//! # terminal-pet
//!
//! A pet whose mood follows the shell and the machine. Like every renderer it
//! is thin: connect to the socket, read frames, redraw. It never touches a
//! sensor and never reads the shell.
//!
//! Usage:
//! ```text
//!   terminal-pet [--socket <path>]
//!   terminal-pet --help | --version
//! ```
//! Socket defaults to `$XDG_RUNTIME_DIR/signald.sock`, falling back to
//! `~/.local/state/signald/sock`.

use std::collections::BTreeMap;
use std::path::{Path, PathBuf};

use signal_schema::Signal;
use terminal_pet::{pet_from_signals, render};

const USAGE: &str = "\
Usage: terminal-pet [--socket <path>]

  --socket <path>   signald's socket (default $XDG_RUNTIME_DIR/signald.sock,
                    else ~/.local/state/signald/sock)
  -h, --help        print this and exit
  -V, --version     print the version and exit
";

fn main() {
    let socket = parse_socket();
    if let Err(e) = run(&socket) {
        eprintln!("terminal-pet: could not read signald at {}: {e}", socket.display());
        eprintln!("terminal-pet: is signald running? (signald --socket {})", socket.display());
        std::process::exit(1);
    }
}

/// Connect and render live. Frames this build cannot decode are skipped by the
/// iterator, so a metric appended after this renderer was built does not end
/// the stream.
fn run(socket: &Path) -> std::io::Result<()> {
    let frames = signal_client::Frames::connect(socket)?;
    // Keyed by (name, source) so a metric and the health of the collector that
    // produced it stay distinct, matching the daemon's own cache.
    let mut latest: BTreeMap<(u8, u8), Signal> = BTreeMap::new();
    for sig in frames {
        let sig = sig?;
        latest.insert((sig.name.to_u8(), sig.source.to_u8()), sig);
        let snapshot: Vec<Signal> = latest.values().cloned().collect();
        let pet = pet_from_signals(&snapshot, now_millis());
        print!("\x1b[2J\x1b[H{}", render(&pet));
    }
    Ok(())
}

fn now_millis() -> u64 {
    std::time::SystemTime::now()
        .duration_since(std::time::UNIX_EPOCH)
        .map(|d| d.as_millis() as u64)
        .unwrap_or(0)
}

fn parse_socket() -> PathBuf {
    let mut args = std::env::args().skip(1);
    while let Some(arg) = args.next() {
        match arg.as_str() {
            "--help" | "-h" => {
                print!("{USAGE}");
                std::process::exit(0);
            }
            "--version" | "-V" => {
                println!("terminal-pet {}", env!("CARGO_PKG_VERSION"));
                std::process::exit(0);
            }
            "--socket" => {
                if let Some(path) = args.next() {
                    return PathBuf::from(path);
                }
            }
            _ => {}
        }
    }
    signal_client::default_socket_path()
}