use anyhow::Result;
use clap::Parser;
use std::{
    fs::File,
    io::{BufRead, BufReader},
};

/// Print information about an existing message queue
#[derive(Debug, Parser)]
pub struct Info {
    /// Id of the queue
    #[clap(short, long, required_unless_present_any = &["key"], conflicts_with = "key")]
    id: Option<i32>,
    /// Key of the queue
    #[clap(short, long, required_unless_present_any = &["id"], conflicts_with = "id")]
    key: Option<i32>,
}

fn print_line(line: &str) {
    for field in line.split_whitespace().collect::<Vec<&str>>() {
        print!("{0: <10}", field);
    }

    println!();
}

impl Info {
    pub fn run(&self) -> Result<()> {
        let mut lines = BufReader::new(File::open("/proc/sysvipc/msg")?).lines();

        print_line(&lines.next().unwrap_or_else(|| Ok(String::new()))?);

        for line in lines {
            let line = line?;

            if let Some(id) = self.id {
                if id == line.split_whitespace().collect::<Vec<&str>>()[1].parse::<i32>()? {
                    print_line(&line);

                    break;
                }
            } else if let Some(key) = self.key {
                if key == line.split_whitespace().collect::<Vec<&str>>()[0].parse::<i32>()? {
                    print_line(&line);

                    break;
                }
            }
        }

        Ok(())
    }
}