pkh/src/ui/deb.rs

//! Live build view (`pkh deb`, `pkh build`): a status bar with the current
//! build phase on top and a rolling pane of rewritten log lines below
//! ("a terminal in the terminal").
//!
//! Subprocess output is captured through a [`LineSink`] implementation,
//! rewritten by classifiers ([`crate::logfmt`]) and rendered in place
//! with indicatif, so pkh's own log lines keep printing above the widget via
//! `indicatif-log-bridge`. Every raw captured line is also tee'd to a log
//! file under the pkh cache directory.

use std::collections::VecDeque;
use std::fs::{self, File};
use std::io::Write;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::{Arc, Mutex};
use std::time::{Duration, Instant};

use crossterm::{cursor, execute, style::Stylize, terminal::Clear, terminal::ClearType};
use directories::ProjectDirs;
use indicatif::{MultiProgress, ProgressBar, ProgressStyle};

use crate::context::{LineSink, Stream};
use crate::logfmt::{Action, Classifier, GenericClassifier};
use crate::report::BuildTarget;

/// Number of lines displayed in the rolling pane
const PANE_LINES: usize = 10;

/// Minimum interval between pane redraws
const REDRAW_INTERVAL: Duration = Duration::from_millis(50);

/// Visual kind of a pane line, driving its color
#[derive(Debug, Clone, Copy, PartialEq)]
enum Kind {
    Normal,
    Warning,
    Error,
}

/// Mutable state shared between the sink and the widget
struct Pipeline {
    classifier: Box<dyn Classifier>,
    lines: VecDeque<(Kind, String)>,
    errors: Vec<String>,
    last_draw: Instant,
    bar_total: u64,
}

/// State shared between [`DebUi`] and its sinks
struct Shared {
    top: ProgressBar,
    pane: ProgressBar,
    state: Mutex<Pipeline>,
    tee: Mutex<Option<File>>,
    log_path: Mutex<PathBuf>,
    timestamp: String,
    enabled: bool,
    /// Set once the widget has been removed from the terminal; afterwards all
    /// rendering is skipped so late events cannot redraw stale frames.
    suspended: AtomicBool,
    started: Instant,
}

/// Live build view for `pkh deb` / `pkh build`
///
/// Create one per build (it disables itself automatically when stdout is not
/// a TTY) and pass it down through the [`crate::report::BuildView`] port.
/// Subprocess output reaches it through [`crate::report::BuildView::sink`].
pub struct DebUi {
    shared: Arc<Shared>,
}

impl DebUi {
    /// Create a live view attached to `multi`
    ///
    /// When stdout is not a TTY, the widget is disabled: no bars are drawn,
    /// but captured output is still tee'd to the log file.
    pub fn new(multi: &MultiProgress) -> Self {
        let enabled = is_stdout_tty();

        let top = if enabled {
            let pb = multi.add(ProgressBar::new(0));
            pb.enable_steady_tick(Duration::from_millis(80));
            pb.set_style(spinner_style());
            pb.set_prefix("Building package");
            pb.set_message("(starting…)");
            pb
        } else {
            ProgressBar::hidden()
        };

        let pane = if enabled {
            let pb = multi.add(ProgressBar::new(0));
            pb.enable_steady_tick(Duration::from_millis(150));
            // No template margin: multi-line messages are only prefixed by
            // the template on their first line, which would misalign the
            // pane; each rendered line carries its own indent instead.
            pb.set_style(
                ProgressStyle::default_bar()
                    .template("{msg}")
                    .expect("valid template"),
            );
            pb.set_message("  │ (starting…)");
            pb
        } else {
            ProgressBar::hidden()
        };

        let timestamp = chrono::Utc::now().format("%Y%m%dT%H%M%S").to_string();
        let log_path = default_log_path(&timestamp);

        let ui = Self {
            shared: Arc::new(Shared {
                top,
                pane,
                state: Mutex::new(Pipeline {
                    classifier: Box::new(GenericClassifier::new()),
                    lines: VecDeque::new(),
                    errors: Vec::new(),
                    last_draw: Instant::now(),
                    bar_total: 0,
                }),
                tee: Mutex::new(None),
                log_path: Mutex::new(log_path.clone()),
                timestamp,
                enabled,
                suspended: AtomicBool::new(false),
                started: Instant::now(),
            }),
        };

        if ui.shared.enabled {
            install_sigint_hook(&log_path);
        }

        ui
    }

    /// Identify the binary package being built; names the log file and the
    /// status bar
    pub fn set_target(&self, package: &str, version: &str, series: &str, arch: &str) {
        if self.shared.enabled {
            self.shared.top.set_prefix(format!(
                "Building {package} ({version}) for {series}/{arch}"
            ));
        }
        self.open_log("deb", package, version, &format!("for {series}/{arch}"));
    }

