Find and Replace Refactor (#311)

### Description

@austincondiff has been building out the 'replace' functionality and
realized the way we had structured the panel, controller, target, and
model was extremely overcomplicating things. This PR is an attempt to
fix that

Changes:
- Moves all 'business logic' into the `FindPanelViewModel` observable
object. This includes clarified methods like `find`, `replace`, and
`moveToNextMatch/moveToPreviousMatch`. All state has been moved to this
object as well, out of a combination of both the SwiftUI view and the
find view controller.
- Removes the `FindPanelDelegate` type entirely. All that type was doing
was passing method calls from the find panel to it's controller. Since
all that logic is now in the shared view model, the controller & view
can just call the necessary methods on the model.
- Simplifies the `FindViewController` to only handle view/model setup
and layout.
- Changes the focus state variable to an enum instead of two `Bool`s.
This fixes an issue where there was a moment of nothing being focused
when switching between the find and replace text fields.
- Removes the unnecessary `NSHostingView -> NSView -> SwiftUI View`
structure, replacing it with an `NSHostingView` subclass
`FindPanelHostingView` that hosts a `FindPanelView`.
- Clarifies some view naming to reflect what each type does.
  - `FindPanel` -> `FindPanelHostingView`
  - `FindPanelView` search fields moved to:
    - `FindSearchField`
    - `ReplaceSearchField`

### Related Issues

* #295 

### Checklist

<!--- Add things that are not yet implemented above -->

- [x] I read and understood the [contributing
guide](https://github.com/CodeEditApp/CodeEdit/blob/main/CONTRIBUTING.md)
as well as the [code of
conduct](https://github.com/CodeEditApp/CodeEdit/blob/main/CODE_OF_CONDUCT.md)
- [x] The issues this PR addresses are related to each other
- [x] My changes generate no new warnings
- [x] My code builds and runs on my machine
- [x] My changes are all related to the related issue above
- [x] I documented my code

### Screenshots

<!--- REQUIRED: if issue is UI related -->

<!--- IMPORTANT: Fill out all required fields. Otherwise we might close
this PR temporarily -->

Author: thecoolwinter

Sources/CodeEditSourceEditor/Controller/TextViewController+Cursor.swift

@@ -11,7 +11,7 @@ import AppKit
 extension TextViewController {
     /// Sets new cursor positions.
     /// - Parameter positions: The positions to set. Lines and columns are 1-indexed.
-    public func setCursorPositions(_ positions: [CursorPosition]) {
+    public func setCursorPositions(_ positions: [CursorPosition], scrollToVisible: Bool = false) {
         if isPostingCursorNotification { return }
         var newSelectedRanges: [NSRange] = []
         for position in positions {
@@ -33,6 +33,10 @@ extension TextViewController {
             }
         }
         textView.selectionManager.setSelectedRanges(newSelectedRanges)
+
+        if scrollToVisible {
+            textView.scrollSelectionToVisible()
+        }
     }
 
     /// Update the ``TextViewController/cursorPositions`` variable with new text selections from the text view.

Sources/CodeEditSourceEditor/Controller/TextViewController+FindPanelTarget.swift

@@ -5,10 +5,14 @@
 //  Created by Khan Winter on 3/16/25.
 //
 
-import Foundation
+import AppKit
 import CodeEditTextView
 
 extension TextViewController: FindPanelTarget {
+    var findPanelTargetView: NSView {
+        textView
+    }
+
     func findPanelWillShow(panelHeight: CGFloat) {
         updateContentInsets()
     }
@@ -17,9 +21,8 @@ extension TextViewController: FindPanelTarget {
         updateContentInsets()
     }
 
-    func findPanelModeDidChange(to mode: FindPanelMode, panelHeight: CGFloat) {
-        scrollView.contentInsets.top += mode == .replace ? panelHeight/2 : -panelHeight
-        gutterView.frame.origin.y = -scrollView.contentInsets.top
+    func findPanelModeDidChange(to mode: FindPanelMode) {
+        updateContentInsets()
     }
 
     var emphasisManager: EmphasisManager? {

Sources/CodeEditSourceEditor/Controller/TextViewController+LoadView.swift

@@ -220,7 +220,7 @@ extension TextViewController {
             self.findViewController?.showFindPanel()
             return nil
         case (0, "\u{1b}"): // Escape key
-            self.findViewController?.findPanel.dismiss()
+            self.findViewController?.hideFindPanel()
             return nil
         case (_, _):
             return event

Sources/CodeEditSourceEditor/Controller/TextViewController+StyleViews.swift

@@ -96,7 +96,11 @@ extension TextViewController {
         minimapView.scrollView.contentInsets.bottom += additionalTextInsets?.bottom ?? 0
 
         // Inset the top by the find panel height
-        let findInset = (findViewController?.isShowingFindPanel ?? false) ? findViewController?.panelHeight ?? 0 : 0
+        let findInset: CGFloat = if findViewController?.viewModel.isShowingFindPanel ?? false {
+            findViewController?.viewModel.panelHeight ?? 0
+        } else {
+            0
+        }
         scrollView.contentInsets.top += findInset
         minimapView.scrollView.contentInsets.top += findInset
 

Sources/CodeEditSourceEditor/Find/FindPanelDelegate.swift

@@ -0,0 +1,20 @@
+//
+//  FindPanelMode.swift
+//  CodeEditSourceEditor
+//
+//  Created by Khan Winter on 4/18/25.
+//
+
+enum FindPanelMode: CaseIterable {
+    case find
+    case replace
+
+    var displayName: String {
+        switch self {
+        case .find:
+            return "Find"
+        case .replace:
+            return "Replace"
+        }
+    }
+}

Sources/CodeEditSourceEditor/Find/FindPanelMode.swift

@@ -5,18 +5,19 @@
 //  Created by Khan Winter on 3/10/25.
 //
 
-import Foundation
+import AppKit
 import CodeEditTextView
 
 protocol FindPanelTarget: AnyObject {
     var emphasisManager: EmphasisManager? { get }
     var text: String { get }
+    var findPanelTargetView: NSView { get }
 
     var cursorPositions: [CursorPosition] { get }
-    func setCursorPositions(_ positions: [CursorPosition])
+    func setCursorPositions(_ positions: [CursorPosition], scrollToVisible: Bool)
     func updateCursorPosition()
 
     func findPanelWillShow(panelHeight: CGFloat)
     func findPanelWillHide(panelHeight: CGFloat)
-    func findPanelModeDidChange(to mode: FindPanelMode, panelHeight: CGFloat)
+    func findPanelModeDidChange(to mode: FindPanelMode)
 }