Add issue comment editing

TESTING.md

@@ -174,6 +174,16 @@ xcrun simctl launch booted de.rfc1437.gotcha
       appears beside the title and VoiceOver announces the state; author
       metadata, Markdown body, and comments remain correct. Links and
       selectable text use normal iOS interaction.
+- [ ] Tap the **Add comment** icon on an issue. Enter headings, emphasis, a
+      list, link, and fenced code block; **Write** syntax-highlights the
+      Markdown, **Preview** renders it, and switching modes preserves the exact
+      source. Save and verify the rendered comment appears after the detail
+      refresh; Cancel leaves the issue unchanged.
+- [ ] Each comment authored by the signed-in account has its own **Edit**
+      button and comments by other accounts do not. Edit an owned comment in
+      Write and Preview modes, save it, refresh and relaunch, and verify the
+      Markdown change persists. Check Add/Edit/Cancel/Save with Dynamic Type
+      and VoiceOver, including the empty-comment Save state.
 
 ## Repositories and commits
 

crates/app/src/api.rs

@@ -466,14 +466,16 @@ pub async fn load_issue(
     let client =
         Client::new(&server.url, Some(&server.token)).map_err(|error| error.to_string())?;
     let configuration = client.configuration();
-    let (issue, comments) = tokio::join!(
+    let (issue, comments, viewer) = tokio::join!(
         apis::issue_api::issue_get_issue(&configuration, owner, repository, number),
         load_issue_comments(&configuration, owner, repository, number, page),
+        client.current_user(),
     );
     Ok(IssueDetails {
         issue: issue.map_err(|error| error.to_string())?,
         has_more: false,
         comments: comments?,
+        viewer_id: viewer.map_err(|error| error.to_string())?.id,
     })
 }
 
@@ -492,6 +494,67 @@ async fn load_issue_comments(
         .map_err(|error| error.to_string())
 }
 
+pub async fn save_issue_comment(
+    server: &Server,
+    owner: &str,
+    repository: &str,
+    number: i64,
+    comment_id: Option<i64>,
+    body: String,
+) -> Result<(), String> {
+    let client =
+        Client::new(&server.url, Some(&server.token)).map_err(|error| error.to_string())?;
+    let configuration = client.configuration();
+    match comment_id {
+        Some(id) => {
+            let (comment, viewer) = tokio::join!(
+                apis::issue_api::issue_get_comment(&configuration, owner, repository, id),
+                client.current_user(),
+            );
+            let comment = comment.map_err(|error| error.to_string())?;
+            let viewer = viewer.map_err(|error| error.to_string())?;
+            let owned = matches!(
+                (comment.user.as_ref().and_then(|user| user.id), viewer.id),
+                (Some(author), Some(viewer)) if author == viewer
+            );
+            if !owned || !comment_belongs_to_issue(&comment, number) {
+                return Err("You can only edit your own comments.".into());
+            }
+            apis::issue_api::issue_edit_comment(
+                &configuration,
+                owner,
+                repository,
+                id,
+                Some(models::EditIssueCommentOption::new(body)),
+            )
+            .await
+            .map_err(|error| error.to_string())?;
+        }
+        None => {
+            apis::issue_api::issue_create_comment(
+                &configuration,
+                owner,
+                repository,
+                number,
+                Some(models::CreateIssueCommentOption::new(body)),
+            )
+            .await
+            .map_err(|error| error.to_string())?;
+        }
+    }
+    Ok(())
+}
+
+fn comment_belongs_to_issue(comment: &models::Comment, number: i64) -> bool {
+    comment
+        .issue_url
+        .as_deref()
+        .map(|url| url.trim_end_matches('/'))
+        .and_then(|url| url.rsplit('/').next())
+        .and_then(|index| index.parse().ok())
+        == Some(number)
+}
+
 pub async fn load_issue_editor(
     server: &Server,
     owner: &str,
@@ -1041,4 +1104,15 @@ mod tests {
         assert_eq!(edit.milestone, Some(0));
         assert_eq!(edit.unset_due_date, Some(true));
     }
+
+    #[test]
+    fn scopes_comment_edits_to_the_selected_issue() {
+        let comment = models::Comment {
+            issue_url: Some("https://gitea.example/api/v1/repos/o/r/issues/4/".into()),
+            ..Default::default()
+        };
+        assert!(comment_belongs_to_issue(&comment, 4));
+        assert!(!comment_belongs_to_issue(&comment, 5));
+        assert!(!comment_belongs_to_issue(&models::Comment::default(), 4));
+    }
 }

