basis 0.3.0

//! A workspace opened once, minting runs cheaply.
//!
//! Everything a run needs but does not change divides in two, and until now basis
//! kept both halves in one [`RunConfig`](crate::RunConfig) and re-resolved the
//! lot for every prompt. ADR-0010 named the cost: a twenty-agent fan-out read
//! `AGENTS.md` twenty times, resolved the model twenty times, and opened twenty
//! copies of every MCP server the workspace configures.
//!
//! So:
//!
//! - **[`WorkspaceBuilder::open`]** settles what belongs to the workspace —
//!   context documents, the resolved model, skills, templates, hooks, MCP
//!   connections, the command posture, the approval gate.
//!   It is `async` and it does real I/O, once.
//! - **[`Workspace::prepare`]** mints one run from a [`RunSpec`]. It is *not*
//!   `async`, which is the honest signal that nothing is discovered, resolved,
//!   or connected here: a session is spawned on the runtime that already
//!   exists, and that is all.
//!
//! What belongs to the *process* rather than to either — the provider and
//! credential, the history store, the host's interceptors — is a third thing,
//! [`Runtime`] (ADR-0018). A workspace borrows one through an
//! `Arc`, and a host opening many workspaces builds it once.
//!
//! ```no_run
//! # async fn example() -> Result<(), basis::RunError> {
//! use basis::{CollectingSink, Workspace};
//!
//! let workspace = Workspace::open("/repo").await?;
//!
//! // Two runs, one discovery, driven together.
//! let mut first = workspace.prepare("what does this repo do?")?;
//! let mut second = workspace.prepare("what is not tested?")?;
//! let (a, b) = tokio::join!(
//!     first.execute(CollectingSink::default()),
//!     second.execute(CollectingSink::default()),
//! );
//! # let _ = (a?, b?);
//! # Ok(())
//! # }
//! ```
//!
//! The free functions in [`crate::run`](mod@crate::run) — `run`, `prepare`,
//! `resume` and the rest — are thin wrappers that open a workspace, mint one
//! run from it, and drop the workspace when the run ends. There is one
//! resolution path, and this is it.

mod builder;
mod spec;

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

use mentra::{ModelInfo, Session, agent::AgentConfig, provider::ReasoningOptions};

pub use builder::WorkspaceBuilder;
pub use spec::RunSpec;

pub(crate) use builder::{load_templates, resolved_workspace};
pub(crate) use spec::DEFAULT_SESSION_NAME;

#[cfg(feature = "mcp")]
use crate::mcp::connections::McpConnections;
use crate::{
    context::WorkspaceContext,
    event::ContextFile,
    fingerprint::{self, Snapshot},
    run::{Effort, LoadedSkill, PreparedRun, RunContext, RunError},
    runtime::{Runtime, dispatch::HookRegistration},
    templates::Template,
};

/// One workspace, resolved: the runtime it borrows, the model, and everything
/// discovered on disk, ready to mint runs from.
///
/// Held by reference by every run it mints, so a host keeps one per repository
/// for as long as it wants to send prompts at it. Dropping it does not end the
/// runs already minted — a [`PreparedRun`] owns its session — but the MCP
/// connections go with it, and so does the runtime when this held the last
/// `Arc`.
///
/// `Send` and `Sync`: the runtime is shared through `Arc`s and creates
/// sessions from `&self`, so concurrent minting from one workspace needs no
/// lock of basis's own.
pub struct Workspace {
    /// The path the caller asked for. What the agent is scoped to, and what
    /// policy roots are built from.
    path: PathBuf,
    /// The same directory as discovery resolved it, symlinks followed. What
    /// the run header reports, so `workspace` and `context_files` name one
    /// place.
    root: PathBuf,
    runtime: Arc<Runtime>,
    model: ModelInfo,
    provider: String,
    /// [`store::runtime_identifier`](crate::store::runtime_identifier) for
    /// `path`, computed once: what this workspace's conversations are (or, on
    /// a shared runtime, should be — see [`WorkspaceBuilder::open`]) tagged
    /// with.
    identifier: String,
    context: WorkspaceContext,
    /// Built once from the context, cloned per run: none of its inputs vary.
    agent: AgentConfig,
    skills_dirs: Vec<PathBuf>,
    skills: Vec<LoadedSkill>,
    templates_dirs: Vec<PathBuf>,
    templates: Vec<Template>,
    mcp_files: Vec<ContextFile>,
    mcp_servers: Vec<String>,
    /// Keeps this workspace's hooks and guards registered on the runtime's
    /// dispatcher; deregisters on drop.
    #[allow(dead_code, reason = "held for its Drop")]
    hook_registration: HookRegistration,
    #[cfg(feature = "mcp")]
    #[allow(dead_code, reason = "held for its Drop")]
    mcp_connections: McpConnections,
}

