use anyhow::{Context, Result, anyhow};
use clap::Parser;
use portable_pty::{CommandBuilder, NativePtySystem, PtySize, PtySystem};
use std::ffi::OsStr;
use std::fmt::Write as _;
use std::fs;
use std::io::Read;
use std::path::PathBuf;
use std::process::Command;
use std::sync::mpsc;
use std::time::{Duration, Instant};

#[derive(Debug, Parser)]
#[command(
    name = "dosh-bench",
    version = dosh::build_info::VERSION,
    long_version = dosh::build_info::LONG_VERSION
)]
struct Args {
    #[arg(long, default_value = "local")]
    server: String,
    #[arg(long, default_value = "default")]
    session: String,
    #[arg(long, default_value_t = 22)]
    ssh_port: u16,
    #[arg(long, default_value_t = 50000)]
    dosh_port: u16,
    #[arg(long)]
    dosh_host: Option<String>,
    #[arg(long, default_value_t = 3)]
    iterations: usize,
    #[arg(long)]
    local_auth: bool,
    /// Benchmark native cold auth (no cache, native handshake) terminal-ready time.
    #[arg(long)]
    cold_native: bool,
    /// Benchmark cached attach-ticket terminal-ready time (warms the cache first).
    #[arg(long)]
    cached_ticket: bool,
    /// Benchmark UDP resume terminal-ready time (warms the cache first).
    #[arg(long)]
    resume: bool,
    #[arg(long)]
    client: Option<PathBuf>,
    #[arg(long, default_value = "~/.local/bin/dosh-auth")]
    ssh_auth_command: String,
    #[arg(long)]
    ssh_key: Option<PathBuf>,
    #[arg(long)]
    ssh_known_hosts: Option<PathBuf>,
    #[arg(long)]
    ssh_control_path: Option<PathBuf>,
    #[arg(long)]
    controlmaster: bool,
    #[arg(long)]
    no_cache: bool,
    #[arg(long)]
    warm_cache: bool,
    #[arg(long)]
    skip_ssh_baseline: bool,
    #[arg(long)]
    include_mosh: bool,
    #[arg(long, default_value = "mosh")]
    mosh: PathBuf,
    #[arg(long, default_value = "mosh-server")]
    mosh_server_command: String,
    #[arg(long)]
    mosh_port: Option<String>,
    /// Emit machine-readable JSON (one object per metric, with raw samples).
    #[arg(long)]
    json: bool,
    /// Emit a publishable Markdown benchmark report.
    #[arg(long)]
    markdown: bool,
    /// Write the report to a file instead of stdout.
    #[arg(long)]
    output: Option<PathBuf>,
    /// Optional label printed in summary/JSON output (e.g. machine/OS identifier).
    #[arg(long)]
    label: Option<String>,
    #[arg(long)]
    assert_ssh_plus_ms: Option<f64>,
    #[arg(long)]
    assert_mosh_minus_ms: Option<f64>,
    #[arg(long)]
    assert_dosh_max_ms: Option<f64>,
}

/// One Dosh attach path to benchmark.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum DoshPath {
    /// `--auth native --no-cache`: full native handshake, no cache.
    ColdNative,
    /// Cached attach-ticket fast path (requires a warmed cache).
    CachedTicket,
    /// UDP resume fast path (requires a warmed cache + `cache_attach_tickets = false`).
    Resume,
    /// `--local-auth`: self-contained local bootstrap, no SSH.
    LocalAuth,
    /// SSH-bootstrap cold attach (cache controlled by `--no-cache` / `--warm-cache`).
    SshBootstrap,
}

impl DoshPath {
    fn metric(self) -> &'static str {
        match self {
            DoshPath::ColdNative => "dosh_cold_native_ms",
            DoshPath::CachedTicket => "dosh_cached_attach_ms",
            DoshPath::Resume => "dosh_resume_ms",
            DoshPath::LocalAuth => "dosh_local_attach_ms",
            DoshPath::SshBootstrap => "dosh_attach_ms",
        }
    }

