//! Native upload of built source packages (`pkh put`): the dput
//! replacement. Resolves the upload target, discovers and validates the
//! `.changes` file and its artifacts, then pushes them over SFTP with
//! host-key verification and an upload record preventing accidental
//! duplicate uploads.
//!
//! Payload files are uploaded first and the `.changes` file last, like
//! dput does, so a partially uploaded set cannot be picked up by the
//! server-side queue processors. A run that fails mid-upload removes its
//! already-uploaded files from the incoming queue (best effort), so a
//! retried upload starts from a clean queue; a failed upload is never
//! recorded in the upload log, so a re-run replays every file.

pub mod changes;
pub mod ssh;
pub mod target;

use std::cmp::Ordering;
use std::path::{Path, PathBuf};

use indicatif::{MultiProgress, ProgressBar};
use log::info;
use serde::{Deserialize, Serialize};

use crate::debian::changelog::parse_changelog_entry;
use crate::debian::checksums::FileChecksums;
use crate::debian::control::ControlInfo;
use crate::debian::version::DebianVersion;
use crate::launchpad;
use crate::ui;

/// Everything `put` needs to run.
pub struct PutOptions {
    /// PPA to upload to, `user/ppa_name` format.
    pub ppa: String,
    /// Explicit `.changes` file to upload; when `None`, the one matching the
    /// current package (from `debian/changelog`) is discovered next to the
    /// source tree.
    pub changes: Option<PathBuf>,
    /// Upload even if this exact `.changes` file was already uploaded to the
    /// target.
    pub force: bool,
    /// Source package directory (the one containing `debian/`).
    pub cwd: PathBuf,
}

/// Upload the package described by `opts` to its target through `multi`'s
/// progress bars.
pub async fn put(
    opts: &PutOptions,
    multi: &MultiProgress,
) -> Result<(), Box<dyn std::error::Error>> {
    let target = launchpad::ppa_target(&opts.ppa)?;

    let ssh_config = ssh::lookup_ssh_config(&target.fqdn);
    let host = ssh_config
        .host_name
        .clone()
        .unwrap_or_else(|| target.fqdn.clone());
    let port = ssh_config.port.unwrap_or(target.port);
    // Launchpad's SFTP server requires a real Launchpad account name as the
    // username: the git configuration (`lp.user`) first, then an SSH
    // configuration `User`, then the local user name
    let login = launchpad::username(&opts.cwd)
        .or(ssh_config.user.clone())
        .or(target.login.clone())
        .or_else(|| std::env::var("USER").ok())
        .ok_or_else(|| {
            format!(
                "cannot determine the Launchpad username for {host}: set it \
                 with `git config --global lp.user <your-launchpad-id>`, or \
                 with a 'User' in the SSH configuration for {host}"
            )
        })?;

    let changes_path = match &opts.changes {
        Some(path) => path.clone(),
        None => discover_changes(&opts.cwd)?,
    };
    let changes = changes::parse(&changes_path)?;

    // The summary line stays up for the whole flow: the completion message
    // replaces it on success, and the `PutBars` guard clears it on every
    // early `?` bail so the error logged by main is not preceded by stale
    // bars
    let mut bars = PutBars::default();
    let summary = multi.add(ProgressBar::new(0));
    // Style and prefix go in before the steady tick: otherwise the first
    // tick can render one frame with the default bar template
    summary.set_style(ui::spinner_style());
    summary.set_prefix(format!(
        "Uploading {} {} to {}",
        changes.source, changes.version, target.label
    ));
    summary.enable_steady_tick(TICK);
    bars.track(summary.clone());
    changes::validate(&changes)?;

    // Pre-flight checks for everything the upload queue only rejects after
    // processing: a valid Section, a known target series, and the target
    // PPA actually existing (the SFTP queue itself is a blind write)
    match section_check_target(opts.changes.as_deref(), &opts.cwd) {
        SectionCheckTarget::Dir(dir) => check_control_section(&dir, "ubuntu")?,
        SectionCheckTarget::Skip => log::warn!(
            "cannot check the Section: '{}' has no debian/control next to \
             it, skipping the pre-flight (the archive still rejects uploads \
             with unknown sections)",
            changes_path.display()
        ),
    }

    let checking = multi.add(ProgressBar::new(0));
    checking.set_style(ui::spinner_style());
    checking.set_prefix(format!("Checking {} on Launchpad...", target.label));
    checking.enable_steady_tick(TICK);
    bars.track(checking.clone());
    launchpad::ppa_info(&opts.ppa).await?;
    launchpad::check_ppa_series(&changes.distribution).await?;
    clear_bar(&checking);

    // Last pre-flight check: a version the PPA already publishes at or
    // above the changes' one would supersede (or reject) this upload
    let published = launchpad::published_versions(&opts.ppa, &changes.source).await?;
    check_not_superseded(&target, &changes, &published, opts.force)?;

    let record = upload_record(&target, &changes_path)?;
    if !opts.force
        && let Some(previous) = find_previous_upload(&upload_log_path()?, &record)?
    {
        return Err(format!(
            "'{}' was already uploaded to {} on {} (use --force to upload again)",
            record.file, target.label, previous.date
        )
        .into());
    }

    let connecting = multi.add(ProgressBar::new(0));
    connecting.set_style(ui::spinner_style());
    connecting.set_prefix(format!("Connecting to {login}@{host}:{port}..."));
    connecting.enable_steady_tick(TICK);
    bars.track(connecting.clone());
    let session = ssh::connect(&host, port, &login, &ssh_config)?;
    let sftp = ssh::sftp(&session)?;
    clear_bar(&connecting);

