ao-core 0.1.0

use crate::{
    config::ProjectConfig,
    error::AoError,
    error::Result,
    prompt_builder,
    scm::{
        AutomatedComment, CheckRun, CiStatus, CreateIssueInput, Issue, IssueFilters, IssueUpdate,
        MergeMethod, MergeReadiness, PrState, PrSummary, PullRequest, Review, ReviewComment,
        ReviewDecision, ScmWebhookEvent, ScmWebhookRequest, ScmWebhookVerificationResult,
    },
    scm_transitions::ScmObservation,
    types::{ActivityState, CostEstimate, Session, WorkspaceCreateConfig},
};
use async_trait::async_trait;
use std::collections::HashMap;
use std::path::{Path, PathBuf};

/// How an agent process is executed (tmux, raw process, docker, ...).
///
/// The runtime returns an opaque `handle` string that the caller stores in
/// `Session::runtime_handle` and passes back to other methods.
#[async_trait]
pub trait Runtime: Send + Sync {
    /// Spawn a new isolated execution context (e.g. tmux session) and run the
    /// given launch command in it. `launch_command` is a single shell string
    /// — the runtime is responsible for any escaping/wrapping it needs.
    async fn create(
        &self,
        session_id: &str,
        cwd: &Path,
        launch_command: &str,
        env: &[(String, String)],
    ) -> Result<String>;

    async fn send_message(&self, handle: &str, msg: &str) -> Result<()>;
    async fn is_alive(&self, handle: &str) -> Result<bool>;
    async fn destroy(&self, handle: &str) -> Result<()>;
}

/// How a session's working directory is materialized (git worktree, full clone, ...).
#[async_trait]
pub trait Workspace: Send + Sync {
    /// Create an isolated copy of the repo on a new branch, returning its path.
    async fn create(&self, cfg: &WorkspaceCreateConfig) -> Result<PathBuf>;
    async fn destroy(&self, workspace_path: &Path) -> Result<()>;

    /// Report whether a previously-created workspace is still usable at
    /// `workspace_path`. Session restore uses this to decide whether the
    /// session can be brought back up or whether the user has to spawn a
    /// fresh one.
    ///
    /// The default impl treats any directory that exists on disk as
    /// usable — good enough for plugins that don't have backend-specific
    /// validation. Plugins backed by git (worktree / clone) override this
    /// to also verify the directory is still a working tree (catches the
    /// case where someone `rm -rf`'d `.git` or the repo was corrupted).
    async fn exists(&self, workspace_path: &Path) -> Result<bool> {
        Ok(workspace_path.exists())
    }
}

/// A specific AI coding tool (Claude Code, Codex, Aider, Cursor, ...).
///
/// Mostly a metadata provider (launch command, env, prompt), plus one async
/// hook — `detect_activity` — which the lifecycle loop polls to learn what
/// the underlying agent process is currently doing. The TS reference does
/// this by tailing a JSONL log file the agent writes; Slice 1 Phase C's
/// stub just returns `Ready` so the polling loop has something to drive.
#[async_trait]
pub trait Agent: Send + Sync {
    /// Single shell string the runtime will run inside its execution context.
    fn launch_command(&self, session: &Session) -> String;
    fn environment(&self, session: &Session) -> Vec<(String, String)>;
    /// First prompt to deliver after the process is up.
    fn initial_prompt(&self, session: &Session) -> String;

    /// System rules / workflow guidance that must be prepended to the user
    /// prompt by the caller.
    ///
    /// Agents that support a dedicated system-prompt CLI flag (e.g.
    /// Claude Code's `--append-system-prompt`) inject rules at launch
    /// time via [`launch_command`](Self::launch_command) and return
    /// `None` here. Agents without such a flag (e.g. Cursor) return
    /// `Some(rules)` so callers composing a richer prompt via
    /// [`build_prompt`](crate::prompt_builder::build_prompt) can prepend
    /// them before delivery.
    ///
    /// Default: `None` — no system prompt to inject separately.
    fn system_prompt(&self) -> Option<String> {
        None
    }

