//! A repository on disk: the `.oxy` directory, one workspace, the operation

//! log, and the working-copy change (spec §12, §13.1).

//!

//! Not yet implemented from the spec: packs, checkpoints, multiple

//! workspaces, multi-signer policy updates, and the `objects`/`checkpoint`

//! endpoints. A repository without a policy is unverified and accepts

//! unsigned pushes; with one, everything received is checked (spec §14.5). Changes are signed individually when `core.sign` is

//! `change`; the default `seal` leaves them unsigned until push exists.

use crate::attest::{Attest, AttestBody};

use crate::diff::{ranges, split_lines, text_edits};

use crate::hash::{hash_object, ChangeHash, KeyId, ObjectRef, ObjectType};

use crate::identity::{verify as verify_signature, Domain, Identity, SecretKey, Signature};

use crate::ids::{ChangeId, NodeId, WorkspaceId};

use crate::objects::{

    Blob, Change, ChangeKind, Edit, Hlc, Mode, NodeKind, OpRef, StateObject, TreeOp,

};

use crate::oplog::{Format1Op, Op, View, SNAPSHOT_SUFFIX};

use crate::protocol::{

    open_remote, Bundle, RefResult, RefUpdate, RefsResponse, RemoteOptions, RemoteRef,

    SignedAttest, SignedPolicy,

};

use crate::state::{FileContent, Snapshot, State};

use crate::store::{Store, StoreError};

#[allow(unused_imports)]

use crate::subrepo::Pin;

use crate::tree::OpKey;

use rand::RngCore;

use std::collections::{BTreeMap, BTreeSet, HashMap};

use std::fs;

use std::io::Write;

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

pub const OXY_DIR: &str = ".oxy";

pub const FORMAT_LINE: &str = "oxy repository format 2\n";

const FORMAT1_LINE: &str = "oxy repository format 1\n";

const BINARY_SNIFF: usize = 8 * 1024;

/// Loose objects tolerated before a commit packs them (spec §13.4).

pub const AUTOPACK_THRESHOLD: usize = 4096;

#[derive(Debug, thiserror::Error)]

pub enum RepoError {

    #[error("io: {0}")]

    Io(#[from] std::io::Error),

    #[error(transparent)]

    Store(#[from] StoreError),

    #[error(transparent)]

    Object(#[from] crate::objects::ObjectError),

    #[error(transparent)]

    State(#[from] crate::state::StateError),

    #[error("{0}")]

    Msg(String),

}

pub type Result<T> = std::result::Result<T, RepoError>;

fn fail<T>(s: impl Into<String>) -> Result<T> {

    Err(RepoError::Msg(s.into()))

}

mod bookmarks;

mod checkout;

mod checkpoint;

mod config;

mod gc;

mod git;

mod history;

mod hooks;

mod identity;

mod inspect;

mod policy;

mod prompt;

mod snapshot;

mod subrepos;

mod sync;

mod tags;

#[cfg(test)]

mod tests;

mod workspace;

pub use bookmarks::{BookmarkInfo, MergeReport};

pub use checkout::CheckoutReport;

pub use config::{parse_size, read_config_file, Config};

pub use gc::GcReport;

pub use git::{GitExportReport, GitImportReport};

pub use hooks::{json_array, json_str, HookOutcome};

pub use identity::{Rotation, SignatureStatus};

pub use inspect::{BisectStep, BlameLine};

pub use policy::PolicyUpdate;

pub use prompt::{PromptInfo, DEFAULT_PROMPT_FORMAT, GLYPH_PROMPT_FORMAT};

pub use snapshot::{

    added_node_paths, diff_files_of, has_conflict_markers, is_binary, referenced_changes,

    render_change, render_hunks, similarity, ChangeStatus, DiffHunk, FileDiff, Hunk, PathStatus,

    Selection, SnapshotResult,

};

pub use subrepos::{SubrepoInfo, SubrepoSync};

pub use sync::{FetchReport, PullReport};

pub use tags::TagInfo;

pub use workspace::{SnapshotLock, WorkspaceInfo};

fn write_atomic(path: &Path, data: &[u8]) -> Result<()> {

    let tmp = path.with_extension("tmp");

    {

        let mut f = fs::File::create(&tmp)?;

        f.write_all(data)?;

        f.sync_all()?;

    }

    fs::rename(&tmp, path)?;

    Ok(())

}

pub struct LogEntry {

    pub hash: ChangeHash,

    /// Metadata from the state; the full change may be absent in a shallow repository.

    pub change: crate::state::ChangeMeta,

    pub is_working_copy: bool,

    pub is_head: bool,

}

/// A file as found on disk or in an imported tree.

