auths-sdk 0.1.8

//! Trusted-root pinning — the `roots` allowlist of root `did:keri:` prefixes a
//! verifier accepts as delegation anchors.
//!
//! This is the successor to `allowed_signers` as the **root** of trust. Under the
//! delegation model a commit carries its signer's root in the `Auths-Id` trailer,
//! but that trailer is attacker-controllable: it may only **select** among pinned
//! roots, never **establish** a new one. TOFS on a device is bounded (the root can
//! revoke it); TOFS on the root is unbounded — so the trusted root set is pinned
//! out-of-band in `<auths_dir>/roots`, one `did:keri:` per line (blank lines and
//! `#` comments ignored).

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

use auths_verifier::IdentityDID;

use crate::ports::{ConfigStore, ConfigStoreError};

const ROOTS_FILE: &str = "roots";

/// Path to the pin file within `auths_dir`.
fn roots_path(auths_dir: &Path) -> PathBuf {
    auths_dir.join(ROOTS_FILE)
}

/// Load the pinned trusted-root `did:keri:` set. Empty when the file is absent.
///
/// Blank lines and `#`-prefixed comments are ignored; entries are trimmed.
///
/// Args:
/// * `store`: File-access port for the pin file.
/// * `auths_dir`: Directory holding the `roots` pin file.
///
/// Usage:
/// ```ignore
/// let roots = load_pinned_roots(&store, &auths_dir)?;
/// ```
pub fn load_pinned_roots(
    store: &dyn ConfigStore,
    auths_dir: &Path,
) -> Result<Vec<String>, ConfigStoreError> {
    match store.read(&roots_path(auths_dir))? {
        Some(content) => Ok(parse_roots(&content)),
        None => Ok(Vec::new()),
    }
}

/// Parse pin-file content into the trusted-root set (pure; no I/O).
///
/// Args:
/// * `content`: Raw `roots` file contents.
///
/// Usage:
/// ```ignore
/// let roots = parse_roots("did:keri:Eabc\n# note\n\n");
/// assert_eq!(roots, vec!["did:keri:Eabc".to_string()]);
/// ```
pub fn parse_roots(content: &str) -> Vec<String> {
    content
        .lines()
        .map(str::trim)
        .filter(|line| !line.is_empty() && !line.starts_with('#'))
        .map(str::to_string)
        .collect()
}

/// Whether `did` (a `did:keri:` string) is a pinned trusted root.
///
/// Args:
/// * `store`: File-access port for the pin file.
/// * `auths_dir`: Directory holding the `roots` pin file.
/// * `did`: The candidate root `did:keri:`.
///
/// Usage:
/// ```ignore
/// if is_pinned_root(&store, &auths_dir, &trailer_root_did)? { /* trust it */ }
/// ```
pub fn is_pinned_root(
    store: &dyn ConfigStore,
    auths_dir: &Path,
    did: &str,
) -> Result<bool, ConfigStoreError> {
    Ok(load_pinned_roots(store, auths_dir)?
        .iter()
        .any(|root| root == did))
}

/// Pin a trusted root `did:keri:` (idempotent — never duplicates an existing entry).
///
/// Creates `auths_dir` if needed (the store's `write` creates parent directories).
/// Used by `auths init` to seed the local root.
///
/// Args:
/// * `store`: File-access port for the pin file.
/// * `auths_dir`: Directory holding the `roots` pin file.
/// * `did`: The root `did:keri:` to pin.
///
/// Usage:
/// ```ignore
/// add_pinned_root(&store, &auths_dir, &controller_did)?;
/// ```
pub fn add_pinned_root(
    store: &dyn ConfigStore,
    auths_dir: &Path,
    did: &str,
) -> Result<(), ConfigStoreError> {
    let mut roots = load_pinned_roots(store, auths_dir)?;
    if roots.iter().any(|root| root == did) {
        return Ok(());
    }
    roots.push(did.to_string());
    store.write(&roots_path(auths_dir), &format!("{}\n", roots.join("\n")))
}

/// What [`pin_root_in_repo`] did, so the caller can report it accurately.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum RootPinOutcome {
    /// The root was newly pinned and the pin file staged.
    PinnedAndStaged,
    /// The root was already pinned but the pin file was untracked; it is now staged.
    Staged,
    /// The root was already pinned and the pin file already tracked. Nothing to do.
    AlreadyTracked,
}

