mockforge-http 0.3.106

//! Deceptive Canary Middleware
//!
//! Middleware that routes a percentage of team traffic to deceptive deploys.

use axum::body::Body;
use axum::extract::Request;
use axum::http::{HeaderValue, StatusCode};
use axum::middleware::Next;
use axum::response::{IntoResponse, Response};
use mockforge_core::deceptive_canary::DeceptiveCanaryRouter;
use std::collections::HashMap;
use std::sync::Arc;
use tokio::sync::RwLock;
use tracing::{debug, warn};

/// Deceptive canary middleware state
#[derive(Clone)]
pub struct DeceptiveCanaryState {
    /// Router for canary routing decisions (wrapped in RwLock for config updates)
    pub router: Arc<RwLock<DeceptiveCanaryRouter>>,
}

impl DeceptiveCanaryState {
    /// Create new deceptive canary state
    pub fn new(router: DeceptiveCanaryRouter) -> Self {
        Self {
            router: Arc::new(RwLock::new(router)),
        }
    }
}

/// Deceptive canary middleware
///
/// Intercepts requests and routes a percentage to deceptive deploy endpoints
/// based on team identification criteria.
pub async fn deceptive_canary_middleware(req: Request, next: Next) -> Response {
    // Extract state from extensions (set by router)
    let state = req.extensions().get::<DeceptiveCanaryState>().cloned().unwrap_or_else(|| {
        // Return default state if not found (canary disabled)
        DeceptiveCanaryState::new(DeceptiveCanaryRouter::default())
    });
    // Extract request information
    let user_agent = req
        .headers()
        .get("user-agent")
        .and_then(|h| h.to_str().ok())
        .map(|s| s.to_string());

    // Extract IP address from headers or connection info
    let ip_address = req
        .extensions()
        .get::<std::net::SocketAddr>()
        .map(|addr| addr.ip().to_string())
        .or_else(|| {
            req.headers()
                .get("x-forwarded-for")
                .or_else(|| req.headers().get("x-real-ip"))
                .and_then(|h| h.to_str().ok())
                .map(|s| s.split(',').next().unwrap_or(s).trim().to_string())
        });

    // Extract headers
    let mut headers_map = HashMap::new();
    for (key, value) in req.headers() {
        let key_str = key.as_str().to_string();
        if let Ok(value_str) = value.to_str() {
            headers_map.insert(key_str, value_str.to_string());
        }
    }

    // Extract query parameters
    let mut query_params = HashMap::new();
    if let Some(query) = req.uri().query() {
        for pair in query.split('&') {
            if let Some((key, value)) = pair.split_once('=') {
                query_params.insert(key.to_string(), value.to_string());
            }
        }
    }

    // Extract user ID from headers (if available)
    let user_id = req
        .headers()
        .get("x-user-id")
        .or_else(|| req.headers().get("authorization"))
        .and_then(|h| h.to_str().ok())
        .map(|s| s.to_string());

    // Check if request should be routed to canary
    let router = state.router.read().await;
    let should_route = router.should_route_to_canary(
        user_agent.as_deref(),
        ip_address.as_deref(),
        &headers_map,
        &query_params,
        user_id.as_deref(),
    );

    if should_route {
        debug!("Routing request to deceptive canary: {} {}", req.method(), req.uri().path());

        // Get deceptive deploy URL from router config
        let canary_url = router.config().deceptive_deploy_url.clone();
        drop(router); // Release read lock before awaiting

        if !canary_url.is_empty() {
            // Proxy request to the canary deployment
            return proxy_to_canary(&canary_url, req).await;
        }
    } else {
        drop(router); // Release read lock before awaiting
    }

    // Continue with normal request processing
    next.run(req).await
}

/// Proxy a request to the canary deployment URL and return the response.
async fn proxy_to_canary(canary_url: &str, req: Request) -> Response {
    let client = reqwest::Client::new();

    // Build the target URL by combining the canary base URL with the request path/query
    let target_url = format!(
        "{}{}{}",
        canary_url.trim_end_matches('/'),
        req.uri().path(),
        req.uri().query().map(|q| format!("?{q}")).unwrap_or_default()
    );

    let method: reqwest::Method = match req.method().as_str().parse() {
        Ok(m) => m,
        Err(_) => {
            warn!("Canary proxy: unsupported HTTP method {}", req.method());
            return StatusCode::BAD_GATEWAY.into_response();
        }
    };

    // Forward headers (skip hop-by-hop headers)
    let mut proxy_req = client.request(method, &target_url);
    for (name, value) in req.headers() {
        let n = name.as_str();
        if !matches!(n, "host" | "connection" | "transfer-encoding" | "keep-alive" | "upgrade") {
            if let Ok(v) = value.to_str() {
                proxy_req = proxy_req.header(n, v);
            }
        }
    }

    // Forward body
    let body_bytes = match axum::body::to_bytes(req.into_body(), 10 * 1024 * 1024).await {
        Ok(b) => b,
        Err(e) => {
            warn!("Canary proxy: failed to read request body: {e}");
            return StatusCode::BAD_GATEWAY.into_response();
        }
    };
    if !body_bytes.is_empty() {
        proxy_req = proxy_req.body(body_bytes.to_vec());
    }

    // Send the proxied request
    let canary_response = match proxy_req.send().await {
        Ok(r) => r,
        Err(e) => {
            warn!("Canary proxy: request to {target_url} failed: {e}");
            return StatusCode::BAD_GATEWAY.into_response();
        }
    };

    // Build the Axum response from the canary response
    let status =
        StatusCode::from_u16(canary_response.status().as_u16()).unwrap_or(StatusCode::BAD_GATEWAY);

    let mut builder = Response::builder().status(status);

    // Copy response headers
    for (name, value) in canary_response.headers() {
        let n = name.as_str();
        if !matches!(n, "transfer-encoding" | "connection") {
            if let Ok(v) = HeaderValue::from_bytes(value.as_bytes()) {
                builder = builder.header(n, v);
            }
        }
    }

    // Mark as canary-routed
    builder = builder.header("X-Deceptive-Canary", "true");

    let response_body = match canary_response.bytes().await {
        Ok(b) => b,
        Err(e) => {
            warn!("Canary proxy: failed to read response body: {e}");
            return StatusCode::BAD_GATEWAY.into_response();
        }
    };

    builder
        .body(Body::from(response_body))
        .unwrap_or_else(|_| StatusCode::INTERNAL_SERVER_ERROR.into_response())
}