Initial extraction from Norganize

1 files changed, 255 insertions, 0 deletions

diff --git a/Sources/NorgEditor/NorgEditor.swift b/Sources/NorgEditor/NorgEditor.swift
new file mode 100644
index 0000000..d026daa
--- /dev/null
+++ b/Sources/NorgEditor/NorgEditor.swift
@@ -0,0 +1,255 @@
+#if canImport(UIKit) || canImport(AppKit)
+  import SwiftUI
+
+  /// A SwiftUI source editor for `.norg` documents with syntax highlighting
+  /// and context-aware indentation.
+  ///
+  /// ```swift
+  /// NorgEditor(text: $draft)
+  ///     .norgEditorTheme(myTheme)
+  /// ```
+  public struct NorgEditor {
+
+    @Binding private var text: String
+    @Environment(\.norgEditorTheme) private var theme
+
+    public init(text: Binding<String>) {
+      self._text = text
+    }
+  }
+#endif
+
+#if canImport(UIKit)
+  import UIKit
+  import NorgKeyboardToolbar
+
+  extension NorgEditor: UIViewRepresentable {
+
+    public func makeUIView(context: Context) -> UITextView {
+      let textView = UITextView()
+      textView.delegate = context.coordinator
+      textView.backgroundColor = .clear
+      textView.textContainerInset = UIEdgeInsets(top: 8, left: 0, bottom: 8, right: 0)
+      textView.textContainer.lineFragmentPadding = 0
+      textView.alwaysBounceVertical = true
+      textView.contentInsetAdjustmentBehavior = .never
+
+      textView.installNorgKeyboardAccessory()
+
+      textView.smartQuotesType = .yes
+      textView.smartDashesType = .no
+      textView.smartInsertDeleteType = .no
+      textView.dataDetectorTypes = []
+      textView.autocorrectionType = .default
+      textView.spellCheckingType = .default
+      textView.autocapitalizationType = .sentences
+
+      #if os(iOS)
+        context.coordinator.observeKeyboard(for: textView)
+      #endif
+      textView.text = text
+      context.coordinator.apply(theme, to: textView)
+      return textView
+    }
+
+    public func updateUIView(_ textView: UITextView, context: Context) {
+      context.coordinator.parent = self
+
+      if textView.text != text {
+        textView.text = text
+        context.coordinator.highlight(textView)
+      }
+    }
+
+    public func makeCoordinator() -> Coordinator { Coordinator(self) }
+
+    public final class Coordinator: NSObject, UITextViewDelegate {
+      fileprivate var parent: NorgEditor
+      private var theme: EditorTheme = .default
+      private var isAutoIndenting = false
+
+      init(_ parent: NorgEditor) { self.parent = parent }
+
+      deinit { NotificationCenter.default.removeObserver(self) }
+
+      // MARK: - Auto-indentation
+
+      public func textView(
+        _ textView: UITextView,
+        shouldChangeTextIn range: NSRange,
+        replacementText text: String
+      ) -> Bool {
+        guard !isAutoIndenting, text == "\n" else { return true }
+
+        let indent = NorgAutoIndent.indentation(
+          for: textView.text, newlineAt: range.location)
+        guard !indent.isEmpty else { return true }
+
+        guard
+          let start = textView.position(
+            from: textView.beginningOfDocument, offset: range.location),
+          let end = textView.position(from: start, offset: range.length),
+          let textRange = textView.textRange(from: start, to: end)
+        else { return true }
+
+        isAutoIndenting = true
+        textView.replace(textRange, withText: "\n" + indent)
+        isAutoIndenting = false
+        return false
+      }
+
+      // MARK: - Highlighting
+
+      func apply(_ theme: EditorTheme, to textView: UITextView) {
+        self.theme = theme
+        textView.font = theme.font
+        textView.typingAttributes = [
+          .font: theme.font,
+          .foregroundColor: theme.textColor,
+        ]
+        highlight(textView)
+      }
+
+      func highlight(_ textView: UITextView) {
+        guard textView.markedTextRange == nil else { return }
+        let storage = textView.textStorage
+        let selection = textView.selectedRange
+        storage.beginEditing()
+        theme.applyHighlighting(to: storage)
+        storage.endEditing()
+        textView.selectedRange = selection
+      }
+
+      public func textViewDidChange(_ textView: UITextView) {
+        parent.text = textView.text
+        highlight(textView)
+      }
+
+      // MARK: - Keyboard avoidance
+
+      #if os(iOS)
+        private weak var textView: UITextView?
