//! `memoryd serve --config <path>`.

use std::ffi::OsString;
use std::path::PathBuf;
use std::process::ExitCode;
use std::sync::Arc;

use bxcore::instance;
use memoryd::config::{Config, ConfigError};
use memoryd::honcho::config::RUNBOOK as HONCHO_INVALID;
use memoryd::serve;

const USAGE: &str = "usage: memoryd serve --config <path>";
const START_FAILED: &str = "see docs/runbook.md#memoryd-start-failed";

fn main() -> ExitCode {
    let args: Vec<OsString> = std::env::args_os().skip(1).collect();
    let Some(path) = parse(&args) else {
        eprintln!("{USAGE}");
        return ExitCode::from(2);
    };
    let config = match Config::load(&path) {
        Ok(config) => config,
        Err(e) => {
            let pointer = match &e {
                ConfigError::Read(..) | ConfigError::Parse(..) => START_FAILED,
                ConfigError::Honcho(..) => HONCHO_INVALID,
            };
            eprintln!("memoryd: {e}\n{pointer}");
            return ExitCode::from(1);
        }
    };
    // One memoryd per home (M5b spec, section 9a). The lock comes before anything under the home
    // is made or bound, so a second copy never takes the sockets of the one that runs. Held until
    // the process ends.
    let lock_path = config.paths.home.join("run/memoryd.lock");
    let _instance = match instance::lock(&lock_path) {
        Ok(held) => held,
        Err(e) => {
            eprintln!("{}", e.line("memoryd", &lock_path));
            return ExitCode::from(1);
        }
    };
    let log: serve::Log = Arc::new(|line: &str| eprintln!("{line}"));
    let running = match serve::start(config, log) {
        Ok(running) => running,
        // The ledger's and a key's lines name their own pointers.
        Err(e @ (serve::StartError::Ledger(_) | serve::StartError::Secret(_))) => {
            eprintln!("memoryd: {e}");
            return ExitCode::from(1);
        }
        Err(e) => {
            eprintln!("memoryd: {e}\n{START_FAILED}");
            return ExitCode::from(1);
        }
    };
    eprintln!("memoryd: serving");
    match running.run() {
        Ok(()) => ExitCode::SUCCESS,
        Err(e) => {
            eprintln!("memoryd: stopped serving: {e}\n{START_FAILED}");
            ExitCode::from(1)
        }
    }
}

/// The config path of `serve --config <path>`, or `None` for any other list.
fn parse(args: &[OsString]) -> Option<PathBuf> {
    match args {
        [serve, flag, path] if serve == "serve" && flag == "--config" => Some(PathBuf::from(path)),
        _ => None,
    }
}