    /// Inspect whatever evidence this agent leaves behind (log files,
    /// terminal scrollback, pid probes, ...) and report its current
    /// activity state. Called once per lifecycle tick.
    ///
    /// The default impl consults `{workspace}/.ao/activity.jsonl` via
    /// `activity_log::detect_activity_from_log` and surfaces:
    /// - `Exited` when the last entry is terminal (no staleness
    ///   downgrade — exit is a one-way signal).
    /// - `WaitingInput` / `Blocked` when the last entry is actionable
    ///   and fresh (within `ACTIVITY_INPUT_STALENESS_SECS`).
    ///
    /// Falls back to `Ready` when there's no workspace, no log, or the
    /// log only carries noisy signals (`Active` / `Ready` / `Idle` /
    /// stale actionable). Plugins with richer native detection (JSONL
    /// tailing, git-index mtime, ...) override this entirely.
    async fn detect_activity(&self, session: &Session) -> Result<ActivityState> {
        if let Some(ref ws) = session.workspace_path {
            if let Some(state) = crate::activity_log::detect_activity_from_log(ws) {
                return Ok(state);
            }
        }
        Ok(ActivityState::Ready)
    }

    /// Poll current aggregated token usage / cost from the agent's logs.
    ///
    /// Called by the lifecycle loop when a session's status changes (not
    /// every tick). The default impl consults
    /// `{workspace}/.ao/usage.jsonl` via `cost_log::parse_usage_jsonl`
    /// and returns the aggregate when entries exist. Returns `None`
    /// when cost tracking is unavailable — either because there's no
    /// workspace, the file is missing, or it aggregates to zero tokens.
    /// Plugins with native cost sources (e.g. `agent-claude-code`
    /// reading `~/.claude/projects/**`) override this.
    async fn cost_estimate(&self, session: &Session) -> Result<Option<CostEstimate>> {
        let Some(ref ws) = session.workspace_path else {
            return Ok(None);
        };
        let ws = ws.clone();
        let estimate = tokio::task::spawn_blocking(move || crate::cost_log::parse_usage_jsonl(&ws))
            .await
            .unwrap_or_else(|e| {
                tracing::warn!("cost_estimate task failed: {e}");
                None
            });
        Ok(estimate)
    }
}

/// Source-code-management plugin — PR lifecycle, CI, reviews.
///
/// Slice 2's richest plugin slot. Mirrors the TS `SCM` interface in
/// `packages/core/src/types.ts` (line ~577), trimmed to the surface the
/// reaction engine actually needs:
///
/// - PR discovery (`detect_pr`) is called once per session per tick.
/// - CI + review summaries drive status transitions inside
///   `LifecycleManager::poll_one` (e.g. `working → ci_failed`).
/// - `pending_comments` feeds the `changes-requested` reaction.
/// - `mergeability` + `merge` implement the `approved-and-green` flow.
///
/// Methods on this trait come in two tiers:
///
/// - **Required** — the reaction loop calls these every tick, so every SCM
///   plugin has to implement them.
/// - **Optional** — webhook verification/parsing, PR resolve/close/assign/
///   checkout, bot-comment fetch, PR summary. Each has a default
///   implementation that either returns an "unsupported" `AoError::Scm`
///   (for writes) or an empty value (for reads), mirroring the TS
///   interface's `?:` optional methods. Plugins opt in as their backend
///   supports the capability; `scm-github` implements all of them.
#[async_trait]
pub trait Scm: Send + Sync {
    /// Human-readable plugin name for logs and CLI output (`"github"`).
    fn name(&self) -> &str;

    /// Look up the open PR for a session, usually by branch name.
    /// `None` means "no PR yet" — the lifecycle loop stays in `working`
    /// until one appears.
    async fn detect_pr(&self, session: &Session) -> Result<Option<PullRequest>>;