crates/app/src/domain.rs

@@ -154,6 +154,7 @@ pub struct HomeData {
 pub struct IssueDetails {
     pub issue: models::Issue,
     pub comments: Vec<models::Comment>,
+    pub viewer_id: Option<i64>,
     pub has_more: bool,
 }
 

crates/app/src/lib.rs

@@ -353,6 +353,25 @@ impl GotchaCore {
         ))
     }
 
+    pub async fn save_issue_comment(
+        &self,
+        owner: String,
+        repository: String,
+        number: i64,
+        comment_id: Option<i64>,
+        body: String,
+    ) -> Result<(), GotchaError> {
+        let (owner, repository) = validate_repository(&owner, &repository)?;
+        if number <= 0 || comment_id.is_some_and(|id| id <= 0) {
+            return Err("Invalid issue comment selection.".into());
+        }
+        if body.trim().is_empty() {
+            return Err("Enter a comment.".into());
+        }
+        save_issue_comment(&self.server()?, owner, repository, number, comment_id, body).await?;
+        Ok(())
+    }
+
     pub async fn issue_editor(
         &self,
         owner: String,

crates/app/src/presentation.rs

@@ -64,9 +64,11 @@ pub struct PullRow {
 
 #[derive(Clone, uniffi::Record)]
 pub struct CommentRow {
+    pub id: i64,
     pub author: String,
     pub body: String,
     pub meta: String,
+    pub can_edit: bool,
 }
 
 #[derive(Clone, uniffi::Record)]
@@ -514,7 +516,11 @@ pub fn issue_page(details: IssueDetails) -> IssuePage {
             .body
             .filter(|body| !body.is_empty())
             .unwrap_or_else(|| "No description provided.".into()),
-        comments: details.comments.iter().map(comment_row).collect(),
+        comments: details
+            .comments
+            .iter()
+            .map(|comment| comment_row(comment, details.viewer_id))
+            .collect(),
         has_more: details.has_more,
     }
 }
@@ -627,7 +633,11 @@ pub fn pull_page(details: PullDetails) -> PullPage {
             .unwrap_or_else(|| "No description provided.".into()),
         files_ref: pull_files_ref(pull),
         files: details.files.iter().filter_map(file_row).collect(),
-        comments: details.comments.iter().map(comment_row).collect(),
+        comments: details
+            .comments
+            .iter()
+            .map(|comment| comment_row(comment, None))
+            .collect(),
         has_more: details.has_more,
     }
 }
@@ -985,8 +995,9 @@ fn label_row(label: &models::Label) -> Option<LabelRow> {
     })
 }
 
-fn comment_row(comment: &models::Comment) -> CommentRow {
+fn comment_row(comment: &models::Comment, viewer_id: Option<i64>) -> CommentRow {
     CommentRow {
+        id: comment.id.unwrap_or_default(),
         author: comment
             .user
             .as_ref()
@@ -1005,6 +1016,14 @@ fn comment_row(comment: &models::Comment) -> CommentRow {
                 .as_deref()
                 .or(comment.created_at.as_deref()),
         ),
+        can_edit: matches!(
+            (
+                comment.id,
+                comment.user.as_ref().and_then(|user| user.id),
+                viewer_id,
+            ),
+            (Some(_), Some(author), Some(viewer)) if author == viewer
+        ),
     }
 }
 
