dv-review 0.34.26

//! `Space a`: run Claude Code on this review (the dv-review skill), without leaving dv. Inside
//! zellij it gets a pane on the right (an interactive session to watch and steer); elsewhere it runs
//! in the background. Either way its review shows up as it writes the file.
use super::*;

#[derive(Clone, Copy)]
pub(super) enum Ask {
    Review,
    Answer,
    /// Make the changes the review's open comments ask for (Claude's and yours), and/or what
    /// your instructions say.
    Fix,
    /// Propose a new description for the PR (in the review file), for you to approve.
    Describe,
    /// On someone else's PR: make the changes (as `Fix` does on yours), here, for you to push
    /// to their branch, rather than suggest them.
    Edit,
    /// Your PR's CI fails: find out why from the failed runs' logs, and fix it here.
    FixChecks,
    /// Draft a comment closing the PR (in the review file), for you to close it with.
    Close,
}

/// What `claude -p` may do in the background: edit files (the review, and code when asked),
/// and run only the commands the skill needs.
const ALLOWED: &[&str] = &[
    "Bash(dv review-info:*)",
    "Bash(dv review-check:*)",
    "Bash(dv review-comments:*)",
    "Bash(git diff:*)",
    "Bash(git show:*)",
    "Bash(git log:*)",
    "Bash(git rev-parse:*)",
    // The PR's description and conversation, to propose a new description from.
    "Bash(gh pr view:*)",
    // Why CI fails, to fix it.
    "Bash(gh pr checks:*)",
    "Bash(gh run view:*)",
    // To check a change it made still builds and passes.
    "Bash(cargo check:*)",
    "Bash(cargo build:*)",
    "Bash(cargo test:*)",
    "Bash(cargo clippy:*)",
];

/// (Fixing CI, a transient failure's failed jobs once more: once a head, see `fix_checks_prompt`.)
/// What a background run may do beyond `ALLOWED`: rerun the failed jobs of PR `n`'s CI only
/// when fixing it (that PR's: no other).
pub(crate) fn tools_for(fixing_ci: Option<u64>) -> Option<String> {
    fixing_ci.map(|n| format!("Bash(dv rerun-failed -p {n})"))
}

/// What drafting a replacement needs on top: reading the PRs it replaces, and committing (to
/// its own local branch; dv never pushes it without you).
pub(crate) const REPLACE_TOOLS: &[&str] = &[
    "Bash(dv replace-info:*)",
    "Bash(gh pr view:*)",
    "Bash(gh pr diff:*)",
    "Bash(gh issue view:*)",
    "Bash(git status:*)",
    "Bash(git add:*)",
    "Bash(git commit:*)",
];

/// A background `claude -p` run.
pub(super) struct ClaudeJob {
    pub(super) child: std::process::Child,
    /// Its result (JSON); errors go next to it (`.err`).
    pub(super) log: PathBuf,
    /// What it's doing, for the status bar.
    pub(super) label: &'static str,
    /// It ran on a fork of the PR's session (the session itself is open in a pane), so its
    /// session id isn't the one to keep.
    pub(super) forked: bool,
    pub(super) started: std::time::Instant,
}

/// Whether thread `t` is Claude's own comment (from its review file), not one you left for it.
pub(crate) fn claude_wrote(t: &Thread) -> bool {
    t.claude.is_some() && t.comments.first().is_some_and(|c| c.author == crate::claude::AUTHOR)
}

/// What you can want of Claude on a comment or reply (its `"want"` in the review file): the
/// key, the thread's tag while it waits, what the editor says, the picker's item.
const WANTS: [(&str, &str, &str, &str); 3] = [
    ("ask", "[ask] ", " (Claude answers; it changes nothing)", "Ask: Claude answers (it changes nothing)"),
    (
        "suggest",
        "[suggest] ",
        " (Claude drafts a suggestion for you to post; it doesn't edit the code)",
        "Suggest: Claude drafts a suggestion for you to post on GitHub (no code changes)",
    ),
    ("change", "[change] ", " (Claude makes the change in the code here; nothing goes to GitHub)", "Change: Claude edits the code here"),
];

/// On a thread waiting for Claude: what you want of it (`[change]` …), when you said.
pub(crate) fn want_tag(t: &Thread) -> Option<&'static str> {
    let tag = WANTS.iter().find(|w| w.0 == t.want)?.1;
    (turn(t) == Some("[waiting] ")).then_some(tag)
}

/// Whose turn it is on an open thread of the review file: Claude's (`[waiting]`: you had the
/// last word), or yours once Claude has answered you (`[answered]`).
pub(crate) fn turn(t: &Thread) -> Option<&'static str> {
    let last = t.comments.last().filter(|_| t.claude.is_some() && !t.resolved)?;
    match last.author == "you" {
        true => Some("[waiting] "),
        false => t.comments.iter().any(|c| c.author == "you").then_some("[answered] "),
    }
}

impl App {
    /// Whether thread `t` shows: in the Claude view, only those of Claude's review; in the
    /// pending view, those with a comment of your pending review.
    pub(super) fn in_view(&self, t: &Thread) -> bool {
        self.in_view_of(self.view, t)
    }

    /// `in_view`, for view `v` (the pane's tabs count what each would show).
    pub(super) fn in_view_of(&self, v: View, t: &Thread) -> bool {
        // Comments are on the PR's head: not on commits before it (but one about a commit is
        // on no lines: it shows whatever's shown).
        if self.before_head() && commit_of(&t.conversation).is_none() {
            return false;
        }
        Self::of_view(v, t)
    }

    /// Whether thread `t` is of view `v` (Claude's, your pending review's), shown or not.
    fn of_view(v: View, t: &Thread) -> bool {
        match v {
            View::All => true,
            View::Claude => t.claude.is_some(),
            View::Pending => t.comments.iter().any(|c| c.pending),
        }
    }

    /// The Claude and Pending tabs: the Claude / pending view, or back to the
    /// whole diff.
    pub(super) fn toggle_view(&mut self, v: View) {
        self.view = if self.view == v { View::All } else { v };
        let keep = self.cursor_key();
        self.rebuild(keep);
        let any = self.any_in_view();
        self.msg = match self.view {
            View::Claude if !any && self.claude.summary.is_empty() => "Claude view: Claude hasn't reviewed this yet (Space a asks it; gn / gp: the other tabs)",
            View::Claude => "Claude view: its summary and the code it commented on (gn / gp: the other tabs)",
            View::Pending if !any && self.summary_draft.is_empty() => "pending view: no pending review yet (c queues a comment; gn / gp: the other tabs)",
            View::Pending => "pending view: your pending review and the code it's on (S submits it; gn / gp: the other tabs)",
            View::All => "the whole diff",
        }
        .into();
    }

    /// Before writing a comment or reply for Claude: what you want of it (an answer, a
    /// suggestion for GitHub, or the change made here). Preselected: what you last wanted on
    /// thread `t`, else the change on your PR, a suggestion on theirs.
    pub(super) fn pick_want(&mut self, action: Action, t: Option<usize>) {
        if self.claude.path.is_none() {
            return self.msg = "no review file here (not in a git repo?)".into();
        }
        // About a commit (on no lines): no suggestion to post; an answer, unless you said.
        let commit = matches!(&action, Action::AskConversation { url, .. } if commit_of(url).is_some());
        let wants: Vec<_> = WANTS.iter().filter(|w| !(commit && w.0 == "suggest")).collect();
        let last = t.and_then(|t| wants.iter().position(|w| w.0 == self.threads[t].want));
        let sel = last.unwrap_or(match (commit, self.theirs) {
            (true, _) => 0,
            (false, true) => 1,
            (false, false) => 2,
        });
        let items = wants
            .iter()
            .map(|&&(key, _, _, label)| match key == "change" && self.theirs {
                true => Item::new(format!("{label} (their PR: Space g pushes what you commit)"), Target::Want(key)),
                false => Item::new(label, Target::Want(key)),
            })
            .collect();
        self.wanting = Some(action);
        self.picker = Some(Picker { title: " what do you want of Claude? ", items, query: String::new(), sel });
    }

    /// `a` on a commit in the list: a question about it, or a change to it, for Claude (on no
    /// lines: a thread of its own, under "about commit …").
    pub(super) fn ask_commit(&mut self, i: usize) {
        let Some(c) = self.commits.get(i) else { return };
        let url = match &self.pr {
            Some(p) => format!("{}/commits/{}", p.url, c.sha),
            None => format!("commit:{}", c.sha),
        };
        let prefill = format!("About commit {} ({}):\n", c.short, c.subject);
        // A thread about it already: what you last wanted there.
        let t = self.threads.iter().rposition(|t| t.conversation == url);
        self.pick_want(Action::AskConversation { url, prefill, want: "" }, t);
    }

