use std::io;
use std::path::{self, Path, PathBuf};
use std::result::Result as StdResult;

use git2::{
    BranchType, Commit, DescribeOptions, Oid, Repository as GitRepository, Sort, TreeWalkMode,
    Worktree,
};
use glob::Pattern;
use indexmap::IndexMap;
use lazy_regex::{Lazy, Regex, lazy_regex};
use url::Url;

use crate::config::Remote;
use crate::error::{Error, Result};
use crate::tag::Tag;

/// Regex for replacing the signature part of a tag message.
static TAG_SIGNATURE_REGEX: Lazy<Regex> = lazy_regex!(
    // https://git-scm.com/docs/gitformat-signature#_description
    r"(?s)-----BEGIN (PGP|SSH|SIGNED) (SIGNATURE|MESSAGE)-----(.*?)-----END (PGP|SSH|SIGNED) (SIGNATURE|MESSAGE)-----"
);

/// Name of the cache file for changed files.
const CHANGED_FILES_CACHE: &str = "changed_files_cache";

/// Wrapper for [`Repository`] type from git2.
///
/// [`Repository`]: GitRepository
pub struct Repository {
    inner: GitRepository,
    /// Repository path.
    path: PathBuf,
    /// Cache path for the changed files of the commits.
    changed_files_cache_path: PathBuf,
}

/// Range of commits in a submodule.
pub struct SubmoduleRange {
    /// Repository object to which this range belongs.
    pub repository: Repository,
    /// Commit range in "FIRST..LAST" or "LAST" format, where FIRST is
    /// the first submodule commit and LAST is the last submodule commit.
    pub range: String,
}

impl Repository {
    /// Opens a repository from the given path.
    ///
    /// If `search_parents` is true, it will traverse up through parent
    /// directories to find a repository.
    fn open(path: PathBuf, search_parents: bool) -> Result<Self> {
        if !path.exists() {
            return Err(Error::IoError(io::Error::new(
                io::ErrorKind::NotFound,
                format!("repository path not found: {}", path.display()),
            )));
        }

        let inner = GitRepository::open(&path)
            .or_else(|err| {
                // Optionally search for a Jujutsu repository layout
                let mut current = Some(path.as_path());
                while let Some(dir) = current {
                    let jujutsu_path = dir.join(".jj/repo/store/git");
                    if jujutsu_path.exists() {
                        return GitRepository::open_bare(&jujutsu_path);
                    }
                    // Only continue searching if enabled
                    if !search_parents {
                        break;
                    }
                    current = dir.parent();
                }
                Err(err)
            })
            // If still not found, try discover if traversal is enabled
            .or_else(|err| {
                if search_parents {
                    GitRepository::discover(&path)
                } else {
                    Err(err)
                }
            })?;

        let changed_files_cache_path = inner
            .path()
            .join(env!("CARGO_PKG_NAME"))
            .join(CHANGED_FILES_CACHE);

        Ok(Self {
            inner,
            path,
            changed_files_cache_path,
        })
    }

    /// Discover a repository from the given path by traversing up through
    /// parent directories.
    ///
    /// It first looks for a Git repository using [`GitRepository::discover`].
    /// If no Git repository is found, it checks for a Jujutsu repository layout
    /// (`.jj/repo/store/git`) in this directory and its parents.
    pub fn discover(path: PathBuf) -> Result<Self> {
        Self::open(path, true)
    }

    /// Attempts to open an already-existing repository at the given path.
    ///
    /// It tries to open the repository as a normal or bare Git repository located
    /// exactly at `path`. If that fails, it falls back to checking for a Jujutsu
    /// repository layout (`.jj/repo/store/git`) **only in the specified directory**.
    pub fn init(path: PathBuf) -> Result<Self> {
        Self::open(path, false)
    }

    /// Returns the path of the repository.
    pub fn root_path(&self) -> Result<PathBuf> {
        let mut path = if self.inner.is_worktree() {
            let worktree = Worktree::open_from_repository(&self.inner)?;
            worktree.path().to_path_buf()
        } else {
            self.inner.path().to_path_buf()
        };
        if path.ends_with(".git") {
            path.pop();
        }
        Ok(path)
    }

    /// Returns the initial path of the repository.
    ///
    /// In case of a submodule this is the relative path to the toplevel
    /// repository.
    #[must_use]
    pub fn path(&self) -> &PathBuf {
        &self.path
    }

    /// Sets the range for the commit search.
    ///
    /// When a single SHA is provided as the range, start from the
    /// root.
    fn set_commit_range(
        revwalk: &mut git2::Revwalk<'_>,
        range: Option<&str>,
    ) -> StdResult<(), git2::Error> {
        if let Some(range) = range {
            if range.contains("..") {
                revwalk.push_range(range)?;
            } else {
                revwalk.push(Oid::from_str(range)?)?;
            }
        } else {
            revwalk.push_head()?;
        }
        Ok(())
    }

