// artifact.el — Versioned deliverables subsystem.
//
// Artifacts are the tangible outputs of Neuron-assisted work: plans,
// specifications, architecture docs, reports, design documents.
// Unlike raw memories (ephemeral) or knowledge (reference), artifacts are
// polished, versioned deliverables that external stakeholders consume.
//
// WHY explicit versioning?
// A plan that gets revised without version tracking looks like a single
// authoritative document. With version tracking, you can see when a plan
// changed and compare the reasoning at each revision. This is especially
// important for architectural decisions that need an audit trail.
//
// Status machine:
//   draft → review → approved → archived
//
// Artifacts are never deleted — only archived. A deleted plan loses its
// history. An archived plan retains it.

from types import {
    Artifact,
    NeuronError,
}

// ── Public API ────────────────────────────────────────────────────────────────

// draft_artifact — create a new artifact in draft status.
//
// artifact_types is a list because a document can be multiple things at once:
// ["plan", "spec"] for a planning spec, ["report", "analysis"] for an
// analysis report.
@manager
fn draft_artifact(
    title: String,
    content: String,
    artifact_types: [String],
    project: String,
) -> Result<Artifact, NeuronError> {
    let id = native_uuid()
    let now = native_now()
    // Serialize artifact_types to a comma-joined string for the store.
    // The Axon response formatter re-splits on display.
    let artifact_type = artifact_types[0]
    let artifact = Artifact {
        id: id,
        title: title,
        content: content,
        artifact_type: artifact_type,
        status: "draft",
        project: project,
        version: 1,
        created_at: now,
        updated_at: now,
    }
    native_store_artifact(artifact)?
    native_emit("artifact.drafted", {"id": id, "project": project, "type": artifact_type})
    Ok(artifact)
}

// find_artifacts — list or search artifacts for a project.
//
// When query is provided, uses semantic search (activate) to find artifacts
// by content similarity. When query is empty, returns all project artifacts.
@accessor
fn find_artifacts(project: String, query: String) -> Result<[Artifact], NeuronError> {
    if query == "" {
        let artifacts = native_list_artifacts(project)?
        return Ok(artifacts)
    }
    let results = activate Artifact where "{query} project:{project}"
    Ok(results)
}

// retrieve_artifact — fetch a single artifact by ID.
@accessor
fn retrieve_artifact(id: String) -> Result<Artifact, NeuronError> {
    let artifact = native_get_artifact(id)?
    Ok(artifact)
}

// revise_artifact — update an artifact's content and increment its version.
//
// Every revision is a distinct event in the graph. The version number is
// monotonically increasing — no rollbacks, no overwriting. If you need to
// revert, draft a new artifact that references the old version.
@manager
fn revise_artifact(
    id: String,
    content: String,
    change_summary: String,
) -> Result<Artifact, NeuronError> {
    let artifact = native_get_artifact(id)?
    let now = native_now()
    // Increment version — this is the only place version numbers are assigned.
    let new_version = artifact.version + 1
    let revised = Artifact {
        id: artifact.id,
        title: artifact.title,
        content: content,
        artifact_type: artifact.artifact_type,
        status: artifact.status,
        project: artifact.project,
        version: new_version,
        created_at: artifact.created_at,
        updated_at: now,
    }
    native_update_artifact(revised)?
    native_emit("artifact.revised", {
        "id": id,
        "version": "new_version",
        "summary": change_summary,
    })
    Ok(revised)
}

// manage_artifact — transition an artifact's status.
//
// action: "review" | "approve" | "archive"
// Valid transitions:
//   review:  draft       → review
//   approve: review      → approved
//   archive: *           → archived
@manager
fn manage_artifact(id: String, action: String) -> Result<Artifact, NeuronError> {
    let artifact = native_get_artifact(id)?
    let new_status = if action == "review" {
        if artifact.status == "draft" {
            "review"
        } else {
            return Err(NeuronError::InvalidInput("can only send a draft artifact for review"))
        }
    } else {
        if action == "approve" {
            if artifact.status == "review" {
                "approved"
            } else {
                return Err(NeuronError::InvalidInput("can only approve an artifact under review"))
            }
        } else {
            if action == "archive" {
                "archived"
            } else {
                return Err(NeuronError::InvalidInput("unknown artifact action"))
            }
        }
    }
    let now = native_now()
    let updated = Artifact {
        id: artifact.id,
        title: artifact.title,
        content: artifact.content,
        artifact_type: artifact.artifact_type,
        status: new_status,
        project: artifact.project,
        version: artifact.version,
        created_at: artifact.created_at,
        updated_at: now,
    }
    native_update_artifact(updated)?
    native_emit("artifact.status_changed", {"id": id, "status": new_status, "action": action})
    Ok(updated)
}