outlineview.swift

import Cocoa
import Foundation

class RecallOutlineView: NSOutlineView {
  required init?(coder: NSCoder) {
    super.init(coder: coder)
  }

  var isReceivingDrag = false {
    didSet {
      needsDisplay = true
    }
  }

  override func awakeFromNib() {
    registerForDraggedTypes([NSPasteboard.PasteboardType.fileURL])
    setDraggingSourceOperationMask(.copy, forLocal: false)

    let descriptorName = NSSortDescriptor(key: "name", ascending: true)
    let descriptorDate = NSSortDescriptor(key: "modificationDate", ascending: true)
    let descriptorSize = NSSortDescriptor(key: "size", ascending: true)

    self.tableColumns[0].sortDescriptorPrototype = descriptorName
    self.tableColumns[1].sortDescriptorPrototype = descriptorDate
    self.tableColumns[2].sortDescriptorPrototype = descriptorSize

    self.sortDescriptors.append(descriptorName)

    self.autosaveTableColumns = true
    self.autosaveExpandedItems = true

    self.wantsLayer = true
  }

  override func draw(_ dirtyRect: NSRect) {
    if self.isReceivingDrag {
      NSColor.selectedControlColor.set()

      let path = NSBezierPath(rect: bounds)
      path.lineWidth = 5
      path.stroke()
    }

    super.draw(dirtyRect)
  }

  override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
    self.isReceivingDrag = true
    return .move
  }

  override func draggingUpdated(_ sender: NSDraggingInfo) -> NSDragOperation {
    return .move
  }

  override func draggingExited(_ sender: NSDraggingInfo?) {
    self.isReceivingDrag = false
  }

  override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
    self.isReceivingDrag = false

    guard let pasteboard = sender.draggingPasteboard.propertyList(forType: NSPasteboard.PasteboardType(rawValue: "NSFilenamesPboardType")) as? NSArray,
      let path = pasteboard[0] as? String else { return false }

    if sender.draggingSource != nil {
      return true
    }

    NotificationCenter.default.post(name: Notification.Name("fileDroppedOnTable"), object: nil, userInfo: ["path": path])

    return true
  }
}