    /// Whether this path consumes a warmed credential cache.
    fn needs_warm(self) -> bool {
        matches!(self, DoshPath::CachedTicket | DoshPath::Resume)
    }
}

fn main() -> Result<()> {
    let args = Args::parse();
    let client = args.client.clone().unwrap_or_else(default_client_path);
    if args.no_cache && args.warm_cache {
        return Err(anyhow!("--warm-cache cannot be used with --no-cache"));
    }

    let generated_control_path = if args.controlmaster {
        Some(std::env::temp_dir().join(format!("dosh-bench-control-{}", std::process::id())))
    } else {
        None
    };
    let control_path = generated_control_path
        .as_ref()
        .or(args.ssh_control_path.as_ref());
    let _controlmaster = if let Some(path) = generated_control_path.as_ref() {
        Some(ControlMaster::start(&args, path.clone())?)
    } else {
        None
    };

    // Resolve which Dosh paths to benchmark. Explicit path flags select an
    // explicit matrix; otherwise fall back to the legacy single-path behavior
    // so existing callers (CI docker scripts) keep working unchanged.
    let explicit_paths = explicit_dosh_paths(&args);
    let dosh_paths = if explicit_paths.is_empty() {
        vec![legacy_dosh_path(&args)]
    } else {
        explicit_paths
    };

    let mut results: Vec<MetricSamples> = Vec::new();

    // SSH baseline (shared across the matrix; the comparison is per-iteration
    // ssh-true vs the dosh path startup that replaces it).
    let run_ssh = !args.local_auth && !args.skip_ssh_baseline && !dosh_only(&dosh_paths);
    if run_ssh {
        let mut ssh_times = Vec::new();
        for _ in 0..args.iterations.max(1) {
            let mut ssh = Command::new("ssh");
            add_ssh_options(&mut ssh, &args, control_path);
            ssh.arg(&args.server).arg("true");
            ssh_times.push(time_command(&mut ssh)?);
        }
        results.push(MetricSamples::new("ssh_true_ms", ssh_times));
    }

    for path in &dosh_paths {
        if path.needs_warm() {
            // Prime the cache with one attach so the fast path has credentials.
            let _ = time_dosh_attach(&client, &args, *path, control_path, true)?;
        }
        let mut samples = Vec::new();
        for _ in 0..args.iterations.max(1) {
            samples.push(time_dosh_attach(
                &client,
                &args,
                *path,
                control_path,
                false,
            )?);
        }
        results.push(MetricSamples::new(path.metric(), samples));
    }

    if args.include_mosh {
        let mut mosh_times = Vec::new();
        for _ in 0..args.iterations.max(1) {
            mosh_times.push(time_mosh_in_pty(&args)?);
        }
        results.push(MetricSamples::new("mosh_start_true_ms", mosh_times));
    }

    let report = if args.json {
        render_json(&args, &results)
    } else if args.markdown {
        render_markdown(&args, &results)
    } else {
        render_table(&args, &results)
    };
    write_report(&args, &report)?;

    run_assertions(&args, &results)?;
    Ok(())
}

/// Paths explicitly requested via flags.
fn explicit_dosh_paths(args: &Args) -> Vec<DoshPath> {
    let mut paths = Vec::new();
    if args.cold_native {
        paths.push(DoshPath::ColdNative);
    }
    if args.cached_ticket {
        paths.push(DoshPath::CachedTicket);
    }
    if args.resume {
        paths.push(DoshPath::Resume);
    }
    paths
}

/// The single path implied by legacy flags when no explicit path is requested.
fn legacy_dosh_path(args: &Args) -> DoshPath {
    if args.local_auth {
        DoshPath::LocalAuth
    } else if args.warm_cache {
        DoshPath::CachedTicket
    } else {
        DoshPath::SshBootstrap
    }
}

