use std::path::PathBuf;

use std::path::{ Path, PathBuf };

use log::debug;

    /// Filter log output, showing only log entries that touched the specified 
    /// files. Accepted as a list of paths relative to your current directory.
    #[clap(last = true)]
    filters: Vec<String>,
}
/// The user gives a list of patterns to say they only want to see the log
/// entries that affected those files. The patterns are given relative to the directory
/// they're calling from, not relative to the repository root, but we need to then
/// strip the repository path off the canonicalized filter path so
/// that we can match the file paths as they appear in the pijul change files, which
/// are recorded relative to the repository's root.
fn mk_filters(repo_path: &Path, mut pats: Vec<String>) -> Result<Vec<String>, anyhow::Error> {
    for pat in &mut pats {
        let canon_path = match Path::new(pat).canonicalize() {
            Err(e) if matches!(e.kind(), std::io::ErrorKind::NotFound) => return Err(
                anyhow::Error::msg(format!("pijul log couldn't find a file or directory corresponding to `{}`", pat))
            ),
            Err(e) => return Err(e.into()),
            Ok(p) => p
        };
        match canon_path.strip_prefix(repo_path) {
            Err(_) => return Err(anyhow::Error::msg(
                format!("pijul log couldn't assemble file prefix for pattern `{}`", pat)
            )),
            Ok(stripped) => { *pat = format!("{}", stripped.display()); },
        };
    }
    debug!("log filters: {:#?}\n", pats);
    Ok(pats)

/// Figure out whether a given change touched one of the files
/// the user is filtering for.
fn filter_hit(
    filters: &[String],
    h: libpijul::Hash,
    changes: &filesystem::FileSystem
) -> Result<bool, anyhow::Error> {
    match changes.filename(&h).to_str() {
        None => return Err(anyhow::Error::msg(format!("internal error: changefile had non-utf8 name"))),
        Some(changefile_name) => {
            let changefile = libpijul::change::ChangeFile::open(h, changefile_name)?;
            if changefile.hashed().changes.iter().any(|hunk| {
                filters.iter().any(|f| hunk.path().starts_with(f) || hunk.path() == f)
            }) {
                return Ok(true)
            }
            Ok(false)
        }
    }
}

        let log_filters = mk_filters(repo.path.as_ref(), self.filters)?;

                writeln!(stdout, "Change {}", h.to_base32())?;
                writeln!(stdout, "Author: {:?}", header.authors)?;
                writeln!(stdout, "Date: {}", header.timestamp)?;
                if states {
                    writeln!(stdout, "State: {}", mrk.to_base32())?;
                }
                writeln!(stdout, "\n    {}\n", header.message)?;
                if self.descriptions {
                    if let Some(ref descr) = header.description {
                        writeln!(stdout, "\n    {}\n", descr)?;

                if log_filters.is_empty() || filter_hit(log_filters.as_slice(), h, &changes)? {
                    writeln!(stdout, "Change {}", h.to_base32())?;
                    writeln!(stdout, "Author: {:?}", header.authors)?;
                    writeln!(stdout, "Date: {}", header.timestamp)?;
                    if states {
                        writeln!(stdout, "State: {}", mrk.to_base32())?;
                    }
                    writeln!(stdout, "\n    {}\n", header.message)?;
                    if self.descriptions {
                        if let Some(ref descr) = header.description {
                            writeln!(stdout, "\n    {}\n", descr)?;
                        }