/// Lists the transitive closure of the reverse dependency relation
    Dependents(Dependents),

        SubCommand::Dependents(deps) => deps.run(),

        // #[cfg(debug_assertions)]

mod dependents;
pub use dependents::Dependents;

use std::path::PathBuf;
use std::io::Write;
use clap::Parser;
use libpijul::*;
use crate::repository::*;
#[derive(Parser, Debug)]
pub struct Dependents {
    /// Use the repository at PATH instead of the current directory
    #[clap(long = "repository", value_name = "PATH")]
    repo_path: Option<PathBuf>,
    /// The hash of the change to show, or an unambiguous prefix thereof
    #[clap(value_name = "HASH")]
    hash: Option<String>,
}
impl Dependents {
    pub fn run(self) -> Result<(), anyhow::Error> {
        let repo = Repository::find_root(self.repo_path.clone())?;
        let txn = repo.pristine.txn_begin()?;
        let hash = if let Some(hash) = self.hash {
            if let Some(h) = Hash::from_base32(hash.as_bytes()) {
                h
            } else {
                txn.hash_from_prefix(&hash)?.0
            }
        } else {
            let channel_name = txn.current_channel().unwrap_or(crate::DEFAULT_CHANNEL);
            let channel = if let Some(channel) = txn.load_channel(&channel_name)? {
                channel
            } else {
                return Ok(());
            };
            let channel = channel.read();
            if let Some(h) = txn.reverse_log(&*channel, None)?.next() {
                (h?.1).0.into()
            } else {
                return Ok(());
            }
        };
        let mut ids = vec![(txn.get_internal(&hash.into())?.unwrap(), false)];
        let mut seen = HashSet::new();
        let mut stdout = std::io::stdout();
        while let Some((id, v)) = ids.pop() {
            if v {
                let h: Hash = txn.get_external(&id)?.unwrap().into();
                writeln!(stdout, "{}", h.to_base32())?;
            } else if seen.insert(id) {
                ids.push((id, true));
                for t in txn.iter_revdep(&id).unwrap() {
                    let (_, t) = t?;
                    ids.push((t, false));
                }
            }
        }
        Ok(())
    }
}