use std::{fs::File, path::PathBuf};

use tower_http::services::ServeDir;
use tracing::level_filters::LevelFilter;
use tracing_subscriber::EnvFilter;

use statsrv::{service::ServiceConfig, AppState};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let filter = EnvFilter::builder()
        .with_default_directive(LevelFilter::INFO.into())
        .from_env_lossy();
    tracing_subscriber::fmt().with_env_filter(filter).init();

    let config = match Config::parse() {
        Ok(c) => c,
        Err(err) => {
            tracing::error!("Failed to read config file, using defaults: `{err}`");
            Default::default()
        }
    };

    let state = AppState::new(config.services);
    let mut router = statsrv::router().with_state(state);

    if let Some(path) = config.serve_dir {
        router = router.nest_service("/", ServeDir::new(path));
    }

    router = router.layer(tower_http::trace::TraceLayer::new_for_http());

    let listener = tokio::net::TcpListener::bind(config.address).await?;
    tracing::info!("listening on {}", listener.local_addr().unwrap());

    axum::serve(listener, router).await.map_err(Into::into)
}

#[derive(Debug, Clone, serde::Deserialize)]
#[serde(default)]
pub struct Config {
    pub serve_dir: Option<PathBuf>,
    pub address: String,
    pub services: Vec<ServiceConfig>,
}

impl Config {
    const DEFAULT_CONFIG: &str = "/etc/statsrv.toml";

    fn parse() -> Result<Self, Box<dyn std::error::Error>> {
        let config_file = match std::env::args().nth(1) {
            Some(p) => File::open(&p)?,
            None => {
                tracing::debug!("Falling back to default config location");
                File::open(Self::DEFAULT_CONFIG)?
            }
        };
        let config_toml = std::io::read_to_string(config_file)?;
        toml::from_str(&config_toml).map_err(Into::into)
    }
}

impl Default for Config {
    fn default() -> Self {
        Self {
            serve_dir: None,
            address: String::from("127.0.0.1:8080"),
            services: Default::default(),
        }
    }
}