/// True when none of the selected paths needs an SSH baseline comparison
/// (i.e. all are local-auth or cache fast paths driven without SSH).
fn dosh_only(paths: &[DoshPath]) -> bool {
    paths.iter().all(|p| {
        matches!(
            p,
            DoshPath::LocalAuth | DoshPath::CachedTicket | DoshPath::Resume
        )
    })
}

fn time_dosh_attach(
    client: &PathBuf,
    args: &Args,
    path: DoshPath,
    control_path: Option<&PathBuf>,
    warm: bool,
) -> Result<Duration> {
    let mut cmd = Command::new(client);
    cmd.arg("--attach-only")
        .arg("--session")
        .arg(&args.session)
        .arg("--dosh-port")
        .arg(args.dosh_port.to_string());
    if let Some(host) = &args.dosh_host {
        cmd.arg("--dosh-host").arg(host);
    }

    match path {
        DoshPath::LocalAuth => {
            cmd.arg("--local-auth");
            // While warming, write the cache; measured runs honor --no-cache.
            if args.no_cache && !warm {
                cmd.arg("--no-cache");
            }
            cmd.arg(&args.server);
        }
        DoshPath::CachedTicket | DoshPath::Resume => {
            // Fast paths must read the warmed cache, so never pass --no-cache here.
            // Whether the cache uses tickets vs resume is decided by the client
            // config (`cache_attach_tickets`) the harness wrote into HOME.
            if args.local_auth {
                cmd.arg("--local-auth");
            }
            add_bootstrap_args(&mut cmd, args, control_path);
            cmd.arg(&args.server);
        }
        DoshPath::ColdNative => {
            cmd.arg("--auth").arg("native");
            // Cold path: never use a warmed cache.
            cmd.arg("--no-cache");
            add_bootstrap_args(&mut cmd, args, control_path);
            cmd.arg(&args.server);
        }
        DoshPath::SshBootstrap => {
            add_bootstrap_args(&mut cmd, args, control_path);
            // Cold SSH bootstrap honors --no-cache on measured runs.
            if args.no_cache && !warm {
                cmd.arg("--no-cache");
            }
            cmd.arg(&args.server);
        }
    }
    time_command(&mut cmd)
}

/// Append the SSH bootstrap arguments shared by the non-local paths. Native
/// auth reuses the same SSH key/known-hosts/port plumbing.
fn add_bootstrap_args(cmd: &mut Command, args: &Args, control_path: Option<&PathBuf>) {
    if args.local_auth {
        return;
    }
    cmd.arg("--ssh-port")
        .arg(args.ssh_port.to_string())
        .arg("--ssh-auth-command")
        .arg(&args.ssh_auth_command);
    if let Some(key) = &args.ssh_key {
        cmd.arg("--ssh-key").arg(key);
    }
    if let Some(known_hosts) = &args.ssh_known_hosts {
        cmd.arg("--ssh-known-hosts").arg(known_hosts);
    }
    if let Some(control_path) = control_path {
        cmd.arg("--ssh-control-path").arg(control_path);
    }
}

fn add_ssh_options(cmd: &mut Command, args: &Args, control_path: Option<&PathBuf>) {
    cmd.arg("-p").arg(args.ssh_port.to_string()).arg("-T");
    if let Some(key) = &args.ssh_key {
        cmd.arg("-i").arg(key);
    }
    if let Some(known_hosts) = &args.ssh_known_hosts {
        cmd.arg("-o")
            .arg(format!("UserKnownHostsFile={}", known_hosts.display()));
    }
    if let Some(control_path) = control_path {
        cmd.arg("-S").arg(control_path);
    }
}

fn mosh_ssh_command(args: &Args) -> String {
    let mut parts = vec![
        "ssh".to_string(),
        "-p".to_string(),
        args.ssh_port.to_string(),
    ];
    if let Some(key) = &args.ssh_key {
        parts.push("-i".to_string());
        parts.push(shell_word(key.as_os_str()));
    }
    if let Some(known_hosts) = &args.ssh_known_hosts {
        parts.push("-o".to_string());
        parts.push(shell_word(OsStr::new(&format!(
            "UserKnownHostsFile={}",
            known_hosts.display()
        ))));
    }
    parts.join(" ")
}