    /// The want picked: on to the editor.
    pub(super) fn want(&mut self, w: &'static str) {
        self.action = match self.wanting.take() {
            Some(Action::AskClaude { anchor, code, about, .. }) => Some(Action::AskClaude { anchor, code, about, want: w }),
            Some(Action::ClaudeReply(k, _, q)) => Some(Action::ClaudeReply(k, w, q)),
            Some(Action::AskConversation { url, prefill, .. }) => Some(Action::AskConversation { url, prefill, want: w }),
            other => other,
        };
    }

    /// Whether the view has threads in it (on an earlier commit too, where they're hidden).
    pub(super) fn any_in_view(&self) -> bool {
        self.threads.iter().any(|t| Self::of_view(self.view, t))
    }

    /// Whether `ask` may change the code (or reads it whole: a review): answering does when a
    /// reply waiting wants a change.
    pub(super) fn edits(&self, ask: Ask) -> bool {
        match ask {
            Ask::Describe | Ask::Close => false,
            Ask::Answer => self.threads.iter().any(|t| turn(t) == Some("[waiting] ") && t.want == "change"),
            _ => true,
        }
    }

    /// Replies of yours that Claude hasn't answered yet.
    pub(super) fn waiting_replies(&self) -> usize {
        self.threads.iter().filter(|t| turn(t) == Some("[waiting] ")).count()
    }

    /// The commit Claude last reviewed, if there's been more since that build on it (a push,
    /// your commits): then an update need only look at those. Not after a rebase or force-push:
    /// that's all new.
    pub(super) fn reviewed_before(&self) -> Option<&str> {
        let old = self.claude.head.as_str();
        let head = diff::git(&["rev-parse", "HEAD"]).ok()?;
        let newer = !old.is_empty() && !head.trim().starts_with(old);
        (newer && diff::git(&["merge-base", "--is-ancestor", old, "HEAD"]).is_ok()).then_some(old)
    }

    /// What "make the changes" acts on: the review file's open comments, Claude's and the ones
    /// you left it (`a`), not resolved or outdated. The one place that's decided.
    pub(super) fn change_requests(&self) -> usize {
        self.threads.iter().filter(|t| t.claude.is_some() && !t.resolved && !t.outdated && (claude_wrote(t) || !matches!(t.want.as_str(), "ask" | "suggest"))).count()
    }

    /// Why Claude can't take a request right now (checked before asking you for instructions,
    /// so nothing you write is lost to it): still busy, or a rebase stopped (`pane_cant`: where
    /// it goes to the pane). `ask`: what's asked (`None`: amending, which changes the code but needs no review file).
    /// What changes the code (or reads it whole: a review) waits for a stopped rebase, whose
    /// conflicts are in the way; a question, a description, a closing comment don't.
    pub(super) fn claude_blocked(&self, ask: Option<Ask>) -> Option<String> {
        let edits = ask.is_none_or(|a| self.edits(a));
        let busy = self.claude.job.is_some();
        if busy {
            return Some("Claude is still working on the last request".into());
        }
        // A rebase stopped part way: the tree has its conflicts, HEAD is detached.
        if edits && super::rebase::rebasing(&self.root) {
            return Some(super::rebase::stopped_says(&self.root).into());
        }
        None
    }

    /// Why `ask` can't go to the PR's Claude pane, where it would (one is open): the pane is
    /// from an older dv that can't reach the review files, and `ask` needs them. (A run of its
    /// own, as answering is, reaches them whatever the pane.)
    fn pane_cant(&self, ask: Ask) -> Option<String> {
        let needs_files = !matches!(ask, Ask::Fix | Ask::Edit) || self.change_requests() > 0;
        let (_, cmd) = self.claude_pane_cmd()?;
        let dv = crate::claude::dv_dir().map(|d| d.display().to_string()).unwrap_or_default();
        (needs_files && !dv.is_empty() && !cmd.contains(&dv)).then(|| {
            "Claude's pane for this PR can't reach dv's review files (it's from an older dv): close it, and Space a starts a new one".into()
        })
    }

    pub(super) fn claude_menu(&mut self) {
        if self.claude.path.is_none() {
            return self.msg = "no review file here (not in a git repo?)".into();
        }
        let has_review = self.threads.iter().any(claude_wrote) || !self.claude.summary.is_empty();
        let review = match (has_review, self.reviewed_before()) {
            (true, Some(old)) => format!("Update Claude's review: what changed since it reviewed {}", &old[..old.len().min(8)]),
            (true, None) => "Update Claude's review (keeps comments that still apply, and your replies)".into(),
            (false, _) => "Ask Claude to review this".into(),
        };
        let n = self.waiting_replies();
        let open = self.change_requests();
        let notes = match crate::claude::notes_path().is_ok_and(|p| p.exists()) {
            true => "Edit Claude's notes on this repo (it reads them before each task)",
            false => "Write notes for Claude on this repo (it reads them before each task)",
        };
        let mut items = vec![
            Item::new(review, Target::Claude(Ask::Review)),
            Item::new(format!("Ask Claude to answer your replies ({n} waiting)"), Target::Claude(Ask::Answer)),
            Item::new(
                match (open, self.theirs) {
                    (0, false) => "Ask Claude to make a change (no open comments: you say what)".to_owned(),
                    (n, false) => format!("Ask Claude to make the changes ({n} open comments)"),
                    // Someone else's PR: as suggestions you can post, not edits.
                    (0, true) => "Ask Claude to suggest a change (you say what; their PR: no edits)".to_owned(),
                    (n, true) => format!("Ask Claude to suggest the changes ({n} open comments; their PR: no edits)"),
                },
                Target::Claude(Ask::Fix),
            ),
        ];
        // Someone else's PR: Claude can make the changes all the same, here, for you to push to
        // their branch (when they let maintainers: else they stay here).
        if self.theirs {
            let push = match self.pr.as_ref().is_some_and(|p| p.maintainer_can_modify || !p.cross_repo) {
                true => "Space g pushes them to their branch",
                false => "they don't allow maintainer edits: the commits stay here",
            };
            let what = if open == 0 { "a change (you say what)".to_owned() } else { format!("the changes ({open} open comments)") };
            items.push(Item::new(format!("Ask Claude to make {what} here, as commits ({push})"), Target::Claude(Ask::Edit)));
        }
        // Your PR's CI failing: Claude finds out why; or found it isn't the PR's doing, and had
        // a fix of its own in mind, a new PR's.
        if let Some(n) = self.pr.as_ref().map(|p| p.number).filter(|_| self.failing > 0 && !self.theirs) {
            let s = if self.failing == 1 { "" } else { "s" };
            items.push(Item::new(format!("Ask Claude to fix the failing CI ({} check{s}: it reads the failed runs' logs; you push)", self.failing), Target::Claude(Ask::FixChecks)));
            if let Some(c) = self.ci_note(n).filter(|c| !c.task.is_empty()) {
                items.insert(0, Item::new(format!("Have Claude draft a PR fixing CI (not this PR's doing: {})…", c.why), Target::CiFixPr));
            }
        }
        items.push(Item::new("Ask Claude a question about this PR… (it answers in the Claude tab)", Target::ClaudeQuestion));
        items.extend([
            Item::new(notes, Target::ClaudeNotes),
            Item::new("Check Claude's review now (dv watches it; this reads it again)", Target::ClaudeCheck),
        ]);
        if self.claude_pane().is_some() {
            items.insert(0, Item::new("Show Claude's pane (its session on this PR)", Target::ClaudePane));
        }
        // A description Claude proposed: yours to approve (posted then), take further, or drop.
        if !self.claude.description.is_empty() {
            items.insert(0, Item::new("Discard Claude's proposed description", Target::DescDiscard));
            items.insert(0, Item::new("Ask Claude for more changes to the description…", Target::Claude(Ask::Describe)));
            items.insert(0, Item::new("Approve Claude's description: it replaces the PR's on GitHub…", Target::DescApprove(false)));
        } else if self.pr.is_some() {
            items.push(Item::new("Ask Claude to change the PR's description (you approve it)…", Target::Claude(Ask::Describe)));
        }
        // Closing it: Claude drafts the comment; you edit it, then close with it (or don't).
        // (Closed or merged meanwhile: the draft can only go.)
        let open = self.pr_state.is_some_and(|s| matches!(s.0, "OPEN" | "DRAFT"));
        let drafted = !self.claude.closing.trim().is_empty();
        if drafted {
            items.insert(0, Item::new("Discard Claude's closing comment", Target::CloseDiscard));
        }
        if drafted && open {
            items.insert(0, Item::new("Ask Claude for changes to the closing comment…", Target::Claude(Ask::Close)));
            items.insert(0, Item::new("Close the PR with Claude's comment (your editor first)…", Target::ClosePr));
        } else if self.pr.is_some() && open {
            items.push(Item::new("Ask Claude to draft a comment closing the PR (you edit it, then close)…", Target::Claude(Ask::Close)));
        }
        // One that seems stuck: it can be stopped (the session stays, so the next run resumes it).
        if let Some(j) = &self.claude.job {
            items.insert(0, Item::new(format!("Stop Claude ({} for {})", j.label, ago(j.started)), Target::ClaudeStop));
        }
        let outdated = self.outdated_claude_comments().len();
        if outdated > 0 {
            items.push(Item::new(format!("Dismiss Claude's outdated comments ({outdated})"), Target::ClaudeDismissOutdated(false)));
        }
        if self.claude.session.is_some() {
            items.push(Item::new("Start a fresh Claude session for this PR (the review stays)", Target::ClaudeFresh));
        }
        // A replacement: Claude writes the change itself, unpublished, for you to review here.
        match (&self.pr, &self.replacement) {
            (Some(p), _) => items.push(Item::new(
                format!("Draft a replacement for #{} (Claude writes it properly, unpublished, in the background)", p.number),
                Target::ClaudeReplace(vec![p.number]),
            )),
            (None, Some(r)) if r.drafting_now() => items.push(Item::new("Claude is drafting this replacement (dv shows it as it goes)", Target::Nothing)),
            (None, Some(r)) => items.push(Item::new(
                "Redraft this (Claude carries on, with your instructions)",
                Target::ClaudeReplace(r.ids()),
            )),
            _ => {}
        }
        // Preselected: answering your replies if any wait, else the review (never Stop: Enter
        // out of habit mustn't end a run).
        let want = |t: &Target| matches!(t, Target::Claude(a) if matches!((a, n > 0), (Ask::Answer, true) | (Ask::Review, false)));
        let sel = items.iter().position(|i| want(&i.target)).unwrap_or(0);
        self.picker = Some(Picker { title: " claude ", items, query: String::new(), sel });
    }