pub(crate) struct FsEntry {

    pub kind: NodeKind,

    pub exec: bool,

    /// File content, or a symlink's target. Empty when `blob` is set.

    pub content: Vec<u8>,

    /// The stored blob of an opaque file whose size and mtime are unchanged

    /// since the last manifest (spec §12.3 stat cache); the content was not

    /// read.

    pub blob: Option<ObjectRef>,

    /// BLAKE3 of the content, carried over from the manifest when the stat

    /// is unchanged, so the manifest can be rewritten without rehashing.

    pub content_hash: Option<String>,

}

impl FsEntry {

    pub(crate) fn new(kind: NodeKind, exec: bool, content: Vec<u8>) -> FsEntry {

        FsEntry {

            kind,

            exec,

            content,

            blob: None,

            content_hash: None,

        }

    }

}

pub struct Repo {

    /// Oxygen-pinned subrepos skipped by the running Git export.

    pub(crate) git_export_skipped: std::cell::Cell<usize>,

    root: PathBuf,

    oxy: PathBuf,

    store: Store,

    workspace: WorkspaceId,

    /// A hosted repository with no working copy (spec §12.2, hub spec §4.1).

    bare: bool,

    keys_dir: PathBuf,

    user_config: PathBuf,

    pub config: Config,

}

/// Marker file of a bare repository, inside `.oxy/`.

const BARE_MARKER: &str = "bare";

/// Marker of a hosted repository that has no id yet: the first push binds

/// it to the pusher's id (spec §16.1).

const UNBOUND_MARKER: &str = "unbound";

/// The user's oxy directory: `$OXY_HOME`, else `$XDG_CONFIG_HOME/oxy`, else

/// `~/.config/oxy`. It holds `config.toml` (spec §19) and `keys/`.

pub fn default_home() -> PathBuf {

    if let Ok(h) = std::env::var("OXY_HOME") {

        return PathBuf::from(h);

    }

    if let Ok(x) = std::env::var("XDG_CONFIG_HOME") {

        return PathBuf::from(x).join("oxy");

    }

    let home = std::env::var("HOME").unwrap_or_else(|_| ".".into());

    PathBuf::from(home).join(".config").join("oxy")

}

pub fn default_keys_dir() -> PathBuf {

    default_home().join("keys")

}

pub fn default_user_config() -> PathBuf {

    default_home().join("config.toml")

}

/// Where `create_identity` records the author.

#[derive(Clone, Copy, Debug, PartialEq, Eq)]

pub enum IdentityScope {

    /// The user file: every repository of this user signs with it.

    User,

    /// This repository only.

    Repo,

}

impl Repo {

    // ------------------------------------------------------------ lifecycle

    pub fn init(root: &Path) -> Result<Repo> {

        let mut id = [0u8; 16];

        rand::rngs::OsRng.fill_bytes(&mut id);

        Self::init_with_id(root, id)

    }

    /// Initialize a repository with a given repository ID (clones share the

    /// ID of their origin, spec §14.4).

    pub fn init_with_id(root: &Path, id: [u8; 16]) -> Result<Repo> {

        fs::create_dir_all(root)?;

        let root = root.canonicalize().unwrap_or_else(|_| root.to_path_buf());

        let oxy = root.join(OXY_DIR);

        if oxy.exists() {

            return fail(format!("{} is already an oxy repository", root.display()));

        }

        fs::create_dir_all(oxy.join("ops"))?;

        write_atomic(&oxy.join("format"), FORMAT_LINE.as_bytes())?;

        write_atomic(&oxy.join("id"), hex::encode(id).as_bytes())?;

        let config = Config::load(Some(&default_user_config()), &oxy.join("config"))?;

        config.save(&oxy.join("config"))?;

        let workspace = WorkspaceId::random();

        write_atomic(&oxy.join("workspace"), workspace.to_hex().as_bytes())?;

        let store = Store::open(oxy.join("objects"))?;

        let repo = Repo {

            git_export_skipped: Default::default(),

            root,

            oxy,

            store,

            workspace,

            bare: false,

            keys_dir: default_keys_dir(),

            user_config: default_user_config(),

            config,

        };

        repo.register_workspace(&workspace, &repo.root)?;

        let wc = repo.new_working_copy(vec![], "");

        let wc_hash = repo.store.put_change(&wc)?;

        let mut view = View::default();

        view.bookmarks.insert(

            repo.config.bookmark.clone(),

            repo.store.put_state(&StateObject::new(vec![]))?,

        );

        view.workspaces.insert(workspace, wc_hash);

        repo.record_op(&[], "oxy init", view)?;

        Ok(repo)

