use crate::commands::Command;
use crate::error::CommandError;
use crate::ui::utf8_to_local;
use crate::ui::Ui;
use hg::operations::{list_rev_tracked_files, ListRevTrackedFilesError};
use hg::operations::{Dirstate, ListDirstateTrackedFilesError};
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 = std::env::current_dir()
            .or_else(|e| Err(CommandError::CurrentDirNotFound(e)))?;
        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()?;
        repo.check_requirements()?;
        if let Some(rev) = self.rev {
            let files = list_rev_tracked_files(&repo, rev)
                .map_err(|e| map_rev_error(rev, e))?;
            self.display_files(ui, &repo, files.iter())
        } else {
            let distate = Dirstate::new(&repo).map_err(map_dirstate_error)?;
            let files = distate.tracked_files().map_err(map_dirstate_error)?;
            self.display_files(ui, &repo, files)
        }
    }
}

/// Convert `ListRevTrackedFilesError` to `CommandError`
fn map_rev_error(rev: &str, err: ListRevTrackedFilesError) -> CommandError {
    match err {
        ListRevTrackedFilesError::IoError(err) => CommandError::Abort(Some(
            utf8_to_local(&format!("abort: {}\n", err)).into(),
        )),
        ListRevTrackedFilesError::InvalidRevision => {
            CommandError::Abort(Some(
                utf8_to_local(&format!(
                    "abort: invalid revision identifier {}\n",
                    rev
                ))
                .into(),
            ))
        }
        ListRevTrackedFilesError::AmbiguousPrefix => {
            CommandError::Abort(Some(
                utf8_to_local(&format!(
                    "abort: ambiguous revision identifier {}\n",
                    rev
                ))
                .into(),
            ))
        }
        ListRevTrackedFilesError::UnsuportedRevlogVersion(version) => {
            CommandError::Abort(Some(
                utf8_to_local(&format!(
                    "abort: unsupported revlog version {}\n",
                    version
                ))
                .into(),
            ))
        }
        ListRevTrackedFilesError::CorruptedRevlog => {
            CommandError::Abort(Some("abort: corrupted revlog\n".into()))
        }
        ListRevTrackedFilesError::UnknowRevlogDataFormat(format) => {
            CommandError::Abort(Some(
                utf8_to_local(&format!(
                    "abort: unknow revlog dataformat {:?}\n",
                    format
                ))
                .into(),
            ))
        }
    }
}

/// Convert `ListDirstateTrackedFilesError` to `CommandError`
fn map_dirstate_error(err: ListDirstateTrackedFilesError) -> CommandError {
    match err {
        ListDirstateTrackedFilesError::IoError(err) => CommandError::Abort(
            Some(utf8_to_local(&format!("abort: {}\n", err)).into()),
        ),
        ListDirstateTrackedFilesError::ParseError(_) => {
            CommandError::Abort(Some(
                // TODO find a better error message
                b"abort: parse error\n".to_vec(),
            ))
        }
    }
}