    /// `Space a` → check now: the review file read again (as if it had changed), and the
    /// background run's state, rather than waiting for dv to notice.
    pub(super) fn check_claude(&mut self) {
        // Read it, changed or not (or gone: `None` would look unchanged then).
        self.claude.mtime = Some(std::time::SystemTime::UNIX_EPOCH);
        self.watch_claude();
        let ran = self.claude.job.is_some();
        self.poll_claude(); // a run that's ended says how (that's the news, then)
        if let Some(j) = &self.claude.job {
            self.msg = format!("Claude is still {} ({} so far); Space a can stop it", j.label, ago(j.started));
        } else if !ran && !self.claude.path.as_ref().is_some_and(|p| p.exists()) {
            self.msg = "Claude hasn't written a review yet (Space a → review asks for one)".into();
        }
    }

    /// `Space a` → stop: end the background run (its log stays). The session is kept, so the
    /// next run resumes where it left off.
    pub(super) fn stop_claude(&mut self) {
        let Some(mut j) = self.claude.job.take() else { return self.msg = "Claude isn't working on anything".into() };
        if let Some(p) = self.pr.as_ref().filter(|_| !j.forked) {
            crate::claude::clear_running(p.number);
        }
        // Its process group: Claude and the commands it's running (a build, the tests).
        let group = format!("-{}", j.child.id());
        _ = std::process::Command::new("kill").args(["-KILL", "--", &group]).stderr(std::process::Stdio::null()).status();
        _ = j.child.kill();
        _ = j.child.wait();
        self.claude.again = false;
        self.reload_tree(); // what it changed before it stopped
        self.msg = format!("stopped Claude ({} for {}); its log: {} (and .err)", j.label, ago(j.started), j.log.display());
    }

    /// Forget the PR's Claude session, so the next run starts a new one: when it has got
    /// something wrong into its head, or grown long. The review file is what carries over.
    pub(super) fn fresh_claude_session(&mut self) {
        if self.claude.job.is_some() {
            return self.msg = "Claude is still working on the last request; once it's done".into();
        }
        let pane = self.claude_pane().is_some();
        self.set_session(None);
        self.msg = match pane {
            true => "the next Claude run starts a new session; close Claude's pane, which has the old one".into(),
            false => "the next Claude run starts a new session".into(),
        };
    }

    /// `Space a` → approve Claude's description: after a confirmation (`sure`), it replaces
    /// the PR's on GitHub, and the proposal goes.
    pub(super) fn approve_description(&mut self, sure: bool) {
        let (Some(pr), Some(path)) = (self.pr.as_ref().map(|p| p.number), self.claude.path.clone()) else { return };
        if !sure {
            let items = vec![
                Item::new("No, not yet", Target::Nothing),
                Item::new(format!("Yes, replace #{pr}'s description on GitHub with Claude's"), Target::DescApprove(true)),
            ];
            return self.picker = Some(Picker { title: " description ", items, query: String::new(), sel: 0 });
        }
        let text = self.claude.description.clone();
        let body = (0..self.info.len()).find(|&i| self.is_description(i)).map(|h| h + 1).filter(|&b| self.info.get(b).is_some_and(|l| l.md));
        let shown = body.map_or(String::new(), |b| self.info[b].text.clone());
        // Edited on GitHub since dv showed it: the proposal's diff was against an older text.
        let now = match crate::gh::body(pr) {
            Ok(t) => t,
            Err(e) => return self.msg = format!("description not changed: {e:#}"),
        };
        if now.trim() != shown.trim() {
            if let Some(b) = body {
                self.info[b].text = now;
            }
            let keep = self.cursor_key();
            self.rebuild(keep);
            return self.msg = "description not changed: it was edited on GitHub since; dv shows it now against Claude's: approve again if it's still right".into();
        }
        if let Err(e) = crate::gh::set_body(pr, &text) {
            return self.msg = format!("description not changed: {e:#}");
        }
        self.github_changed();
        // What's on GitHub now, without waiting for the next fetch.
        if let Some(b) = body {
            self.info[b].text = text;
        }
        let cleared = crate::claude::clear_description(&path);
        let keep = self.cursor_key();
        self.load_claude();
        self.rebuild(keep);
        self.msg = match cleared {
            Ok(()) => format!("#{pr}'s description is Claude's now"),
            Err(e) => format!("#{pr}'s description is Claude's now, but its proposal is still in the review file: {e:#} (Space a discards it)"),
        };
    }

    /// `Space a` → close the PR with Claude's comment: in your editor first (an empty one, or
    /// `:cq`, closes nothing), then posted, and the PR closed.
    pub(super) fn close_pr(&mut self) -> Result<String> {
        let (Some(n), Some(path)) = (self.pr.as_ref().map(|p| p.number), self.claude.path.clone()) else { return Ok(String::new()) };
        let what = format!("comment closing #{n} (posted on its conversation, then it's closed; empty closes nothing)");
        let Some(text) = compose_with(&what, false, self.claude.closing.trim(), true)?.filter(|t| !t.trim().is_empty()) else {
            return Ok(format!("#{n} not closed"));
        };
        keep_on_error(crate::gh::close(n, Some(text.trim())), &text)?;
        _ = crate::claude::clear_closing(&path);
        self.pr_state = Some(("CLOSED", "da3633"));
        self.github_changed();
        let keep = self.cursor_key();
        self.load_claude();
        self.rebuild(keep);
        Ok(format!("#{n} closed, with your comment"))
    }

    /// `Space a` → discard Claude's closing comment.
    pub(super) fn discard_closing(&mut self) {
        let Some(path) = self.claude.path.clone() else { return };
        self.msg = match crate::claude::clear_closing(&path) {
            Ok(()) => {
                let keep = self.cursor_key();
                self.load_claude();
                self.rebuild(keep);
                "Claude's closing comment discarded".into()
            }
            Err(e) => format!("{e:#}"),
        };
    }

    /// `Space a` → discard Claude's proposed description.
    pub(super) fn discard_description(&mut self) {
        let Some(path) = self.claude.path.clone() else { return };
        self.msg = match crate::claude::clear_description(&path) {
            Ok(()) => {
                let keep = self.cursor_key();
                self.load_claude();
                self.rebuild(keep);
                "Claude's proposed description discarded".into()
            }
            Err(e) => format!("{e:#}"),
        };
    }

    /// The ids of Claude's own comments whose code has changed (not your comments for it).
    pub(super) fn outdated_claude_comments(&self) -> Vec<String> {
        self.threads.iter().filter(|t| claude_wrote(t) && t.outdated).filter_map(|t| t.claude.clone()).collect()
    }

    /// From the `Space a` menu: dismiss every outdated comment of Claude's, after a confirmation
    /// (`sure`: the "Yes" in it).
    pub(super) fn dismiss_outdated(&mut self, sure: bool) {
        let keys = self.outdated_claude_comments();
        if keys.is_empty() {
            return self.msg = "no outdated comments from Claude".into();
        }
        if !sure {
            let items = vec![
                Item::new("No, keep them", Target::Nothing),
                Item::new(format!("Yes, dismiss Claude's {} outdated comment(s)", keys.len()), Target::ClaudeDismissOutdated(true)),
            ];
            return self.picker = Some(Picker { title: " dismiss outdated? ", items, query: String::new(), sel: 0 });
        }
        let Some(p) = self.claude.path.clone() else { return };
        let keep = self.cursor_key();
        let res = crate::claude::dismiss_all(&p, &keys);
        self.load_claude();
        self.rebuild(keep);
        self.msg = match res {
            Ok(n) => format!("dismissed {n} outdated comment(s) from Claude"),
            Err(e) => format!("{e:#}"),
        };
    }