@@ -1264,17 +1283,41 @@ mod tests {
     }
 
     #[test]
-    fn issue_page_exposes_state() {
+    fn issue_page_exposes_state_and_owned_comment_editing() {
         let page = issue_page(IssueDetails {
             issue: models::Issue {
                 state: Some("closed".into()),
                 ..Default::default()
             },
-            comments: Vec::new(),
+            comments: vec![
+                models::Comment {
+                    id: Some(7),
+                    user: Some(Box::new(models::User {
+                        id: Some(3),
+                        login: Some("viewer".into()),
+                        ..Default::default()
+                    })),
+                    body: Some("Comment".into()),
+                    ..Default::default()
+                },
+                models::Comment {
+                    id: Some(8),
+                    user: Some(Box::new(models::User {
+                        id: Some(4),
+                        login: Some("someone-else".into()),
+                        ..Default::default()
+                    })),
+                    ..Default::default()
+                },
+            ],
+            viewer_id: Some(3),
             has_more: false,
         });
 
         assert_eq!(page.state, "closed");
+        assert_eq!(page.comments[0].id, 7);
+        assert!(page.comments[0].can_edit);
+        assert!(!page.comments[1].can_edit);
     }
 
     #[test]

ios/Generated/gotcha_core.swift

@@ -649,6 +649,8 @@ public protocol GotchaCoreProtocol: AnyObject, Sendable {
 
     func saveIssue(owner: String, repository: String, number: Int64?, title: String, body: String, labelIds: [Int64], milestoneId: Int64?, dueDate: Int64?) async throws  -> Int64
 
+    func saveIssueComment(owner: String, repository: String, number: Int64, commentId: Int64?, body: String) async throws
+
     func selectServer(index: UInt32) throws
 
     func servers()  -> [ServerRow]
@@ -1073,6 +1075,22 @@ open func saveIssue(owner: String, repository: String, number: Int64?, title: St
         )
 }
 
+open func saveIssueComment(owner: String, repository: String, number: Int64, commentId: Int64?, body: String)async throws   {
+    return
+        try  await uniffiRustCallAsync(
+            rustFutureFunc: {
+                uniffi_gotcha_core_fn_method_gotchacore_save_issue_comment(
+                        self.uniffiCloneHandle(),FfiConverterString.lower(owner),FfiConverterString.lower(repository),FfiConverterInt64.lower(number),FfiConverterOptionInt64.lower(commentId),FfiConverterString.lower(body)
+                )
+            },
+            pollFunc: ffi_gotcha_core_rust_future_poll_void,
+            completeFunc: ffi_gotcha_core_rust_future_complete_void,
+            freeFunc: ffi_gotcha_core_rust_future_free_void,
+            liftFunc: { $0 },
+            errorHandler: FfiConverterTypeGotchaError_lift
+        )
+}
+
 open func selectServer(index: UInt32)throws   {try rustCallWithError(FfiConverterTypeGotchaError_lift) {
         uniffiCallStatus in
     uniffi_gotcha_core_fn_method_gotchacore_select_server(
@@ -1299,16 +1317,20 @@ public func FfiConverterTypeActivityRow_lower(_ value: ActivityRow) -> RustBuffe
 
 
 public struct CommentRow: Equatable, Hashable {
+    public var id: Int64
     public var author: String
     public var body: String
     public var meta: String
+    public var canEdit: Bool
 
     // Default memberwise initializers are never public by default, so we
     // declare one manually.
-    public init(author: String, body: String, meta: String) {
+    public init(id: Int64, author: String, body: String, meta: String, canEdit: Bool) {
+        self.id = id
         self.author = author
         self.body = body
         self.meta = meta
+        self.canEdit = canEdit
     }
 