    /// Parses and returns the commits.
    ///
    /// Sorts the commits by their time.
    pub fn commits(
        &self,
        range: Option<&str>,
        include_path: Option<Vec<Pattern>>,
        exclude_path: Option<Vec<Pattern>>,
        topo_order_commits: bool,
    ) -> Result<Vec<Commit<'_>>> {
        let mut revwalk = self.inner.revwalk()?;
        if topo_order_commits {
            revwalk.set_sorting(Sort::TOPOLOGICAL)?;
        } else {
            revwalk.set_sorting(Sort::TIME)?;
        }

        Self::set_commit_range(&mut revwalk, range).map_err(|e| {
            Error::SetCommitRangeError(range.map_or_else(|| "?".to_string(), String::from), e)
        })?;
        let mut commits: Vec<Commit> = revwalk
            .filter_map(StdResult::ok)
            .filter_map(|id| self.inner.find_commit(id).ok())
            .collect();
        if include_path.is_some() || exclude_path.is_some() {
            let include_patterns = include_path
                .map(|patterns| patterns.into_iter().map(Self::normalize_pattern).collect());
            let exclude_patterns = exclude_path
                .map(|patterns| patterns.into_iter().map(Self::normalize_pattern).collect());
            commits.retain(|commit| {
                self.should_retain_commit(commit, &include_patterns, &exclude_patterns)
            });
        }
        Ok(commits)
    }

    /// Returns submodule repositories for a given commit range.
    ///
    /// For one or two given commits in this repository, a list of changed
    /// submodules is calculated. If only one commit is given, then all
    /// submodule commits up to the referenced commit will be included. This is
    /// usually the case if a submodule is added to the repository.
    ///
    ///  For each submodule a [`SubmoduleRange`] object is created
    ///
    /// This can then be used to query the submodule's commits by using
    /// [`Repository::commits`].
    pub fn submodules_range(
        &self,
        old_commit: Option<Commit<'_>>,
        new_commit: Commit<'_>,
    ) -> Result<Vec<SubmoduleRange>> {
        let old_tree = old_commit.and_then(|commit| commit.tree().ok());
        let new_tree = new_commit.tree().ok();
        let diff = self
            .inner
            .diff_tree_to_tree(old_tree.as_ref(), new_tree.as_ref(), None)?;
        // iterate through all diffs and accumulate old/new commit ids
        let before_and_after_deltas = diff.deltas().filter_map(|delta| {
            let old_file_id = delta.old_file().id();
            let new_file_id = delta.new_file().id();
            let range = if old_file_id == new_file_id || new_file_id.is_zero() {
                // no changes or submodule removed
                None
            } else if old_file_id.is_zero() {
                // submodule added
                Some(new_file_id.to_string())
            } else {
                // submodule updated
                Some(format!("{old_file_id}..{new_file_id}"))
            };
            log::trace!("Release commit range for submodules: {range:?}");
            delta.new_file().path().and_then(Path::to_str).zip(range)
        });
        // iterate through all path diffs and find corresponding submodule if
        // possible
        let submodule_range = before_and_after_deltas.filter_map(|(path, range)| {
            // NOTE:
            // libgit2 recommends using `git_submodule_open`, whereas `git_repository_discover` is
            // used here. Since it seems to be working fine for now, we don't think we
            // should change this. Just leaving this message as a reminder.
            let repository = self
                .inner
                .find_submodule(path)
                .ok()
                .and_then(|submodule| Self::discover(submodule.path().into()).ok());
            repository.map(|repository| SubmoduleRange { repository, range })
        });
        Ok(submodule_range.collect())
    }

    /// Normalizes the glob pattern to match the git diff paths.
    ///
    /// It removes the leading `./` and adds `**` to the end if the pattern is a
    /// directory.
    fn normalize_pattern(pattern: Pattern) -> Pattern {
        let star_added = if pattern.as_str().ends_with(path::MAIN_SEPARATOR) {
            Pattern::new(&format!("{pattern}**")).expect("failed to add '**' to the end of glob")
        } else {
            pattern
        };
        match star_added.as_str().strip_prefix("./") {
            Some(stripped) => {
                Pattern::new(stripped).expect("failed to remove leading ./ from glob")
            }
            None => star_added,
        }
    }