    /// `extra`: the user's own instructions for this run (may be empty).
    pub(super) fn claude_prompt(&self, ask: Ask, extra: &str) -> String {
        let what = match &self.pr {
            Some(p) => format!("PR #{}", p.number),
            None => "the current branch".into(),
        };
        let prompt = match ask {
            Ask::Review => match self.reviewed_before() {
                Some(old) => update_prompt(&what, old),
                None => review_prompt(&what),
            },
            Ask::Answer => answer_prompt(&what, self.theirs),
            Ask::FixChecks => fix_checks_prompt(self.pr.as_ref().map_or(0, |p| p.number)),
            Ask::Close => format!(
                "Use the dv-review skill to draft a comment closing {what}, as the user asks below, in the review file's \
                 top-level \"closing\" field (see \"Draft a closing comment\"). Start from the draft already there, if there \
                 is one. Don't close the PR or comment on GitHub: the user closes it in dv."
            ),
            Ask::Describe => format!(
                "Use the dv-review skill to propose a new description for {what}, as the user asks below: the whole new text, \
                 in the review file's top-level \"description\" field (see \"Propose a description\"). Start from the proposal \
                 already there, if there is one, else from the PR's current description. Don't change the PR on GitHub: the user \
                 approves it in dv."
            ),
            Ask::Fix if self.theirs && self.change_requests() == 0 => format!(
                "Use the dv-review skill to suggest the change the user asks for below, in the dv review of {what}: \
                 it's someone else's PR, so don't edit the code; add a comment of yours there with a suggestion block."
            ),
            Ask::Fix if self.theirs => format!(
                "Use the dv-review skill to suggest the changes the open comments in the dv review of {what} ask for \
                 (see \"Suggest the changes\"): it's someone else's PR, so don't edit the code."
            ),
            // Making them (yours, or someone else's when you ask Claude to all the same).
            Ask::Fix | Ask::Edit if self.change_requests() == 0 => format!(
                "Make the change the user asks for below, in {what}. First run `dv review-info`: if the notes it lists \
                 exist, read them and follow them (they're the dv-review skill's notes on this repo)."
            ),
            Ask::Fix | Ask::Edit => format!(
                "Use the dv-review skill to make the changes the open comments in the dv review of {what} ask for \
                 (your own, and the user's: those with \"author\": \"user\"; every one that isn't resolved or outdated), \
                 replying on each with what you changed and resolving the ones you addressed."
            ),
        };
        // Claude Code knows the date but not the time, and makes one up for `created`.
        with_instructions(&format!("{prompt} (It's {} now.)", crate::claude::now()), extra)
    }

    /// Claude's note that PR `n`'s failing CI isn't its doing, written at its head now.
    pub(super) fn ci_note(&self, n: u64) -> Option<crate::claude::CiNote> {
        crate::claude::ci_note(n, &self.pr.as_ref()?.head_oid)
    }

    /// Open Claude's notes on the repo in hx (they're plain markdown; you can write them too).
    pub(super) fn edit_claude_notes(&mut self) {
        match crate::claude::notes_path() {
            Ok(p) => {
                _ = std::fs::create_dir_all(p.parent().unwrap_or(&p));
                self.action = Some(Action::Open(p.display().to_string()));
            }
            Err(e) => self.msg = format!("{e:#}"),
        }
    }

    /// `a`: leave a comment for Claude on the selected lines (or the cursor's), in the review
    /// file; Claude answers right away, as it does replies. Nothing goes to GitHub.
    pub(super) fn start_ask_claude(&mut self) {
        // On a replacement's drafts: a redraft, with what it's about quoted.
        if let Some(which) = self.replacement_draft(self.head.row) {
            let (s, e) = self.ordered();
            let info = self.rows[self.head.row].info;
            let lines: Vec<String> = (s.row..=e.row)
                .filter(|&r| self.rows[r].info == info)
                .map(|r| format!("> {}", self.rows[r].line.text.trim_end()))
                .collect();
            let prs = self.replacement.as_ref().map(crate::replace::Record::ids).unwrap_or_default();
            self.select = false;
            return self.action = Some(Action::Replace(prs, Some(format!("About the {which}:\n{}\n\n", lines.join("\n")))));
        }
        if self.claude.path.is_none() {
            return self.msg = "no review file here (not in a git repo?)".into();
        }
        // On Claude's review summary: a reply to it, about what's selected there (quoted).
        let row = &self.rows[self.head.row];
        if row.info == Some(SUMMARY) && row.thread.is_none() {
            let prefill = match self.selected_quote() {
                Some(q) => format!("About this part of your review:\n{q}"),
                None => String::new(),
            };
            self.select = false;
            return self.action = Some(Action::AskConversation { url: ON_SUMMARY.into(), prefill, want: "" });
        }
        // On the PR's description: Claude proposes a new one (more changes, if it has).
        if self.section_of(self.head.row) == Some(DESCRIPTION) {
            return self.pick_claude(Ask::Describe);
        }
        // On Claude's closing comment: changes to it.
        if self.section_of(self.head.row) == Some(CLOSING_PR) {
            return self.pick_claude(Ask::Close);
        }
        // On a comment in the PR's conversation: a question about it, under it.
        if let Some((url, prefill)) = self.conversation_at_cursor() {
            return self.action = Some(Action::AskConversation { url, prefill, want: "" });
        }
        // On a thread of Claude's review (its comment, or your question and its answer): a reply
        // there, quoting what's selected of it.
        if let Some((t, k)) = self.claude_at_cursor() {
            let quote = self.selected_quote().map_or(String::new(), |q| format!("About this:\n{q}\n"));
            self.select = false;
            let reply = Action::ClaudeReply(k, "", quote);
            return match self.threads[t].conversation.is_empty() {
                true => self.pick_want(reply, Some(t)),
                false => self.action = Some(reply),
            };
        }
        // On a GitHub review thread: ask Claude about the comment under the cursor.
        if let Some(t) = self.rows[self.head.row].thread.filter(|&t| self.threads[t].claude.is_none()) {
            return self.ask_about(t);
        }
        let anchor = match self.selection_anchor() {
            Ok(a) => a,
            Err(_) => return self.msg = "a on code lines leaves Claude a comment there".into(),
        };
        // Line numbers are per side; a range across removed and added lines has no one side.
        if anchor.start.is_some_and(|(_, left)| left != anchor.left) {
            return self.msg = "select lines on one side (removed, or added/unchanged) to leave Claude a comment".into();
        }
        // Their text, so the comment follows its code (as review-check records for Claude's).
        let first = anchor.start.map_or(anchor.line, |s| s.0);
        let code = self.files.iter().find(|f| f.path == anchor.path).and_then(|f| crate::claude::code_at(f, anchor.left, first, anchor.line));
        match code {
            Some(code) => self.pick_want(Action::AskClaude { anchor, code, about: None, want: "" }, None),
            None => self.msg = "those lines aren't in this diff".into(),
        }
    }

    /// The conversation comment under the cursor (its author line or text): its URL, and the
    /// start of a question about it (who, the link, the comment quoted).
    fn conversation_at_cursor(&self) -> Option<(String, String)> {
        let row = &self.rows[self.head.row];
        let body = row.info.filter(|_| row.file == INFO && row.thread.is_none() && row.main.is_none())?;
        let text = self.info.get(body).filter(|l| l.md)?;
        let head = self.info.get(body.checked_sub(1)?).filter(|h| h.heading && !h.url.is_empty() && !h.event)?;
        let who = head.text.split(" · ").next().unwrap_or("");
        // What's selected of it, else all of it.
        // (Hidden on GitHub, unseen: not quoted; Claude reads it at the link.)
        let quote = match self.seen_info(body) {
            None => format!("— {}, not shown here", hidden_words(&head.hidden)),
            Some(_) => self.selected_quote().unwrap_or_else(|| super::quote(&text.text)),
        };
        Some((head.url.clone(), format!("About {who}'s comment ({}):\n{quote}", head.url)))
    }

    /// The selected text, quoted (`> `), when there's a selection.
    fn selected_quote(&self) -> Option<String> {
        (self.select || self.anchor != self.head).then(|| super::quote(self.selection_text(false).trim_end())).filter(|q| !q.is_empty())
    }

    /// Which of a replacement's drafts row `r` is a line of: "description" or "closing note".
    pub(super) fn replacement_draft(&self, r: usize) -> Option<&'static str> {
        self.replacement.as_ref()?;
        let row = &self.rows[r];
        let i = row.info.filter(|_| row.file == INFO)?;
        let heading = self.info.get(i.checked_sub(1)?).filter(|h| h.heading && self.info[i].md)?;
        [("description", "description"), ("closing note", "closing note")].into_iter().find(|(h, _)| heading.text.starts_with(h)).map(|x| x.1)
    }

