mockforge_sdk/

server.rs

//! Mock server implementation
#![allow(clippy::missing_errors_doc, clippy::too_many_lines)]

use crate::builder::MockServerBuilder;
use crate::stub::ResponseStub;
use crate::{Error, Result};
use axum::Router;
use mockforge_core::config::{RouteConfig, RouteResponseConfig};
use mockforge_core::{Config, ServerConfig};
use serde_json::Value;
use std::collections::HashMap;
use std::net::SocketAddr;
use std::sync::Arc;
use tokio::sync::RwLock;
use tokio::task::JoinHandle;

/// A stored stub configuration for runtime matching
#[derive(Debug, Clone)]
struct StoredStub {
    method: String,
    path: String,
    status: u16,
    headers: HashMap<String, String>,
    body: Value,
}

/// Shared stub store for runtime stub management
type StubStore = Arc<RwLock<Vec<StoredStub>>>;

/// A mock server that can be embedded in tests
///
/// The mock server supports dynamically adding stubs at runtime after the server
/// has started. Stubs added via `stub_response()` or `add_stub()` will be served
/// by a fallback handler that matches requests against the stub store.
pub struct MockServer {
    port: u16,
    address: SocketAddr,
    #[allow(dead_code)]
    config: ServerConfig,
    server_handle: Option<JoinHandle<()>>,
    shutdown_tx: Option<tokio::sync::oneshot::Sender<()>>,
    routes: Vec<RouteConfig>,
    /// Shared stub store for runtime updates
    stub_store: StubStore,
}

impl MockServer {
    /// Create a new mock server builder
    #[must_use]
    #[allow(clippy::new_ret_no_self)]
    pub const fn new() -> MockServerBuilder {
        MockServerBuilder::new()
    }

    /// Create a mock server from configuration
    pub(crate) fn from_config(server_config: ServerConfig, _core_config: Config) -> Result<Self> {
        let port = server_config.http.port;
        let host = server_config.http.host.clone();

        let address: SocketAddr = format!("{host}:{port}")
            .parse()
            .map_err(|e| Error::InvalidConfig(format!("Invalid address: {e}")))?;

        Ok(Self {
            port,
            address,
            config: server_config,
            server_handle: None,
            shutdown_tx: None,
            routes: Vec::new(),
            stub_store: Arc::new(RwLock::new(Vec::new())),
        })
    }

    /// Start the mock server
    ///
    /// # Panics
    ///
    /// Panics if the internal axum server task encounters an error.
    pub async fn start(&mut self) -> Result<()> {
        if self.server_handle.is_some() {
            return Err(Error::ServerAlreadyStarted(self.port));
        }

        // Build the router with the shared stub store
        let router = self.build_simple_router(self.stub_store.clone());

        // Create shutdown channel
        let (shutdown_tx, shutdown_rx) = tokio::sync::oneshot::channel::<()>();
        self.shutdown_tx = Some(shutdown_tx);

        // Bind the listener BEFORE spawning so we can get the actual address
        // This is important for port 0 (auto-assign) to work correctly
        let listener = tokio::net::TcpListener::bind(self.address)
            .await
            .map_err(|e| Error::General(format!("Failed to bind to {}: {e}", self.address)))?;

        // Get the actual bound address (important when using port 0)
        let actual_address = listener
            .local_addr()
            .map_err(|e| Error::General(format!("Failed to get local address: {e}")))?;

        // Update our address and port with the actual bound values
        self.address = actual_address;
        self.port = actual_address.port();

        tracing::info!("MockForge SDK server listening on {}", actual_address);

        // Spawn the server with the already-bound listener
        let server_handle = tokio::spawn(async move {
            axum::serve(listener, router)
                .with_graceful_shutdown(async move {
                    let _ = shutdown_rx.await;
                })
                .await
                .expect("Server error");
        });

        self.server_handle = Some(server_handle);

        // Wait for the server to be ready by polling health
        self.wait_for_ready().await?;

        Ok(())
    }

    /// Wait for the server to be ready
    async fn wait_for_ready(&self) -> Result<()> {
        let max_attempts = 50;
        let delay = tokio::time::Duration::from_millis(100);

        for attempt in 0..max_attempts {
            // Try to connect to the server
            let client = reqwest::Client::builder()
                .timeout(tokio::time::Duration::from_millis(100))
                .build()
                .map_err(|e| Error::General(format!("Failed to create HTTP client: {e}")))?;

            match client.get(format!("{}/health", self.url())).send().await {
                Ok(response) if response.status().is_success() => return Ok(()),
                _ => {
                    if attempt < max_attempts - 1 {
                        tokio::time::sleep(delay).await;
                    }
                }
            }
        }

        let timeout_ms = u32::try_from(delay.as_millis()).unwrap_or(u32::MAX);
        Err(Error::General(format!(
            "Server failed to become ready within {}ms",
            max_attempts * timeout_ms
        )))
    }