/// Failure pinning a trusted root into a repository.
#[derive(Debug, thiserror::Error)]
pub enum PinRootError {
    /// The pin file could not be read or written.
    #[error(transparent)]
    Store(#[from] ConfigStoreError),
    /// The pin file could not be staged into the index.
    #[error(transparent)]
    Index(#[from] crate::ports::git::IndexError),
}

/// Pin `did` as a trusted root in `<repo_root>/.auths/roots` **and stage it**, so
/// the declaration travels with the repository.
///
/// The pin is the only trust anchor the delegation model permits: an `Auths-Id`
/// trailer may *select* among pinned roots, never *establish* one. A pin that is
/// written but never staged therefore never reaches a cloner, and every
/// third-party verification path dead-ends on it.
///
/// Staging (rather than committing) is deliberate: `auths init` must not author a
/// commit on the user's behalf. The pin rides along with their next commit, which
/// is the one they are about to make anyway.
///
/// Idempotent: staging an unchanged tracked file is a no-op.
///
/// Args:
/// * `store`: File-access port for the pin file.
/// * `index`: Repository index port used to stage the pin file.
/// * `repo_root`: The repository's top level (the directory containing `.auths/`).
/// * `did`: The root `did:keri:` to pin.
///
/// Usage:
/// ```ignore
/// match pin_root_in_repo(&store, &index, &repo_root, &root_did)? {
///     RootPinOutcome::AlreadyTracked => {}
///     _ => println!("pinned — clones can now verify your commits"),
/// }
/// ```
pub fn pin_root_in_repo(
    store: &dyn ConfigStore,
    index: &dyn crate::ports::git::RepoIndex,
    repo_root: &Path,
    did: &str,
) -> Result<RootPinOutcome, PinRootError> {
    let auths_dir = repo_root.join(".auths");
    let pin_file = roots_path(&auths_dir);

    let already_pinned = is_pinned_root(store, &auths_dir, did)?;
    if already_pinned && index.is_tracked(&pin_file) {
        return Ok(RootPinOutcome::AlreadyTracked);
    }

    if !already_pinned {
        add_pinned_root(store, &auths_dir, did)?;
    }
    index.stage(&pin_file)?;

    Ok(if already_pinned {
        RootPinOutcome::Staged
    } else {
        RootPinOutcome::PinnedAndStaged
    })
}

/// Failure loading the typed pinned-root set: a line that is not a well-formed
/// `did:keri:` identity DID is rejected (fail-closed) rather than silently skipped.
#[derive(Debug, thiserror::Error)]
pub enum RootsError {
    /// The `roots` pin file could not be read.
    #[error("could not read roots pin file: {0}")]
    Store(#[from] ConfigStoreError),

    /// A non-comment, non-blank line is not a valid `did:keri:` root.
    #[error("roots pin line {line} ({value:?}) is not a valid did:keri: root: {source}")]
    MalformedRoot {
        /// 1-based line number in the pin file.
        line: usize,
        /// The offending (trimmed) line content.
        value: String,
        /// The underlying DID parse error.
        #[source]
        source: auths_verifier::DidParseError,
    },
}

/// Parse pin-file content into typed trusted-root identities (pure; no I/O).
///
/// Each non-blank, non-`#` line must be a well-formed `did:keri:` identity DID;
/// a malformed line fails closed with [`RootsError::MalformedRoot`]. The pin file
/// names **identities only** — capabilities come from the presented credential's
/// scope seal, never this file.
///
/// Args:
/// * `content`: Raw `roots` file contents.
///
/// Usage:
/// ```ignore
/// let roots = parse_roots_typed("did:keri:Eabc\n")?;
/// ```
pub fn parse_roots_typed(content: &str) -> Result<Vec<IdentityDID>, RootsError> {
    content
        .lines()
        .enumerate()
        .map(|(idx, raw)| (idx + 1, raw.trim()))
        .filter(|(_, line)| !line.is_empty() && !line.starts_with('#'))
        .map(|(line, value)| {
            IdentityDID::parse(value).map_err(|source| RootsError::MalformedRoot {
                line,
                value: value.to_string(),
                source,
            })
        })
        .collect()
}