    /// `a` on a GitHub review thread: a comment for Claude on its lines, asking about the comment
    /// under the cursor (quoted unless it's hidden on GitHub, with its link, else its id, so
    /// Claude reads it and the thread).
    fn ask_about(&mut self, t: usize) {
        let th = &self.threads[t];
        let Some(line) = th.line else { return self.msg = "this thread is outdated: its lines aren't in the diff to ask about".into() };
        let Some(c) = self.comment_under_cursor(t) else { return self.msg = "move onto a comment to ask about it".into() };
        let anchor = Anchor { path: th.path.clone(), line, left: th.left, start: th.start_line.filter(|&s| s < line).map(|s| (s, th.left)) };
        let first_line = anchor.start.map_or(line, |s| s.0);
        let Some(code) = self.files.iter().find(|f| f.path == anchor.path).and_then(|f| crate::claude::code_at(f, anchor.left, first_line, line)) else {
            return self.msg = "those lines aren't in this diff".into();
        };
        let link = self.pr.as_ref().map(|p| format!(" ({}#discussion_r{})", p.url, c.id)).unwrap_or_default();
        // (Hidden on GitHub, unseen: not quoted; said so, for Claude to read it there.)
        let quote: String = match self.seen_body(c) {
            Some(body) => body.lines().map(|l| format!("> {l}\n")).collect(),
            None => format!("— {}, not shown here\n", hidden_words(&c.hidden)),
        };
        // (Its id, where there's no link with it.)
        let link = if link.is_empty() { format!(" (id {})", c.id) } else { link };
        let prefill = format!("About @{}'s comment{link}:\n{quote}\n", c.author);
        self.action = Some(Action::AskClaude { anchor, code, about: Some((c.id, prefill)), want: "" });
    }

    /// From the `Space a` menu. Reviewing and making the changes first ask for your own
    /// instructions (an editor; optional, except for a change with no open comments to act on,
    /// where they're the request); answering replies just goes. Anything that would stop Claude
    /// taking it is checked first, so what you write isn't lost.
    pub(super) fn pick_claude(&mut self, ask: Ask) {
        // (Before the editor: nothing you write is lost to it.)
        if let Some(why) = self.claude_blocked(Some(ask)).or_else(|| self.pane_cant(ask)) {
            return self.msg = why;
        }
        match ask {
            Ask::Describe | Ask::Close if self.pr.is_none() => self.msg = "no PR here".into(),
            Ask::Review | Ask::Fix | Ask::Edit | Ask::Describe | Ask::Close => self.action = Some(Action::ClaudeWith(ask)),
            ask => _ = self.run_claude(ask, ""),
        }
    }

    /// Ask Claude (`extra`: your instructions, may be empty). Whether it was asked: if not,
    /// `msg` says why.
    pub(super) fn run_claude(&mut self, ask: Ask, extra: &str) -> bool {
        if matches!(ask, Ask::Answer) && self.waiting_replies() == 0 {
            self.msg = "no replies waiting for Claude (r on a Claude comment replies)".into();
            return false;
        }
        let requests = self.change_requests();
        if matches!(ask, Ask::Fix | Ask::Edit) && requests == 0 && extra.trim().is_empty() {
            self.msg = "nothing to change: no open comments, and no instructions written".into();
            return false;
        }
        if let Some(why) = self.claude_blocked(Some(ask)) {
            self.msg = why;
            return false;
        }
        // Fixing CI afresh: Claude's last word that it isn't the PR's doing goes (it says so
        // again, if it still finds that).
        if let (Ask::FixChecks, Some(p)) = (ask, &self.pr) {
            crate::claude::ci_note_path(p.number).map(std::fs::remove_file).ok();
        }
        let prompt = self.claude_prompt(ask, extra);
        let label = match ask {
            Ask::Review => "reviewing",
            Ask::Answer => "answering your replies",
            Ask::Describe => "proposing a description",
            Ask::Fix if self.theirs => "suggesting the changes",
            Ask::Edit => "making the changes",
            Ask::Close => "drafting a closing comment",
            Ask::Fix => "making the changes",
            Ask::FixChecks => "fixing CI",
        };
        // Claude already open on this PR in a pane: put the request there, rather than open
        // another. Pasted, not sent: what the pane is showing (a permission prompt, your own
        // half-typed text) isn't dv's to answer, so you press Enter there.
        if let Some(pane) = self.claude_pane() {
            if let Some(why) = self.pane_cant(ask) {
                self.msg = why;
                return false;
            }
            let (msg, asked) = match offer_to_pane(pane, &prompt) {
                Ok(true) => (format!("{label}: the request is in Claude's pane, press Enter there to send it"), true),
                Ok(false) => ("Claude's pane is waiting for you to answer it; ask again after".into(), false),
                Err(e) => (format!("Claude's pane: {e:#}"), false),
            };
            self.msg = msg;
            return asked;
        }
        let mut path_env = std::ffi::OsString::from("PATH=");
        path_env.push(path_for_claude());
        let (msg, asked) = match in_zellij() {
            // A real session in a pane (the PR's, as the background runs use): watch it, approve
            // what it asks, talk to it.
            // Floating and unfocused: hidden while zellij's floating panes are (`Space a` →
            // show it, or zellij's own toggle); dv says when it's asking you something, and
            // closes it once Claude's done there (`close_if_done`).
            true => match std::process::Command::new("zellij")
                .args(["run", "--floating", "--no-focus", "--name", &format!("claude: {label}"), "--cwd"])
                .arg(&self.root)
                .args(["--", "env"])
                .arg(path_env) // the pane gets zellij's environment, not dv's
                .args(data_env()) // and so the same dv directory as this one, which it watches
                .args(["claude", &prompt])
                .args(self.session_args())
                .args(claude_dirs())
                .stdin(std::process::Stdio::null())
                .stdout(std::process::Stdio::null())
                .stderr(std::process::Stdio::null())
                .status()
            {
                Ok(s) if s.success() => {
                    // For dv list: at it while its pane is open (a session: when it's done
                    // working there, only the pane knows).
                    if let (Some(p), Some(id)) = (&self.pr, &self.claude.session) {
                        crate::claude::mark_running(p.number, &format!("{label} (in its pane)"), None, Some(id));
                    }
                    (format!("Claude is {label} in a hidden pane (Space a shows it; it closes when Claude's done); its comments show up here as it writes them"), true)
                }
                Ok(s) => (format!("zellij run failed ({s})"), false),
                Err(e) => (format!("running zellij: {e}"), false),
            },
            false => match self.spawn_claude(&prompt, label, false, tools_for(self.pr.as_ref().filter(|_| matches!(ask, Ask::FixChecks)).map(|p| p.number)).as_deref().as_slice()) {
                Ok(job) => {
                    self.claude.job = Some(job);
                    (format!("Claude is {label} in the background…"), true)
                }
                Err(e) => (format!("starting claude: {e:#}"), false),
            },
        };
        self.msg = msg;
        asked
    }

    /// After `r` on Claude's comment (or `a`): have Claude answer right away, in the
    /// background (also in zellij: a pane per reply would get in the way). If the PR's session
    /// is open in a pane, this runs on a fork of it: the same conversation so far, without two
    /// processes on one session. Replies made while it's working get one more run when it
    /// finishes. Returns what to tell the user.
    pub(super) fn answer_now(&mut self) -> String {
        if self.claude.job.is_some() {
            self.claude.again = true;
            return "reply saved; Claude answers it when it's done with what it's doing".into();
        }
        if let Some(why) = self.claude_blocked(Some(Ask::Answer)) {
            return format!("reply saved; {why} (then Space a has Claude answer)");
        }
        let prompt = self.claude_prompt(Ask::Answer, "");
        let forked = self.claude_pane().is_some();
        match self.spawn_claude(&prompt, "answering", forked, &[]) {
            Ok(job) => {
                self.claude.job = Some(job);
                "reply sent; Claude is answering…".into()
            }
            Err(e) => format!("reply saved, but starting claude failed: {e:#} (Space a to retry)"),
        }
    }

    /// The zellij pane running this PR's Claude Code session, if one is open: dv starts those
    /// with the session id on the command line, which no other pane has.
    pub(super) fn claude_pane(&self) -> Option<u64> {
        self.claude_pane_cmd().map(|p| p.0)
    }

    /// `Space a` → show Claude's pane (`show_pane`).
    pub(super) fn show_claude_pane(&mut self) {
        let Some((pane, ..)) = self.claude_pane_cmd() else { return self.msg = "Claude's pane is closed".into() };
        if show_pane(pane).is_err() {
            self.msg = "zellij couldn't show Claude's pane".into();
        }
    }