    // Payload first, the .changes file last (like dput), so the server-side
    // queue processor can never pick up an incomplete upload
    let dir = changes_path.parent().unwrap_or_else(|| Path::new("."));
    let mut uploads: Vec<(PathBuf, String)> = changes
        .files
        .iter()
        .map(|f| (dir.join(&f.name), f.name.clone()))
        .collect();
    let changes_name = changes_path
        .file_name()
        .and_then(|n| n.to_str())
        .ok_or_else(|| format!("invalid .changes path: {}", changes_path.display()))?
        .to_string();
    uploads.push((changes_path.clone(), changes_name.clone()));

    let incoming = target.incoming.trim_end_matches('/');

    // Remote names of the files uploaded so far, in upload order (the
    // .changes last). A run failing mid-upload removes these from the
    // write-only incoming queue before returning: the uploaded payloads
    // would otherwise linger in the queue area forever, and a .changes
    // truncated by a failed close could even be picked up by the scanner.
    let mut uploaded: Vec<String> = Vec::new();

    for (path, name) in &uploads {
        let size = match path.metadata() {
            Ok(metadata) => metadata.len(),
            Err(e) => {
                // Nothing was attempted for this file: only what earlier
                // iterations uploaded needs removing
                let error: Box<dyn std::error::Error> =
                    format!("cannot stat '{}': {}", path.display(), e).into();
                cleanup_partial_upload(&sftp, incoming, &uploaded, None, &host);
                return Err(error);
            }
        };
        // Same transfer view as pull: prefix line, bar on its own line
        let bar = multi.add(ProgressBar::new(size));
        bar.enable_steady_tick(std::time::Duration::from_millis(50));
        bar.set_style(ui::transfer_style());
        bar.set_prefix(format!("Uploading {name}..."));

        let remote = format!("{incoming}/{name}");
        let result = ssh::upload_file(&sftp, path, &remote, &host, &bar);
        bar.finish_and_clear();
        if let Err(e) = result {
            // The failed file itself joins the cleanup: its remote `create`
            // may have succeeded before the failure, leaving a partial — or,
            // on a failed close, a truncated — file behind
            cleanup_partial_upload(&sftp, incoming, &uploaded, Some(name), &host);
            return Err(e);
        }
        uploaded.push(name.clone());
    }

    // Recorded only once the whole upload succeeded: the log backs the
    // duplicate-upload guard, and a failed upload must not count as
    // uploaded (a re-run replays every file — `sftp.create` truncates, so
    // replaying is safe).
    record_upload(&upload_log_path()?, &record)?;

    // The completion lines replace the summary bar; the guard's own clear
    // at scope exit is a no-op for the already-finished bars
    clear_bar(&summary);
    info!(
        "Upload of {} {} to {} complete.",
        changes.source, changes.version, target.label
    );
    info!(
        "Launchpad processes it asynchronously; watch the PPA page or your \
         inbox for acceptance/rejection"
    );
    Ok(())
}

/// The remote names to attempt removing after a failed upload: everything
/// already uploaded plus, when set, `failed` (the file whose upload just
/// failed — its remote `create` may have succeeded before the failure,
/// leaving a partial or truncated file behind) — in reverse upload order,
/// so a `.changes` is removed before the payloads it references and the
/// queue scanner never observes the payload set shrinking under a
/// still-present `.changes`. Pure so the ordering decision is testable
/// without a server; the network side is [`cleanup_partial_upload`].
fn cleanup_list(uploaded: &[String], failed: Option<&str>) -> Vec<String> {
    let mut names: Vec<String> = uploaded.to_vec();
    if let Some(failed) = failed {
        names.push(failed.to_string());
    }
    names.reverse();
    names
}

/// Best-effort removal of what a failed upload left in the target's
/// incoming queue: the already-uploaded payloads, and a `.changes`
/// truncated by a failed close, would otherwise linger in the write-only
/// area until the queue is manually cleaned. Launchpad re-validates every
/// upload, so this is pure hygiene: a removal failure is logged and
/// skipped, and the caller returns the original upload error — never a
/// cleanup one.
fn cleanup_partial_upload(
    sftp: &ssh2::Sftp,
    incoming: &str,
    uploaded: &[String],
    failed: Option<&str>,
    host: &str,
) {
    for name in cleanup_list(uploaded, failed) {
        let remote = format!("{incoming}/{name}");
        match ssh::remove_file(sftp, &remote, host) {
            Ok(()) => info!("Removed leftover {remote} from the failed upload"),
            Err(e) => {
                log::warn!("Could not remove the leftover {remote} of the failed upload: {e}")
            }
        }
    }
}