 
@@ -1327,16 +1349,20 @@ public struct FfiConverterTypeCommentRow: FfiConverterRustBuffer {
     public static func read(from buf: inout (data: Data, offset: Data.Index)) throws -> CommentRow {
         return
             try CommentRow(
+                id: FfiConverterInt64.read(from: &buf),
                 author: FfiConverterString.read(from: &buf),
                 body: FfiConverterString.read(from: &buf),
-                meta: FfiConverterString.read(from: &buf)
+                meta: FfiConverterString.read(from: &buf),
+                canEdit: FfiConverterBool.read(from: &buf)
         )
     }
 
     public static func write(_ value: CommentRow, into buf: inout [UInt8]) {
+        FfiConverterInt64.write(value.id, into: &buf)
         FfiConverterString.write(value.author, into: &buf)
         FfiConverterString.write(value.body, into: &buf)
         FfiConverterString.write(value.meta, into: &buf)
+        FfiConverterBool.write(value.canEdit, into: &buf)
     }
 }
 
@@ -3882,6 +3908,9 @@ private let initializationResult: InitializationResult = {
     if (uniffi_gotcha_core_checksum_method_gotchacore_save_issue() != 55053) {
         return InitializationResult.apiChecksumMismatch
     }
+    if (uniffi_gotcha_core_checksum_method_gotchacore_save_issue_comment() != 58596) {
+        return InitializationResult.apiChecksumMismatch
+    }
     if (uniffi_gotcha_core_checksum_method_gotchacore_select_server() != 22721) {
         return InitializationResult.apiChecksumMismatch
     }

ios/Generated/gotcha_coreFFI.h

@@ -374,6 +374,11 @@ uint64_t uniffi_gotcha_core_fn_method_gotchacore_repository_file(uint64_t ptr, R
 uint64_t uniffi_gotcha_core_fn_method_gotchacore_save_issue(uint64_t ptr, RustBuffer owner, RustBuffer repository, RustBuffer number, RustBuffer title, RustBuffer body, RustBuffer label_ids, RustBuffer milestone_id, RustBuffer due_date
 );
 #endif
+#ifndef UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_FN_METHOD_GOTCHACORE_SAVE_ISSUE_COMMENT
+#define UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_FN_METHOD_GOTCHACORE_SAVE_ISSUE_COMMENT
+uint64_t uniffi_gotcha_core_fn_method_gotchacore_save_issue_comment(uint64_t ptr, RustBuffer owner, RustBuffer repository, int64_t number, RustBuffer comment_id, RustBuffer body
+);
+#endif
 #ifndef UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_FN_METHOD_GOTCHACORE_SELECT_SERVER
 #define UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_FN_METHOD_GOTCHACORE_SELECT_SERVER
 void uniffi_gotcha_core_fn_method_gotchacore_select_server(uint64_t ptr, uint32_t index, RustCallStatus *_Nonnull out_status
@@ -820,6 +825,12 @@ uint16_t uniffi_gotcha_core_checksum_method_gotchacore_repository_file(void
 #define UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_CHECKSUM_METHOD_GOTCHACORE_SAVE_ISSUE
 uint16_t uniffi_gotcha_core_checksum_method_gotchacore_save_issue(void
 
+);
+#endif
+#ifndef UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_CHECKSUM_METHOD_GOTCHACORE_SAVE_ISSUE_COMMENT
+#define UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_CHECKSUM_METHOD_GOTCHACORE_SAVE_ISSUE_COMMENT
+uint16_t uniffi_gotcha_core_checksum_method_gotchacore_save_issue_comment(void
+
 );
 #endif
 #ifndef UNIFFI_FFIDEF_UNIFFI_GOTCHA_CORE_CHECKSUM_METHOD_GOTCHACORE_SELECT_SERVER

