use std::process::{Command, ExitStatus, Output};

use crate::{Session, SessionSource};

pub use error::Error;

mod error;

#[derive(Debug)]
pub struct Tmux {
    socket_name: String,
}

impl Tmux {
    const SESSION_FORMAT: &str = r##"Session(name: "#S", #{?session_last_attached,timestamp: #{session_last_attached}#, state: Updated,timestamp: #{session_created}#, state: Connected})"##;

    pub fn new(socket_name: String) -> Self {
        Self { socket_name }
    }

    pub fn show(&self, name: &String) -> Result<Session, Error> {
        let output = Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("display")
            .arg("-p")
            .arg("-t")
            .arg(name)
            .arg(Self::SESSION_FORMAT)
            .output()?
            .stdout;

        let output_str = std::str::from_utf8(&output)?;

        Ok(ron::from_str(output_str)?)
    }

    pub fn list(&self) -> Result<Output, Error> {
        Ok(Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("list-sessions")
            .arg("-F")
            .arg(Self::SESSION_FORMAT)
            .output()?)
    }

    pub fn switch(&self, host: &String) -> Result<ExitStatus, Error> {
        if Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("has-session")
            .arg("-t")
            .arg(host)
            .status()?
            .success()
        {
            self.create(host)?;
        }

        if std::env::var("TMUX").is_ok() {
            self.attach(host)
        } else {
            self.detach_then_attach(host)
        }
    }

    fn create(&self, host: &String) -> Result<ExitStatus, Error> {
        Ok(Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("new-session")
            .arg("-ds")
            .arg(host)
            .arg("ssh")
            .arg("-t")
            .arg(host)
            .arg("zsh -l -c 'tmux new -A'")
            .status()?)
    }

    fn attach(&self, host: &String) -> Result<ExitStatus, Error> {
        Ok(Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("attach-session")
            .arg("-t")
            .arg(host)
            .status()?)
    }

    fn detach_then_attach(&self, host: &String) -> Result<ExitStatus, Error> {
        Ok(Command::new("tmux")
            .arg("detach")
            .arg("-E")
            .arg(format!("tmux -L ssh attach -t {host}"))
            .status()?)
    }
}

impl SessionSource for Tmux {
    type Error = Error;

    type Iter = Vec<Session>;

    fn sessions(&self) -> Result<Self::Iter, Self::Error> {
        let output = Command::new("tmux")
            .arg("-L")
            .arg(&self.socket_name)
            .arg("list-sessions")
            .arg("-F")
            .arg(Self::SESSION_FORMAT)
            .output()?
            .stdout;

        let sessions = std::str::from_utf8(&output)?
            .lines()
            .filter_map(|s| match ron::from_str(s) {
                Ok(session) => Some(session),
                Err(err) => {
                    tracing::warn!(%err, "Invalid session format");
                    None
                }
            })
            .collect();

        Ok(sessions)
    }
}