/// Steady tick interval of every bar rendered by a `put` run
const TICK: std::time::Duration = std::time::Duration::from_millis(50);

/// Stop `bar`'s steady tick and clear it from the terminal. The tick is
/// disabled first: a tick firing right after the clear would redraw a stale
/// frame, the race [`crate::ui::deb::DebUi::suspend`] guards against too.
/// Clearing twice is harmless: finished bars stay finished.
fn clear_bar(bar: &ProgressBar) {
    bar.disable_steady_tick();
    bar.finish_and_clear();
}

/// The bars rendered by one `put` run, cleared when the guard drops. The
/// error paths bail out early through `?` and `main` logs the error
/// afterwards, so a bar left unfinished would linger on screen above it.
#[derive(Default)]
struct PutBars {
    bars: Vec<ProgressBar>,
}

impl PutBars {
    /// Track `bar` so it is cleared with the rest when the guard drops
    fn track(&mut self, bar: ProgressBar) {
        self.bars.push(bar);
    }
}

impl Drop for PutBars {
    fn drop(&mut self) {
        for bar in &self.bars {
            clear_bar(bar);
        }
    }
}

/// Validate the source package's `Section` (debian/control source stanza)
/// against the distribution's valid sections: a bare section or a
/// `section/subsection` is accepted. Archives reject uploads carrying an
/// unknown section during queue processing, so this fails before anything
/// is uploaded.
fn check_control_section(cwd: &Path, dist: &str) -> Result<(), Box<dyn std::error::Error>> {
    let control_path = cwd.join("debian/control");
    let control = ControlInfo::parse(&control_path)?;
    let section = control.section();

    if section == "-" {
        return Err(format!(
            "'{}' has no Section field: add one (e.g. utils, devel, net), \
             the upload would be rejected otherwise",
            control_path.display()
        )
        .into());
    }

    let base = section.split('/').next().unwrap_or(section);
    if crate::distro_info::get_sections(dist)?
        .iter()
        .any(|valid| valid == base)
    {
        return Ok(());
    }

    Err(format!(
        "Invalid section '{section}' in '{}': {dist} rejects uploads with \
         unknown sections. Pick a valid one in debian/control (e.g. utils, \
         devel, net, graphics, sound...)",
        control_path.display()
    )
    .into())
}

/// What the Section pre-flight decided to validate: a directory holding a
/// `debian/control` ([`check_control_section`]'s expected layout), or that
/// it cannot run where the upload lives and must be skipped.
#[derive(Debug, PartialEq, Eq)]
enum SectionCheckTarget {
    /// Validate `debian/control` in this directory
    Dir(PathBuf),
    /// No `debian/control` next to the `.changes`: skip the check
    Skip,
}

/// Decide which tree the Section pre-flight validates. An explicit
/// `--changes` file must be followed by its own directory — it can name a
/// different package than the current tree — so the check runs against the
/// `.changes`' directory when it directly holds a `debian/control` (the
/// `.changes` inside the package root), and is skipped otherwise: pkh
/// writes the `.changes` next to the source tree (an artifacts-only
/// directory as far as `debian/control` goes), and checking `cwd` there
/// would validate whatever package the user happens to be in. Without
/// `--changes` the upload comes from the current tree, which keeps getting
/// checked exactly as before. Pure decision, factored out so the
/// wrong-tree rule is testable with plain tempdirs.
fn section_check_target(changes_path: Option<&Path>, cwd: &Path) -> SectionCheckTarget {
    let Some(changes) = changes_path else {
        return SectionCheckTarget::Dir(cwd.to_path_buf());
    };
    let dir = changes.parent().unwrap_or_else(|| Path::new("."));
    if dir.join("debian/control").is_file() {
        SectionCheckTarget::Dir(dir.to_path_buf())
    } else {
        SectionCheckTarget::Skip
    }
}

/// The highest version among `published` that parses as a Debian version,
/// `None` when the list is empty or nothing in it parses (entries that
/// cannot be parsed are skipped rather than failing the check: the API
/// data is trusted to carry valid Debian versions)
fn max_published(published: &[String]) -> Option<DebianVersion> {
    published
        .iter()
        .filter_map(|version| DebianVersion::parse(version).ok())
        .max()
}

/// Refuse an upload the target PPA already supersedes: when a version equal
/// to or higher than the changes' one is published there for the same
/// source, the queue would reject the upload (equal version) or silently
/// supersede it (older one) — Launchpad never replaces a published version
/// with a lower one. `force` downgrades the refusal to a warning.
fn check_not_superseded(
    target: &target::UploadTarget,
    changes: &changes::ChangesFile,
    published: &[String],
    force: bool,
) -> Result<(), Box<dyn std::error::Error>> {
    let local = match DebianVersion::parse(&changes.version) {
        Ok(version) => version,
        Err(e) => {
            // Only the pre-flight comparison is skipped: the upload itself
            // is valid as far as this check is concerned
            log::warn!(
                "cannot compare {} against the published versions of {} ({e}): \
                 skipping the published-version check",
                changes.version,
                changes.source
            );
            return Ok(());
        }
    };

