use crate::commands::Command;
use crate::error::CommandError;
use crate::ui::Ui;
use hg::operations::list_rev_tracked_files;
use hg::operations::Dirstate;
use hg::repo::Repo;
use hg::utils::files::{get_bytes_from_path, relativize_path};
use hg::utils::hg_path::{HgPath, HgPathBuf};

pub const HELP_TEXT: &str = "
List tracked files.

Returns 0 on success.
";

pub struct FilesCommand<'a> {
    rev: Option<&'a str>,
}

impl<'a> FilesCommand<'a> {
    pub fn new(rev: Option<&'a str>) -> Self {
        FilesCommand { rev }
    }

    fn display_files(
        &self,
        ui: &Ui,
        repo: &Repo,
        files: impl IntoIterator<Item = &'a HgPath>,
    ) -> Result<(), CommandError> {
        let cwd = hg::utils::current_dir()?;
        let rooted_cwd = cwd
            .strip_prefix(repo.working_directory_path())
            .expect("cwd was already checked within the repository");
        let rooted_cwd = HgPathBuf::from(get_bytes_from_path(rooted_cwd));

        let mut stdout = ui.stdout_buffer();

        for file in files {
            stdout.write_all(relativize_path(file, &rooted_cwd).as_ref())?;
            stdout.write_all(b"\n")?;
        }
        stdout.flush()?;
        Ok(())
    }
}

impl<'a> Command for FilesCommand<'a> {
    fn run(&self, ui: &Ui) -> Result<(), CommandError> {
        let repo = Repo::find()?;
        if let Some(rev) = self.rev {
            let files =
                list_rev_tracked_files(&repo, rev).map_err(|e| (e, rev))?;
            self.display_files(ui, &repo, files.iter())
        } else {
            let distate = Dirstate::new(&repo)?;
            let files = distate.tracked_files()?;
            self.display_files(ui, &repo, files)
        }
    }
}