//! Remote-host bench execution (`sm121 bench --ssh-host <host>`): the
//! tool-eval-bench runs on the remote host over SSH (the local machine only
//! orchestrates), keeping the bench client's own network (a WiFi laptop) off
//! the measurement path. The tokenizer is uploaded to the host; the report +
//! run package still land locally (the remote json/md are downloaded back).

use std::path::Path;
use std::process::Command;

use anyhow::Result;

/// Build the SSH command that runs the tool on the remote host. `ssh -t`
/// allocates a pty (the rich Live display deadlocks on a non-tty pipe);
/// `stty -onlcr` keeps the log LF-only; TTY_COMPATIBLE/NO_COLOR match the
/// local run. The `cwd` is a remote path embedded in the shell string.
pub fn remote_command(host: &str, cwd: &Path, bin: &str, args: &[String]) -> Command {
    let remote = format!(
        "mkdir -p '{}' && cd '{}' || exit 127; stty -onlcr 2>/dev/null; TTY_COMPATIBLE=0 NO_COLOR=1 exec {} {}",
        cwd.display(),
        cwd.display(),
        bin,
        args.join(" ")
    );
    let mut c = Command::new("ssh");
    c.arg("-t");
    c.arg(host);
    c.arg(&remote);
    c
}

/// Create the remote scratch dir + upload the tokenizer there so the bench
/// client's own network stays off the measurement path.
pub fn prepare(host: &str, tool_scratch: &Path, tokenizer: &Option<String>) -> Result<()> {
    let st = Command::new("ssh")
        .arg(host)
        .arg(format!("mkdir -p '{}'", tool_scratch.display()))
        .output()
        .map_err(|e| anyhow::anyhow!("ssh mkdir to {host}: {e}"))?;
    if !st.status.success() {
        anyhow::bail!("mkdir on {host}: {}", String::from_utf8_lossy(&st.stderr));
    }
    if let Some(tok) = tokenizer {
        let st = Command::new("scp")
            .arg("-r")
            .arg(tok)
            .arg(format!("{host}:{}", tool_scratch.display()))
            .output()
            .map_err(|e| anyhow::anyhow!("scp tokenizer to {host}: {e}"))?;
        if !st.status.success() {
            anyhow::bail!(
                "scp tokenizer to {host}: {}",
                String::from_utf8_lossy(&st.stderr)
            );
        }
        eprintln!("bench: tokenizer uploaded to {host}");
    }
    Ok(())
}

/// Download the json + the md from the remote scratch dir so the local report
/// generation is unchanged. A download failure warns (the run is not lost);
/// the local json is simply missing (the run package is skipped). Perf-only
/// runs write no JSON by design — pass `expect_json = false` to skip the
/// scp (and the warning) entirely.
pub fn collect(
    host: &str,
    tool_json: &Path,
    json_path: &Path,
    tool_scratch: &Path,
    scratch: &Path,
    expect_json: bool,
) -> Result<()> {
    if expect_json {
        let st = Command::new("scp")
            .arg(format!("{host}:{}", tool_json.display()))
            .arg(json_path)
            .output()
            .map_err(|e| anyhow::anyhow!("scp json from {host}: {e}"))?;
        if !st.status.success() {
            eprintln!("bench: WARNING could not download json from {host}");
        }
    }
    let st = Command::new("ssh")
        .arg(host)
        .arg(format!(
            "find '{}' -name '*.md' -printf '%T@\\t%p\\n' 2>/dev/null | sort -n | tail -1 | cut -f2",
            tool_scratch.join("runs").display()
        ))
        .output()
        .map_err(|e| anyhow::anyhow!("ssh find md on {host}: {e}"))?;
    let remote_md = String::from_utf8_lossy(&st.stdout).trim().to_string();
    if !remote_md.is_empty() {
        let md_name = remote_md
            .rsplit('/')
            .next()
            .unwrap_or("report.md")
            .to_string();
        let local_runs = scratch.join("runs");
        std::fs::create_dir_all(&local_runs)?;
        let local_md_path = local_runs.join(&md_name);
        let st = Command::new("scp")
            .arg(format!("{host}:{remote_md}"))
            .arg(&local_md_path)
            .output()
            .map_err(|e| anyhow::anyhow!("scp md from {host}: {e}"))?;
        if !st.status.success() {
            eprintln!("bench: WARNING could not download md from {host}");
        }
    }
    Ok(())
}