    /// Every few seconds: whether Claude's pane (hidden, maybe) is asking you something, a
    /// permission prompt it won't get past alone; said once each time it starts asking.
    pub(super) fn watch_claude_pane(&mut self) {
        if self.claude.session.is_none() || !in_zellij() || self.claude.pane_check.is_some_and(|t| t.elapsed() < std::time::Duration::from_secs(3)) {
            return;
        }
        self.claude.pane_check = Some(std::time::Instant::now());
        let pane = self.claude_pane();
        let screen = pane.map(pane_screen);
        let asking_now = screen.as_deref().is_some_and(asking);
        if asking_now && !self.claude.asking {
            self.msg = "Claude is asking you something in its pane: Space a → Show Claude's pane".into();
        }
        self.claude.asking = asking_now;
        // Claude Code says how to stop it while it's working.
        self.claude.pane_busy = screen.as_deref().is_some_and(working);
        // Done there: its pane closes (`close_if_done`); the session stays, for the next ask.
        // (The PR's marker may be another checkout's run: only this one's session counts.)
        let (Some(pr), Some(pane)) = (self.pr.as_ref().map(|p| p.number), pane) else { return };
        let Some((session, since)) = crate::claude::pane_run(pr).filter(|r| Some(&r.0) == self.claude.session.as_ref()) else { return };
        if close_if_done(pane, &session, since) {
            crate::claude::clear_running(pr);
            self.msg = "Claude's done: its pane closed (Space a asks it more, in the same session)".into();
        }
    }

    /// What Claude is doing here, for the pinned title: a run in the background, or its pane
    /// busy (or waiting on you). `None` when it's idle.
    pub(super) fn claude_doing(&self) -> Option<String> {
        match &self.claude.job {
            Some(j) => Some(format!("◐ claude: {} {}", j.label, ago(j.started))),
            None if self.claude.asking => Some("◐ claude is asking you (Space a)".into()),
            None if self.claude.pane_busy => Some("◐ claude working (its pane)".into()),
            None => None,
        }
    }

    /// The PR's Claude pane and its command line.
    fn claude_pane_cmd(&self) -> Option<(u64, String)> {
        let id = self.claude.session.as_ref().filter(|_| in_zellij())?;
        super::term::zellij_panes(&["-c", "-t"]).unwrap_or_default().iter().find_map(|p| {
            let cmd = p["pane_command"].as_str().filter(|c| p["exited"] != true && c.contains(id.as_str()))?;
            Some((p["id"].as_u64()?, cmd.to_owned()))
        })
    }

    /// The PR's Claude Code session in this checkout: resume it if Claude Code has it, else
    /// start it under a new id. The id is saved next to the review file (per checkout, as Claude
    /// Code keeps sessions per directory), so the next run continues the same conversation. One
    /// that never started (a pane that failed) isn't resumed: Claude Code doesn't have it.
    fn session_args(&mut self) -> [String; 2] {
        match self.claude.session.clone().filter(|id| crate::claude::session_exists(id)) {
            Some(id) => ["--resume".into(), id],
            None => {
                let id = crate::claude::new_session_id();
                self.set_session(Some(id.clone()));
                ["--session-id".into(), id]
            }
        }
    }

    /// Remember (or, with `None`, forget) the PR's session in this checkout, on disk too.
    pub(super) fn set_session(&mut self, id: Option<String>) {
        if let Some(p) = &self.claude.path {
            _ = crate::claude::save_session(p, &self.root, id.as_deref());
        }
        self.claude.session = id;
    }

    /// `claude -p` in the background: its result (JSON) in a log file, its errors next to it.
    /// It runs in the PR's session (or, `forked`, a fork of it), so Claude keeps the review's
    /// context across runs.
    /// `more`: tools it may use on top of `ALLOWED`.
    pub(super) fn spawn_claude(&mut self, prompt: &str, label: &'static str, forked: bool, more: &[&str]) -> Result<ClaudeJob> {
        use std::os::unix::process::CommandExt;
        // One log per run, so a follow-up run doesn't wipe the one a message points to.
        self.claude.runs += 1;
        let log = std::env::temp_dir().join(format!("dv-claude-{}-{}.log", std::process::id(), self.claude.runs));
        let err = log.with_extension("err");
        let mut session = self.session_args().to_vec();
        if forked {
            session.push("--fork-session".into());
        }
        let child = claude_command(prompt, &self.root, &session, more, None)
            .stdin(std::process::Stdio::null())
            .stdout(std::fs::File::create(&log)?)
            .stderr(std::fs::File::create(&err)?)
            .process_group(0) // so stopping it stops what it's running too
            .spawn()
            .context("is Claude Code (`claude`) installed?")?;
        self.claude.log = Some(log.clone());
        // For dv list (a fork, its pane open: that pane's marker stays, for closing it later).
        if let Some(p) = self.pr.as_ref().filter(|_| !forked) {
            crate::claude::mark_running(p.number, label, Some(child.id()), None);
        }
        Ok(ClaudeJob { child, log, label, forked, started: std::time::Instant::now() })
    }

    /// When a background run ends: keep its session for the next one, say how it went (its
    /// writes have already shown up via `watch_claude`), and answer replies made meanwhile.
    pub(super) fn poll_claude(&mut self) {
        let Some(job) = &mut self.claude.job else { return };
        let Ok(Some(st)) = job.child.try_wait() else { return };
        let Some(ClaudeJob { log, label, forked, .. }) = self.claude.job.take() else { return };
        if let Some(p) = self.pr.as_ref().filter(|_| !forked) {
            crate::claude::clear_running(p.number);
        }
        self.reload_tree(); // it may have changed code (making changes, or answering a request)
        let out: Option<serde_json::Value> = std::fs::read_to_string(&log).ok().and_then(|t| serde_json::from_str(&t).ok());
        let failed = !st.success() || out.as_ref().is_none_or(|v| v["is_error"] == true);
        // A fork's id isn't the PR's session (that one's open in a pane): keep the PR's.
        match out.as_ref().and_then(|v| v["session_id"].as_str()) {
            _ if forked => {}
            Some(id) if !failed => self.set_session(Some(id.to_owned())),
            _ => self.set_session(None), // e.g. the session is gone: start afresh next time
        }
        // A run can end "successfully" having been refused what it needed: say what.
        let refused = out.as_ref().and_then(refusal);
        let cost = out.as_ref().and_then(|v| v["total_cost_usd"].as_f64());
        self.claude.spent += cost.unwrap_or(0.0);
        let took = match (out.as_ref().and_then(|v| v["num_turns"].as_u64()), cost) {
            (Some(n), Some(c)) => format!(" ({n} turns, ${c:.2})"),
            _ => String::new(),
        };
        self.msg = match (failed, &refused) {
            (false, None) => format!("Claude is done {label}{took}"),
            (false, Some(r)) => format!("Claude finished {label}, but was refused {r}: see {}", log.display()),
            (true, Some(r)) => format!("Claude stopped while {label}, refused {r}: see {}", log.display()),
            (true, None) => format!("Claude stopped ({st}) while {label}: see {} (and .err)", log.display()),
        };
        // A rebase Claude carried on: how it stands now.
        if label == super::rebase::REBASE_LABEL {
            self.rebase_ended();
        }
        // Placing changes for an amend: its answers, in the picker.
        // (Not over what you're at: a picker, a prompt, an action on its way.)
        if label == super::amend::AMEND_LABEL && !failed && refused.is_none() {
            match self.picker.is_none() && self.prompt.is_none() && self.action.is_none() {
                true => self.amend_menu(),
                false => self.msg += " (Space g → amend shows where it put them)",
            }
        }
        // Replies made meanwhile: one more run, unless this one went wrong (then that's the news,
        // and retrying would hit the same wall).
        if std::mem::take(&mut self.claude.again) && self.waiting_replies() > 0 {
            match failed || refused.is_some() || super::rebase::rebasing(&self.root) {
                true => self.msg += " · your newer replies wait (Space a to retry)",
                false => self.msg = self.answer_now(),
            }
        }
    }

}

/// What a run's result says it was refused, in a few words: the first refusal's tool and its
/// target (first line, kept short for the status bar), "and N more" if there were others.
pub(super) fn refusal(out: &serde_json::Value) -> Option<String> {
    let denied = out["permission_denials"].as_array().filter(|d| !d.is_empty())?;
    let d = &denied[0];
    let input = &d["tool_input"];
    let target = ["file_path", "path", "command", "pattern", "url"].iter().find_map(|k| input[*k].as_str()).unwrap_or("");
    let target: String = target.lines().next().unwrap_or("").chars().take(60).collect();
    let more = match denied.len() {
        1 => String::new(),
        n => format!(" (and {} more)", n - 1),
    };
    Some(format!("{} {target}{more}", d["tool_name"].as_str().unwrap_or("a tool")).replace("  ", " ").trim().to_owned())
}