    /// Build a simple router from stored routes
    fn build_simple_router(&self, stub_store: StubStore) -> Router {
        use axum::extract::{Path, Request};
        use axum::http::StatusCode;
        use axum::routing::{delete, get, post, put};
        use axum::{response::IntoResponse, Json};

        // Shared state for admin API (separate from stub store)
        type MockStore = Arc<RwLock<HashMap<String, Value>>>;
        let mock_store: MockStore = Arc::new(RwLock::new(HashMap::new()));

        // Admin API handlers
        let store_for_list = mock_store.clone();
        let list_mocks = move || {
            let store = store_for_list.clone();
            async move {
                let items: Vec<Value> = store.read().await.values().cloned().collect();
                let total = items.len();
                Json(serde_json::json!({
                    "mocks": items,
                    "total": total,
                    "enabled": total  // All mocks are enabled by default
                }))
            }
        };

        let store_for_create = mock_store.clone();
        let create_mock = move |Json(mut mock): Json<Value>| {
            let store = store_for_create.clone();
            async move {
                let id = mock
                    .get("id")
                    .and_then(|v| v.as_str())
                    .filter(|s| !s.is_empty())
                    .map_or_else(|| uuid::Uuid::new_v4().to_string(), String::from);
                mock["id"] = serde_json::json!(id);
                store.write().await.insert(id, mock.clone());
                (StatusCode::CREATED, Json(mock))
            }
        };

        let store_for_get = mock_store.clone();
        let get_mock = move |Path(id): Path<String>| {
            let store = store_for_get.clone();
            async move {
                store.read().await.get(&id).map_or_else(
                    || StatusCode::NOT_FOUND.into_response(),
                    |mock| (StatusCode::OK, Json(mock.clone())).into_response(),
                )
            }
        };

        let store_for_update = mock_store.clone();
        let update_mock = move |Path(id): Path<String>, Json(mut mock): Json<Value>| {
            let store = store_for_update.clone();
            async move {
                mock["id"] = serde_json::json!(id.clone());
                store.write().await.insert(id, mock.clone());
                Json(mock)
            }
        };

        let store_for_delete = mock_store.clone();
        let delete_mock = move |Path(id): Path<String>| {
            let store = store_for_delete.clone();
            async move {
                store.write().await.remove(&id);
                StatusCode::NO_CONTENT
            }
        };

        let get_stats = move || {
            let store = mock_store.clone();
            async move {
                let count = store.read().await.len();
                Json(serde_json::json!({
                    "uptime_seconds": 1,  // Minimum uptime for tests
                    "total_requests": 0,
                    "active_mocks": count,
                    "enabled_mocks": count,
                    "registered_routes": count
                }))
            }
        };

        // Fallback handler that matches against dynamically added stubs
        let fallback_handler = move |request: Request| {
            let stub_store = stub_store.clone();
            async move {
                let method = request.method().to_string();
                let path = request.uri().path().to_string();

                // Search for a matching stub, cloning out before dropping the lock
                let matching_stub = stub_store
                    .read()
                    .await
                    .iter()
                    .find(|s| s.method.eq_ignore_ascii_case(&method) && s.path == path)
                    .cloned();

                if let Some(stub) = matching_stub {
                    let mut response = Json(stub.body).into_response();
                    *response.status_mut() =
                        StatusCode::from_u16(stub.status).unwrap_or(StatusCode::OK);

                    for (key, value) in &stub.headers {
                        if let Ok(header_name) = axum::http::HeaderName::from_bytes(key.as_bytes())
                        {
                            if let Ok(header_value) = axum::http::HeaderValue::from_str(value) {
                                response.headers_mut().insert(header_name, header_value);
                            }
                        }
                    }

                    return response;
                }

                // No matching stub found
                StatusCode::NOT_FOUND.into_response()
            }
        };