ios/Gotcha.xcodeproj/project.pbxproj

@@ -10,6 +10,7 @@
 		1AED04075E363FBC0FF55773 /* ContentScreens.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE5E10787062D1175125BB4C /* ContentScreens.swift */; };
 		25BDBDED14B3B886E19F511C /* DetailScreens.swift in Sources */ = {isa = PBXBuildFile; fileRef = 13EFB48F40AEB3016D3CF643 /* DetailScreens.swift */; };
 		374320EB00185A0C8E40D985 /* ListScreens.swift in Sources */ = {isa = PBXBuildFile; fileRef = AC828923A1E11A58AE348A74 /* ListScreens.swift */; };
+		381A27D70EA30C1A3BA1BBC1 /* CommentEditorViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8F9FFCC06E0313760524EBD2 /* CommentEditorViewController.swift */; };
 		7DD332583B169B3CA1CA46E0 /* Highlighter in Frameworks */ = {isa = PBXBuildFile; productRef = EC5F999F50905E3801E8A71A /* Highlighter */; };
 		950C584D58E80106DF350A22 /* AppDelegate.swift in Sources */ = {isa = PBXBuildFile; fileRef = 9C0921C76676A14A024BA417 /* AppDelegate.swift */; };
 		96C4AFC206A1DBAE3D3E00CE /* SettingsViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8F145F13B8ED83A5AB0009A4 /* SettingsViewController.swift */; };
@@ -26,6 +27,7 @@
 		5FB3250A93766966A60A685E /* Gotcha.app */ = {isa = PBXFileReference; includeInIndex = 0; lastKnownFileType = wrapper.application; path = Gotcha.app; sourceTree = BUILT_PRODUCTS_DIR; };
 		722405F999984C7CBE838711 /* IssueEditorViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IssueEditorViewController.swift; sourceTree = "<group>"; };
 		8F145F13B8ED83A5AB0009A4 /* SettingsViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SettingsViewController.swift; sourceTree = "<group>"; };
+		8F9FFCC06E0313760524EBD2 /* CommentEditorViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CommentEditorViewController.swift; sourceTree = "<group>"; };
 		9C0921C76676A14A024BA417 /* AppDelegate.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AppDelegate.swift; sourceTree = "<group>"; };
 		AC828923A1E11A58AE348A74 /* ListScreens.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ListScreens.swift; sourceTree = "<group>"; };
 		CE5E10787062D1175125BB4C /* ContentScreens.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ContentScreens.swift; sourceTree = "<group>"; };
@@ -53,6 +55,7 @@
 			children = (
 				F61515849F6AACD721FE915C /* AppContext.swift */,
 				9C0921C76676A14A024BA417 /* AppDelegate.swift */,
+				8F9FFCC06E0313760524EBD2 /* CommentEditorViewController.swift */,
 				CE5E10787062D1175125BB4C /* ContentScreens.swift */,
 				13EFB48F40AEB3016D3CF643 /* DetailScreens.swift */,
 				722405F999984C7CBE838711 /* IssueEditorViewController.swift */,
@@ -193,6 +196,7 @@
 			files = (
 				EC7F8B4703DDE37A0B10CD9B /* AppContext.swift in Sources */,
 				950C584D58E80106DF350A22 /* AppDelegate.swift in Sources */,
+				381A27D70EA30C1A3BA1BBC1 /* CommentEditorViewController.swift in Sources */,
 				1AED04075E363FBC0FF55773 /* ContentScreens.swift in Sources */,
 				25BDBDED14B3B886E19F511C /* DetailScreens.swift in Sources */,
 				D2B9B033E92BF8E7C0BDCDB0 /* IssueEditorViewController.swift in Sources */,