/// Load the pinned trusted-root set as typed [`IdentityDID`]s, failing closed on a
/// malformed line. Empty when the file is absent.
///
/// This is the typed successor to [`load_pinned_roots`]: the relying-party middleware
/// pins delegation anchors by parsed identity, so a malformed pin is a hard error at
/// load rather than a silently-dropped root.
///
/// Args:
/// * `store`: File-access port for the pin file.
/// * `auths_dir`: Directory holding the `roots` pin file.
///
/// Usage:
/// ```ignore
/// let roots = load_pinned_roots_typed(&store, &auths_dir)?;
/// ```
pub fn load_pinned_roots_typed(
    store: &dyn ConfigStore,
    auths_dir: &Path,
) -> Result<Vec<IdentityDID>, RootsError> {
    match store.read(&roots_path(auths_dir))? {
        Some(content) => parse_roots_typed(&content),
        None => Ok(Vec::new()),
    }
}

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

    struct FsStore;

    impl ConfigStore for FsStore {
        fn read(&self, path: &Path) -> Result<Option<String>, ConfigStoreError> {
            match std::fs::read_to_string(path) {
                Ok(content) => Ok(Some(content)),
                Err(e) if e.kind() == std::io::ErrorKind::NotFound => Ok(None),
                Err(e) => Err(ConfigStoreError::Read {
                    path: path.to_path_buf(),
                    source: e,
                }),
            }
        }

        fn write(&self, path: &Path, content: &str) -> Result<(), ConfigStoreError> {
            if let Some(parent) = path.parent() {
                std::fs::create_dir_all(parent).map_err(|e| ConfigStoreError::Write {
                    path: path.to_path_buf(),
                    source: e,
                })?;
            }
            std::fs::write(path, content).map_err(|e| ConfigStoreError::Write {
                path: path.to_path_buf(),
                source: e,
            })
        }
    }

    #[test]
    fn parse_roots_ignores_blanks_and_comments() {
        let content = "did:keri:Eaaa\n\n# a comment\n  did:keri:Ebbb  \n";
        assert_eq!(
            parse_roots(content),
            vec!["did:keri:Eaaa".to_string(), "did:keri:Ebbb".to_string()]
        );
    }

    #[test]
    fn typed_roots_parse_valid_did_keri() {
        let roots = parse_roots_typed("did:keri:Eaaa\n# c\n  did:keri:Ebbb \n").expect("parse");
        assert_eq!(
            roots.iter().map(|r| r.as_str()).collect::<Vec<_>>(),
            ["did:keri:Eaaa", "did:keri:Ebbb"]
        );
    }

    #[test]
    fn typed_roots_reject_malformed_line_fail_closed() {
        // A non-did:keri line is a hard error (with its line number), never skipped.
        let err = parse_roots_typed("did:keri:Eaaa\nnot-a-did\n").expect_err("must fail closed");
        assert!(
            matches!(err, RootsError::MalformedRoot { line: 2, .. }),
            "expected MalformedRoot at line 2, got {err:?}"
        );
    }

    #[test]
    fn typed_roots_absent_file_is_empty() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        assert!(
            load_pinned_roots_typed(&FsStore, tmp.path())
                .expect("load")
                .is_empty()
        );
    }

    #[test]
    fn add_and_membership_roundtrip() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        let dir = tmp.path();
        let store = FsStore;

        // Absent file → empty + not pinned.
        assert!(load_pinned_roots(&store, dir).expect("load").is_empty());
        assert!(!is_pinned_root(&store, dir, "did:keri:Eroot").expect("check"));

        add_pinned_root(&store, dir, "did:keri:Eroot").expect("add");
        assert!(is_pinned_root(&store, dir, "did:keri:Eroot").expect("check pinned"));
        assert!(!is_pinned_root(&store, dir, "did:keri:Eother").expect("check unpinned"));

        // Idempotent.
        add_pinned_root(&store, dir, "did:keri:Eroot").expect("add again");
        assert_eq!(load_pinned_roots(&store, dir).expect("load").len(), 1);