    let Some(latest) = max_published(published) else {
        return Ok(());
    };
    if local.cmp(&latest) == Ordering::Greater {
        return Ok(());
    }

    let bump = "bump the version with `pkh chlog` and rebuild, or pass --force to upload anyway";
    if force {
        log::warn!(
            "{} {} is superseded by {} {} already published in {}: \
             uploading anyway (--force)",
            changes.source,
            local.full(),
            changes.source,
            latest.full(),
            target.label
        );
        return Ok(());
    }

    match local.cmp(&latest) {
        Ordering::Equal => Err(format!(
            "{} {} is already published in {} (published version {}): {bump}",
            changes.source,
            local.full(),
            target.label,
            latest.full()
        )
        .into()),
        _ => Err(format!(
            "{} {} is older than the {} {} already published in {}: {bump}",
            changes.source,
            local.full(),
            changes.source,
            latest.full(),
            target.label
        )
        .into()),
    }
}

/// Find the `.changes` file of the package in `cwd`: the exact
/// `<source>_<version>_source.changes` written by `pkh build` (in the source
/// directory's parent or the directory itself), or the only other
/// `<source>_*.changes` present. Errors listing the candidates when several
/// exist.
fn discover_changes(cwd: &Path) -> Result<PathBuf, Box<dyn std::error::Error>> {
    let entry = parse_changelog_entry(&cwd.join("debian/changelog"))?;
    let sversion = entry.version.no_epoch();
    let expected_name = format!("{}_{}_source.changes", entry.source, sversion);

    let mut search_dirs: Vec<PathBuf> = Vec::new();
    if let Some(parent) = cwd.parent() {
        search_dirs.push(parent.to_path_buf());
    }
    search_dirs.push(cwd.to_path_buf());

    for dir in &search_dirs {
        let candidate = dir.join(&expected_name);
        if candidate.is_file() {
            return Ok(candidate);
        }
    }

    // The exact build output is gone: accept any other single .changes of
    // this package, preferring source uploads
    let prefix = format!("{}_", entry.source);
    let mut candidates: Vec<PathBuf> = Vec::new();
    for dir in &search_dirs {
        if let Ok(entries) = dir.read_dir() {
            for entry in entries.flatten() {
                let path = entry.path();
                let Some(name) = path.file_name().and_then(|n| n.to_str()) else {
                    continue;
                };
                if name.starts_with(&prefix) && name.ends_with(".changes") && path.is_file() {
                    candidates.push(path);
                }
            }
        }
    }

    let source_only: Vec<&PathBuf> = candidates
        .iter()
        .filter(|p| {
            p.file_name()
                .and_then(|n| n.to_str())
                .is_some_and(|n| n.ends_with("_source.changes"))
        })
        .collect();

    if let [only] = source_only.as_slice() {
        log::warn!(
            "'{expected_name}' not found, uploading the other build output {}",
            only.display()
        );
        return Ok((*only).clone());
    }

    match candidates.as_slice() {
        [only] => {
            log::warn!(
                "'{expected_name}' not found, uploading the other build output {}",
                only.display()
            );
            Ok(only.clone())
        }
        [] => Err(format!(
            "no .changes file for package '{}' found (looked in the package \
             directory and its parent): build one with `pkh build` first",
            entry.source
        )
        .into()),
        many => Err(format!(
            "multiple .changes files found for package '{}': {}. \
             Pass the one to upload explicitly",
            entry.source,
            many.iter()
                .map(|p| ui::display_path(p))
                .collect::<Vec<_>>()
                .join(", ")
        )
        .into()),
    }
}

/// One recorded upload: target, `.changes` name, its SHA-256 digest and the
/// upload date. Matching on the digest makes `--force` the only way to
/// re-upload an identical file, while a rebuilt file (new digest) never
/// trips the guard.
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
struct UploadRecord {
    target: String,
    file: String,
    sha256: String,
    date: String,
}

/// Build the upload record for a `.changes` file, hashing its content
fn upload_record(
    target: &target::UploadTarget,
    changes: &Path,
) -> Result<UploadRecord, Box<dyn std::error::Error>> {
    let mut checksums = FileChecksums::new();
    checksums.add_file(changes)?;
    let entry = checksums
        .get(changes.file_name().and_then(|n| n.to_str()).unwrap_or(""))
        .ok_or_else(|| format!("cannot hash '{}'", changes.display()))?;

    Ok(UploadRecord {
        target: target.label.clone(),
        file: changes
            .file_name()
            .and_then(|n| n.to_str())
            .unwrap_or_default()
            .to_string(),
        sha256: entry.sha256.clone(),
        date: chrono::Local::now().format("%Y-%m-%d %H:%M").to_string(),
    })
}

/// Path of the upload log (`<data dir>/pkh/uploads.json`)
fn upload_log_path() -> Result<PathBuf, Box<dyn std::error::Error>> {
    let dirs = directories::ProjectDirs::from("com", "pkh", "pkh")
        .ok_or("cannot determine the pkh data directory")?;
    let path = dirs.data_dir().join("uploads.json");
    if let Some(parent) = path.parent() {
        std::fs::create_dir_all(parent)?;
    }
    Ok(path)
}

