import Cocoa
import SwiftUI

class MapTextEditorController: NSViewController {

  @Binding var text: String
  var colorScheme: ColorScheme

  private let vertexRegex = MapParsingPatterns.vertex
  private let edgeRegex = MapParsingPatterns.edge
  private let blockerRegex = MapParsingPatterns.blocker
  private let opportunityRegex = MapParsingPatterns.opportunity
  private let stageRegex = MapParsingPatterns.stage

  private let debouncer: Debouncer = Debouncer(seconds: 0.2)

  init(text: Binding<String>, colorScheme: ColorScheme) {
    self._text = text
    self.colorScheme = colorScheme
    super.init(nibName: nil, bundle: nil)
  }

  required init?(coder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }

  override func loadView() {
    let scrollView = NSTextView.scrollableTextView()
    let textView = scrollView.documentView as! NSTextView

    scrollView.translatesAutoresizingMaskIntoConstraints = false

    textView.allowsUndo = true
    textView.delegate = self
    textView.textStorage?.delegate = self
    textView.string = self.text
    textView.isEditable = true
    textView.font = .monospacedSystemFont(ofSize: 16.0, weight: .regular)
    self.view = scrollView
  }

  override func viewDidAppear() {
    self.view.window?.makeFirstResponder(self.view)
  }

  func updateColorScheme(_ colorScheme: ColorScheme) {
    self.colorScheme = colorScheme
  }
}

extension MapTextEditorController: NSTextViewDelegate {

  func textDidChange(_ obj: Notification) {
    if let textField = obj.object as? NSTextView {
      self.text = textField.string
    }
  }

  func textView(_ view: NSTextView, shouldChangeTextIn: NSRange, replacementString: String?) -> Bool
  {
    let range = Range(shouldChangeTextIn, in: view.string)
    let target = view.string[range!]

    if target == "--" {
      return false
    }

    return true
  }
}

extension MapTextEditorController: NSTextStorageDelegate {
  override func textStorageDidProcessEditing(_ obj: Notification) {
    if let textStorage = obj.object as? NSTextStorage {
      debouncer.debounce {
        DispatchQueue.main.async {
          self.colorizeText(textStorage: textStorage)
        }
      }
    }
  }

  private func colorizeText(textStorage: NSTextStorage) {
    let range = NSMakeRange(0, textStorage.length)
    var matches = vertexRegex.matches(in: textStorage.string, options: [], range: range)
    let colors = MapColor.colorForScheme(colorScheme)

    for match in matches {
      textStorage.addAttributes([.foregroundColor: colors.syntax.vertex], range: match.range(at: 1))
      textStorage.addAttributes([.foregroundColor: colors.syntax.number], range: match.range(at: 2))
      textStorage.addAttributes([.foregroundColor: colors.syntax.number], range: match.range(at: 3))
      textStorage.addAttributes([.foregroundColor: colors.syntax.option], range: match.range(at: 4))
    }

    matches = edgeRegex.matches(in: textStorage.string, options: [], range: range)

    for match in matches {
      textStorage.addAttributes([.foregroundColor: colors.syntax.vertex], range: match.range(at: 1))
      let arrowRange = match.range(at: 2)
      textStorage.addAttributes(
        [.foregroundColor: colors.syntax.symbol],
        range: NSMakeRange(arrowRange.lowerBound - 1, arrowRange.length + 1))
      textStorage.addAttributes([.foregroundColor: colors.syntax.vertex], range: match.range(at: 3))
    }

    matches = opportunityRegex.matches(in: textStorage.string, options: [], range: range)

    for match in matches {
      textStorage.addAttributes([.foregroundColor: colors.syntax.option], range: match.range(at: 1))
      textStorage.addAttributes([.foregroundColor: colors.syntax.vertex], range: match.range(at: 2))
      textStorage.addAttributes([.foregroundColor: colors.syntax.symbol], range: match.range(at: 3))
      textStorage.addAttributes([.foregroundColor: colors.syntax.number], range: match.range(at: 4))
    }

    matches = blockerRegex.matches(in: textStorage.string, options: [], range: range)

    for match in matches {
      textStorage.addAttributes([.foregroundColor: colors.syntax.option], range: match.range(at: 1))
      textStorage.addAttributes([.foregroundColor: colors.syntax.vertex], range: match.range(at: 2))
    }

    matches = stageRegex.matches(in: textStorage.string, options: [], range: range)

    for match in matches {
      textStorage.addAttributes([.foregroundColor: colors.syntax.option], range: match.range(at: 1))
      textStorage.addAttributes([.foregroundColor: colors.syntax.number], range: match.range(at: 2))
    }
  }
}

struct MapTextEditor: NSViewControllerRepresentable {

  @Binding var text: String
  let colorScheme: ColorScheme

  func makeNSViewController(
    context: NSViewControllerRepresentableContext<MapTextEditor>
  ) -> MapTextEditorController {
    return MapTextEditorController(text: $text, colorScheme: colorScheme)
  }

  func updateNSViewController(
    _ nsViewController: MapTextEditorController,
    context: NSViewControllerRepresentableContext<MapTextEditor>
  ) {
    nsViewController.updateColorScheme(context.environment.colorScheme)
  }
}