClick?.(index) === false) return
      setViewerIndex(index)
      setViewerOpen(true)
    },
    [onClick]
  )

  const closeViewer = useCallback(() => setViewerOpen(false), [])

  return { viewerOpen, viewerIndex, handleActivate, closeViewer }
}