fn time_mosh_in_pty(args: &Args) -> Result<Duration> {
    let pty_system = NativePtySystem::default();
    let pair = pty_system
        .openpty(PtySize {
            rows: 24,
            cols: 80,
            pixel_width: 0,
            pixel_height: 0,
        })
        .context("open pty for mosh benchmark")?;
    let mut command_line = vec![
        shell_word(args.mosh.as_os_str()),
        shell_word(OsStr::new(&format!("--ssh={}", mosh_ssh_command(args)))),
        shell_word(OsStr::new(&format!(
            "--server={}",
            args.mosh_server_command
        ))),
        "--no-init".to_string(),
    ];
    if let Some(port) = &args.mosh_port {
        command_line.push("-p".to_string());
        command_line.push(shell_word(OsStr::new(port)));
    }
    command_line.push(shell_word(OsStr::new(&args.server)));
    command_line.push("--".to_string());
    command_line.push("true".to_string());

    let mut cmd = CommandBuilder::new("/bin/sh");
    cmd.arg("-c");
    cmd.arg(command_line.join(" "));

    let start = Instant::now();
    let mut child = pair
        .slave
        .spawn_command(cmd)
        .context("spawn mosh benchmark in pty")?;
    drop(pair.slave);

    let mut reader = pair.master.try_clone_reader().context("clone pty reader")?;
    let (tx, rx) = mpsc::channel();
    std::thread::spawn(move || {
        let mut output = Vec::new();
        let _ = reader.read_to_end(&mut output);
        let _ = tx.send(output);
    });

    {
        let _writer = pair.master.take_writer().context("take pty writer")?;
    }

    let status = child.wait().context("wait for mosh benchmark")?;
    let elapsed = start.elapsed();
    drop(pair.master);
    let output = rx.recv().unwrap_or_default();
    if !status.success() {
        return Err(anyhow!(
            "mosh command failed with status {status:?}\noutput:\n{}",
            String::from_utf8_lossy(&output)
        ));
    }
    Ok(elapsed)
}

fn shell_word(value: &OsStr) -> String {
    let value = value.to_string_lossy();
    format!("'{}'", value.replace('\'', "'\\''"))
}

struct ControlMaster {
    server: String,
    ssh_port: u16,
    ssh_key: Option<PathBuf>,
    ssh_known_hosts: Option<PathBuf>,
    control_path: PathBuf,
}

impl ControlMaster {
    fn start(args: &Args, control_path: PathBuf) -> Result<Self> {
        let mut cmd = Command::new("ssh");
        cmd.arg("-p")
            .arg(args.ssh_port.to_string())
            .arg("-T")
            .arg("-M")
            .arg("-S")
            .arg(&control_path)
            .arg("-f")
            .arg("-N")
            .arg("-o")
            .arg("ControlPersist=60")
            .arg("-o")
            .arg("ExitOnForwardFailure=yes");
        if let Some(key) = &args.ssh_key {
            cmd.arg("-i").arg(key);
        }
        if let Some(known_hosts) = &args.ssh_known_hosts {
            cmd.arg("-o")
                .arg(format!("UserKnownHostsFile={}", known_hosts.display()));
        }
        cmd.arg(&args.server);
        time_command(&mut cmd).context("start SSH ControlMaster")?;
        Ok(Self {
            server: args.server.clone(),
            ssh_port: args.ssh_port,
            ssh_key: args.ssh_key.clone(),
            ssh_known_hosts: args.ssh_known_hosts.clone(),
            control_path,
        })
    }
}

