use cm_domain::{AgentId, UserId, WorkspaceId};
use sqlx::PgPool;
use uuid::Uuid;

use crate::DbError;

/// Who performed an audited action (§15: every decision is attributable).
#[derive(Debug, Clone, Copy)]
pub enum Actor {
    User(UserId),
    Agent(AgentId),
    System,
}

impl Actor {
    fn kind(&self) -> &'static str {
        match self {
            Actor::User(_) => "user",
            Actor::Agent(_) => "agent",
            Actor::System => "system",
        }
    }

    fn id(&self) -> Option<Uuid> {
        match self {
            Actor::User(id) => Some(id.as_uuid()),
            Actor::Agent(id) => Some(id.as_uuid()),
            Actor::System => None,
        }
    }
}

/// Appends an audit entry and returns its sequence id. The table rejects
/// UPDATE/DELETE at the database level (see migration 0001).
pub async fn append(
    pool: &PgPool,
    workspace_id: WorkspaceId,
    actor: Actor,
    event_type: &str,
    subject_type: &str,
    subject_id: &str,
    detail: serde_json::Value,
) -> Result<i64, DbError> {
    let row = sqlx::query!(
        "INSERT INTO audit_log
            (workspace_id, actor_kind, actor_id, event_type, subject_type,
             subject_id, detail)
         VALUES ($1, $2, $3, $4, $5, $6, $7)
         RETURNING id",
        workspace_id.as_uuid(),
        actor.kind(),
        actor.id(),
        event_type,
        subject_type,
        subject_id,
        detail,
    )
    .fetch_one(pool)
    .await?;
    Ok(row.id)
}