scv-client 0.3.0

//! Where an SCV instance keeps everything, in one place.
//!
//! An instance home (`SCV_HOME`, default `~/.scv`) holds exactly:
//!
//! - `config.toml`: every setting a person edits, including channel accounts;
//! - `credentials/`: sign-ins SCV writes itself (channel logins);
//! - `agents/<name>/`: the private homes of delegated agent CLIs, which keep
//!   their own sign-ins and configuration there;
//! - `skills/`: the user's SCV skills;
//! - `state/`: runtime data SCV writes: the daemon socket and lock, delegated
//!   run records, conversation markers, import records, channel delivery
//!   state and locks, and chat media.
//!
//! Anything else in the home is not read by SCV; [`Layout::strays`] lists it.
//!
//! A process selects its instance once, with [`Layout::from_env`], and hands
//! the `Layout` to everything that needs a path; the environment only carries
//! the selection on to child processes.

use anyhow::{Context, Result};
use sha2::{Digest, Sha256};
use std::path::{Path, PathBuf};

/// Top-level entries of an instance home, in display order.
pub(crate) const ENTRIES: [&str; 5] = ["config.toml", "credentials", "agents", "skills", "state"];

/// Paths earlier releases used, which SCV no longer reads.
const LEGACY: [&str; 7] = [
    "adapters",
    "channels",
    "run",
    "server.sock",
    "server.lock",
    "clawbot",
    "clawbot.toml",
];

/// The paths of one SCV instance.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Layout {
    home: PathBuf,
    /// Selected by default (`~/.scv`) rather than by `SCV_HOME`.
    default: bool,
}

/// Something in an instance home that SCV does not read.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Stray {
    pub path: PathBuf,
    /// A path an earlier SCV release used, rather than an unknown file.
    pub legacy: bool,
}

impl Layout {
    /// The instance at `home`, selected explicitly as `SCV_HOME` selects one.
    pub fn new(home: impl Into<PathBuf>) -> Self {
        Self {
            home: home.into(),
            default: false,
        }
    }

    /// The instance selected by `SCV_HOME`, or `~/.scv`, with its home
    /// resolved: canonical when it exists, otherwise made absolute. Service
    /// unit names and delegation records hash this path, so every process of
    /// an instance must resolve it the same way.
    pub fn from_env() -> Result<Self> {
        let selected = std::env::var_os("SCV_HOME").map(PathBuf::from);
        let default = selected.is_none();
        let home = selected
            .or_else(|| dirs::home_dir().map(|path| path.join(".scv")))
            .context("cannot determine SCV_HOME")?;
        Ok(Self {
            home: resolve(home)?,
            default,
        })
    }

    pub fn home(&self) -> &Path {
        &self.home
    }

    /// Whether this is the default instance, which `SCV_HOME` did not select.
    pub fn is_default(&self) -> bool {
        self.default
    }

    /// The instance's systemd user unit: `scv.service` for the default
    /// instance, otherwise `scv-<hash of the home>.service`, so instances
    /// never share a unit and a release finds the unit an earlier one wrote.
    pub fn service_name(&self) -> String {
        if self.default {
            return "scv.service".into();
        }
        let digest = Sha256::digest(self.home.to_string_lossy().as_bytes());
        let suffix = digest[..8]
            .iter()
            .map(|byte| format!("{byte:02x}"))
            .collect::<String>();
        format!("scv-{suffix}.service")
    }

    /// The settings file a person edits.
    pub fn config(&self) -> PathBuf {
        self.home.join("config.toml")
    }

    /// Sign-ins SCV writes itself.
    pub fn credentials(&self) -> PathBuf {
        self.home.join("credentials")
    }

    /// One channel's account credentials, `<account>.json` each.
    pub fn channel_credentials(&self, channel: &str) -> PathBuf {
        self.credentials().join(channel)
    }

    /// The private homes of delegated agent CLIs.
    pub fn agents(&self) -> PathBuf {
        self.home.join("agents")
    }

    pub fn agent_home(&self, agent: &str) -> PathBuf {
        self.agents().join(agent)
    }

    pub fn skills(&self) -> PathBuf {
        self.home.join("skills")
    }

    /// Runtime data SCV writes and reads back; never edited by hand.
    pub fn state(&self) -> PathBuf {
        self.home.join("state")
    }

    pub fn socket(&self) -> PathBuf {
        self.state().join("server.sock")
    }

    /// Records of running delegated agents.
    pub fn delegations(&self) -> PathBuf {
        self.state().join("delegations")
    }

    /// Markers of live delegated conversations, for `scv agents gc`.
    pub fn conversations(&self) -> PathBuf {
        self.state().join("conversations")
    }

    /// What each `scv agents import` copied, and from where.
    pub fn imports(&self) -> PathBuf {
        self.state().join("imports")
    }

    /// One channel's delivery state and account locks.
    pub fn channel_state(&self, channel: &str) -> PathBuf {
        self.state().join("channels").join(channel)
    }

    /// Files chat users sent, under `<channel>/<account>`, and copies of files
    /// the model sends back, under `outbox`.
    pub fn media(&self) -> PathBuf {
        self.state().join("media")
    }

    /// Copies of files the model attached, waiting to be sent to a chat.
    pub fn outbox(&self) -> PathBuf {
        self.media().join("outbox")
    }

    /// A planned restart in progress.
    pub fn update_plan(&self) -> PathBuf {
        self.state().join("update.json")
    }

    /// The chat the account owner last wrote from.
    pub fn last_owner(&self) -> PathBuf {
        self.state().join("last-owner.json")
    }

    /// Present while a daemon runs; one left behind means it did not shut
    /// down cleanly.
    pub fn daemon_marker(&self) -> PathBuf {
        self.state().join("daemon.json")
    }

    /// Serializes SCV's own edits of `config.toml`.
    pub fn config_lock(&self) -> PathBuf {
        self.state().join("config.lock")
    }

    /// Entries of the home that SCV does not read, sorted by name.
    pub fn strays(&self) -> Result<Vec<Stray>> {
        let entries = match std::fs::read_dir(&self.home) {
            Ok(entries) => entries,
            Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Ok(Vec::new()),
            Err(error) => {
                return Err(error).with_context(|| format!("read {}", self.home.display()));
            }
        };
        let mut strays = Vec::new();
        for entry in entries {
            let name = entry?.file_name();
            let Some(text) = name.to_str() else {
                strays.push(Stray {
                    path: self.home.join(&name),
                    legacy: false,
                });
                continue;
            };
            if ENTRIES.contains(&text) {
                continue;
            }
            strays.push(Stray {
                path: self.home.join(text),
                legacy: LEGACY.contains(&text),
            });
        }
        strays.sort_by(|a, b| a.path.cmp(&b.path));
        Ok(strays)
    }
}

/// `path` resolved as an instance home: canonical when it exists, otherwise
/// made absolute against the working directory.
fn resolve(path: PathBuf) -> Result<PathBuf> {
    if path.exists() {
        Ok(std::fs::canonicalize(&path).unwrap_or(path))
    } else if path.is_absolute() {
        Ok(path)
    } else {
        Ok(std::env::current_dir()
            .context("cannot determine SCV instance home")?
            .join(path))
    }
}

#[cfg(test)]
mod tests;