//! Structured HTTP request logging middleware using slog.
//!
//! Logs every incoming request with method, path, status code,
//! response time, client IP, and authenticated user ID.

use actix_web::dev::{Service, ServiceRequest, ServiceResponse, Transform};
use futures::future::{LocalBoxFuture, Ready, ok};
use session::SessionExt;
use slog::{error as slog_error, info as slog_info, warn as slog_warn};
use std::sync::Arc;
use std::task::{Context, Poll};
use std::time::Instant;
use uuid::Uuid;

/// Default log format: `{method} {path} {status} {duration_ms}ms`
pub struct RequestLogger {
    log: slog::Logger,
}

impl RequestLogger {
    pub fn new(log: slog::Logger) -> Self {
        Self { log }
    }
}

impl<S, B> Transform<S, ServiceRequest> for RequestLogger
where
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error> + 'static,
    S::Future: 'static,
    B: 'static,
{
    type Response = ServiceResponse<B>;
    type Error = actix_web::Error;
    type Transform = RequestLoggerMiddleware<S>;
    type InitError = ();
    type Future = Ready<Result<Self::Transform, Self::InitError>>;

    fn new_transform(&self, service: S) -> Self::Future {
        ok(RequestLoggerMiddleware {
            service: Arc::new(service),
            log: self.log.clone(),
        })
    }
}

pub struct RequestLoggerMiddleware<S> {
    service: Arc<S>,
    log: slog::Logger,
}

impl<S> Clone for RequestLoggerMiddleware<S> {
    fn clone(&self) -> Self {
        Self {
            service: self.service.clone(),
            log: self.log.clone(),
        }
    }
}

impl<S, B> Service<ServiceRequest> for RequestLoggerMiddleware<S>
where
    S: Service<ServiceRequest, Response = ServiceResponse<B>, Error = actix_web::Error> + 'static,
    S::Future: 'static,
    B: 'static,
{
    type Response = ServiceResponse<B>;
    type Error = actix_web::Error;
    type Future = LocalBoxFuture<'static, Result<Self::Response, Self::Error>>;

    fn poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.service.poll_ready(cx)
    }

    fn call(&self, req: ServiceRequest) -> Self::Future {
        let started = Instant::now();
        let log = self.log.clone();
        let method = req.method().to_string();
        let path = req.path().to_string();
        let query = req.query_string().to_string();
        let remote = req
            .connection_info()
            .realip_remote_addr()
            .map(|s| s.to_string())
            .unwrap_or_else(|| "unknown".to_string());
        let user_id: Option<Uuid> = req.get_session().user();

        let full_path = if query.is_empty() {
            path.clone()
        } else {
            format!("{}?{}", path, query)
        };

        // Clone the Arc<S> so it can be moved into the async block
        let service = self.service.clone();

        Box::pin(async move {
            let res = service.call(req).await?;
            let elapsed = started.elapsed();
            let status = res.status();
            let status_code = status.as_u16();
            let is_health = path == "/health";

            if !is_health {
                let user_id_str = user_id
                    .map(|u: Uuid| u.to_string())
                    .unwrap_or_else(|| "-".to_string());
                let log_message = format!(
                    "HTTP request | method={} | path={} | status={} | duration_ms={} | remote={} | user_id={}",
                    method,
                    full_path,
                    status_code,
                    elapsed.as_millis(),
                    remote,
                    user_id_str
                );

                match status_code {
                    200..=299 => slog_info!(&log, "{}", log_message),
                    400..=499 => slog_warn!(&log, "{}", log_message),
                    _ => slog_error!(&log, "{}", log_message),
                }
            }
            Ok(res)
        })
    }
}