use std::path::{Path, PathBuf};
use serde::Deserialize;
use structopt::StructOpt;
use warp::Filter;

#[derive(Debug, Deserialize)]
struct Config {
    webroot: PathBuf,
    port: u16,
    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)]
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() {
    let opt = Opt::from_args();
    let config = read_config(&opt.config).unwrap();

    let webroot = config.webroot.canonicalize().unwrap();
    eprintln!("webroot: {:?}", webroot);
    let webroot = warp::any().and(warp::fs::dir(webroot));

    eprintln!("starting server: {:?}", config);
    warp::serve(webroot)
        .tls()
        .key_path(config.tls_key)
        .cert_path(config.tls_cert)
        .run(([127, 0, 0, 1], config.port))
        .await;
}

fn read_config(filename: &Path) -> anyhow::Result<Config> {
    let config = std::fs::read_to_string(filename)?;
    let config: Config = serde_yaml::from_str(&config)?;
    check_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(())
}