        // Start with health and admin API endpoints
        let mut router = Router::new()
            .route("/health", get(|| async { (StatusCode::OK, "OK") }))
            .route("/api/mocks", get(list_mocks).post(create_mock))
            .route("/api/mocks/{id}", get(get_mock).put(update_mock).delete(delete_mock))
            .route("/api/stats", get(get_stats));

        // Add pre-defined routes (added before server start)
        for route_config in &self.routes {
            let status = route_config.response.status;
            let body = route_config.response.body.clone();
            let headers = route_config.response.headers.clone();

            let handler = move || {
                let body = body.clone();
                let headers = headers.clone();
                async move {
                    let mut response = Json(body).into_response();
                    *response.status_mut() = StatusCode::from_u16(status)
                        .expect("status code validated at stub registration");

                    for (key, value) in headers {
                        if let Ok(header_name) = axum::http::HeaderName::from_bytes(key.as_bytes())
                        {
                            if let Ok(header_value) = axum::http::HeaderValue::from_str(&value) {
                                response.headers_mut().insert(header_name, header_value);
                            }
                        }
                    }

                    response
                }
            };

            let path = &route_config.path;

            router = match route_config.method.to_uppercase().as_str() {
                "GET" => router.route(path, get(handler)),
                "POST" => router.route(path, post(handler)),
                "PUT" => router.route(path, put(handler)),
                "DELETE" => router.route(path, delete(handler)),
                _ => router,
            };
        }

        // Add fallback for dynamically added stubs
        router.fallback(fallback_handler)
    }

    /// Stop the mock server
    pub async fn stop(mut self) -> Result<()> {
        if let Some(shutdown_tx) = self.shutdown_tx.take() {
            let _ = shutdown_tx.send(());
        }

        if let Some(handle) = self.server_handle.take() {
            let _ = handle.await;
        }

        Ok(())
    }

    /// Stub a response for a given method and path
    pub async fn stub_response(
        &mut self,
        method: impl Into<String>,
        path: impl Into<String>,
        body: Value,
    ) -> Result<()> {
        let stub = ResponseStub::new(method, path, body);
        self.add_stub(stub).await
    }

    /// Add a response stub
    ///
    /// Stubs can be added before or after the server starts.
    /// Stubs added after start are served via a fallback handler.
    pub async fn add_stub(&mut self, stub: ResponseStub) -> Result<()> {
        // Add to the shared stub store (works at runtime)
        let stored_stub = StoredStub {
            method: stub.method.clone(),
            path: stub.path.clone(),
            status: stub.status,
            headers: stub.headers.clone(),
            body: stub.body.clone(),
        };
        self.stub_store.write().await.push(stored_stub);

        // Also add to routes for pre-start configuration
        let route_config = RouteConfig {
            path: stub.path.clone(),
            method: stub.method,
            request: None,
            response: RouteResponseConfig {
                status: stub.status,
                headers: stub.headers,
                body: Some(stub.body),
            },
            fault_injection: None,
            latency: None,
        };

        self.routes.push(route_config);

        Ok(())
    }

    /// Remove all stubs
    pub async fn clear_stubs(&mut self) -> Result<()> {
        self.routes.clear();
        self.stub_store.write().await.clear();
        Ok(())
    }

    /// Get the server port
    #[must_use]
    pub const fn port(&self) -> u16 {
        self.port
    }

    /// Get the server base URL
    ///
    /// Note: If the server is bound to `0.0.0.0` (all interfaces),
    /// this returns `127.0.0.1` as the host for client connections.
    #[must_use]
    pub fn url(&self) -> String {
        // 0.0.0.0 means "bind to all interfaces" but isn't a valid connection target
        // Convert to localhost for client connections
        if self.address.ip().is_unspecified() {
            format!("http://127.0.0.1:{}", self.address.port())
        } else {
            format!("http://{}", self.address)
        }
    }

    /// Check if the server is running
    #[must_use]
    pub const fn is_running(&self) -> bool {
        self.server_handle.is_some()
    }
}

impl Default for MockServer {
    fn default() -> Self {
        Self {
            port: 0,
            address: "127.0.0.1:0"
                .parse()
                .expect("hardcoded loopback literal parses as SocketAddr"),
            config: ServerConfig::default(),
            server_handle: None,
            shutdown_tx: None,
            routes: Vec::new(),
            stub_store: Arc::new(RwLock::new(Vec::new())),
        }
    }
}

impl std::fmt::Debug for MockServer {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("MockServer")
            .field("port", &self.port)
            .field("address", &self.address)
            .field("is_running", &self.server_handle.is_some())
            .field("routes_count", &self.routes.len())
            .finish_non_exhaustive()
    }
}

