#[cfg(unix)]
use std::os::unix::process::ExitStatusExt;
use std::process::{ExitStatus, Stdio};
use std::sync::{Arc, Mutex};

use anyhow::{anyhow, bail, Result};
use async_process::Command;
use async_trait::async_trait;
use futures::io::BufReader as FuturesBufReader;
use futures::{AsyncBufReadExt as _, AsyncWriteExt as _};
use inferno::collapse::dtrace::Folder as DtraceFolder;
use inferno::collapse::perf::Folder as PerfFolder;
use inferno::collapse::Collapse;
use nameof::name_of;
use tokio::io::{AsyncBufReadExt as _, BufReader as TokioBufReader};
use tokio::sync::{mpsc, oneshot};
use tokio_util::compat::FuturesAsyncReadCompatExt;
use tokio_util::io::SyncIoBridge;

use crate::hydroflow_crate::flamegraph::handle_fold_data;
use crate::hydroflow_crate::tracing_options::TracingOptions;
use crate::progress::ProgressTracker;
use crate::util::prioritized_broadcast;
use crate::LaunchedBinary;

pub struct LaunchedLocalhostBinary {
    child: Mutex<async_process::Child>,
    tracing: Option<TracingOptions>,
    stdin_sender: mpsc::UnboundedSender<String>,
    stdout_deploy_receivers: Arc<Mutex<Option<oneshot::Sender<String>>>>,
    stdout_receivers: Arc<Mutex<Vec<mpsc::UnboundedSender<String>>>>,
    stderr_receivers: Arc<Mutex<Vec<mpsc::UnboundedSender<String>>>>,
}

#[cfg(unix)]
impl Drop for LaunchedLocalhostBinary {
    fn drop(&mut self) {
        let mut child = self.child.lock().unwrap();

        if let Ok(Some(_)) = child.try_status() {
            return;
        }

        let pid = child.id();
        if let Err(e) = nix::sys::signal::kill(
            nix::unistd::Pid::from_raw(pid as i32),
            nix::sys::signal::SIGTERM,
        ) {
            ProgressTracker::println(format!("Failed to SIGTERM process {}: {}", pid, e));
        }
    }
}

impl LaunchedLocalhostBinary {
    pub fn new(
        mut child: async_process::Child,
        id: String,
        tracing: Option<TracingOptions>,
    ) -> Self {
        let (stdin_sender, mut stdin_receiver) = mpsc::unbounded_channel::<String>();
        let mut stdin = child.stdin.take().unwrap();
        tokio::spawn(async move {
            while let Some(line) = stdin_receiver.recv().await {
                if stdin.write_all(line.as_bytes()).await.is_err() {
                    break;
                }

                stdin.flush().await.ok();
            }
        });

        let id_clone = id.clone();
        let (stdout_deploy_receivers, stdout_receivers) = prioritized_broadcast(
            FuturesBufReader::new(child.stdout.take().unwrap()).lines(),
            move |s| ProgressTracker::println(format!("[{id_clone}] {s}")),
        );
        let (_, stderr_receivers) = prioritized_broadcast(
            FuturesBufReader::new(child.stderr.take().unwrap()).lines(),
            move |s| ProgressTracker::println(format!("[{id} stderr] {s}")),
        );

        Self {
            child: Mutex::new(child),
            tracing,
            stdin_sender,
            stdout_deploy_receivers,
            stdout_receivers,
            stderr_receivers,
        }
    }
}

#[async_trait]
impl LaunchedBinary for LaunchedLocalhostBinary {
    fn stdin(&self) -> mpsc::UnboundedSender<String> {
        self.stdin_sender.clone()
    }

    fn deploy_stdout(&self) -> oneshot::Receiver<String> {
        let mut receivers = self.stdout_deploy_receivers.lock().unwrap();

        if receivers.is_some() {
            panic!("Only one deploy stdout receiver is allowed at a time");
        }

        let (sender, receiver) = oneshot::channel::<String>();
        *receivers = Some(sender);
        receiver
    }