    /// Current open/merged/closed state of the PR.
    async fn pr_state(&self, pr: &PullRequest) -> Result<PrState>;

    /// Individual CI check results. Used by the reaction engine to
    /// format a useful `ci-failed` message with which checks broke.
    async fn ci_checks(&self, pr: &PullRequest) -> Result<Vec<CheckRun>>;

    /// Rolled-up CI status (pending/passing/failing/none).
    async fn ci_status(&self, pr: &PullRequest) -> Result<CiStatus>;

    /// All reviews on the PR (human + bot).
    async fn reviews(&self, pr: &PullRequest) -> Result<Vec<Review>>;

    /// Overall review decision, as GitHub shows it on the PR header.
    async fn review_decision(&self, pr: &PullRequest) -> Result<ReviewDecision>;

    /// Unresolved review comments — forwarded verbatim to the agent by
    /// the `changes-requested` reaction.
    async fn pending_comments(&self, pr: &PullRequest) -> Result<Vec<ReviewComment>>;

    /// Can the PR be merged right now, and if not, why?
    async fn mergeability(&self, pr: &PullRequest) -> Result<MergeReadiness>;

    /// Merge the PR. Called by the `approved-and-green` reaction and by
    /// `ao-rs merge <id>`. `None` lets the plugin pick its default method.
    async fn merge(&self, pr: &PullRequest, method: Option<MergeMethod>) -> Result<()>;

    // --- Optional methods (default no-op / unsupported) -------------------
    //
    // These map to TS `SCM?.method` optional members. Default impls let
    // non-GitHub plugins (e.g. `scm-gitlab`) compile against the enriched
    // trait without immediately implementing every method. Callers that
    // *rely* on a method must handle the "unsupported" error rather than
    // assuming universal support.

    /// Verify an inbound webhook delivery (HMAC signature, headers, body
    /// size). Default returns `ok: false` with an "unsupported" reason so
    /// a plugin that hasn't opted in can't be mistaken for a verified
    /// pass-through.
    async fn verify_webhook(
        &self,
        _request: &ScmWebhookRequest,
        _project: &ProjectConfig,
    ) -> Result<ScmWebhookVerificationResult> {
        Ok(ScmWebhookVerificationResult {
            ok: false,
            reason: Some("scm plugin does not support webhook verification".into()),
            ..Default::default()
        })
    }

    /// Parse a webhook delivery into a normalised event. `None` means the
    /// payload was recognised but carries no actionable data for the
    /// reaction engine (e.g. a `ping` event). Default returns `None`.
    async fn parse_webhook(
        &self,
        _request: &ScmWebhookRequest,
        _project: &ProjectConfig,
    ) -> Result<Option<ScmWebhookEvent>> {
        Ok(None)
    }

    /// Resolve a PR reference (number like `"42"`, or a full URL) to a
    /// canonical `PullRequest`. `detect_pr` is branch-based; this one
    /// answers "give me the PR for this number/URL".
    async fn resolve_pr(&self, _reference: &str, _project: &ProjectConfig) -> Result<PullRequest> {
        Err(AoError::Scm(
            "scm plugin does not support PR resolution".into(),
        ))
    }

    /// Assign the PR to the authenticated user. Used by `ao-rs claim-pr`
    /// so the human picking up a session also owns the PR in GitHub's UI.
    async fn assign_pr_to_current_user(&self, _pr: &PullRequest) -> Result<()> {
        Err(AoError::Scm(
            "scm plugin does not support PR assignment".into(),
        ))
    }

    /// Check out `pr.branch` into `workspace_path`. Returns `true` when the
    /// branch changed, `false` when the workspace was already on the right
    /// branch. Implementations must refuse to switch if the worktree has
    /// uncommitted changes — the caller's work is never worth silently
    /// trashing.
    async fn checkout_pr(&self, _pr: &PullRequest, _workspace_path: &Path) -> Result<bool> {
        Err(AoError::Scm(
            "scm plugin does not support PR checkout".into(),
        ))
    }

