use serde::Deserialize;
use std::net::{SocketAddr, ToSocketAddrs};
use std::path::{Path, PathBuf};
use structopt::StructOpt;
use warp::Filter;
#[macro_use]
extern crate log;

#[derive(Debug, Deserialize)]
struct Config {
    webroot: PathBuf,
    listen: String,
    tls_key: PathBuf,
    tls_cert: PathBuf,
}

#[derive(Debug, StructOpt)]
#[structopt(name = "ewww", about = "Web server for static sites")]
struct Opt {
    #[structopt(parse(from_os_str))]
    config: PathBuf,
}

#[derive(Debug, thiserror::Error)]
#[allow(clippy::enum_variant_names)]
enum EwwwError {
    #[error("Web root {0} does not exist")]
    WebrootNotFound(PathBuf),

    #[error("TLS certificate {0} does not exist")]
    TlsCertNotFound(PathBuf),

    #[error("TLS key {0} does not exist")]
    TlsKeyNotFound(PathBuf),
}

#[tokio::main]
async fn main() -> anyhow::Result<()> {
    pretty_env_logger::init();
    info!("ewww starting up");

    let opt = Opt::from_args();
    let config = read_config(&opt.config).unwrap();

    let webroot = config.webroot.canonicalize().unwrap();
    let addr: SocketAddr = config.listen.to_socket_addrs().unwrap().next().unwrap();

    info!("webroot: {:?}", webroot);
    info!("listen on {}", addr);

    let log = warp::log("ewww");
    let webroot = warp::any().and(warp::fs::dir(webroot)).with(log);

    warp::serve(webroot)
        .tls()
        .key_path(config.tls_key)
        .cert_path(config.tls_cert)
        .run(addr)
        .await;

    Ok(())
}

fn read_config(filename: &Path) -> anyhow::Result<Config> {
    debug!("reading config from {:?}", filename);
    let config = std::fs::read_to_string(filename)?;
    let config: Config = serde_yaml::from_str(&config)?;
    check_config(&config)?;
    info!("config: {:?}", config);
    Ok(config)
}

fn check_config(config: &Config) -> anyhow::Result<()> {
    if !config.webroot.exists() {
        return Err(EwwwError::WebrootNotFound(config.webroot.clone()).into());
    }
    if !config.tls_cert.exists() {
        return Err(EwwwError::TlsCertNotFound(config.tls_cert.clone()).into());
    }
    if !config.tls_key.exists() {
        return Err(EwwwError::TlsKeyNotFound(config.tls_key.clone()).into());
    }
    Ok(())
}