/// Hand-written because neither the runtime nor the registration is `Debug`
/// material, and because the context documents hold whole files — a derived
/// impl would dump them.
impl std::fmt::Debug for Workspace {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("Workspace")
            .field("root", &self.root)
            .field("provider", &self.provider)
            .field("model", &self.model.id)
            .field("context_files", &self.context.documents().len())
            .field("skills", &self.skills.len())
            .field("templates", &self.templates.len())
            .field("mcp_servers", &self.mcp_servers)
            .finish_non_exhaustive()
    }
}

impl Workspace {
    /// Opens `path` with basis's defaults: a private runtime with the provider
    /// auto-detected from the environment, the newest model it offers, and
    /// every convention discovered where convention says to look.
    ///
    /// [`builder`](Self::builder) is the same call with the knobs exposed —
    /// including [`with_runtime`](WorkspaceBuilder::with_runtime), for the
    /// host that opens many workspaces on one [`Runtime`].
    pub async fn open(path: impl Into<PathBuf>) -> Result<Self, RunError> {
        Self::builder(path).open().await
    }

    /// Configures a workspace before opening it.
    pub fn builder(path: impl Into<PathBuf>) -> WorkspaceBuilder {
        WorkspaceBuilder::new(path)
    }

    /// Mints a run: a fresh conversation against this workspace.
    ///
    /// Synchronous, and deliberately so — everything expensive already
    /// happened. What this does is spawn a session on the existing runtime and
    /// hand back the [`PreparedRun`] that drives it.
    ///
    /// The spec's prompt may be empty. Once a session outlives a turn, a
    /// conversation with nothing said yet is a real state — it is what ACP's
    /// `session/new` opens — so the emptiness check belongs where a prompt is
    /// actually sent, which is [`PreparedRun::execute`] and
    /// [`PreparedRun::send`]. (The free [`prepare`](crate::run::prepare) keeps
    /// its own up-front check, because a one-shot caller that passed nothing
    /// wants to hear about it before a session exists.)
    pub fn prepare(&self, spec: impl Into<RunSpec>) -> Result<PreparedRun, RunError> {
        let spec = spec.into();
        let mut session = self.runtime.mint(
            spec.session_name.clone(),
            self.model.clone(),
            self.minted_agent(),
            &self.identifier,
        )?;
        apply_effort(&mut session, spec.effort)?;

        Ok(self.minted(session, spec))
    }

    /// Picks up a conversation a previous process left behind.
    ///
    /// `agent_id` is [`PreparedRun::agent_id`], not the session id: mentra
    /// persists agents, and a session is one process's view of one. Resuming
    /// replays the transcript from the store, so the first turn after this
    /// already knows everything the last one did.
    ///
    /// The workspace has to be the one the conversation belongs to. Nothing
    /// here checks that — mentra's store is keyed by agent, not by path — so
    /// resuming an agent under a workspace it never ran in gives it that
    /// workspace's context and tools alongside its own history.
    pub fn resume(
        &self,
        agent_id: &str,
        spec: impl Into<RunSpec>,
    ) -> Result<PreparedRun, RunError> {
        let spec = spec.into();
        let mut session = self.runtime.resume_minted(agent_id)?;
        apply_effort(&mut session, spec.effort)?;

        Ok(self.minted(session, spec))
    }

    /// A cheap stand-in for everything in this workspace a run could see.
    ///
    /// The utility ADR-0014 kept when `watch` was deleted, on the type its
    /// ledger row promised it to. The semantics are [`crate::fingerprint`]'s
    /// verbatim: a digest over `git ls-files` plus `HEAD`, `stat` only, and
    /// every uncertain answer resolving to *changed* rather than unchanged.
    ///
    /// Fingerprints the workspace **as it is now**, not as it was when the
    /// workspace was opened — that is the whole point, since a caller's loop
    /// asks it repeatedly against one long-lived workspace.
    ///
    /// Blocking: it spawns `git` and stats files. An async caller belongs on a
    /// blocking thread — `tokio::task::spawn_blocking`, or the equivalent.
    pub fn fingerprint(&self) -> Snapshot {
        fingerprint::snapshot(&self.root)
    }

    /// The path this workspace was opened with, which is what its runs are
    /// scoped to.
    pub fn path(&self) -> &Path {
        &self.path
    }

    /// The same directory as discovery resolved it, symlinks followed. What the
    /// run header reports, and what [`fingerprint`](Self::fingerprint) reads.
    pub fn root(&self) -> &Path {
        &self.root
    }

    /// The model every run from this workspace uses, resolved once.
    pub fn model(&self) -> &str {
        &self.model.id
    }

    pub fn provider(&self) -> &str {
        &self.provider
    }

    /// The context documents discovered at open, weakest precedence first.
    pub fn context(&self) -> &WorkspaceContext {
        &self.context
    }