    /// Rename the placeholder log file to include the build identity
    /// (best-effort), then open it so subsequent captured lines are tee'd
    fn open_log(&self, kind: &str, package: &str, version: &str, detail: &str) {
        let old_path = self.shared.log_path.lock().unwrap().clone();
        let log_path = match old_path.parent() {
            Some(dir) => dir.join(format!(
                "{kind}-{package}-{version}-{}.log",
                self.shared.timestamp
            )),
            None => old_path.clone(),
        };
        let _ = fs::rename(&old_path, &log_path);
        *self.shared.log_path.lock().unwrap() = log_path.clone();
        update_sigint_log_path(&log_path);

        if let Some(dir) = log_path.parent() {
            let _ = fs::create_dir_all(dir);
        }
        match File::create(&log_path) {
            Ok(mut file) => {
                let _ = writeln!(
                    file,
                    "# pkh {kind} {package} ({version}) {detail} started {}",
                    chrono::Utc::now().to_rfc3339()
                );
                *self.shared.tee.lock().unwrap() = Some(file);
            }
            Err(e) => {
                log::warn!(
                    "Could not create build log file {}: {}",
                    log_path.display(),
                    e
                );
            }
        }
    }

    /// Switch to an arbitrary status label with a custom classifier
    fn phase_custom(&self, label: &str, classifier: Box<dyn Classifier>) {
        {
            let mut st = self.shared.state.lock().unwrap();
            st.classifier = classifier;
            st.lines.clear();
            st.bar_total = 0;
            st.last_draw = Instant::now();
        }
        if self.shared.enabled {
            self.shared.top.set_style(spinner_style());
            self.shared.top.set_message(label.to_string());
            self.shared.pane.set_message("");
        }
    }

    /// Whether the widget is enabled and still drawn
    fn active(&self) -> bool {
        self.shared.enabled && !self.shared.suspended.load(Ordering::SeqCst)
    }

    /// Release the widget from the terminal (e.g. before printing
    /// passthrough diagnostics or letting child cleanup commands write to
    /// the terminal); idempotent
    ///
    /// Steady ticks are disabled first: otherwise a tick can redraw a frame
    /// right after the clear, leaving stale copies of the widget on screen.
    fn suspend(&self) {
        if !self.shared.enabled {
            return;
        }
        if self.shared.suspended.swap(true, Ordering::SeqCst) {
            return;
        }
        self.shared.top.disable_steady_tick();
        self.shared.pane.disable_steady_tick();
        self.shared.top.finish_and_clear();
        self.shared.pane.finish_and_clear();
    }

    /// Success outcome body: clear the widget and print the artifacts,
    /// rendered relative to the working directory when possible
    fn success_summary(&self, artifacts: &[PathBuf], elapsed: Duration) {
        self.suspend();
        if self.shared.enabled && !artifacts.is_empty() {
            println!("Built in {}s:", elapsed.as_secs());
            for artifact in artifacts {
                println!("  {}", crate::report::display_path(artifact));
            }
        }
    }

    /// Failure outcome body: clear the widget and print a summary (recent
    /// captured errors and the path to the full log)
    fn failure_summary(&self) {
        self.suspend();

        let st = self.shared.state.lock().unwrap();
        if self.shared.enabled && !st.errors.is_empty() {
            eprintln!("Last captured errors:");
            for err in st
                .errors
                .iter()
                .rev()
                .take(5)
                .collect::<Vec<_>>()
                .iter()
                .rev()
            {
                eprintln!("  {}", err);
            }
        }
        let log_path = self.shared.log_path.lock().unwrap().clone();
        if log_path.exists() {
            eprintln!("Full log: {}", log_path.display());
        }
    }
}