/// Load the upload log, empty when the file does not exist yet.
///
/// The log only backs the advisory duplicate-upload guard (Launchpad
/// re-verifies every upload), so a corrupt log must not abort the upload:
/// like the context configuration in [`crate::context::manager`], the corrupt
/// file is first backed up to `<path>.bak` (best effort) so a later
/// [`record_upload`] cannot destroy it, then an empty log is used.
fn load_upload_log(path: &Path) -> Vec<UploadRecord> {
    let content = match std::fs::read_to_string(path) {
        Ok(content) => content,
        Err(e) => {
            if e.kind() != std::io::ErrorKind::NotFound {
                log::error!(
                    "Cannot read upload log {}: {e}; continuing as if nothing had been uploaded",
                    path.display()
                );
            }
            return Vec::new();
        }
    };
    match serde_json::from_str(&content) {
        Ok(entries) => entries,
        Err(e) => {
            log::error!(
                "Upload log {} is corrupt ({e}); ignoring its content, earlier uploads may not be detected as duplicates anymore",
                path.display()
            );
            backup_corrupt_log(path);
            Vec::new()
        }
    }
}

/// Back up a corrupt upload log (best effort) so a later
/// [`record_upload`] cannot silently destroy its content.
fn backup_corrupt_log(path: &Path) {
    let mut os = path.as_os_str().to_os_string();
    os.push(".bak");
    let backup_path = PathBuf::from(os);
    match std::fs::copy(path, &backup_path) {
        Ok(_) => log::warn!("Corrupt upload log backed up to {}", backup_path.display()),
        Err(e) => log::warn!(
            "Could not back up corrupt upload log to {}: {e}",
            backup_path.display()
        ),
    }
}

/// The previous upload of `record` from the log at `log`, if any (same
/// target, file and content)
fn find_previous_upload(
    log: &Path,
    record: &UploadRecord,
) -> Result<Option<UploadRecord>, Box<dyn std::error::Error>> {
    Ok(load_upload_log(log)
        .into_iter()
        .find(|r| r.target == record.target && r.file == record.file && r.sha256 == record.sha256))
}

/// Append `record` to the upload log at `log`
fn record_upload(log: &Path, record: &UploadRecord) -> Result<(), Box<dyn std::error::Error>> {
    let mut entries = load_upload_log(log);
    entries.push(record.clone());
    // Write to a temporary file next to the log, then rename it over the
    // log: rename is atomic within a filesystem, so a crash mid-write leaves
    // the previous log intact instead of a truncated (corrupt) file.
    // The temporary file is created with default permissions; the log holds
    // no secrets and lives in the user's data directory, so the previous
    // mode is not carried over (same choice as `Files::save_atomic`).
    let tmp = log.with_extension("new");
    std::fs::write(&tmp, serde_json::to_string_pretty(&entries)?)
        .map_err(|e| format!("cannot write '{}': {}", tmp.display(), e))?;
    std::fs::rename(&tmp, log).map_err(|e| format!("cannot install '{}': {}", log.display(), e))?;
    Ok(())
}

#[cfg(test)]
mod tests {
    use super::*;

    /// Changelog of a package `hello` at version `1.0-1`
    fn changelog_fixture(dir: &Path) {
        std::fs::create_dir_all(dir.join("debian")).unwrap();
        std::fs::write(
            dir.join("debian/changelog"),
            "hello (1.0-1) resolute; urgency=medium\n\n  * Something.\n\n \
             -- A B <a@b>  Mon, 01 Sep 2025 10:00:00 +0000\n",
        )
        .unwrap();
    }

    #[test]
    fn discover_finds_exact_build_output_in_parent() {
        let dir = tempfile::tempdir().unwrap();
        let pkg = dir.path().join("hello");
        changelog_fixture(&pkg);
        std::fs::write(dir.path().join("hello_1.0-1_source.changes"), b"changes").unwrap();

        let found = discover_changes(&pkg).unwrap();
        assert_eq!(found, dir.path().join("hello_1.0-1_source.changes"));
    }

    #[test]
    fn discover_finds_exact_build_output_in_cwd() {
        let dir = tempfile::tempdir().unwrap();
        changelog_fixture(dir.path());
        std::fs::write(dir.path().join("hello_1.0-1_source.changes"), b"changes").unwrap();

        let found = discover_changes(dir.path()).unwrap();
        assert_eq!(found, dir.path().join("hello_1.0-1_source.changes"));
    }

    #[test]
    fn discover_prefers_source_changes_among_several() {
        let dir = tempfile::tempdir().unwrap();
        let pkg = dir.path().join("hello");
        changelog_fixture(&pkg);
        // A stale exact match does not exist; a source changes and a binary
        // changes are present
        std::fs::write(dir.path().join("hello_1.0-1_source.changes"), b"changes").unwrap();
        std::fs::write(dir.path().join("hello_1.0-1_amd64.changes"), b"binary").unwrap();

        let found = discover_changes(&pkg).unwrap();
        assert_eq!(found, dir.path().join("hello_1.0-1_source.changes"));
    }

