use actix_web::{web::Json, App, HttpRequest, HttpServer, Responder};
use clap::Parser;
use serde::Serialize;
use std::collections::BTreeMap;

#[derive(Parser)]
#[command(author, version, about, long_about = None)]
struct CliArgs {
    /// Port to run on.
    #[arg(short, long, default_value_t = 8080)]
    port: u16,

    /// Listen to IP mask
    #[arg(short, long, default_value = "0.0.0.0")]
    ips: String,
}

#[derive(Serialize)]
struct EchoHeader {
    name: String,
    value: String,
}

#[derive(Serialize)]
struct EchoResponse {
    method: String,
    path: String,
    host: String,
    headers: BTreeMap<String, String>,
}

impl EchoResponse {
    fn new(req: &HttpRequest) -> Self {
        let req_uri = req.uri();
        let mut headers = BTreeMap::new();
        for (header_name, header_value) in req.headers().iter() {
            headers.insert(
                header_name.to_string(),
                header_value.to_str().unwrap_or("ERROR").to_string(),
            );
        }
        EchoResponse {
            method: req.method().to_string(),
            path: req_uri.path().to_string(),
            host: req_uri.host().unwrap_or("").to_string(),
            headers,
        }
    }
}

async fn echo_request(request: HttpRequest) -> actix_web::Result<impl Responder> {
    let echo = EchoResponse::new(&request);
    Ok(Json(echo))
}

#[actix_web::main]
async fn main() -> std::io::Result<()> {
    let cli_args = CliArgs::parse();
    let listen_on = (cli_args.ips, cli_args.port);
    HttpServer::new(|| App::new().default_service(actix_web::web::route().to(echo_request)))
        .bind(listen_on)?
        .run()
        .await
}