    /// Calculates whether the commit should be retained or not.
    ///
    /// This function is used to filter the commits based on the changed files,
    /// and include/exclude patterns.
    fn should_retain_commit(
        &self,
        commit: &Commit,
        include_patterns: &Option<Vec<Pattern>>,
        exclude_patterns: &Option<Vec<Pattern>>,
    ) -> bool {
        let changed_files = self.commit_changed_files(commit);
        match (include_patterns, exclude_patterns) {
            (Some(include_pattern), Some(exclude_pattern)) => {
                // check if the commit has any changed files that match any of the
                // include patterns and none of the exclude patterns.
                changed_files.iter().any(|path| {
                    include_pattern
                        .iter()
                        .any(|pattern| pattern.matches_path(path)) &&
                        !exclude_pattern
                            .iter()
                            .any(|pattern| pattern.matches_path(path))
                })
            }
            (Some(include_pattern), None) => {
                // check if the commit has any changed files that match the include
                // patterns.
                changed_files.iter().any(|path| {
                    include_pattern
                        .iter()
                        .any(|pattern| pattern.matches_path(path))
                })
            }
            (None, Some(exclude_pattern)) => {
                // check if the commit has at least one changed file that does not
                // match all exclude patterns.
                changed_files.iter().any(|path| {
                    !exclude_pattern
                        .iter()
                        .any(|pattern| pattern.matches_path(path))
                })
            }
            (None, None) => true,
        }
    }

    /// Returns the changed files of the commit.
    ///
    /// It uses a cache to speed up checks to store the changed files of the
    /// commits under `./.git/git-cliff-core/changed_files_cache`. The speed-up
    /// was measured to be around 260x for large repositories.
    ///
    /// If the cache is not found, it calculates the changed files and adds them
    /// to the cache via [`Self::commit_changed_files_no_cache`].
    fn commit_changed_files(&self, commit: &Commit) -> Vec<PathBuf> {
        // Cache key is generated from the repository path and commit id
        let cache_key = format!("commit_id:{}", commit.id());

        // Check the cache first.
        {
            if let Ok(result) = cacache::read_sync(&self.changed_files_cache_path, &cache_key) {
                if let Ok((files, _)) =
                    bincode::decode_from_slice(&result, bincode::config::standard())
                {
                    return files;
                }
            }
        }

        // If the cache is not found, calculate the result and set it to the cache.
        let result = self.commit_changed_files_no_cache(commit);
        match bincode::encode_to_vec(
            self.commit_changed_files_no_cache(commit),
            bincode::config::standard(),
        ) {
            Ok(v) => {
                if let Err(e) = cacache::write_sync_with_algo(
                    cacache::Algorithm::Xxh3,
                    &self.changed_files_cache_path,
                    cache_key,
                    v,
                ) {
                    log::error!("Failed to set cache for repo {:?}: {e}", self.path);
                }
            }
            Err(e) => {
                log::error!("Failed to serialize cache for repo {:?}: {e}", self.path);
            }
        }

        result
    }

    /// Calculate the changed files of the commit.
    ///
    /// This function does not use the cache (directly calls git2).
    fn commit_changed_files_no_cache(&self, commit: &Commit) -> Vec<PathBuf> {
        let mut changed_files = Vec::new();
        if let Ok(prev_commit) = commit.parent(0) {
            // Compare the current commit with the previous commit to get the
            // changed files.
            // libgit2 does not provide a way to get the changed files directly, so
            // the full diff is calculated here.
            if let Ok(diff) = self.inner.diff_tree_to_tree(
                commit.tree().ok().as_ref(),
                prev_commit.tree().ok().as_ref(),
                None,
            ) {
                changed_files.extend(
                    diff.deltas()
                        .filter_map(|delta| delta.new_file().path().map(PathBuf::from)),
                );
            }
        } else {
            // If there is no parent, it is the first commit.
            // So get all the files in the tree.
            if let Ok(tree) = commit.tree() {
                tree.walk(TreeWalkMode::PreOrder, |dir, entry| {
                    if entry.kind().expect("failed to get entry kind") != git2::ObjectType::Blob {
                        return 0;
                    }
                    let name = entry.name().expect("failed to get entry name");
                    let entry_path = if dir == "," {
                        name.to_string()
                    } else {
                        format!("{dir}/{name}")
                    };
                    changed_files.push(entry_path.into());
                    0
                })
                .expect("failed to get the changed files of the first commit");
            }
        }
        changed_files
    }

    /// Returns the current tag.
    ///
    /// It is the same as running `git describe --tags`
    #[must_use]
    pub fn current_tag(&self) -> Option<Tag> {
        self.inner
            .describe(DescribeOptions::new().describe_tags())
            .ok()
            .and_then(|describe| {
                describe
                    .format(None)
                    .ok()
                    .map(|name| self.resolve_tag(&name))
            })
    }