    #[test]
    fn discover_errors_when_nothing_matches() {
        let dir = tempfile::tempdir().unwrap();
        let pkg = dir.path().join("hello");
        changelog_fixture(&pkg);

        let err = discover_changes(&pkg).unwrap_err().to_string();
        assert!(err.contains("no .changes file"), "unexpected: {err}");
    }

    /// debian/control's Section must be a known distribution section; the
    /// `section/subsection` form validates on the part before the '/'
    #[test]
    fn control_section_check() {
        let dir = tempfile::tempdir().unwrap();
        std::fs::create_dir_all(dir.path().join("debian")).unwrap();
        let control = dir.path().join("debian/control");

        std::fs::write(&control, "Source: hello\nSection: utils\n").unwrap();
        assert!(check_control_section(dir.path(), "ubuntu").is_ok());

        std::fs::write(&control, "Source: hello\nSection: devel/i386\n").unwrap();
        assert!(check_control_section(dir.path(), "ubuntu").is_ok());

        std::fs::write(&control, "Source: hello\nSection: unknown\n").unwrap();
        let err = check_control_section(dir.path(), "ubuntu")
            .unwrap_err()
            .to_string();
        assert!(
            err.contains("Invalid section 'unknown'"),
            "unexpected: {err}"
        );

        std::fs::write(&control, "Source: hello\n").unwrap();
        let err = check_control_section(dir.path(), "ubuntu")
            .unwrap_err()
            .to_string();
        assert!(err.contains("has no Section"), "unexpected: {err}");
    }

    /// An explicit `--changes` file of a different package must be checked
    /// in its own directory (A), not in the current tree (B): B's control
    /// file decided the pre-flight before the fix
    #[test]
    fn section_check_follows_explicit_changes_directory() {
        let dir = tempfile::tempdir().unwrap();
        let artifacts = dir.path().join("artifacts");
        let elsewhere = dir.path().join("elsewhere");
        std::fs::create_dir_all(artifacts.join("debian")).unwrap();
        std::fs::create_dir_all(elsewhere.join("debian")).unwrap();
        let changes = artifacts.join("hello_1.0-1_source.changes");
        std::fs::write(&changes, b"changes").unwrap();
        std::fs::write(
            artifacts.join("debian/control"),
            "Source: hello\nSection: utils\n",
        )
        .unwrap();
        std::fs::write(
            elsewhere.join("debian/control"),
            "Source: other\nSection: unknown\n",
        )
        .unwrap();

        assert_eq!(
            section_check_target(Some(&changes), &elsewhere),
            SectionCheckTarget::Dir(artifacts.clone())
        );

        // The decided directory carries the valid section, while the tree
        // the old code checked would have failed the upload
        match section_check_target(Some(&changes), &elsewhere) {
            SectionCheckTarget::Dir(d) => check_control_section(&d, "ubuntu").unwrap(),
            SectionCheckTarget::Skip => panic!("the .changes directory has debian/control"),
        }
        assert!(check_control_section(&elsewhere, "ubuntu").is_err());
    }

    /// A `.changes` in a directory without `debian/control` — pkh's own
    /// layout puts it next to the source tree, and artifacts can be
    /// collected away from any source — skips the check instead of
    /// validating whatever tree `cwd` points at
    #[test]
    fn section_check_skips_when_changes_dir_has_no_control() {
        let dir = tempfile::tempdir().unwrap();
        let artifacts = dir.path().join("artifacts");
        std::fs::create_dir_all(&artifacts).unwrap();
        let changes = artifacts.join("hello_1.0-1_source.changes");
        std::fs::write(&changes, b"changes").unwrap();

        assert_eq!(
            section_check_target(Some(&changes), dir.path()),
            SectionCheckTarget::Skip
        );
    }

    /// Without `--changes` the upload comes from the current tree: the
    /// decision stays the cwd, byte-identical to the pre-fix behavior
    #[test]
    fn section_check_without_changes_validates_cwd() {
        let dir = tempfile::tempdir().unwrap();
        let pkg = dir.path().join("hello");
        std::fs::create_dir_all(pkg.join("debian")).unwrap();

        assert_eq!(
            section_check_target(None, &pkg),
            SectionCheckTarget::Dir(pkg)
        );
    }

    #[test]
    fn discover_errors_when_several_candidates() {
        let dir = tempfile::tempdir().unwrap();
        let pkg = dir.path().join("hello");
        changelog_fixture(&pkg);
        std::fs::write(dir.path().join("hello_1.0-1_amd64.changes"), b"binary").unwrap();
        std::fs::write(dir.path().join("hello_1.0-2_amd64.changes"), b"binary2").unwrap();

        let err = discover_changes(&pkg).unwrap_err().to_string();
        assert!(err.contains("multiple .changes"), "unexpected: {err}");
    }

    #[test]
    fn upload_record_is_stable_and_content_hashed() {
        let dir = tempfile::tempdir().unwrap();
        let changes = dir.path().join("hello_1.0-1_source.changes");
        std::fs::write(&changes, b"changes content").unwrap();

        let target = launchpad::ppa_target("user/ppa").unwrap();
        let record = upload_record(&target, &changes).unwrap();
        assert_eq!(record.target, "ppa:user/ppa");
        assert_eq!(record.file, "hello_1.0-1_source.changes");
        // sha256("changes content")
        assert_eq!(
            record.sha256,
            "104a1c78c7f8e6d28da700ac5eed27fd9cdace4a5d9b3caeeb08ab7558ece6b0"
        );
    }

