tmx-cli 0.1.2

use std::io;
use std::process::{Command, Stdio};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Session {
    pub name: String,
    pub windows: u32,
    pub attached: bool,
}

pub fn list_sessions() -> io::Result<Vec<Session>> {
    let output = Command::new("tmux")
        .args([
            "list-sessions",
            "-F",
            "#{session_name}:#{session_windows}:#{session_attached}",
        ])
        .output()?;

    if !output.status.success() {
        return Err(io::Error::other(format!(
            "tmux list-sessions failed: {}",
            String::from_utf8_lossy(&output.stderr).trim()
        )));
    }

    let stdout = String::from_utf8_lossy(&output.stdout);
    Ok(parse_sessions(&stdout))
}

pub fn parse_sessions(stdout: &str) -> Vec<Session> {
    stdout
        .trim()
        .lines()
        .filter(|line| !line.is_empty())
        .filter_map(parse_session_line)
        .collect()
}

fn parse_session_line(line: &str) -> Option<Session> {
    let mut parts = line.splitn(3, ':');
    let name = parts.next()?.to_string();
    let windows = parts.next()?.parse().ok()?;
    let attached_raw = parts.next()?;
    Some(Session {
        name,
        windows,
        attached: attached_raw == "1",
    })
}

pub fn session_exists(name: &str) -> bool {
    Command::new("tmux")
        .args(["has-session", "-t", name])
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .status()
        .map(|s| s.success())
        .unwrap_or(false)
}

pub fn create_session(name: &str, path: &str) -> io::Result<()> {
    let mut cmd = Command::new("tmux");
    cmd.args(["new-session", "-d", "-s", name]);
    if !path.is_empty() {
        cmd.args(["-c", path]);
    }
    let status = cmd.status()?;
    if !status.success() {
        return Err(io::Error::other(format!(
            "tmux new-session exited with status {status}"
        )));
    }
    Ok(())
}

pub fn switch_session(name: &str) -> io::Result<()> {
    // Inside tmux: switch the current client.
    if std::env::var_os("TMUX").is_some() {
        let status = Command::new("tmux")
            .args(["switch-client", "-t", name])
            .status()?;
        if !status.success() {
            return Err(io::Error::other(format!(
                "tmux switch-client exited with status {status}"
            )));
        }
        return Ok(());
    }
    // Otherwise attach — inherit stdio so the user sees the session.
    let status = Command::new("tmux")
        .args(["attach-session", "-t", name])
        .stdin(Stdio::inherit())
        .stdout(Stdio::inherit())
        .stderr(Stdio::inherit())
        .status()?;
    if !status.success() {
        return Err(io::Error::other(format!(
            "tmux attach-session exited with status {status}"
        )));
    }
    Ok(())
}

pub fn kill_session(name: &str) -> io::Result<()> {
    let status = Command::new("tmux")
        .args(["kill-session", "-t", name])
        .status()?;
    if !status.success() {
        return Err(io::Error::other(format!(
            "tmux kill-session exited with status {status}"
        )));
    }
    Ok(())
}

/// Kill a session by its stable id (e.g. `$3`). Safer than by name when
/// sessions may be renamed concurrently.
pub fn kill_session_id(id: &str) -> io::Result<()> {
    let status = Command::new("tmux")
        .args(["kill-session", "-t", id])
        .status()?;
    if !status.success() {
        return Err(io::Error::other(format!(
            "tmux kill-session exited with status {status}"
        )));
    }
    Ok(())
}

/// Return the current tmux session id (e.g. `$3`), or `None` if not inside
/// a tmux server or the query fails.
pub fn current_session_id() -> Option<String> {
    let output = Command::new("tmux")
        .args(["display-message", "-p", "#{session_id}"])
        .output()
        .ok()?;
    if !output.status.success() {
        return None;
    }
    let id = String::from_utf8_lossy(&output.stdout).trim().to_string();
    if id.is_empty() { None } else { Some(id) }
}

pub fn apply_layout(session_name: &str, _project_type: &str) -> io::Result<()> {
    Command::new("tmux")
        .args([
            "rename-window",
            "-t",
            &format!("{session_name}:0"),
            "editor",
        ])
        .stdout(Stdio::null())
        .stderr(Stdio::null())
        .status()
        .ok();
    Ok(())
}

pub fn cleanup_sessions() -> io::Result<Vec<String>> {
    let sessions = list_sessions()?;
    let mut killed = Vec::new();
    for session in sessions {
        if !session.attached && kill_session(&session.name).is_ok() {
            killed.push(session.name);
        }
    }
    Ok(killed)
}

/// Normalise a tmux session name. Mirrors the convention used elsewhere
/// (dots and slashes become safe characters).
pub fn safe_session_name(repo: &str, branch: &str) -> String {
    let combined = format!("{repo}-{branch}");
    combined.replace('/', "-").replace('.', "_")
}

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

    #[test]
    fn parse_sessions_handles_multiple_lines() {
        let input = "main:3:1\nside:1:0\n";
        let sessions = parse_sessions(input);
        assert_eq!(sessions.len(), 2);
        assert_eq!(
            sessions[0],
            Session {
                name: "main".into(),
                windows: 3,
                attached: true
            }
        );
        assert_eq!(
            sessions[1],
            Session {
                name: "side".into(),
                windows: 1,
                attached: false
            }
        );
    }

    #[test]
    fn parse_sessions_handles_session_with_colons_in_name() {
        // splitn(3) means trailing colons stay in the windows/attached fields,
        // not the name. The Go version behaves identically.
        let input = "weird:name:5:1";
        let sessions = parse_sessions(input);
        assert_eq!(sessions.len(), 0); // "name" is not a valid u32 → dropped
    }

    #[test]
    fn parse_sessions_skips_empty_lines() {
        let input = "\nfoo:1:0\n\n";
        let sessions = parse_sessions(input);
        assert_eq!(sessions.len(), 1);
        assert_eq!(sessions[0].name, "foo");
    }

    #[test]
    fn parse_sessions_empty_input() {
        assert!(parse_sessions("").is_empty());
        assert!(parse_sessions("\n\n").is_empty());
    }

    #[test]
    fn safe_session_name_replaces_special_chars() {
        assert_eq!(safe_session_name("my.repo", "feat/x"), "my_repo-feat-x");
        assert_eq!(safe_session_name("plain", "main"), "plain-main");
    }
}