        // A second distinct root.
        add_pinned_root(&store, dir, "did:keri:Esecond").expect("add second");
        assert_eq!(load_pinned_roots(&store, dir).expect("load").len(), 2);
    }

    /// Records what was staged, and lets a test declare what git already tracks.
    struct FakeIndex {
        staged: std::sync::Mutex<Vec<PathBuf>>,
        tracked: Vec<PathBuf>,
    }

    impl FakeIndex {
        fn new() -> Self {
            Self {
                staged: std::sync::Mutex::new(Vec::new()),
                tracked: Vec::new(),
            }
        }

        fn with_tracked(tracked: Vec<PathBuf>) -> Self {
            Self {
                staged: std::sync::Mutex::new(Vec::new()),
                tracked,
            }
        }

        fn staged(&self) -> Vec<PathBuf> {
            self.staged.lock().expect("staged lock").clone()
        }
    }

    impl crate::ports::git::RepoIndex for FakeIndex {
        fn stage(&self, path: &Path) -> Result<(), crate::ports::git::IndexError> {
            self.staged
                .lock()
                .expect("staged lock")
                .push(path.to_path_buf());
            Ok(())
        }

        fn is_tracked(&self, path: &Path) -> bool {
            self.tracked.iter().any(|p| p == path)
        }
    }

    #[test]
    fn pin_root_in_repo_writes_and_stages_the_pin() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        let repo = tmp.path();
        let index = FakeIndex::new();

        let outcome = pin_root_in_repo(&FsStore, &index, repo, "did:keri:Eroot").expect("pin");

        assert_eq!(outcome, RootPinOutcome::PinnedAndStaged);
        assert!(is_pinned_root(&FsStore, &repo.join(".auths"), "did:keri:Eroot").expect("pinned"));
        assert_eq!(
            index.staged(),
            vec![repo.join(".auths").join("roots")],
            "the pin must be staged, or it never reaches a cloner"
        );
    }

    /// The regression that made third-party verification impossible: `auths init`
    /// wrote `.auths/roots` but never staged it, and the file's mere existence then
    /// made the hook's `[ ! -e ]` guard false forever — so nothing ever staged it
    /// and the pin never travelled. Pinning must stage an already-written pin.
    #[test]
    fn pin_root_in_repo_stages_a_previously_written_but_untracked_pin() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        let repo = tmp.path();
        let auths_dir = repo.join(".auths");

        // Simulate the old init: pin written, never staged.
        add_pinned_root(&FsStore, &auths_dir, "did:keri:Eroot").expect("pre-write");
        let index = FakeIndex::new(); // tracks nothing

        let outcome = pin_root_in_repo(&FsStore, &index, repo, "did:keri:Eroot").expect("pin");

        assert_eq!(outcome, RootPinOutcome::Staged);
        assert_eq!(
            index.staged(),
            vec![auths_dir.join("roots")],
            "an already-written but untracked pin must still be staged"
        );
    }

    #[test]
    fn pin_root_in_repo_is_a_noop_when_already_pinned_and_tracked() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        let repo = tmp.path();
        let auths_dir = repo.join(".auths");
        add_pinned_root(&FsStore, &auths_dir, "did:keri:Eroot").expect("pre-write");
        let index = FakeIndex::with_tracked(vec![auths_dir.join("roots")]);

        let outcome = pin_root_in_repo(&FsStore, &index, repo, "did:keri:Eroot").expect("pin");

        assert_eq!(outcome, RootPinOutcome::AlreadyTracked);
        assert!(
            index.staged().is_empty(),
            "nothing to do; must not touch the index"
        );
    }

    #[test]
    fn pin_root_in_repo_appends_a_second_root_without_dropping_the_first() {
        let tmp = tempfile::TempDir::new().expect("temp dir");
        let repo = tmp.path();
        let index = FakeIndex::new();

        pin_root_in_repo(&FsStore, &index, repo, "did:keri:Efirst").expect("first");
        pin_root_in_repo(&FsStore, &index, repo, "did:keri:Esecond").expect("second");

        let roots = load_pinned_roots(&FsStore, &repo.join(".auths")).expect("load");
        assert_eq!(roots, vec!["did:keri:Efirst", "did:keri:Esecond"]);
    }
}