/// [`crate::report::BuildView`] port: forwards build events to the live
/// widget, so core flows drive the view without knowing it is a terminal
/// widget.
impl crate::report::BuildView for DebUi {
    fn target(&self, target: BuildTarget<'_>) {
        if self.shared.enabled {
            self.shared.top.set_prefix(target.display.clone());
        }
        if target.tee_log {
            let kind = if target.source_only { "build" } else { "deb" };
            self.open_log(
                kind,
                target.package,
                target.version,
                &format!("for {}", target.target),
            );
        }
    }

    fn phase(&self, name: &str, classifier: Box<dyn Classifier>) {
        self.phase_custom(name, classifier);
    }

    fn message(&self, text: &str) {
        if self.active() {
            self.shared.top.set_message(text.to_string());
        }
    }

    fn progress(&self, label: &str, pos: usize, total: usize) {
        if !self.active() || total == 0 {
            return;
        }
        apply_progress(
            &self.shared.top,
            &mut self.shared.state.lock().unwrap(),
            pos as u64,
            total as u64,
        );
        self.shared.top.set_message(label.to_string());
    }

    fn sink(&self) -> Option<Arc<dyn LineSink>> {
        Some(Arc::new(Sink {
            shared: self.shared.clone(),
        }))
    }

    fn finish_success(&self, artifacts: &[PathBuf]) {
        self.success_summary(artifacts, self.shared.started.elapsed());
    }

    fn finish_failure(&self) {
        self.failure_summary();
    }

    fn suspend(&self) {
        DebUi::suspend(self);
    }

    fn is_enabled(&self) -> bool {
        self.shared.enabled
    }
}

impl Drop for DebUi {
    fn drop(&mut self) {
        // Safety net: clear the widget on early returns/unwinds
        self.suspend();
    }
}

/// Bridge forwarding captured subprocess lines into the pipeline
struct Sink {
    shared: Arc<Shared>,
}

impl LineSink for Sink {
    fn line(&self, stream: Stream, line: &str) {
        // Tee the raw line first: nothing should be lost, even when the
        // widget is disabled.
        {
            let mut tee = self.shared.tee.lock().unwrap();
            if let Some(file) = tee.as_mut() {
                let _ = writeln!(file, "{line}");
            }
        }

        if !self.shared.enabled || self.shared.suspended.load(Ordering::SeqCst) {
            return;
        }

        let mut st = self.shared.state.lock().unwrap();
        for action in st.classifier.feed(stream, line) {
            match action {
                Action::Hidden => {}
                Action::Progress { pos, total } => {
                    apply_progress(&self.shared.top, &mut st, pos, total)
                }
                Action::Shown(text) => push_line(&self.shared, &mut st, Kind::Normal, text),
                Action::Warning(text) => push_line(&self.shared, &mut st, Kind::Warning, text),
                Action::Error(text) => {
                    if st.errors.len() < 100 {
                        st.errors.push(text.clone());
                    }
                    push_line(&self.shared, &mut st, Kind::Error, text);
                }
            }
        }
    }
}

/// Update the determinate progress bar, restyling it when needed
fn apply_progress(top: &ProgressBar, st: &mut Pipeline, pos: u64, total: u64) {
    if total == 0 {
        return;
    }
    if st.bar_total != total {
        st.bar_total = total;
        top.set_style(determinate_style());
        top.set_length(total);
    }
    top.set_position(pos.min(total));
}

/// Push a line into the rolling pane and redraw (throttled)
///
/// When the pane is full, the oldest non-error line is dropped first so
/// errors stay visible longer.
fn push_line(shared: &Shared, st: &mut Pipeline, kind: Kind, text: String) {
    st.lines.push_back((kind, text));
    while st.lines.len() > PANE_LINES {
        let drop_idx = st
            .lines
            .iter()
            .position(|(k, _)| *k != Kind::Error)
            .unwrap_or(0);
        st.lines.remove(drop_idx);
    }

    let now = Instant::now();
    if now.duration_since(st.last_draw) >= REDRAW_INTERVAL {
        st.last_draw = now;
        shared.pane.set_message(render_pane(&st.lines));
    }
}

