Function useFileViewer

packages/session-ui/src/components/file.tsx:159–370

(config: ViewerConfig)

}

function useFileViewer(config: ViewerConfig) {
  let wrapper!: HTMLDivElement
  let container!: HTMLDivElement
  let overlay!: HTMLDivElement
  let selectionFrame: number | undefined
  let dragFrame: number | undefined
  let dragStart: number | undefined
  let dragEnd: number | undefined
  let dragMoved = false
  let lastSelection: SelectedLineRange | null = null
  let pendingSelectionEnd = false

  const ready = createReadyWatcher()
  const bridge = createLineNumberSelectionBridge()
  const [rendered, setRendered] = createSignal(0)

  const getRoot = () => getViewerRoot(container)
  const getHost = () => getViewerHost(container)

  const find = createFileFind({
    wrapper: () => wrapper,
    overlay: () => overlay,
    getRoot,
  })

  // -- selection scheduling --

  const scheduleSelectionUpdate = () => {
    if (selectionFrame !== undefined) return
    selectionFrame = requestAnimationFrame(() => {
      selectionFrame = undefined
      const finishing = pendingSelectionEnd
      config.updateSelection(finishing)
      if (!pendingSelectionEnd) return
      pendingSelectionEnd = false
      config.onLineSelectionEnd(lastSelection)
    })
  }

  const scheduleDragUpdate = () => {
    if (dragFrame !== undefined) return
    dragFrame = requestAnimationFrame(() => {
      dragFrame = undefined
      const selected = config.buildDragSelection()
      if (selected) config.setSelectedLines(selected)
    })
  }

  // -- mouse handlers --

  const handleMouseDown = (event: MouseEvent) => {
    if (!config.enableLineSelection()) return
    if (event.button !== 0) return

    const hit = config.lineFromMouseEvent(event)
    if (hit.numberColumn) {
      bridge.begin(true, hit.line)
      return