    #[test]
    fn upload_log_round_trip_and_dedup() {
        let dir = tempfile::tempdir().unwrap();
        let log = dir.path().join("uploads.json");

        let record = UploadRecord {
            target: "ppa:user/ppa".to_string(),
            file: "hello_1.0-1_source.changes".to_string(),
            sha256: "abc".to_string(),
            date: "2025-09-16 12:00".to_string(),
        };
        assert!(find_previous_upload(&log, &record).unwrap().is_none());

        record_upload(&log, &record).unwrap();
        record_upload(&log, &record).unwrap();

        let previous = find_previous_upload(&log, &record).unwrap().unwrap();
        assert_eq!(previous.date, record.date);

        // A rebuilt file (different digest) is not a duplicate
        let mut rebuilt = record.clone();
        rebuilt.sha256 = "def".to_string();
        assert!(find_previous_upload(&log, &rebuilt).unwrap().is_none());
    }

    /// A plain upload record for the log tests
    fn upload_log_record(sha256: &str) -> UploadRecord {
        UploadRecord {
            target: "ppa:user/ppa".to_string(),
            file: "hello_1.0-1_source.changes".to_string(),
            sha256: sha256.to_string(),
            date: "2025-09-16 12:00".to_string(),
        }
    }

    /// A corrupt log must not be silently reset: it is backed up byte for
    /// byte, and the guard restarts from an empty log.
    #[test]
    fn corrupt_upload_log_is_backed_up_and_reset() {
        let dir = tempfile::tempdir().unwrap();
        let log = dir.path().join("uploads.json");
        let corrupt = b"{ \"not\": valid json";
        std::fs::write(&log, corrupt).unwrap();

        assert!(load_upload_log(&log).is_empty());

        let backup = dir.path().join("uploads.json.bak");
        assert_eq!(std::fs::read(&backup).unwrap(), corrupt);

        // Recording after a corrupt log starts a fresh, parseable log
        // without clobbering the backup
        record_upload(&log, &upload_log_record("abc")).unwrap();
        assert_eq!(load_upload_log(&log), vec![upload_log_record("abc")]);
        assert_eq!(std::fs::read(&backup).unwrap(), corrupt);
    }

    /// `record_upload` leaves a log that parses back, with no temporary
    /// file left behind
    #[test]
    fn recorded_upload_parses_back_atomically() {
        let dir = tempfile::tempdir().unwrap();
        let log = dir.path().join("uploads.json");

        record_upload(&log, &upload_log_record("abc")).unwrap();

        assert_eq!(load_upload_log(&log), vec![upload_log_record("abc")]);
        assert!(!dir.path().join("uploads.new").exists());
    }

    /// Recording a second upload appends to the log instead of replacing it
    #[test]
    fn record_over_existing_log_preserves_prior_entries() {
        let dir = tempfile::tempdir().unwrap();
        let log = dir.path().join("uploads.json");

        record_upload(&log, &upload_log_record("abc")).unwrap();
        record_upload(&log, &upload_log_record("def")).unwrap();

        assert_eq!(
            load_upload_log(&log),
            vec![upload_log_record("abc"), upload_log_record("def")]
        );
    }

    /// A minimal in-memory changes file for the superseded-version check
    fn changes_fixture(version: &str) -> changes::ChangesFile {
        changes::ChangesFile {
            path: PathBuf::from("hello_1.0-1_source.changes"),
            source: "hello".to_string(),
            version: version.to_string(),
            distribution: "resolute".to_string(),
            files: Vec::new(),
        }
    }

    fn versions(list: &[&str]) -> Vec<String> {
        list.iter().map(|v| v.to_string()).collect()
    }

    #[test]
    fn superseded_check_rejects_equal_published_version() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let changes = changes_fixture("1.2.3-1");
        let err = check_not_superseded(&target, &changes, &versions(&["1.2.3-1"]), false)
            .unwrap_err()
            .to_string();
        assert!(
            err.contains("hello 1.2.3-1 is already published in ppa:user/ppa"),
            "unexpected: {err}"
        );
        assert!(
            err.contains("published version 1.2.3-1"),
            "unexpected: {err}"
        );
        assert!(err.contains("--force"), "unexpected: {err}");
    }

    #[test]
    fn superseded_check_rejects_older_upload() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let changes = changes_fixture("1.0-1");
        let err = check_not_superseded(&target, &changes, &versions(&["2.0-1"]), false)
            .unwrap_err()
            .to_string();
        assert!(
            err.contains("hello 1.0-1 is older than the hello 2.0-1 already published"),
            "unexpected: {err}"
        );
    }

    #[test]
    fn superseded_check_accepts_newer_version() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let changes = changes_fixture("2.0-1");
        check_not_superseded(&target, &changes, &versions(&["1.0-1"]), false).unwrap();
    }