/// Render the pane content with per-kind colors
fn render_pane(lines: &VecDeque<(Kind, String)>) -> String {
    lines
        .iter()
        .map(|(kind, text)| match kind {
            Kind::Normal => format!("  │ {text}"),
            Kind::Warning => format!("  │ {}", text.as_str().yellow()),
            Kind::Error => format!("  │ {}", text.as_str().red()),
        })
        .collect::<Vec<_>>()
        .join("\n")
}

/// Status bar style while no determinate progress is known
///
/// The target lives on the first line and the current phase/message on its own
/// line below, so narrow terminals are not overflowed.
fn spinner_style() -> ProgressStyle {
    ProgressStyle::default_bar()
        .template("> {spinner:.blue} {prefix}\n {msg}")
        .expect("valid template")
}

/// Status bar style with a determinate progress bar
///
/// Same two-line layout as [`spinner_style`], plus the bar on a third line.
fn determinate_style() -> ProgressStyle {
    ProgressStyle::default_bar()
        .template("> {spinner:.blue} {prefix}\n {msg} [{bar:24.cyan/blue}] {pos}/{len}")
        .expect("valid template")
        .progress_chars("=> ")
}

/// Whether stdout is a terminal
fn is_stdout_tty() -> bool {
    // SAFETY: isatty only inspects the file descriptor
    unsafe { libc::isatty(libc::STDOUT_FILENO) == 1 }
}

/// Default (placeholder) log file path for a given timestamp; renamed by
/// [`DebUi::set_target`] / [`DebUi::set_build_target`] once the target is known
fn default_log_path(timestamp: &str) -> PathBuf {
    let dir = ProjectDirs::from("com", "pkh", "pkh")
        .map(|dirs| dirs.cache_dir().join("logs"))
        .unwrap_or_else(std::env::temp_dir);
    dir.join(format!("pkh-{timestamp}.log"))
}

static SIGINT_LOG_PATH: Mutex<Option<PathBuf>> = Mutex::new(None);
static SIGINT_INSTALLED: AtomicBool = AtomicBool::new(false);

/// Install a best-effort Ctrl+C handler clearing the widget and pointing at
/// the log file before exiting
fn install_sigint_hook(log_path: &Path) {
    update_sigint_log_path(log_path);
    if SIGINT_INSTALLED.swap(true, Ordering::SeqCst) {
        return;
    }

    // SAFETY: installing a signal handler; the handler itself is best-effort
    // (it performs non async-signal-safe operations, acceptable here because
    // it immediately exits afterwards).
    unsafe {
        libc::signal(libc::SIGINT, on_sigint as *const () as usize);
    }
}

/// Point the sigint handler at the current log file location
fn update_sigint_log_path(log_path: &Path) {
    *SIGINT_LOG_PATH.lock().unwrap() = Some(log_path.to_path_buf());
}

extern "C" fn on_sigint(_sig: libc::c_int) {
    // Best-effort cleanup: clear leftover widget lines and show the cursor
    let _ = execute!(
        std::io::stdout(),
        Clear(ClearType::FromCursorDown),
        cursor::Show
    );
    if let Ok(guard) = SIGINT_LOG_PATH.try_lock()
        && let Some(path) = guard.as_ref()
    {
        eprintln!("\nInterrupted — full log: {}", path.display());
    }
    // Run the registered cleanup hooks (currently: unmount and remove the
    // ephemeral build chroot, see `deb::ephemeral::sigint_cleanup_chroot`),
    // then exit with the conventional 130 status.
    //
    // Like the terminal restoration above, this is NOT strictly
    // async-signal-safe: it locks a mutex, spawns subprocesses and does I/O.
    // That is a deliberate tradeoff, no worse than the rest of this handler:
    // exiting immediately would skip all destructors and leak the chroot
    // together with its bind-mounted /proc and overlay mounts. The hooks are
    // self-contained (they only touch stored paths and spawn umount/rm
    // directly), so they cannot deadlock on a lock the interrupted thread
    // might have held; the hook registry itself is only ever taken with
    // try_lock plus a bounded retry for the same reason. Note that SIGINT
    // stays blocked for the duration of the handler, so a second Ctrl-C will
    // not interrupt a slow cleanup — send SIGTERM/SIGKILL if it ever hangs.
    crate::deb::ephemeral::run_cleanup_hooks();
    // SAFETY: raw exit bypassing destructors, intended in a signal handler
    unsafe {
        libc::_exit(130);
    }
}