    }

    /// Create a bare repository: an object store, operation log and

    /// references with no workspace and no working copy, for hosting

    /// (hub spec §4.1). `root` holds `.oxy/` and nothing else.

    pub fn init_bare(root: &Path) -> Result<Repo> {

        let mut id = [0u8; 16];

        rand::rngs::OsRng.fill_bytes(&mut id);

        Self::init_bare_with_id(root, id)

    }

    pub fn init_bare_with_id(root: &Path, id: [u8; 16]) -> Result<Repo> {

        fs::create_dir_all(root)?;

        let root = root.canonicalize().unwrap_or_else(|_| root.to_path_buf());

        let oxy = root.join(OXY_DIR);

        if oxy.exists() {

            return fail(format!("{} is already an oxy repository", root.display()));

        }

        fs::create_dir_all(oxy.join("ops"))?;

        write_atomic(&oxy.join("format"), FORMAT_LINE.as_bytes())?;

        write_atomic(&oxy.join("id"), hex::encode(id).as_bytes())?;

        write_atomic(&oxy.join(BARE_MARKER), b"")?;

        let config = Config::load(Some(&default_user_config()), &oxy.join("config"))?;

        config.save(&oxy.join("config"))?;

        let store = Store::open(oxy.join("objects"))?;

        let repo = Repo {

            git_export_skipped: Default::default(),

            root,

            oxy,

            store,

            workspace: WorkspaceId::ZERO,

            bare: true,

            keys_dir: default_keys_dir(),

            user_config: default_user_config(),

            config,

        };

        let mut view = View::default();

        view.bookmarks.insert(

            repo.config.bookmark.clone(),

            repo.store.put_state(&StateObject::new(vec![]))?,

        );

        repo.record_op(&[], "oxy init --bare", view)?;

        Ok(repo)

    }

    /// A bare repository with no id yet. Its `id()` is all zero until the

    /// first push binds it (`bind_id`), so an existing repository can be

    /// pushed to a freshly created hosted one and keep its identity.

    pub fn init_bare_unbound(root: &Path) -> Result<Repo> {

        let repo = Self::init_bare_with_id(root, [0; 16])?;

        fs::remove_file(repo.oxy.join("id"))?;

        write_atomic(&repo.oxy.join(UNBOUND_MARKER), b"")?;

        Ok(repo)

    }

    pub fn is_unbound(&self) -> bool {

        self.oxy.join(UNBOUND_MARKER).is_file()

    }

    /// Give an unbound repository its id.

    pub fn bind_id(&self, id: [u8; 16]) -> Result<()> {

        if !self.is_unbound() {

            return fail("this repository already has an id");

        }

        if id == [0; 16] {

            return fail("a repository id cannot be all zero");

        }

        write_atomic(&self.oxy.join("id"), hex::encode(id).as_bytes())?;

        fs::remove_file(self.oxy.join(UNBOUND_MARKER))?;

        Ok(())

    }

    /// Whether this repository has no working copy (`init_bare`).

    pub fn is_bare(&self) -> bool {

        self.bare

    }

    /// Open the repository containing `start` (searching upwards).

    pub fn open(start: &Path) -> Result<Repo> {

        let start = start.canonicalize()?;

        let mut dir: Option<&Path> = Some(&start);

        while let Some(d) = dir {

            let oxy = d.join(OXY_DIR);

            if oxy.is_file() {

                // A secondary workspace (spec §12.2): the file points at the repository.

                let text = fs::read_to_string(&oxy)?;

                let Some((shared, workspace)) = workspace::parse_workspace_file(&text) else {

                    return fail(format!("{} is not a valid workspace file", oxy.display()));

                };

                let format = fs::read_to_string(shared.join("format"))?;

                if format != FORMAT_LINE {

                    return fail(format!("unsupported repository format: {}", format.trim()));

                }

                let config = Config::load(Some(&default_user_config()), &shared.join("config"))?;

                let store = Store::open(shared.join("objects"))?;

                let mut repo = Repo {

                    git_export_skipped: Default::default(),

                    root: d.to_path_buf(),

                    oxy: shared,

                    store,

                    workspace,

                    bare: false,

                    keys_dir: default_keys_dir(),

                    user_config: default_user_config(),

                    config,

                };

                repo.apply_workspace_bookmark();

                return Ok(repo);

            }

            if oxy.is_dir() {

                let format = fs::read_to_string(oxy.join("format"))?;

                let config = Config::load(Some(&default_user_config()), &oxy.join("config"))?;

                let bare = oxy.join(BARE_MARKER).is_file();

                let workspace = if bare {

                    WorkspaceId::ZERO

                } else {

                    WorkspaceId::from_hex(fs::read_to_string(oxy.join("workspace"))?.trim())

                        .ok_or_else(|| RepoError::Msg("corrupt .oxy/workspace".into()))?