+
+        func observeKeyboard(for textView: UITextView) {
+          self.textView = textView
+          NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(keyboardFrameChanged(_:)),
+            name: UIResponder.keyboardWillChangeFrameNotification,
+            object: nil
+          )
+        }
+
+        @objc private func keyboardFrameChanged(_ note: Notification) {
+          guard let textView, let window = textView.window,
+            let endFrame = note.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect
+          else { return }
+
+          let keyboardInWindow = window.convert(endFrame, from: window.screen.fixedCoordinateSpace)
+          let textViewInWindow = textView.convert(textView.bounds, to: window)
+          let overlap = max(0, textViewInWindow.maxY - keyboardInWindow.minY)
+
+          textView.contentInset.bottom = overlap
+          textView.verticalScrollIndicatorInsets.bottom = overlap
+        }
+      #endif
+    }
+  }
+#elseif canImport(AppKit)
+  import AppKit
+
+  extension NorgEditor: NSViewRepresentable {
+
+    public func makeNSView(context: Context) -> NSScrollView {
+      let scrollView = NSTextView.scrollableTextView()
+      scrollView.drawsBackground = false
+      guard let textView = scrollView.documentView as? NSTextView else { return scrollView }
+
+      textView.delegate = context.coordinator
+      textView.drawsBackground = false
+      textView.isRichText = false
+      textView.allowsUndo = true
+      textView.textContainerInset = NSSize(width: 0, height: 8)
+      textView.textContainer?.lineFragmentPadding = 0
+
+      textView.isAutomaticQuoteSubstitutionEnabled = true
+      textView.isAutomaticDashSubstitutionEnabled = false
+      textView.isAutomaticTextReplacementEnabled = false
+      textView.isAutomaticLinkDetectionEnabled = false
+
+      textView.string = text
+      context.coordinator.apply(theme, to: textView)
+      return scrollView
+    }
+
+    public func updateNSView(_ scrollView: NSScrollView, context: Context) {
+      context.coordinator.parent = self
+      guard let textView = scrollView.documentView as? NSTextView else { return }
+
+      if textView.string != text {
+        textView.string = text
+        context.coordinator.highlight(textView)
+      }
+    }
+
+    public func makeCoordinator() -> Coordinator { Coordinator(self) }
+
+    // AppKit's `NSTextViewDelegate` isn't `@MainActor`-annotated (UIKit's is),
+    // so isolation isn't inferred for these callbacks even though the text view
+    // only ever calls them on the main thread; state the isolation explicitly.
+    @MainActor
+    public final class Coordinator: NSObject, NSTextViewDelegate {
+      fileprivate var parent: NorgEditor
+      private var theme: EditorTheme = .default
+      private var isAutoIndenting = false
+
+      init(_ parent: NorgEditor) { self.parent = parent }
+
+      // MARK: - Auto-indentation
+
+      public func textView(
+        _ textView: NSTextView,
+        shouldChangeTextIn affectedCharRange: NSRange,
+        replacementString: String?
+      ) -> Bool {
+        guard !isAutoIndenting, replacementString == "\n" else { return true }
+
+        let indent = NorgAutoIndent.indentation(
+          for: textView.string, newlineAt: affectedCharRange.location)
+        guard !indent.isEmpty else { return true }
+
+        isAutoIndenting = true
+        textView.insertText("\n" + indent, replacementRange: affectedCharRange)
+        isAutoIndenting = false
+        return false
+      }
+
+      // MARK: - Highlighting
+
+      func apply(_ theme: EditorTheme, to textView: NSTextView) {
+        self.theme = theme
+        textView.font = theme.font
+        textView.typingAttributes = [
+          .font: theme.font,
+          .foregroundColor: theme.textColor,
+        ]
+        highlight(textView)
+      }
+
+      func highlight(_ textView: NSTextView) {
+        guard !textView.hasMarkedText(), let storage = textView.textStorage else { return }
+        let selection = textView.selectedRange()
+        storage.beginEditing()
+        theme.applyHighlighting(to: storage)
+        storage.endEditing()
+        textView.setSelectedRange(selection)
+      }
+
+      public func textDidChange(_ notification: Notification) {
+        guard let textView = notification.object as? NSTextView else { return }
+        parent.text = textView.string
+        highlight(textView)
+      }
+    }
+  }
+#endif