    fn stdout(&self) -> mpsc::UnboundedReceiver<String> {
        let mut receivers = self.stdout_receivers.lock().unwrap();
        let (sender, receiver) = mpsc::unbounded_channel::<String>();
        receivers.push(sender);
        receiver
    }

    fn stderr(&self) -> mpsc::UnboundedReceiver<String> {
        let mut receivers = self.stderr_receivers.lock().unwrap();
        let (sender, receiver) = mpsc::unbounded_channel::<String>();
        receivers.push(sender);
        receiver
    }

    fn exit_code(&self) -> Option<i32> {
        self.child
            .lock()
            .unwrap()
            .try_status()
            .ok()
            .flatten()
            .map(exit_code)
    }

    async fn wait(&mut self) -> Result<i32> {
        Ok(exit_code(self.child.get_mut().unwrap().status().await?))
    }

    async fn stop(&mut self) -> Result<()> {
        if let Err(err) = self.child.get_mut().unwrap().kill() {
            if !matches!(err.kind(), std::io::ErrorKind::InvalidInput) {
                Err(err)?;
            }
        }

        // Run perf post-processing and download perf output.
        if let Some(tracing) = self.tracing.as_ref() {
            let fold_data = if cfg!(target_os = "macos") || cfg!(target_family = "windows") {
                let dtrace_outfile = tracing.dtrace_outfile.as_ref().ok_or_else(|| {
                    anyhow!(
                        "`{}` must be set for `dtrace` on localhost.",
                        name_of!(dtrace_outfile in TracingOptions)
                    )
                })?;
                let mut fold_er =
                    DtraceFolder::from(tracing.fold_dtrace_options.clone().unwrap_or_default());

                let fold_data =
                    ProgressTracker::leaf("fold dtrace output".to_owned(), async move {
                        let mut fold_data = Vec::new();
                        fold_er.collapse_file(Some(dtrace_outfile), &mut fold_data)?;
                        Result::<_>::Ok(fold_data)
                    })
                    .await?;
                fold_data
            } else if cfg!(target_family = "unix") {
                let perf_raw_outfile = tracing.perf_raw_outfile.as_ref().ok_or_else(|| {
                    anyhow!(
                        "`{}` must be set for `perf` on localhost.",
                        name_of!(perf_raw_outfile in TracingOptions)
                    )
                })?;

                // Run perf script.
                let mut perf_script = Command::new("perf")
                    .args(["script", "--symfs=/", "-i"])
                    .arg(perf_raw_outfile)
                    .stdout(Stdio::piped())
                    .stderr(Stdio::piped())
                    .spawn()?;

                let stdout = perf_script.stdout.take().unwrap().compat();
                let mut stderr_lines =
                    TokioBufReader::new(perf_script.stderr.take().unwrap().compat()).lines();

                let mut fold_er =
                    PerfFolder::from(tracing.fold_perf_options.clone().unwrap_or_default());

                // Pattern on `()` to make sure no `Result`s are ignored.
                let ((), fold_data, ()) = tokio::try_join!(
                    async move {
                        // Log stderr.
                        while let Ok(Some(s)) = stderr_lines.next_line().await {
                            ProgressTracker::println(format!("[perf script stderr] {s}"));
                        }
                        Result::<_>::Ok(())
                    },
                    async move {
                        // Stream `perf script` stdout and fold.
                        tokio::task::spawn_blocking(move || {
                            let mut fold_data = Vec::new();
                            fold_er.collapse(
                                SyncIoBridge::new(tokio::io::BufReader::new(stdout)),
                                &mut fold_data,
                            )?;
                            Ok(fold_data)
                        })
                        .await?
                    },
                    async move {
                        // Close stdin and wait for command exit.
                        perf_script.status().await?;
                        Ok(())
                    },
                )?;
                fold_data
            } else {
                bail!(
                    "Unknown OS for perf/dtrace tracing: {}",
                    std::env::consts::OS
                );
            };

            handle_fold_data(tracing, fold_data).await?;
        };

        Ok(())
    }
}

fn exit_code(c: ExitStatus) -> i32 {
    #[cfg(unix)]
    return c.code().or(c.signal()).unwrap();
    #[cfg(not(unix))]
    return c.code().unwrap();
}