    /// Top-line PR stats (state + title + additions + deletions) in a
    /// single round-trip. Cheaper than calling `pr_state` + a diff query
    /// when all you need is a dashboard row.
    async fn pr_summary(&self, _pr: &PullRequest) -> Result<PrSummary> {
        Err(AoError::Scm(
            "scm plugin does not support PR summary".into(),
        ))
    }

    /// Close a PR without merging. Symmetric with `merge`; used when a
    /// session is abandoned but its PR shouldn't linger open.
    async fn close_pr(&self, _pr: &PullRequest) -> Result<()> {
        Err(AoError::Scm(
            "scm plugin does not support closing PRs".into(),
        ))
    }

    /// Fetch review comments from automated bots (Dependabot, linters,
    /// security scanners). Default returns an empty list — the reaction
    /// engine treats "no bot comments" as the normal case.
    async fn automated_comments(&self, _pr: &PullRequest) -> Result<Vec<AutomatedComment>> {
        Ok(Vec::new())
    }

    /// Batch-enrich multiple PRs in a single API round-trip.
    ///
    /// Returns a map keyed by `"{owner}/{repo}#{number}"`. The lifecycle
    /// loop calls this once per tick before iterating sessions; individual
    /// `poll_scm` calls skip their REST fan-out when the cache has a hit.
    ///
    /// Default: empty map (no batch support). Plugins that implement
    /// GraphQL batch enrichment (e.g. GitHub) override this.
    async fn enrich_prs_batch(
        &self,
        _prs: &[PullRequest],
    ) -> Result<HashMap<String, ScmObservation>> {
        Ok(HashMap::new())
    }
}

/// Issue/task tracker plugin — GitHub Issues, Linear, Jira, ...
///
/// Much thinner than `Scm`. The reaction engine doesn't consume tracker
/// data directly yet; `Tracker` is wired in so `ao-rs spawn --issue` can
/// pull issue metadata and derive a sensible branch name / initial prompt.
///
/// Differences from TS `Tracker`:
///
/// - No `project: ProjectConfig` parameter on every method. The plugin
///   holds any project config it needs via `::new()`, matching how
///   `Runtime` / `Agent` already work.
/// - `list_issues`, `update_issue`, `create_issue` are cut. The port
///   needs exactly `get_issue` + `branch_name` + `generate_prompt` today;
///   the rest can come back when a real use case demands them.
#[async_trait]
pub trait Tracker: Send + Sync {
    /// Human-readable plugin name for logs (`"github"`, `"linear"`, ...).
    fn name(&self) -> &str;

    /// Fetch an issue by identifier. `identifier` is whatever the user
    /// types on the CLI — `#42`, `LIN-1327`, or a full URL. The plugin
    /// is responsible for understanding its own conventions.
    async fn get_issue(&self, identifier: &str) -> Result<Issue>;

    /// `true` if the issue is closed / completed / cancelled. Used by
    /// `ao-rs status` filtering and by future reactions that might
    /// auto-close an issue when the PR merges.
    async fn is_completed(&self, identifier: &str) -> Result<bool>;

    /// Canonical URL for the issue. Synchronous because it's usually
    /// string concatenation — no network needed.
    fn issue_url(&self, identifier: &str) -> String;

    /// Suggested git branch name for a new session on this issue. The
    /// plugin decides the format (`issue-42-add-dark-mode`, `LIN-1327`,
    /// etc.); `ao-rs spawn` prepends its own short-id prefix if needed.
    fn branch_name(&self, identifier: &str) -> String;

    /// Post a comment to an issue.
    ///
    /// Default implementation returns an error so tracker plugins can opt-in
    /// incrementally (read-only parity first).
    async fn comment_issue(&self, _identifier: &str, _body: &str) -> Result<()> {
        Err(AoError::Other(
            "tracker does not support commenting".to_string(),
        ))
    }