impl Drop for ControlMaster {
    fn drop(&mut self) {
        let mut cmd = Command::new("ssh");
        cmd.arg("-p")
            .arg(self.ssh_port.to_string())
            .arg("-T")
            .arg("-S")
            .arg(&self.control_path)
            .arg("-O")
            .arg("exit");
        if let Some(key) = &self.ssh_key {
            cmd.arg("-i").arg(key);
        }
        if let Some(known_hosts) = &self.ssh_known_hosts {
            cmd.arg("-o")
                .arg(format!("UserKnownHostsFile={}", known_hosts.display()));
        }
        let _ = cmd.arg(&self.server).output();
    }
}

fn time_command(cmd: &mut Command) -> Result<Duration> {
    let start = Instant::now();
    let output = cmd.output().with_context(|| format!("run {:?}", cmd))?;
    if !output.status.success() {
        return Err(anyhow!(
            "command failed {:?}\nstdout:\n{}\nstderr:\n{}",
            cmd,
            String::from_utf8_lossy(&output.stdout),
            String::from_utf8_lossy(&output.stderr)
        ));
    }
    Ok(start.elapsed())
}

/// Per-metric samples with summary statistics.
struct MetricSamples {
    name: &'static str,
    samples: Vec<Duration>,
}

impl MetricSamples {
    fn new(name: &'static str, samples: Vec<Duration>) -> Self {
        Self { name, samples }
    }

    fn ms(&self) -> Vec<f64> {
        self.samples
            .iter()
            .map(|d| d.as_secs_f64() * 1000.0)
            .collect()
    }

    fn stats(&self) -> Stats {
        Stats::from_ms(&self.ms())
    }
}

/// Summary statistics for a set of millisecond samples.
struct Stats {
    count: usize,
    min: f64,
    median: f64,
    p95: f64,
    mean: f64,
    max: f64,
}

impl Stats {
    fn from_ms(values: &[f64]) -> Self {
        if values.is_empty() {
            return Self {
                count: 0,
                min: 0.0,
                median: 0.0,
                p95: 0.0,
                mean: 0.0,
                max: 0.0,
            };
        }
        let mut sorted = values.to_vec();
        sorted.sort_by(|a, b| a.partial_cmp(b).unwrap_or(std::cmp::Ordering::Equal));
        let count = sorted.len();
        let mean = sorted.iter().sum::<f64>() / count as f64;
        Self {
            count,
            min: sorted[0],
            median: percentile(&sorted, 50.0),
            p95: percentile(&sorted, 95.0),
            mean,
            max: sorted[count - 1],
        }
    }
}

/// Linear-interpolated percentile over a pre-sorted slice.
fn percentile(sorted: &[f64], pct: f64) -> f64 {
    if sorted.is_empty() {
        return 0.0;
    }
    if sorted.len() == 1 {
        return sorted[0];
    }
    let rank = (pct / 100.0) * (sorted.len() - 1) as f64;
    let lo = rank.floor() as usize;
    let hi = rank.ceil() as usize;
    if lo == hi {
        sorted[lo]
    } else {
        let frac = rank - lo as f64;
        sorted[lo] + (sorted[hi] - sorted[lo]) * frac
    }
}

fn render_table(args: &Args, results: &[MetricSamples]) -> String {
    let mut out = String::new();
    if let Some(label) = &args.label {
        let _ = writeln!(out, "# label: {label}");
    }
    let _ = writeln!(
        out,
        "{:<24} {:>6} {:>9} {:>9} {:>9} {:>9} {:>9}",
        "metric", "n", "min", "median", "p95", "mean", "max"
    );
    for metric in results {
        let s = metric.stats();
        let _ = writeln!(
            out,
            "{:<24} {:>6} {:>9.2} {:>9.2} {:>9.2} {:>9.2} {:>9.2}",
            metric.name, s.count, s.min, s.median, s.p95, s.mean, s.max
        );
    }
    // Raw per-iteration samples, so published numbers can include raw data.
    for metric in results {
        let ms: Vec<String> = metric.ms().iter().map(|v| format!("{v:.2}")).collect();
        let _ = writeln!(out, "{} samples_ms=[{}]", metric.name, ms.join(", "));
    }
    out
}

