use axum::{
    extract::{Extension, Path},
    response::{IntoResponse, Response},
};
use std::{collections::HashMap, sync::Arc};

#[derive(Debug, Clone, Copy)]
struct Resource {
    data: &'static [u8],
    mime: &'static str,
}

impl IntoResponse for &Resource {
    fn into_response(self) -> Response {
        (
            axum::http::StatusCode::OK,
            [("Content-Type", self.mime)],
            self.data,
        )
            .into_response()
    }
}

// TODO replace with the "phf" crate someday
type ResourceTable = Arc<HashMap<&'static str, Resource>>;

#[tracing::instrument]
async fn map_to_static(
    Path(name): Path<String>,
    Extension(resources): Extension<ResourceTable>,
) -> Response {
    tracing::debug!("Searching for {} in the resource table...", name);
    match resources.get(name.as_str()) {
        Some(res) => res.into_response(),
        None => {
            #[cfg(debug_assertions)]
            tracing::error!("Not found");

            (
                axum::http::StatusCode::NOT_FOUND,
                [("Content-Type", "text/plain")],
                "Not found. Sorry.".as_bytes(),
            )
                .into_response()
        }
    }
}

pub fn router<St: Clone + Send + Sync + 'static>() -> axum::Router<St> {
    let resources: ResourceTable = {
        let mut map = HashMap::new();

        macro_rules! register_resource {
            ($map:ident, $prefix:expr, ($filename:literal, $mime:literal)) => {{
                $map.insert($filename, Resource {
                    data: include_bytes!(concat!($prefix, $filename)),
                    mime: $mime
                })
            }};
            ($map:ident, $prefix:expr, ($filename:literal, $mime:literal), $( ($f:literal, $m:literal) ),+) => {{
                register_resource!($map, $prefix, ($filename, $mime));
                register_resource!($map, $prefix, $(($f, $m)),+);
            }};
        }

        register_resource! {
            map,
            concat!(env!("OUT_DIR"), "/", "companion", "/"),
            ("index.html", "text/html; charset=\"utf-8\""),
            ("main.js", "text/javascript"),
            ("micropub_api.js", "text/javascript"),
            ("indieauth.js", "text/javascript"),
            ("base64.js", "text/javascript"),
            ("style.css", "text/css")
        };

        Arc::new(map)
    };

    axum::Router::new().route(
        "/{filename}",
        axum::routing::get(map_to_static).layer(Extension(resources)),
    )
}