    /// Assign an issue (or PR number, on GitHub) to the current authenticated user.
    ///
    /// Default implementation returns an error so tracker plugins can opt-in
    /// incrementally (read-only parity first).
    async fn assign_to_me(&self, _identifier: &str) -> Result<()> {
        Err(AoError::Other(
            "tracker does not support assignment".to_string(),
        ))
    }

    /// Format an issue into a structured prompt section suitable for
    /// inclusion in the agent's initial message.
    ///
    /// Default impl uses `prompt_builder::format_issue_context` which
    /// renders title, URL, labels, assignee, and description. Override
    /// in tracker plugins that need platform-specific context (e.g.
    /// Linear cycle info, Jira sprint fields).
    fn generate_prompt(&self, issue: &Issue) -> String {
        prompt_builder::format_issue_context(issue)
    }

    /// List issues matching `filters`. Mirrors TS `Tracker.listIssues?`.
    ///
    /// Default returns an error so read-only tracker plugins don't need to
    /// implement this until a CLI feature requires it.
    async fn list_issues(&self, _filters: &IssueFilters) -> Result<Vec<Issue>> {
        Err(AoError::Other(
            "tracker does not support listing issues".to_string(),
        ))
    }

    /// Apply a partial update to an existing issue. Mirrors TS `Tracker.updateIssue?`.
    ///
    /// Only `Some` fields in `update` are changed; `None` means "leave unchanged".
    /// Default returns an error so read-only tracker plugins compile without changes.
    async fn update_issue(&self, _identifier: &str, _update: &IssueUpdate) -> Result<()> {
        Err(AoError::Other(
            "tracker does not support updating issues".to_string(),
        ))
    }

    /// Create a new issue and return it. Mirrors TS `Tracker.createIssue?`.
    ///
    /// Default returns an error so read-only tracker plugins compile without changes.
    async fn create_issue(&self, _input: &CreateIssueInput) -> Result<Issue> {
        Err(AoError::Other(
            "tracker does not support creating issues".to_string(),
        ))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::activity_log::{
        append_activity_entry, ActivityLogEntry, ACTIVITY_INPUT_STALENESS_SECS,
    };
    use crate::cost_log::usage_log_path;
    use crate::types::{now_ms, SessionId, SessionStatus};
    use std::io::Write;
    use std::time::{SystemTime, UNIX_EPOCH};

    /// Minimal `Agent` stub that keeps every default intact. Exists so
    /// tests can exercise the trait defaults without depending on any
    /// plugin crate.
    struct StubAgent;

    #[async_trait]
    impl Agent for StubAgent {
        fn launch_command(&self, _session: &Session) -> String {
            String::new()
        }
        fn environment(&self, _session: &Session) -> Vec<(String, String)> {
            Vec::new()
        }
        fn initial_prompt(&self, _session: &Session) -> String {
            String::new()
        }
    }

    fn unique_workspace(label: &str) -> PathBuf {
        let nanos = SystemTime::now()
            .duration_since(UNIX_EPOCH)
            .unwrap()
            .as_nanos();
        let p = std::env::temp_dir().join(format!("ao-rs-trait-default-{label}-{nanos}"));
        std::fs::create_dir_all(&p).unwrap();
        p
    }

    fn session_with(workspace: Option<PathBuf>) -> Session {
        Session {
            id: SessionId("trait-default".into()),
            project_id: "demo".into(),
            status: SessionStatus::Working,
            agent: "stub".into(),
            agent_config: None,
            branch: "feat".into(),
            task: "t".into(),
            workspace_path: workspace,
            runtime_handle: None,
            runtime: "tmux".into(),
            activity: None,
            created_at: now_ms(),
            cost: None,
            issue_id: None,
            issue_url: None,
            claimed_pr_number: None,
            claimed_pr_url: None,
            initial_prompt_override: None,
            spawned_by: None,
            last_merge_conflict_dispatched: None,
            last_review_backlog_fingerprint: None,
        }
    }

