use std::{
    fs::File,
    io::{self, BufRead},
    process::Command,
};

use dialoguer::{theme::ColorfulTheme, Select};

fn main() {
    let sessions = load_sessions();
    let selection = Select::with_theme(&ColorfulTheme::default())
        .with_prompt("Select session")
        .default(0)
        .items(&sessions)
        .interact()
        .unwrap();
    Command::new(&sessions[selection].exec)
        .spawn()
        .expect("failed to run session")
        .wait()
        .expect("failed to wait on child");
}

fn load_sessions() -> Vec<Session> {
    let wayland_sessions = glob::glob("/usr/share/wayland-sessions/*.desktop")
        .unwrap()
        .filter_map(|result| result.ok())
        .map(|path| {
            let mut session_name = None;
            let mut session_exec = None;
            let file = File::open(path).unwrap();
            for line in io::BufReader::new(file).lines() {
                let line = line.unwrap();
                if line.starts_with("Name=") {
                    session_name = Some(String::from(line.trim_start_matches("Name=")));
                } else if line.starts_with("Exec=") {
                    session_exec = Some(String::from(line.trim_start_matches("Exec=")));
                }
            }
            if let (Some(name), Some(exec)) = (session_name, session_exec) {
                Ok(Session { name, exec })
            } else {
                Err(())
            }
        })
        .filter_map(|result| result.ok())
        .collect();

    wayland_sessions
}

struct Session {
    name: String,
    exec: String,
}

impl ToString for Session {
    fn to_string(&self) -> String {
        self.name.clone()
    }
}