ios/Sources/CommentEditorViewController.swift

@@ -0,0 +1,201 @@
+import Highlighter
+import SwiftUI
+import UIKit
+
+@MainActor
+final class CommentEditorViewController: UIViewController, UITextViewDelegate {
+    private let context: AppContext
+    private let owner: String
+    private let repository: String
+    private let number: Int64
+    private let comment: CommentRow?
+    private let saved: () -> Void
+    private let scrollView = UIScrollView()
+    private let modeControl = UISegmentedControl(items: ["Write", "Preview"])
+    private let bodyView = UITextView()
+    private let previewView = UIView()
+    private let spinner = UIActivityIndicatorView(style: .medium)
+    private var task: Task<Void, Never>?
+    private var previewController: UIViewController?
+    private var editorFont: UIFont {
+        UIFontMetrics(forTextStyle: .body).scaledFont(
+            for: .monospacedSystemFont(ofSize: 15, weight: .regular)
+        )
+    }
+
+    init(
+        context: AppContext,
+        owner: String,
+        repository: String,
+        number: Int64,
+        comment: CommentRow? = nil,
+        saved: @escaping () -> Void
+    ) {
+        self.context = context
+        self.owner = owner
+        self.repository = repository
+        self.number = number
+        self.comment = comment
+        self.saved = saved
+        super.init(nibName: nil, bundle: nil)
+        title = comment == nil ? "New Comment" : "Edit Comment"
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) { fatalError("init(coder:) is not supported") }
+
+    deinit { task?.cancel() }
+
+    override func viewDidLoad() {
+        super.viewDidLoad()
+        view.backgroundColor = .systemGroupedBackground
+        navigationItem.leftBarButtonItem = UIBarButtonItem(
+            barButtonSystemItem: .cancel,
+            target: self,
+            action: #selector(cancel)
+        )
+        restoreSaveButton()
+
+        scrollView.translatesAutoresizingMaskIntoConstraints = false
+        scrollView.keyboardDismissMode = .interactive
+        view.addSubview(scrollView)
+        let stack = UIStackView(arrangedSubviews: [modeControl, bodyView, previewView])
+        stack.axis = .vertical
+        stack.spacing = 12
+        stack.translatesAutoresizingMaskIntoConstraints = false
+        scrollView.addSubview(stack)
+
+        modeControl.selectedSegmentIndex = 0
+        modeControl.accessibilityLabel = "Comment editor mode"
+        modeControl.addTarget(self, action: #selector(modeChanged), for: .valueChanged)
+        bodyView.delegate = self
+        bodyView.text = comment?.body ?? ""
+        bodyView.font = editorFont
+        bodyView.adjustsFontForContentSizeCategory = true
+        bodyView.backgroundColor = .secondarySystemGroupedBackground
+        bodyView.layer.cornerRadius = 10
+        bodyView.textContainerInset = UIEdgeInsets(top: 12, left: 8, bottom: 12, right: 8)
+        bodyView.autocapitalizationType = .sentences
+        bodyView.accessibilityLabel = "Comment in Markdown"
+        previewView.backgroundColor = .secondarySystemGroupedBackground
+        previewView.layer.cornerRadius = 10
+        previewView.clipsToBounds = true
+        previewView.accessibilityLabel = "Comment preview"
+        previewView.isHidden = true
+        highlightBody()
+        updateSaveButton()
+
+        NSLayoutConstraint.activate([
+            scrollView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor),
+            scrollView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor),
+            scrollView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
+            scrollView.bottomAnchor.constraint(equalTo: view.keyboardLayoutGuide.topAnchor),
+            stack.leadingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.leadingAnchor, constant: 16),
+            stack.trailingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.trailingAnchor, constant: -16),
+            stack.topAnchor.constraint(equalTo: scrollView.contentLayoutGuide.topAnchor, constant: 16),
+            stack.bottomAnchor.constraint(equalTo: scrollView.contentLayoutGuide.bottomAnchor, constant: -16),