fn render_json(args: &Args, results: &[MetricSamples]) -> String {
    let mut entries = Vec::new();
    for metric in results {
        let s = metric.stats();
        let samples: Vec<String> = metric.ms().iter().map(|v| format!("{v:.4}")).collect();
        entries.push(format!(
            "{{\"metric\":\"{}\",\"count\":{},\"min\":{:.4},\"median\":{:.4},\"p95\":{:.4},\"mean\":{:.4},\"max\":{:.4},\"samples_ms\":[{}]}}",
            metric.name,
            s.count,
            s.min,
            s.median,
            s.p95,
            s.mean,
            s.max,
            samples.join(",")
        ));
    }
    let label = match &args.label {
        Some(label) => format!("\"{}\"", label.replace('"', "\\\"")),
        None => "null".to_string(),
    };
    format!(
        "{{\"label\":{label},\"iterations\":{},\"metrics\":[{}]}}",
        args.iterations.max(1),
        entries.join(",")
    )
}

fn render_markdown(args: &Args, results: &[MetricSamples]) -> String {
    let mut out = String::new();
    let label = args.label.as_deref().unwrap_or("Dosh benchmark");
    let _ = writeln!(out, "# {label}\n");
    let _ = writeln!(out, "- server: `{}`", args.server);
    let _ = writeln!(out, "- iterations: `{}`", args.iterations.max(1));
    let _ = writeln!(
        out,
        "- generated_by: `dosh-bench {}`\n",
        env!("CARGO_PKG_VERSION")
    );
    let _ = writeln!(
        out,
        "| metric | n | min ms | median ms | p95 ms | mean ms | max ms |"
    );
    let _ = writeln!(out, "|---|---:|---:|---:|---:|---:|---:|");
    for metric in results {
        let s = metric.stats();
        let _ = writeln!(
            out,
            "| `{}` | {} | {:.2} | {:.2} | {:.2} | {:.2} | {:.2} |",
            metric.name, s.count, s.min, s.median, s.p95, s.mean, s.max
        );
    }
    let _ = writeln!(out, "\n## Raw Samples\n");
    for metric in results {
        let ms: Vec<String> = metric.ms().iter().map(|v| format!("{v:.2}")).collect();
        let _ = writeln!(out, "- `{}`: [{}]", metric.name, ms.join(", "));
    }
    out
}

fn write_report(args: &Args, report: &str) -> Result<()> {
    if let Some(path) = &args.output {
        if let Some(parent) = path.parent()
            && !parent.as_os_str().is_empty()
        {
            fs::create_dir_all(parent).with_context(|| format!("create {}", parent.display()))?;
        }
        fs::write(path, report).with_context(|| format!("write {}", path.display()))?;
        println!("wrote {}", path.display());
    } else {
        println!("{report}");
    }
    Ok(())
}

fn metric_mean(results: &[MetricSamples], name: &str) -> Option<f64> {
    results
        .iter()
        .find(|m| m.name == name)
        .map(|m| m.stats().mean)
}

/// The headline dosh metric for assertions: prefer cached, then resume, then
/// cold native, then ssh-bootstrap, then local-auth.
fn primary_dosh(results: &[MetricSamples]) -> Option<(&'static str, f64)> {
    const ORDER: [&str; 5] = [
        "dosh_cached_attach_ms",
        "dosh_resume_ms",
        "dosh_cold_native_ms",
        "dosh_attach_ms",
        "dosh_local_attach_ms",
    ];
    for name in ORDER {
        if let Some(mean) = metric_mean(results, name) {
            return Some((name, mean));
        }
    }
    None
}