    #[tokio::test]
    async fn detect_activity_default_no_workspace_returns_ready() {
        let agent = StubAgent;
        let session = session_with(None);
        assert_eq!(
            agent.detect_activity(&session).await.unwrap(),
            ActivityState::Ready
        );
    }

    #[tokio::test]
    async fn detect_activity_default_no_log_returns_ready() {
        let agent = StubAgent;
        let ws = unique_workspace("no-log");
        let session = session_with(Some(ws));
        assert_eq!(
            agent.detect_activity(&session).await.unwrap(),
            ActivityState::Ready
        );
    }

    #[tokio::test]
    async fn detect_activity_default_surfaces_exited_from_log() {
        let agent = StubAgent;
        let ws = unique_workspace("exited");
        append_activity_entry(
            &ws,
            &ActivityLogEntry {
                ts: now_ms().to_string(),
                state: ActivityState::Exited,
                source: "terminal".into(),
                trigger: None,
            },
        )
        .unwrap();
        let session = session_with(Some(ws));
        assert_eq!(
            agent.detect_activity(&session).await.unwrap(),
            ActivityState::Exited
        );
    }

    #[tokio::test]
    async fn detect_activity_default_surfaces_fresh_waiting_input() {
        let agent = StubAgent;
        let ws = unique_workspace("waiting");
        append_activity_entry(
            &ws,
            &ActivityLogEntry {
                ts: now_ms().to_string(),
                state: ActivityState::WaitingInput,
                source: "terminal".into(),
                trigger: Some("approve?".into()),
            },
        )
        .unwrap();
        let session = session_with(Some(ws));
        assert_eq!(
            agent.detect_activity(&session).await.unwrap(),
            ActivityState::WaitingInput
        );
    }

    #[tokio::test]
    async fn detect_activity_default_stale_waiting_falls_back_to_ready() {
        let agent = StubAgent;
        let ws = unique_workspace("stale-waiting");
        let stale_ms = now_ms().saturating_sub((ACTIVITY_INPUT_STALENESS_SECS + 60) * 1000);
        append_activity_entry(
            &ws,
            &ActivityLogEntry {
                ts: stale_ms.to_string(),
                state: ActivityState::WaitingInput,
                source: "terminal".into(),
                trigger: None,
            },
        )
        .unwrap();
        let session = session_with(Some(ws));
        assert_eq!(
            agent.detect_activity(&session).await.unwrap(),
            ActivityState::Ready
        );
    }

    #[tokio::test]
    async fn cost_estimate_default_no_workspace_returns_none() {
        let agent = StubAgent;
        let session = session_with(None);
        assert!(agent.cost_estimate(&session).await.unwrap().is_none());
    }

    #[tokio::test]
    async fn cost_estimate_default_no_log_returns_none() {
        let agent = StubAgent;
        let ws = unique_workspace("cost-missing");
        let session = session_with(Some(ws));
        assert!(agent.cost_estimate(&session).await.unwrap().is_none());
    }

    #[tokio::test]
    async fn cost_estimate_default_reads_usage_log() {
        let agent = StubAgent;
        let ws = unique_workspace("cost-present");
        let path = usage_log_path(&ws);
        std::fs::create_dir_all(path.parent().unwrap()).unwrap();
        let mut f = std::fs::File::create(&path).unwrap();
        writeln!(
            f,
            r#"{{"input_tokens":100,"output_tokens":50,"cost_usd":0.5}}"#
        )
        .unwrap();
        writeln!(
            f,
            r#"{{"input_tokens":200,"output_tokens":75,"cost_usd":0.25}}"#
        )
        .unwrap();

        let session = session_with(Some(ws));
        let cost = agent.cost_estimate(&session).await.unwrap().expect("some");
        assert_eq!(cost.input_tokens, 300);
        assert_eq!(cost.output_tokens, 125);
        assert!((cost.cost_usd.unwrap() - 0.75).abs() < 1e-9);
    }
}