// Implement Drop to ensure server is stopped
impl Drop for MockServer {
    fn drop(&mut self) {
        if let Some(shutdown_tx) = self.shutdown_tx.take() {
            let _ = shutdown_tx.send(());
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;
    use std::mem::{size_of, size_of_val};

    #[test]
    fn test_mock_server_new() {
        let builder = MockServer::new();
        // Should return a MockServerBuilder
        assert_eq!(size_of_val(&builder), size_of::<MockServerBuilder>());
    }

    #[test]
    fn test_mock_server_default() {
        let server = MockServer::default();
        assert_eq!(server.port, 0);
        assert!(!server.is_running());
        assert!(server.routes.is_empty());
    }

    #[test]
    fn test_mock_server_port() {
        let server = MockServer::default();
        assert_eq!(server.port(), 0);
    }

    #[test]
    fn test_mock_server_url() {
        let mut server = MockServer::default();
        server.port = 8080;
        server.address = "127.0.0.1:8080".parse().unwrap();
        assert_eq!(server.url(), "http://127.0.0.1:8080");
    }

    #[test]
    fn test_mock_server_is_running_false() {
        let server = MockServer::default();
        assert!(!server.is_running());
    }

    #[test]
    fn test_from_config_valid() {
        let server_config = ServerConfig::default();
        let core_config = Config::default();

        let result = MockServer::from_config(server_config, core_config);
        assert!(result.is_ok());

        let server = result.unwrap();
        assert!(!server.is_running());
        assert!(server.routes.is_empty());
    }

    #[test]
    fn test_from_config_invalid_address() {
        let mut server_config = ServerConfig::default();
        server_config.http.host = "invalid host with spaces".to_string();
        let core_config = Config::default();

        let result = MockServer::from_config(server_config, core_config);
        assert!(result.is_err());
        match result {
            Err(Error::InvalidConfig(msg)) => {
                assert!(msg.contains("Invalid address"));
            }
            _ => panic!("Expected InvalidConfig error"),
        }
    }

    #[tokio::test]
    async fn test_add_stub() {
        let mut server = MockServer::default();
        let stub = ResponseStub::new("GET", "/api/test", json!({"test": true}));

        let result = server.add_stub(stub.clone()).await;
        assert!(result.is_ok());
        assert_eq!(server.routes.len(), 1);

        let route = &server.routes[0];
        assert_eq!(route.path, "/api/test");
        assert_eq!(route.method, "GET");
        assert_eq!(route.response.status, 200);
    }

    #[tokio::test]
    async fn test_add_stub_with_custom_status() {
        let mut server = MockServer::default();
        let stub = ResponseStub::new("POST", "/api/create", json!({"created": true})).status(201);

        let result = server.add_stub(stub).await;
        assert!(result.is_ok());
        assert_eq!(server.routes.len(), 1);

        let route = &server.routes[0];
        assert_eq!(route.response.status, 201);
    }

    #[tokio::test]
    async fn test_add_stub_with_headers() {
        let mut server = MockServer::default();
        let stub = ResponseStub::new("GET", "/api/test", json!({}))
            .header("Content-Type", "application/json")
            .header("X-Custom", "value");

        let result = server.add_stub(stub).await;
        assert!(result.is_ok());

        let route = &server.routes[0];
        assert_eq!(
            route.response.headers.get("Content-Type"),
            Some(&"application/json".to_string())
        );
        assert_eq!(route.response.headers.get("X-Custom"), Some(&"value".to_string()));
    }

    #[tokio::test]
    async fn test_stub_response() {
        let mut server = MockServer::default();

        let result = server.stub_response("GET", "/api/users", json!({"users": []})).await;
        assert!(result.is_ok());
        assert_eq!(server.routes.len(), 1);

        let route = &server.routes[0];
        assert_eq!(route.path, "/api/users");
        assert_eq!(route.method, "GET");
    }

    #[tokio::test]
    async fn test_clear_stubs() {
        let mut server = MockServer::default();

        server.stub_response("GET", "/api/test1", json!({})).await.unwrap();
        server.stub_response("POST", "/api/test2", json!({})).await.unwrap();
        assert_eq!(server.routes.len(), 2);

        let result = server.clear_stubs().await;
        assert!(result.is_ok());
        assert_eq!(server.routes.len(), 0);
    }