/// Put `prompt` in a Claude Code pane's input, as a paste (so a multi-line prompt arrives
/// whole), and focus the pane; you press Enter there. Not if the pane is asking you something
/// (a permission prompt): `Ok(false)`, and nothing is typed.
fn offer_to_pane(pane: u64, prompt: &str) -> Result<bool> {
    let id = format!("terminal_{pane}");
    let zellij = |args: &[&str]| -> Result<std::process::Output> {
        let out = std::process::Command::new("zellij").args(args).stdin(std::process::Stdio::null()).output()?;
        anyhow::ensure!(out.status.success(), "zellij {} failed ({})", args[1], out.status);
        Ok(out)
    };
    let screen = String::from_utf8_lossy(&zellij(&["action", "dump-screen", "-p", &id])?.stdout).into_owned();
    if asking(&screen) {
        return Ok(false);
    }
    // In another tab (an older dv's Claude tab): not pasted into, as it couldn't be focused
    // there (zellij can crash on it), and Enter would go to whichever pane is.
    anyhow::ensure!(!in_other_tab(pane), "it's in another zellij tab (an older dv's): close it there, and Space a starts one here");
    zellij(&["action", "paste", "-p", &id, prompt])?;
    show_pane(pane)?;
    Ok(true)
}

/// Close Claude's pane `pane` (session `session`, run since `since`) if Claude's done there:
/// its transcript says it ended its turn (`turn_ended`: not a guess from the screen), not on a
/// question for you, nor asking you something (a permission), with nothing in its input box (a
/// request waiting for Enter, words of yours), and you aren't looking at it. Whether it closed.
pub(crate) fn close_if_done(pane: u64, session: &str, since: i64) -> bool {
    let Some(last) = crate::claude::turn_ended(session, since) else { return false };
    if last.trim_end().ends_with('?') {
        return false;
    }
    let id = format!("terminal_{pane}");
    let zellij = |args: &[&str]| std::process::Command::new("zellij").arg("action").args(args).stdin(std::process::Stdio::null()).output().ok();
    // With its styling: what's typed, not Claude Code's dimmed suggestions.
    let Some(screen) = zellij(&["dump-screen", "-a", "-p", &id]).map(|o| String::from_utf8_lossy(&o.stdout).into_owned()) else { return false };
    if asking(&strip_ansi(&screen)) || !input_empty(&screen) {
        return false;
    }
    // Focused in its tab, and up there (its tab's floating panes shown, or tiled): you may be
    // reading it.
    let panes = super::term::zellij_panes(&["-c", "-t"]).unwrap_or_default();
    let Some(me) = panes.iter().find(|p| p["id"].as_u64() == Some(pane) && p["is_plugin"] != true) else { return false };
    let tab = me["tab_id"].as_u64().map(|t| t.to_string()).unwrap_or_default();
    let shown = || zellij(&["are-floating-panes-visible", "--tab-id", &tab]).is_some_and(|o| String::from_utf8_lossy(&o.stdout).trim() == "true");
    if me["is_focused"] == true && (me["is_floating"] != true || shown()) {
        return false;
    }
    zellij(&["close-pane", "-p", &id]).is_some_and(|o| o.status.success())
}

/// Whether Claude Code's input box on `screen` (with its styling, `dump-screen -a`) is empty:
/// what's between its last two rules (`────`), past the `❯` prompt, has nothing typed (in the
/// text's own color: its suggestions, dimmed or grey, aren't). Not found: not empty (nothing's
/// closed on a guess).
pub(super) fn input_empty(screen: &str) -> bool {
    let lines: Vec<&str> = screen.lines().collect();
    let rule = |l: &str| {
        let t = strip_ansi(l);
        t.trim().chars().count() >= 10 && t.trim().chars().all(|c| c == '─')
    };
    let rules: Vec<usize> = (0..lines.len()).filter(|&i| rule(lines[i])).collect();
    let [.., a, b] = rules[..] else { return false };
    !lines[a + 1..b].iter().any(|l| typed(l))
}

/// Whether `line` (with its styling) has text in a plain color: not dimmed, not grey.
fn typed(line: &str) -> bool {
    let (mut dim, mut grey) = (false, false);
    let mut chars = line.chars().peekable();
    while let Some(c) = chars.next() {
        if c == '\x1b' {
            if chars.peek() == Some(&'[') {
                chars.next();
                let mut params = String::new();
                for d in chars.by_ref() {
                    if d.is_ascii_alphabetic() {
                        if d == 'm' {
                            sgr(&params, &mut dim, &mut grey);
                        }
                        break;
                    }
                    params.push(d);
                }
            }
            continue;
        }
        if !dim && !grey && !c.is_whitespace() && !matches!(c, '❯' | '>' | '\u{a0}' | '│') {
            return true;
        }
    }
    false
}

/// An SGR's effect on dim and grey (a grey: equal r, g, b below 200; 90; 8 or 232–250).
fn sgr(params: &str, dim: &mut bool, grey: &mut bool) {
    let n: Vec<u32> = params.split(';').map(|p| p.parse().unwrap_or(0)).collect();
    let mut i = 0;
    while i < n.len() {
        match n[i] {
            0 => (*dim, *grey) = (false, false),
            2 => *dim = true,
            22 => *dim = false,
            30..=37 | 39 | 91..=97 => *grey = false,
            90 => *grey = true,
            38 if n.get(i + 1) == Some(&2) && i + 4 < n.len() => {
                let (r, g, b) = (n[i + 2], n[i + 3], n[i + 4]);
                *grey = r == g && g == b && r < 200;
                i += 4;
            }
            38 if n.get(i + 1) == Some(&5) => {
                *grey = n.get(i + 2).is_some_and(|&c| c == 8 || (232..=250).contains(&c));
                i += 2;
            }
            _ => {}
        }
        i += 1;
    }
}

/// `s` without its ANSI escape sequences.
pub(crate) fn strip_ansi(s: &str) -> String {
    let mut out = String::with_capacity(s.len());
    let mut chars = s.chars().peekable();
    while let Some(c) = chars.next() {
        if c == '\x1b' && chars.peek() == Some(&'[') {
            chars.next();
            for d in chars.by_ref() {
                if d.is_ascii_alphabetic() {
                    break;
                }
            }
            continue;
        }
        out.push(c);
    }
    out
}

/// What zellij pane `pane` shows (its screen, plain).
pub(crate) fn pane_screen(pane: u64) -> String {
    let out = std::process::Command::new("zellij").args(["action", "dump-screen", "-p", &format!("terminal_{pane}")]).stdin(std::process::Stdio::null()).output();
    out.map(|o| String::from_utf8_lossy(&o.stdout).into_owned()).unwrap_or_default()
}

/// Bring Claude's pane `pane` up: in another tab (an older dv's Claude tab), that tab; in dv's
/// own, the pane focused. Not focused in another tab: zellij
/// (0.45) can panic doing that, taking the session down ("Cannot focus pane … as it is not
/// selectable").
fn show_pane(pane: u64) -> Result<()> {
    let args = match pane_tab(pane).filter(|_| in_other_tab(pane)) {
        Some(t) => vec!["go-to-tab-by-id".to_owned(), t.to_string()],
        None => vec!["focus-pane-id".to_owned(), format!("terminal_{pane}")],
    };
    let st = std::process::Command::new("zellij").arg("action").args(&args).stdin(std::process::Stdio::null()).status()?;
    anyhow::ensure!(st.success(), "zellij {} failed ({st})", args[0]);
    Ok(())
}

/// Whether a Claude Code pane's screen shows it working: its spinner line, a word and how long
/// it's been at it ("· Moseying… (59s · ↓ 1.3k tokens)"), or, as it used to say, how to stop it.
pub(crate) fn working(screen: &str) -> bool {
    screen.contains("esc to interrupt") || screen.lines().any(|l| l.split_once("… (").is_some_and(|(_, t)| t.starts_with(|c: char| c.is_ascii_digit())))
}

/// Whether a Claude Code pane's screen shows it asking you something: a permission prompt, or
/// (in a folder it hasn't seen) whether you trust it. Typing in then would answer it.
pub(crate) fn asking(screen: &str) -> bool {
    ["Do you want", "Would you like", "❯ 1.", "trust this folder"].iter().any(|p| screen.contains(p))
}

/// Have Claude draft a replacement for `prs` with a dv of its own (`dv replace`), in the
/// background: it carries on if this dv quits. Its output goes to a log in the temp dir.
pub(super) fn spawn_replace(prs: &[u64]) -> Result<()> {
    use std::os::unix::process::CommandExt;
    let log = std::env::temp_dir().join(format!("dv-replace-{}.log", prs[0]));
    std::process::Command::new(crate::self_exe())
        .arg("replace")
        .args(prs.iter().map(u64::to_string))
        .stdin(std::process::Stdio::null())
        .stdout(std::fs::File::create(&log)?)
        .stderr(std::fs::File::create(log.with_extension("err"))?)
        .process_group(0) // not this terminal's: closing it doesn't stop the draft
        .spawn()?;
    Ok(())
}

/// The tab zellij pane `pane` is in.
fn pane_tab(pane: u64) -> Option<u64> {
    super::term::zellij_panes(&["-c", "-t"]).unwrap_or_default().iter().find(|p| p["id"].as_u64() == Some(pane) && p["is_plugin"] != true).and_then(|p| p["tab_id"].as_u64())
}

