use http::Extensions;
use std::fmt::Debug;
use uv_redacted::DisplaySafeUrl;

use reqwest::{Request, Response};
use reqwest_middleware::{Middleware, Next};

/// A custom error type for the offline middleware.
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) struct OfflineError {
    url: DisplaySafeUrl,
}

impl OfflineError {
    /// Returns the URL that caused the error.
    pub(crate) fn url(&self) -> &DisplaySafeUrl {
        &self.url
    }
}

impl std::fmt::Display for OfflineError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(
            f,
            "Network connectivity is disabled, but the requested data wasn't found in the cache for: `{}`",
            self.url
        )
    }
}

impl std::error::Error for OfflineError {}

/// A middleware that always returns an error indicating that the client is offline.
pub(crate) struct OfflineMiddleware;

#[async_trait::async_trait]
impl Middleware for OfflineMiddleware {
    async fn handle(
        &self,
        req: Request,
        _extensions: &mut Extensions,
        _next: Next<'_>,
    ) -> reqwest_middleware::Result<Response> {
        Err(reqwest_middleware::Error::Middleware(
            OfflineError {
                url: DisplaySafeUrl::from(req.url().clone()),
            }
            .into(),
        ))
    }
}