    #[test]
    fn superseded_check_accepts_never_published_source() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let changes = changes_fixture("1.0-1");
        check_not_superseded(&target, &changes, &[], false).unwrap();
    }

    /// The comparison follows dpkg ordering: `~` pre-releases, epochs and
    /// Ubuntu revision suffixes all sort correctly
    #[test]
    fn superseded_check_uses_dpkg_ordering() {
        let target = launchpad::ppa_target("user/ppa").unwrap();

        // A tilde pre-release is older than the real release
        let changes = changes_fixture("1.0~rc1-1");
        assert!(check_not_superseded(&target, &changes, &versions(&["1.0-1"]), false).is_err());

        // The real release supersedes the pre-release
        let changes = changes_fixture("1.0-1");
        check_not_superseded(&target, &changes, &versions(&["1.0~rc1-1"]), false).unwrap();

        // An epoch outranks a higher upstream version
        let changes = changes_fixture("2.0-1");
        assert!(check_not_superseded(&target, &changes, &versions(&["1:1.0-1"]), false).is_err());

        // ubuntu1.1 point updates supersede the base upload
        let changes = changes_fixture("1.0-1ubuntu1");
        assert!(
            check_not_superseded(&target, &changes, &versions(&["1.0-1ubuntu1.1"]), false).is_err()
        );
    }

    #[test]
    fn superseded_check_force_warns_instead_of_erroring() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let changes = changes_fixture("1.0-1");
        check_not_superseded(&target, &changes, &versions(&["1.0-1", "0.9-1"]), true).unwrap();
    }

    /// Versions the parser rejects never fail the upload: an unparseable
    /// local version skips the check, unparseable published entries are
    /// ignored
    #[test]
    fn superseded_check_tolerates_unparseable_versions() {
        let target = launchpad::ppa_target("user/ppa").unwrap();

        let changes = changes_fixture("not_a_debian_version");
        check_not_superseded(&target, &changes, &versions(&["1.0-1"]), false).unwrap();

        let changes = changes_fixture("1.0-1");
        check_not_superseded(&target, &changes, &versions(&["1.0_beta", "0.9-1"]), false).unwrap();
    }

    /// Several published versions (multiple series/pockets): the highest
    /// one decides
    #[test]
    fn superseded_check_compares_against_highest_published() {
        let target = launchpad::ppa_target("user/ppa").unwrap();
        let published = versions(&["1.0-1", "1.6-1", "1.2-3"]);

        // 1.5-1 supersedes everything but the 1.6-1 entry, which decides
        let changes = changes_fixture("1.5-1");
        let err = check_not_superseded(&target, &changes, &published, false)
            .unwrap_err()
            .to_string();
        assert!(err.contains("1.6-1"), "unexpected: {err}");

        // ...and going one higher than the highest entry passes
        let changes = changes_fixture("1.7-1");
        check_not_superseded(&target, &changes, &published, false).unwrap();
    }

    /// The upload loop is network-bound and `ssh2::Sftp` cannot be built
    /// without a live SSH session, so there is no stub seam for it without
    /// heavy refactoring; the cleanup decision is factored into the pure
    /// [`cleanup_list`] and tested directly instead.
    ///
    /// Failure during the final `.changes` upload (the dangerous case: a
    /// partial or close-truncated `.changes` is scanner-visible): the
    /// `.changes` is removed first, then the payloads it references, so the
    /// queue never sees a `.changes` over a shrinking payload set.
    #[test]
    fn cleanup_list_removes_changes_first_then_payloads_in_reverse() {
        let uploaded = vec![
            "hello_1.0.orig.tar.xz".to_string(),
            "hello_1.0-1.debian.tar.xz".to_string(),
            "hello_1.0-1.dsc".to_string(),
        ];
        assert_eq!(
            cleanup_list(&uploaded, Some("hello_1.0-1_source.changes")),
            vec![
                "hello_1.0-1_source.changes",
                "hello_1.0-1.dsc",
                "hello_1.0-1.debian.tar.xz",
                "hello_1.0.orig.tar.xz",
            ]
        );
    }

    /// A failure during a payload upload: the `.changes` was never
    /// attempted (it is uploaded last), so it must not appear in the
    /// cleanup list — only the failed payload (a partial may exist) and the
    /// earlier payloads.
    #[test]
    fn cleanup_list_before_the_changes_covers_the_failed_payload() {
        let uploaded = vec!["hello_1.0.orig.tar.xz".to_string()];
        assert_eq!(
            cleanup_list(&uploaded, Some("hello_1.0-1.debian.tar.xz")),
            vec!["hello_1.0-1.debian.tar.xz", "hello_1.0.orig.tar.xz"]
        );
    }

    /// A stat failure happens before anything was attempted for that file,
    /// so only what earlier iterations uploaded is removed — and with
    /// nothing uploaded yet there is nothing to remove at all.
    #[test]
    fn cleanup_list_without_failed_file_keeps_uploaded_only() {
        assert!(cleanup_list(&[], None).is_empty());
        assert_eq!(
            cleanup_list(&["hello_1.0.orig.tar.xz".to_string()], None),
            vec!["hello_1.0.orig.tar.xz"]
        );
    }
}