                };

                let store = Store::open(oxy.join("objects"))?;

                let mut repo = Repo {

                    git_export_skipped: Default::default(),

                    root: d.to_path_buf(),

                    oxy,

                    store,

                    workspace,

                    bare,

                    keys_dir: default_keys_dir(),

                    user_config: default_user_config(),

                    config,

                };

                if !bare {

                    repo.apply_workspace_bookmark();

                }

                if format == FORMAT1_LINE {

                    repo.migrate_format1()?;

                } else if format != FORMAT_LINE {

                    return fail(format!("unsupported repository format: {}", format.trim()));

                }

                return Ok(repo);

            }

            dir = d.parent();

        }

        fail(format!(

            "no oxy repository found at or above {}",

            start.display()

        ))

    }

    /// Rewrite a format-1 operation log, whose bookmarks were head lists,

    /// into format 2, where each bookmark names a `state` object.

    fn migrate_format1(&self) -> Result<()> {

        let hex = fs::read_to_string(self.oxy.join("ops").join("head"))?;

        let head = ObjectRef::from_hex(hex.trim())

            .ok_or_else(|| RepoError::Msg("corrupt .oxy/ops/head".into()))?;

        // Collect the chain root-first.

        let mut chain: Vec<Format1Op> = Vec::new();

        let mut cur = Some(head);

        while let Some(r) = cur {

            let op = Op::decode_format1(&self.store.get_typed(&r, ObjectType::Op)?)?;

            cur = op.parents.first().copied();

            chain.push(op);

        }

        chain.reverse();

        let mut new_parent: Option<ObjectRef> = None;

        for old in chain {

            let mut view = View::default();

            for (name, heads) in &old.view.bookmarks {

                view.bookmarks.insert(

                    name.clone(),

                    self.store.put_state(&StateObject::new(heads.clone()))?,

                );

            }

            view.workspaces = old.view.workspaces.clone();

            let op = Op {

                parents: new_parent.into_iter().collect(),

                hlc: old.hlc,

                command: old.command,

                view,

            };

            new_parent = Some(self.store.put(ObjectType::Op, &op.encode())?);

        }

        write_atomic(

            &self.oxy.join("ops").join("head"),

            new_parent.unwrap().to_hex().as_bytes(),

        )?;

        write_atomic(&self.oxy.join("format"), FORMAT_LINE.as_bytes())?;

        Ok(())

    }

    /// Pack automatically once many loose objects have accumulated.

    pub(crate) fn maybe_autopack(&self) -> Result<()> {

        if self.store.loose_count()? > AUTOPACK_THRESHOLD {

            self.store.pack_loose()?;

            self.store.merge_packs()?;

        }

        Ok(())

    }

    /// The repository ID (spec §14.4). Repositories made before IDs existed get one on first use.

    pub fn id(&self) -> Result<[u8; 16]> {

        if self.is_unbound() {

            return Ok([0; 16]);

        }

        let path = self.oxy.join("id");

        match fs::read_to_string(&path) {

            Ok(h) => hex::decode(h.trim())

                .ok()

                .and_then(|v| v.try_into().ok())

                .ok_or_else(|| RepoError::Msg("corrupt .oxy/id".into())),

            Err(e) if e.kind() == std::io::ErrorKind::NotFound => {

                let mut id = [0u8; 16];

                rand::rngs::OsRng.fill_bytes(&mut id);

                write_atomic(&path, hex::encode(id).as_bytes())?;

                Ok(id)

            }

            Err(e) => Err(e.into()),

        }

    }

    pub fn root(&self) -> &Path {

        &self.root

    }

    pub fn store(&self) -> &Store {

        &self.store

    }

    pub fn workspace(&self) -> WorkspaceId {

        self.workspace

    }

    /// Use a different user directory for keys and the user config file

    /// (tests, or `$OXY_HOME`). Reloads the effective configuration.

    pub fn with_home(mut self, dir: impl Into<PathBuf>) -> Repo {

        let dir = dir.into();

        self.keys_dir = dir.join("keys");

        self.user_config = dir.join("config.toml");

        if let Ok(c) = Config::load(Some(&self.user_config), &self.oxy.join("config")) {

            self.config = c;

        }

        self.apply_workspace_bookmark();

        self

    }

    /// The workspace's current bookmark (spec §10.1) overrides the

    /// configured default when `oxy bookmark switch` has recorded one.

    fn apply_workspace_bookmark(&mut self) {