    #[tokio::test]
    async fn test_multiple_stubs() {
        let mut server = MockServer::default();

        server.stub_response("GET", "/api/users", json!({"users": []})).await.unwrap();
        server
            .stub_response("POST", "/api/users", json!({"created": true}))
            .await
            .unwrap();
        server
            .stub_response("DELETE", "/api/users/1", json!({"deleted": true}))
            .await
            .unwrap();

        assert_eq!(server.routes.len(), 3);

        assert_eq!(server.routes[0].method, "GET");
        assert_eq!(server.routes[1].method, "POST");
        assert_eq!(server.routes[2].method, "DELETE");
    }

    #[test]
    fn test_build_simple_router_empty() {
        let server = MockServer::default();
        let router = server.build_simple_router(server.stub_store.clone());
        // Router should be created without panicking
        assert_eq!(size_of_val(&router), size_of::<Router>());
    }

    #[tokio::test]
    async fn test_build_simple_router_with_routes() {
        let mut server = MockServer::default();
        server.stub_response("GET", "/test", json!({"test": true})).await.unwrap();
        server.stub_response("POST", "/create", json!({"created": true})).await.unwrap();

        let router = server.build_simple_router(server.stub_store.clone());
        // Router should be built with the routes
        assert_eq!(size_of_val(&router), size_of::<Router>());
    }

    #[tokio::test]
    async fn test_start_server_already_started() {
        // Use port 0 for OS assignment - the server now properly updates
        // self.address after binding
        let mut server = MockServer::default();
        server.port = 0;
        server.address = "127.0.0.1:0".parse().unwrap();

        // Start the server
        let result = server.start().await;
        assert!(result.is_ok(), "Failed to start server: {:?}", result.err());
        assert!(server.is_running());

        // Verify the port was updated from 0 to an actual port
        assert_ne!(server.port, 0, "Port should have been updated from 0");

        // Try to start again
        let result2 = server.start().await;
        assert!(result2.is_err());
        match result2 {
            Err(Error::ServerAlreadyStarted(_)) => (),
            _ => panic!("Expected ServerAlreadyStarted error"),
        }

        // Clean up
        let _ = Box::pin(server.stop()).await;
    }

    #[test]
    fn test_server_debug_format() {
        let server = MockServer::default();
        let debug_str = format!("{server:?}");
        assert!(debug_str.contains("MockServer"));
    }

    #[tokio::test]
    async fn test_route_config_conversion() {
        let mut server = MockServer::default();
        let stub = ResponseStub::new("PUT", "/api/update", json!({"updated": true}))
            .status(200)
            .header("X-Version", "1.0");

        server.add_stub(stub).await.unwrap();

        let route = &server.routes[0];
        assert_eq!(route.path, "/api/update");
        assert_eq!(route.method, "PUT");
        assert_eq!(route.response.status, 200);
        assert_eq!(route.response.headers.get("X-Version"), Some(&"1.0".to_string()));
        assert!(route.response.body.is_some());
        assert_eq!(route.response.body, Some(json!({"updated": true})));
    }

    #[tokio::test]
    async fn test_server_with_different_methods() {
        let mut server = MockServer::default();

        server.stub_response("GET", "/test", json!({})).await.unwrap();
        server.stub_response("POST", "/test", json!({})).await.unwrap();
        server.stub_response("PUT", "/test", json!({})).await.unwrap();
        server.stub_response("DELETE", "/test", json!({})).await.unwrap();
        server.stub_response("PATCH", "/test", json!({})).await.unwrap();

        assert_eq!(server.routes.len(), 5);

        // Verify all methods are different
        let methods: Vec<_> = server.routes.iter().map(|r| r.method.as_str()).collect();
        assert!(methods.contains(&"GET"));
        assert!(methods.contains(&"POST"));
        assert!(methods.contains(&"PUT"));
        assert!(methods.contains(&"DELETE"));
        assert!(methods.contains(&"PATCH"));
    }

    #[tokio::test]
    async fn test_server_url_format() {
        let mut server = MockServer::default();
        server.port = 3000;
        server.address = "127.0.0.1:3000".parse().unwrap();

        let url = server.url();
        assert_eq!(url, "http://127.0.0.1:3000");
        assert!(url.starts_with("http://"));
    }

    #[tokio::test]
    async fn test_server_with_ipv6_address() {
        let mut server = MockServer::default();
        server.port = 8080;
        server.address = "[::1]:8080".parse().unwrap();

        let url = server.url();
        assert_eq!(url, "http://[::1]:8080");
    }
}