fn run_assertions(args: &Args, results: &[MetricSamples]) -> Result<()> {
    if let Some(margin) = args.assert_ssh_plus_ms {
        let ssh = metric_mean(results, "ssh_true_ms")
            .ok_or_else(|| anyhow!("--assert-ssh-plus-ms requires non-local SSH benchmark"))?;
        let (name, dosh) =
            primary_dosh(results).ok_or_else(|| anyhow!("no dosh metric to assert against"))?;
        if dosh > ssh + margin {
            return Err(anyhow!(
                "{name} avg {dosh:.2}ms exceeded ssh avg {ssh:.2}ms + {margin:.2}ms"
            ));
        }
        println!("gate ok: {name} avg {dosh:.2}ms <= ssh avg {ssh:.2}ms + {margin:.2}ms");
    }
    if let Some(margin) = args.assert_mosh_minus_ms {
        let mosh = metric_mean(results, "mosh_start_true_ms")
            .ok_or_else(|| anyhow!("--assert-mosh-minus-ms requires --include-mosh benchmark"))?;
        let (name, dosh) =
            primary_dosh(results).ok_or_else(|| anyhow!("no dosh metric to assert against"))?;
        if dosh + margin > mosh {
            return Err(anyhow!(
                "{name} avg {dosh:.2}ms was not at least {margin:.2}ms faster than mosh avg {mosh:.2}ms"
            ));
        }
        println!("gate ok: {name} avg {dosh:.2}ms + {margin:.2}ms <= mosh avg {mosh:.2}ms");
    }
    if let Some(max_ms) = args.assert_dosh_max_ms {
        let (name, dosh) =
            primary_dosh(results).ok_or_else(|| anyhow!("no dosh metric to assert against"))?;
        if dosh > max_ms {
            return Err(anyhow!("{name} avg {dosh:.2}ms exceeded max {max_ms:.2}ms"));
        }
        println!("gate ok: {name} avg {dosh:.2}ms <= {max_ms:.2}ms");
    }
    Ok(())
}

fn default_client_path() -> PathBuf {
    std::env::current_exe()
        .ok()
        .and_then(|path| path.parent().map(|parent| parent.join("dosh-client")))
        .unwrap_or_else(|| PathBuf::from("dosh-client"))
}

#[cfg(test)]
mod tests {
    use super::*;

    fn args_for_render() -> Args {
        Args {
            server: "local".to_string(),
            session: "default".to_string(),
            ssh_port: 22,
            dosh_port: 50000,
            dosh_host: None,
            iterations: 2,
            local_auth: true,
            cold_native: false,
            cached_ticket: false,
            resume: false,
            client: None,
            ssh_auth_command: "~/.local/bin/dosh-auth".to_string(),
            ssh_key: None,
            ssh_known_hosts: None,
            ssh_control_path: None,
            controlmaster: false,
            no_cache: false,
            warm_cache: false,
            skip_ssh_baseline: true,
            include_mosh: false,
            mosh: PathBuf::from("mosh"),
            mosh_server_command: "mosh-server".to_string(),
            mosh_port: None,
            json: false,
            markdown: true,
            output: None,
            label: Some("test host".to_string()),
            assert_ssh_plus_ms: None,
            assert_mosh_minus_ms: None,
            assert_dosh_max_ms: None,
        }
    }

    #[test]
    fn markdown_report_contains_summary_and_samples() {
        let args = args_for_render();
        let metrics = vec![MetricSamples::new(
            "dosh_cached_attach_ms",
            vec![Duration::from_millis(3), Duration::from_millis(5)],
        )];
        let report = render_markdown(&args, &metrics);
        assert!(report.contains("# test host"));
        assert!(report.contains("| `dosh_cached_attach_ms` | 2 | 3.00"));
        assert!(report.contains("- `dosh_cached_attach_ms`: [3.00, 5.00]"));
    }

    #[test]
    fn json_report_contains_metrics() {
        let args = args_for_render();
        let metrics = vec![MetricSamples::new(
            "dosh_local_attach_ms",
            vec![Duration::from_millis(7)],
        )];
        let report = render_json(&args, &metrics);
        assert!(report.contains("\"label\":\"test host\""));
        assert!(report.contains("\"metric\":\"dosh_local_attach_ms\""));
        assert!(report.contains("\"samples_ms\":[7.0000]"));
    }
}