/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

//! Loads resources using a mapping from well-known shortcuts to resource: urls.
//! Recognized shortcuts:
//! - servo:default-user-agent
//! - servo:experimental-preferences
//! - servo:newtab
//! - servo:preferences

use std::future::Future;
use std::pin::Pin;

use headers::{ContentType, HeaderMapExt};
use net::fetch::methods::{DoneChannel, FetchContext};
use net::protocols::ProtocolHandler;
use net_traits::ResourceFetchTiming;
use net_traits::request::Request;
use net_traits::response::{Response, ResponseBody};
use servo::config::prefs::UserAgentPlatform;

use crate::desktop::protocols::resource::ResourceProtocolHandler;
use crate::prefs::EXPERIMENTAL_PREFS;

#[derive(Default)]
pub struct ServoProtocolHandler {}

impl ProtocolHandler for ServoProtocolHandler {
    fn privileged_paths(&self) -> &'static [&'static str] {
        &["preferences"]
    }

    fn is_fetchable(&self) -> bool {
        true
    }

    fn load(
        &self,
        request: &mut Request,
        done_chan: &mut DoneChannel,
        context: &FetchContext,
    ) -> Pin<Box<dyn Future<Output = Response> + Send>> {
        let url = request.current_url();

        match url.path() {
            "newtab" => ResourceProtocolHandler::response_for_path(
                request,
                done_chan,
                context,
                "/newtab.html",
            ),

            "preferences" => ResourceProtocolHandler::response_for_path(
                request,
                done_chan,
                context,
                "/preferences.html",
            ),

            "experimental-preferences" => {
                let pref_list = EXPERIMENTAL_PREFS
                    .iter()
                    .map(|pref| format!("\"{pref}\""))
                    .collect::<Vec<String>>()
                    .join(",");
                json_response(request, format!("[{pref_list}]"))
            },

            "default-user-agent" => {
                let user_agent = UserAgentPlatform::default().to_user_agent_string();
                json_response(request, format!("\"{user_agent}\""))
            },

            _ => Box::pin(std::future::ready(Response::network_internal_error(
                "Invalid shortcut",
            ))),
        }
    }
}

fn json_response(
    request: &Request,
    body: String,
) -> Pin<Box<dyn Future<Output = Response> + Send>> {
    let mut response = Response::new(
        request.current_url(),
        ResourceFetchTiming::new(request.timing_type()),
    );
    response.headers.typed_insert(ContentType::json());
    *response.body.lock().unwrap() = ResponseBody::Done(body.into_bytes());
    Box::pin(std::future::ready(response))
}