+            stack.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor, constant: -32),
+            bodyView.heightAnchor.constraint(greaterThanOrEqualToConstant: 280),
+            previewView.heightAnchor.constraint(greaterThanOrEqualToConstant: 280),
+        ])
+    }
+
+    override func viewDidAppear(_ animated: Bool) {
+        super.viewDidAppear(animated)
+        if comment == nil { bodyView.becomeFirstResponder() }
+    }
+
+    func textViewDidChange(_ textView: UITextView) {
+        highlightBody()
+        updateSaveButton()
+    }
+
+    private func highlightBody() {
+        let source = bodyView.text ?? ""
+        let selection = bodyView.selectedRange
+        let highlighter = Highlighter()
+        highlighter?.setTheme(traitCollection.userInterfaceStyle == .dark ? "atom-one-dark" : "atom-one-light")
+        highlighter?.theme.setCodeFont(editorFont)
+        bodyView.attributedText = highlighter?.highlight(source, as: "markdown")
+            ?? NSAttributedString(string: source, attributes: [
+                .font: editorFont,
+                .foregroundColor: UIColor.label,
+            ])
+        bodyView.selectedRange = selection
+        bodyView.typingAttributes = [
+            .font: editorFont,
+            .foregroundColor: UIColor.label,
+        ]
+    }
+
+    @objc private func modeChanged() {
+        let preview = modeControl.selectedSegmentIndex == 1
+        if preview {
+            previewController?.willMove(toParent: nil)
+            previewController?.view.removeFromSuperview()
+            previewController?.removeFromParent()
+            let controller = UIHostingController(
+                rootView: RepositoryMarkdownPreview(source: bodyView.text ?? "")
+            )
+            addChild(controller)
+            controller.view.translatesAutoresizingMaskIntoConstraints = false
+            previewView.addSubview(controller.view)
+            NSLayoutConstraint.activate([
+                controller.view.leadingAnchor.constraint(equalTo: previewView.leadingAnchor),
+                controller.view.trailingAnchor.constraint(equalTo: previewView.trailingAnchor),
+                controller.view.topAnchor.constraint(equalTo: previewView.topAnchor),
+                controller.view.bottomAnchor.constraint(equalTo: previewView.bottomAnchor),
+            ])
+            controller.didMove(toParent: self)
+            previewController = controller
+        }
+        bodyView.isHidden = preview
+        previewView.isHidden = !preview
+        view.endEditing(true)
+    }
+
+    @objc private func save() {
+        view.endEditing(true)
+        navigationItem.leftBarButtonItem?.isEnabled = false
+        navigationItem.rightBarButtonItem = UIBarButtonItem(customView: spinner)
+        spinner.startAnimating()
+        task?.cancel()
+        task = Task {
+            do {
+                try await context.core.saveIssueComment(
+                    owner: owner,
+                    repository: repository,
+                    number: number,
+                    commentId: comment?.id,
+                    body: bodyView.text ?? ""
+                )
+                guard !Task.isCancelled else { return }
+                saved()
+            } catch {
+                if !Task.isCancelled {
+                    show(error: error)
+                    restoreSaveButton()
+                }
+            }
+        }
+    }
+
+    private func restoreSaveButton() {
+        spinner.stopAnimating()
+        navigationItem.leftBarButtonItem?.isEnabled = true
+        navigationItem.rightBarButtonItem = UIBarButtonItem(
+            title: "Save",
+            style: .done,
+            target: self,
+            action: #selector(save)
+        )
+        updateSaveButton()
+    }
+
+    private func updateSaveButton() {
+        navigationItem.rightBarButtonItem?.isEnabled = !(bodyView.text ?? "")
+            .trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
+    }
+
+    @objc private func cancel() { dismiss(animated: true) }
+}

