use clap::Parser;
use std::{fs::File, io::BufReader, path::PathBuf};
use trace_recorder_parser::streaming::{event::Event, Error, RecorderData};
use tracing::{error, warn};

#[derive(Parser, Debug, Clone)]
#[clap(name = "streaming example", version, about = "Parse streaming data from file", long_about = None)]
pub struct Opts {
    /// Debug print
    #[clap(long)]
    pub debug: bool,

    /// TODO
    #[clap(long, value_parser=clap_num::maybe_hex::<u16>)]
    pub custom_printf_event_id: Option<u16>,

    /// Path to streaming data file
    #[clap(value_parser)]
    pub path: PathBuf,
}

fn main() {
    match do_main() {
        Ok(()) => (),
        Err(e) => {
            eprintln!("{e}");
            let mut cause = e.source();
            while let Some(err) = cause {
                eprintln!("Caused by: {err}");
                cause = err.source();
            }
            std::process::exit(exitcode::SOFTWARE);
        }
    }
}

fn do_main() -> Result<(), Box<dyn std::error::Error>> {
    let opts = Opts::parse();

    reset_signal_pipe_handler()?;

    tracing_subscriber::fmt::init();

    let f = File::open(&opts.path)?;
    let mut r = BufReader::new(f);

    let mut rd = RecorderData::find(&mut r)?;

    if let Some(custom_printf_event_id) = opts.custom_printf_event_id {
        rd.set_custom_printf_event_id(custom_printf_event_id.into());
    }

    loop {
        let (_event_code, event) = match rd.read_event(&mut r) {
            Ok(Some((ec, ev))) => (ec, ev),
            Ok(None) => break,
            Err(e) => match e {
                Error::TraceRestarted(psf_start_word_endianness) => {
                    warn!("Detected a restarted trace stream");
                    rd = RecorderData::read_with_endianness(psf_start_word_endianness, &mut r)?;
                    continue;
                }
                _ => {
                    error!("{e}");
                    continue;
                }
            },
        };

        if let Event::User(ev) = event {
            if opts.debug {
                println!("{ev:#?}");
            } else {
                println!("{ev}");
            }
        }
    }

    Ok(())
}

// Used to prevent panics on broken pipes.
// See:
//   https://github.com/rust-lang/rust/issues/46016#issuecomment-605624865
fn reset_signal_pipe_handler() -> Result<(), Box<dyn std::error::Error>> {
    #[cfg(target_family = "unix")]
    {
        use nix::sys::signal;

        unsafe {
            signal::signal(signal::Signal::SIGPIPE, signal::SigHandler::SigDfl)?;
        }
    }

    Ok(())
}