    /// The skills this workspace registered on the runtime, after layering.
    ///
    /// Only what *this* workspace registered. The registry itself is the
    /// runtime's and additive, so on a shared runtime a run may also be able
    /// to `load_skill` what a sibling workspace registered — an accepted
    /// consequence of sharing (see [`WorkspaceBuilder::open`]).
    pub fn skills(&self) -> &[LoadedSkill] {
        &self.skills
    }

    /// The prompt templates this workspace defines, after layering,
    /// name-ordered. Over ACP these become the client's commands.
    pub fn templates(&self) -> &[Template] {
        &self.templates
    }

    /// The MCP servers connected at open, by the names that took effect —
    /// which is the configured name unless another workspace on the shared
    /// runtime already held it, in which case it carries a deterministic
    /// suffix. Names only: nothing here echoes a command or a credential.
    pub fn mcp_servers(&self) -> &[String] {
        &self.mcp_servers
    }

    /// The mentra runtime the runs are minted on, for a host that wants
    /// mentra's own surface — the task board, teams, the store — alongside
    /// basis's.
    ///
    /// The same bargain as [`PreparedRun::session`]: basis does not hide mentra,
    /// and reaching past basis's surface is a supported thing to do rather than
    /// a workaround. Renamed from `runtime()` when ADR-0018 gave basis a
    /// `Runtime` of its own, so the name says whose surface comes back.
    pub fn mentra_runtime(&self) -> &mentra::Runtime {
        self.runtime.mentra_runtime()
    }

    /// The agent config this mint offers the model: the one built at open,
    /// with every `mcp__*` tool this workspace does not own hidden.
    ///
    /// Per mint rather than per open, because the shared registry moves as
    /// sibling workspaces come and go, and a roster is honest only about the
    /// registry it was minted against. Hidden, not unregistered — the registry
    /// is single and has no unregister — which also keeps a dropped sibling's
    /// stale bridged tools inert.
    #[cfg(feature = "mcp")]
    fn minted_agent(&self) -> AgentConfig {
        let mut agent = self.agent.clone();

        for descriptor in self.runtime.mentra_runtime().tools() {
            let name = &descriptor.provider.name;
            if let Some((server, _)) = mentra::mcp::parse_mcp_tool_name(name)
                && !self.mcp_servers.iter().any(|own| own == server)
            {
                agent.tool_profile.hidden_tools.insert(name.clone());
            }
        }

        agent
    }

    /// Built without MCP there is nothing to hide: basis registered no bridged
    /// tools, and a host that registered its own past basis's surface asked for
    /// them.
    #[cfg(not(feature = "mcp"))]
    fn minted_agent(&self) -> AgentConfig {
        self.agent.clone()
    }

    /// Wraps a freshly created or resumed session in the run context this
    /// workspace describes.
    ///
    /// Shared by [`prepare`](Self::prepare) and [`resume`](Self::resume) so the
    /// two cannot disagree about what a run from this workspace reports.
    fn minted(&self, session: Session, spec: RunSpec) -> PreparedRun {
        let bounds = spec.turn_options();

        PreparedRun::new(
            session,
            RunContext {
                workspace: self.root.clone(),
                prompt: spec.prompt,
                provider: self.provider.clone(),
                model: self.model.id.clone(),
                context: self.context.clone(),
                skills_dirs: self.skills_dirs.clone(),
                skills: self.skills.clone(),
                templates_dirs: self.templates_dirs.clone(),
                templates: self.templates.clone(),
                mcp_files: self.mcp_files.clone(),
                mcp_servers: self.mcp_servers.clone(),
            },
        )
        .with_bounds(bounds)
    }
}

/// Asks the model for a reasoning effort, when one was requested.
///
/// `None` leaves the session untouched instead of sending a default nobody
/// asked for. Mentra's provider adapter validates the requested level and maps
/// it to that API's wire format.
fn apply_effort(session: &mut Session, effort: Option<Effort>) -> Result<(), RunError> {
    let Some(effort) = effort else {
        return Ok(());
    };

    session.set_reasoning(Some(ReasoningOptions {
        effort: Some(effort.into()),
        summary: None,
    }))?;

    Ok(())
}

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

    /// Concurrent minting is the point of the split, and it holds only if a
    /// workspace can be shared across tasks and threads. Asserted at compile
    /// time so a future field that is neither cannot slip in unnoticed.
    #[test]
    fn a_workspace_can_be_shared_across_tasks() {
        const fn assert_send_sync<T: Send + Sync>() {}

        assert_send_sync::<Workspace>();
        assert_send_sync::<RunSpec>();
    }
}