ios/Sources/DetailScreens.swift

@@ -146,15 +146,41 @@ final class IssueViewController: MarkdownPageViewController {
 
     override func viewDidLoad() {
         super.viewDidLoad()
-        navigationItem.rightBarButtonItem = UIBarButtonItem(
+        let addComment = UIBarButtonItem(
+            image: context.symbol("plus.bubble"),
+            style: .plain,
+            target: self,
+            action: #selector(addComment)
+        )
+        addComment.accessibilityLabel = "Add comment"
+        let editIssue = UIBarButtonItem(
             title: "Edit",
             style: .plain,
             target: self,
             action: #selector(editIssue)
         )
+        navigationItem.rightBarButtonItems = [addComment, editIssue]
         loadContent(refreshing: false)
     }
 
+    @objc private func addComment() { presentCommentEditor() }
+
+    private func editComment(_ comment: CommentRow) { presentCommentEditor(comment) }
+
+    private func presentCommentEditor(_ comment: CommentRow? = nil) {
+        let editor = CommentEditorViewController(
+            context: context,
+            owner: owner,
+            repository: repository,
+            number: number,
+            comment: comment
+        ) { [weak self] in
+            guard let self else { return }
+            self.dismiss(animated: true) { self.loadContent(refreshing: false) }
+        }
+        present(UINavigationController(rootViewController: editor), animated: true)
+    }
+
     @objc private func editIssue() {
         let editor = IssueEditorViewController(
             context: context,
@@ -204,6 +230,7 @@ final class IssueViewController: MarkdownPageViewController {
                         meta: page.meta,
                         body: page.body,
                         comments: page.comments,
+                        editComment: { [weak self] comment in self?.editComment(comment) },
                         milestone: page.milestone
                     ))
                     finishPagination(hasMore: page.hasMore)
@@ -791,6 +818,7 @@ private func detailViews(
     meta: String,
     body: String,
     comments: [CommentRow],
+    editComment: ((CommentRow) -> Void)? = nil,
     milestone: String = ""
 ) -> [UIView] {
     let titleLabel = UILabel()
@@ -815,7 +843,7 @@ private func detailViews(
         milestoneLabel.accessibilityLabel = "Milestone \(milestone)"
         views.append(milestoneLabel)
     }
-    return views + [separator(), bodyView] + commentViews(comments)
+    return views + [separator(), bodyView] + commentViews(comments, editComment: editComment)
 }
 
 private func issueTitle(_ titleLabel: UILabel, state: String) -> UIView {
@@ -843,18 +871,37 @@ private func issueTitle(_ titleLabel: UILabel, state: String) -> UIView {
     return stack
 }
 
-private func commentViews(_ comments: [CommentRow]) -> [UIView] {
+private func commentViews(
+    _ comments: [CommentRow],
+    editComment: ((CommentRow) -> Void)? = nil
+) -> [UIView] {
     guard !comments.isEmpty else { return [] }
     var views: [UIView] = [sectionLabel("Comments")]
     for comment in comments {
         let author = UILabel()
         author.text = comment.author
         author.font = .preferredFont(forTextStyle: .headline)
+        var headerViews: [UIView] = [author, UIView()]
+        if comment.canEdit, let editComment {
+            var configuration = UIButton.Configuration.plain()
+            configuration.title = "Edit"
+            configuration.image = UIImage(systemName: "pencil")
+            configuration.imagePadding = 5
+            configuration.contentInsets = .zero
+            let button = UIButton(
+                configuration: configuration,
+                primaryAction: UIAction { _ in editComment(comment) }
+            )
+            button.accessibilityLabel = "Edit comment by \(comment.author)"
+            headerViews.append(button)
+        }
+        let header = UIStackView(arrangedSubviews: headerViews)
+        header.alignment = .center
         let date = UILabel()
         date.text = comment.meta
         date.font = .preferredFont(forTextStyle: .caption1)
         date.textColor = .tertiaryLabel
-        let stack = UIStackView(arrangedSubviews: [author, markdownView(comment.body), date, separator()])
+        let stack = UIStackView(arrangedSubviews: [header, markdownView(comment.body), date, separator()])
         stack.axis = .vertical
         stack.spacing = 6
         views.append(stack)