lific 1.3.1

pub(crate) mod schemas;
pub(crate) mod tools;

use std::sync::Arc;
use std::sync::Mutex;

use rmcp::{
    ServerHandler,
    handler::server::router::tool::ToolRouter,
    model::{ProtocolVersion, ServerCapabilities, ServerInfo},
};

use crate::db::DbPool;
use crate::db::models::AuthUser;

/// Serialization lock for MCP request handling.
/// Ensures only one MCP request processes at a time, preventing the race
/// condition where concurrent requests could overwrite each other's user identity.
/// Acceptable throughput cost for a local-first, single-user tool.
static MCP_HANDLER_LOCK: tokio::sync::Mutex<()> = tokio::sync::Mutex::const_new(());

/// Per-request user identity storage.
/// Protected from races by MCP_HANDLER_LOCK ensuring serial access.
/// Uses unwrap_or_else to recover from poison (e.g. if a handler panics).
static MCP_REQUEST_USER: Mutex<Option<AuthUser>> = Mutex::new(None);

/// Acquire the MCP handler lock, set the user, run the provided future,
/// then clean up. Guarantees no identity confusion between concurrent requests.
pub async fn with_request_user<F, Fut, R>(user: Option<AuthUser>, f: F) -> R
where
    F: FnOnce() -> Fut,
    Fut: std::future::Future<Output = R>,
{
    let _guard = MCP_HANDLER_LOCK.lock().await;
    *MCP_REQUEST_USER
        .lock()
        .unwrap_or_else(|poisoned| poisoned.into_inner()) = user;
    let result = f().await;
    *MCP_REQUEST_USER
        .lock()
        .unwrap_or_else(|poisoned| poisoned.into_inner()) = None;
    result
}

/// Get the authenticated user for the current MCP request, if any.
pub(crate) fn current_auth_user() -> Option<AuthUser> {
    MCP_REQUEST_USER
        .lock()
        .unwrap_or_else(|poisoned| poisoned.into_inner())
        .clone()
}

#[derive(Clone)]
pub struct LificMcp {
    db: Arc<DbPool>,
    tool_router: ToolRouter<Self>,
}

impl LificMcp {
    pub fn new(db: DbPool) -> Self {
        Self {
            db: Arc::new(db),
            tool_router: Self::create_tool_router(),
        }
    }

    fn read<F, T>(&self, f: F) -> Result<T, String>
    where
        F: FnOnce(&rusqlite::Connection) -> Result<T, crate::error::LificError>,
    {
        let conn = self.db.read().map_err(|e| e.to_string())?;
        f(&conn).map_err(|e| e.to_string())
    }

    fn write<F, T>(&self, f: F) -> Result<T, String>
    where
        F: FnOnce(&rusqlite::Connection) -> Result<T, crate::error::LificError>,
    {
        let conn = self.db.write().map_err(|e| e.to_string())?;
        f(&conn).map_err(|e| e.to_string())
    }
}

impl ServerHandler for LificMcp {
    fn get_info(&self) -> ServerInfo {
        // Pin to 2025-03-26: rmcp defaults to 2025-06-18 which many clients
        // (including Zed) skipped, going straight from 2025-03-26 to 2025-11-25.
        ServerInfo::new(ServerCapabilities::builder().enable_tools().build())
            .with_protocol_version(ProtocolVersion::V_2025_03_26)
            .with_instructions(
                "Lific is a local-first issue tracker. Use list_resources(type='project') to discover projects. \
                 Use list_issues to browse issues with filters. Use get_issue with an identifier like 'PRO-42' \
                 for details. Use workable=true to find issues ready to work on (no unresolved blockers). \
                 Use search to find anything by text across issues and pages.",
            )
    }

    fn list_tools(
        &self,
        _request: Option<rmcp::model::PaginatedRequestParams>,
        _context: rmcp::service::RequestContext<rmcp::service::RoleServer>,
    ) -> impl std::future::Future<Output = Result<rmcp::model::ListToolsResult, rmcp::ErrorData>>
    + rmcp::service::MaybeSendFuture
    + '_ {
        std::future::ready(Ok(rmcp::model::ListToolsResult {
            tools: self.tool_router.list_all(),
            ..Default::default()
        }))
    }

    fn call_tool(
        &self,
        request: rmcp::model::CallToolRequestParams,
        context: rmcp::service::RequestContext<rmcp::service::RoleServer>,
    ) -> impl std::future::Future<Output = Result<rmcp::model::CallToolResult, rmcp::ErrorData>>
    + rmcp::service::MaybeSendFuture
    + '_ {
        let tool_context =
            rmcp::handler::server::tool::ToolCallContext::new(self, request, context);
        self.tool_router.call(tool_context)
    }

    fn get_tool(&self, name: &str) -> Option<rmcp::model::Tool> {
        self.tool_router.get(name).cloned()
    }
}