/// Whether zellij pane `pane` is in another tab than dv's.
fn in_other_tab(pane: u64) -> bool {
    let own = std::env::var("ZELLIJ_PANE_ID").ok().and_then(|id| id.parse().ok()).and_then(pane_tab);
    pane_tab(pane).is_some_and(|t| own.is_some_and(|o| o != t))
}

/// `prompt`, with the user's own instructions (if any) after it.
pub(crate) fn with_instructions(prompt: &str, extra: &str) -> String {
    match extra.trim() {
        "" => prompt.to_owned(),
        e => format!("{prompt}\n\nThe user adds:\n{e}"),
    }
}

/// `--add-dir` for dv's directory (the review files and notes): it's outside the checkout
/// Claude runs in, which is all Claude Code lets it touch otherwise.
pub(super) fn claude_dirs() -> Vec<std::ffi::OsString> {
    match crate::claude::dv_dir() {
        Ok(dv) => vec!["--add-dir".into(), dv.into_os_string()],
        Err(_) => vec![],
    }
}

/// Asking Claude to review `what` ("PR #12").
/// Claude's prompt for updating its review of `what` after new commits on top of `old`.
pub(crate) fn update_prompt(what: &str, old: &str) -> String {
    format!(
        "Use the dv-review skill to update your dv review of {what}: review only what changed since you reviewed {old} \
         (`git diff {old}`), and keep the comments that still apply."
    )
}

/// What the editor says Claude will do with what you write, for `want`.
pub(super) fn want_hint(want: &str) -> &'static str {
    WANTS.iter().find(|w| w.0 == want).map_or(" (it answers right away; nothing goes to GitHub)", |w| w.2)
}

/// Claude's prompt for answering your replies in its review of `what` (`theirs`: someone
/// else's PR, so suggestions where you didn't say).
pub(crate) fn answer_prompt(what: &str, theirs: bool) -> String {
    let base = format!(
        "Use the dv-review skill to answer my replies (and the comments I left for you) in the dv review of {what}. \
         Where I said what I want (\"want\"), do exactly that (see \"What the user wants\")."
    );
    match theirs {
        true => format!(
            "{base} It's someone else's PR: where I didn't say, and ask for a change, suggest it rather than edit the code \
             (see \"Suggest the changes\")."
        ),
        false => base,
    }
}

/// Claude's prompt for fixing PR `n`'s failing CI.
pub(crate) fn fix_checks_prompt(n: u64) -> String {
    let note = crate::claude::ci_note_path(n).map(|p| p.display().to_string()).unwrap_or_else(|_| "ci/pr-N.json in dv's directory".into());
    format!(
        "CI fails on PR #{n}. See which checks fail (`gh pr checks`) and why (`gh run view <run id> --log-failed`), \
         then fix the cause in the code here, and check the fix (build, tests). Don't commit or push: the user \
         reviews and pushes it. If it isn't this PR's fault (a flaky test, CI itself, something already broken on \
         its base branch), change nothing here; instead write {note} as JSON: \
         {{\"head\": \"<git rev-parse HEAD>\", \"why\": \"<one line: what fails and why it isn't this PR>\", \
         \"task\": \"<what a separate PR fixing it should do, a few lines; empty if nothing in the repo would fix \
         it>\", \"rerun\": false}}: the user can have a PR drafted from it. If the failure looks transient (a \
         network error, a timeout, a runner problem, a test known to be flaky), also rerun the failed jobs once \
         (`dv rerun-failed -p {n}`: the failed jobs only, of every failed run on its head) and set \"rerun\": true; but not if {note} \
         already has \"rerun\": true for this head (CI was rerun once already: it isn't transient), and then \
         keep \"rerun\": true in the note you write. First run \
         `dv review-info`: if the notes it lists exist, read them and follow them."
    )
}

pub(crate) fn review_prompt(what: &str) -> String {
    format!("Use the dv-review skill to review {what} for dv. If there's already a review, update it.")
}

/// `claude -p prompt` in `dir` as dv runs it in the background: its result as JSON on stdout,
/// edits allowed, in the session `session` names (`--resume <id>`, `--session-id <id>`, …),
/// with dv's directory reachable, and only the commands the skill needs.
/// `more`: tools allowed on top of the usual ones; `access`: the one directory outside `dir`
/// Claude may write to (`None`: all of dv's).
pub(crate) fn claude_command(prompt: &str, dir: &Path, session: &[String], more: &[&str], access: Option<&Path>) -> std::process::Command {
    let mut cmd = std::process::Command::new("claude");
    // No editor to wait on (`git rebase --continue`, `git commit` without -m).
    cmd.env("PATH", path_for_claude()).env("GIT_EDITOR", "true")
        .args(["-p", prompt, "--output-format", "json", "--permission-mode", "acceptEdits"])
        .args(session);
    match access {
        Some(d) => _ = cmd.arg("--add-dir").arg(d),
        None => _ = cmd.args(claude_dirs()),
    }
    // Last: it takes every argument after it.
    cmd.arg("--allowedTools").args(ALLOWED).args(more).current_dir(dir);
    cmd
}

/// PATH for Claude, with this dv's directory first: the skill runs `dv review-*`, which must
/// be found (dv may have been started by its full path, or from a shell whose PATH a zellij
/// pane doesn't get) and be this version.
fn path_for_claude() -> std::ffi::OsString {
    let own = crate::self_exe().parent().map(Path::to_path_buf).filter(|d| !d.as_os_str().is_empty());
    let rest = std::env::var_os("PATH").map(|p| std::env::split_paths(&p).collect::<Vec<_>>()).unwrap_or_default();
    std::env::join_paths(own.into_iter().chain(rest)).unwrap_or_default()
}

/// `XDG_DATA_HOME=…` as dv has it (set, or its default): where its review files are, whatever
/// the pane's environment says.
fn data_env() -> Option<std::ffi::OsString> {
    let mut v = std::ffi::OsString::from("XDG_DATA_HOME=");
    v.push(crate::claude::data_home().ok()?.parent()?);
    Some(v)
}

/// How long since `t`, for the status bar: "40s", "3m".
pub(super) fn ago(t: std::time::Instant) -> String {
    crate::list::todo::ago_secs(t.elapsed().as_secs() as i64)
}

/// Live: on someone else's PR, a comment saying `"want": "change"` gets the code changed (not
/// a suggestion). Runs `claude` with the installed skill and `dv`.
/// `cargo test live_claude_change_on_their_pr -- --ignored --nocapture`
#[test]
#[ignore]
fn live_claude_change_on_their_pr() {
    let dir = crate::diff::scratch_repo("live-change");
    let data = std::env::temp_dir().join(format!("dv-live-change-data-{}", std::process::id()));
    let git = |args: &[&str]| crate::diff::git_in(&dir, args).unwrap();
    std::fs::write(dir.join("count.py"), "def total(xs):\n    return 0\n").unwrap();
    git(&["add", "."]);
    git(&["commit", "-q", "-m", "base"]);
    git(&["checkout", "-q", "-b", "feat"]);
    std::fs::write(dir.join("count.py"), "def total(xs):\n    x = 0\n    for v in xs:\n        x += v\n    return x\n").unwrap();
    git(&["commit", "-q", "-am", "total: sum them"]);
    // dv's directory for this run: on each command (not the test process's, shared).
    let info = std::process::Command::new("dv").arg("review-info").current_dir(&dir).env("XDG_DATA_HOME", &data).output().unwrap();
    let info = String::from_utf8_lossy(&info.stdout);
    let file = info.lines().find_map(|l| l.strip_prefix("file: ")).expect("review-info's file").trim().to_owned();
    std::fs::create_dir_all(Path::new(&file).parent().unwrap()).unwrap();
    let review = serde_json::json!({ "comments": [{
        "path": "count.py", "line": 2, "side": "new", "author": "user", "code": ["    x = 0"],
        "body": "Rename `x` to `acc`, here and below.", "created": crate::claude::now(), "want": "change",
    }]});
    std::fs::write(&file, review.to_string()).unwrap();
    // (As dv grants the repo it runs in: here the test is elsewhere, so this run's directory.)
    let out = claude_command(&answer_prompt("the current branch", true), &dir, &[], &[], Some(&data.join("dv"))).env("XDG_DATA_HOME", &data).stdin(std::process::Stdio::null()).output().unwrap();
    let said: serde_json::Value = serde_json::from_slice(&out.stdout).unwrap_or_default();
    println!("claude: {}\nrefused: {}", said["result"].as_str().unwrap_or(&String::from_utf8_lossy(&out.stderr)), said["permission_denials"]);
    let code = std::fs::read_to_string(dir.join("count.py")).unwrap();
    println!("count.py:\n{code}");
    let after: serde_json::Value = serde_json::from_str(&std::fs::read_to_string(&file).unwrap()).unwrap();
    println!("review: {after:#}");
    assert!(code.contains("acc = 0") && !code.contains(" x "), "the code wasn't changed");
    assert!(!after.to_string().contains("```suggestion"), "suggested instead");
    _ = std::fs::remove_dir_all(&dir);
    _ = std::fs::remove_dir_all(&data);
}