    /// Returns the tag object of the given name.
    ///
    /// If given name doesn't exist, it still returns `Tag` with the given name.
    #[must_use]
    pub fn resolve_tag(&self, name: &str) -> Tag {
        match self
            .inner
            .resolve_reference_from_short_name(name)
            .and_then(|r| r.peel_to_tag())
        {
            Ok(tag) => Tag {
                name: tag.name().unwrap_or_default().to_owned(),
                message: tag
                    .message()
                    .map(|msg| TAG_SIGNATURE_REGEX.replace(msg, "").trim().to_owned()),
            },
            _ => Tag {
                name: name.to_owned(),
                message: None,
            },
        }
    }

    /// Returns the commit object of the given ID.
    #[must_use]
    pub fn find_commit(&self, id: &str) -> Option<Commit<'_>> {
        if let Ok(oid) = Oid::from_str(id) {
            if let Ok(commit) = self.inner.find_commit(oid) {
                return Some(commit);
            }
        }
        None
    }

    /// Decide whether to include tag.
    ///
    /// `head_commit` is the `latest` commit to generate changelog. It can be a
    /// branch head or a detached head. `tag_commit` is a tagged commit. If the
    /// commit is in the descendant graph of the `head_commit` or is the
    /// `head_commit` itself, Changelog should include the tag.
    fn should_include_tag(&self, head_commit: &Commit, tag_commit: &Commit) -> Result<bool> {
        Ok(self
            .inner
            .graph_descendant_of(head_commit.id(), tag_commit.id())? ||
            head_commit.id() == tag_commit.id())
    }

    /// Parses and returns a commit-tag map.
    ///
    /// It collects lightweight and annotated tags.
    pub fn tags(
        &self,
        pattern: &Option<Regex>,
        topo_order: bool,
        use_branch_tags: bool,
    ) -> Result<IndexMap<String, Tag>> {
        let mut tags: Vec<(Commit, Tag)> = Vec::new();
        let tag_names = self.inner.tag_names(None)?;
        let head_commit = self.inner.head()?.peel_to_commit()?;
        for name in tag_names
            .iter()
            .flatten()
            .filter(|tag_name| pattern.as_ref().is_none_or(|pat| pat.is_match(tag_name)))
            .map(String::from)
        {
            let obj = self.inner.revparse_single(&name)?;
            if let Ok(commit) = obj.clone().into_commit() {
                if use_branch_tags && !self.should_include_tag(&head_commit, &commit)? {
                    continue;
                }

                tags.push((commit, Tag {
                    name,
                    message: None,
                }));
            } else if let Some(tag) = obj.as_tag() {
                if let Some(commit) = tag
                    .target()
                    .ok()
                    .and_then(|target| target.into_commit().ok())
                {
                    if use_branch_tags && !self.should_include_tag(&head_commit, &commit)? {
                        continue;
                    }
                    tags.push((commit, Tag {
                        name: tag.name().map(String::from).unwrap_or(name),
                        message: tag
                            .message()
                            .map(|msg| TAG_SIGNATURE_REGEX.replace(msg, "").trim().to_owned()),
                    }));
                }
            }
        }
        if !topo_order {
            tags.sort_by(|a, b| a.0.time().seconds().cmp(&b.0.time().seconds()));
        }
        Ok(tags
            .into_iter()
            .map(|(a, b)| (a.id().to_string(), b))
            .collect())
    }

    /// Returns the remote of the upstream repository.
    ///
    /// The strategy used here is the following:
    ///
    /// Find the branch that HEAD points to, and read the remote configured for
    /// that branch returns the remote and the name of the local branch.
    ///
    /// Note: HEAD must not be detached.
    pub fn upstream_remote(&self) -> Result<Remote> {
        for branch in self.inner.branches(Some(BranchType::Local))? {
            let branch = branch?.0;
            if branch.is_head() {
                let upstream = &self.inner.branch_upstream_remote(&format!(
                    "refs/heads/{}",
                    &branch.name()?.ok_or_else(|| Error::RepoError(String::from(
                        "branch name is not valid"
                    )))?
                ))?;
                let upstream_name = upstream.as_str().ok_or_else(|| {
                    Error::RepoError(String::from("name of the upstream remote is not valid"))
                })?;
                let origin = &self.inner.find_remote(upstream_name)?;
                let url = origin
                    .url()
                    .ok_or_else(|| Error::RepoError(String::from("failed to get the remote URL")))?
                    .to_string();
                log::trace!("Upstream URL: {url}");
                return find_remote(&url);
            }
        }
        Err(Error::RepoError(String::from(
            "no remotes configured or HEAD is detached",
        )))
    }
}

fn find_remote(url: &str) -> Result<Remote> {
    url_path_segments(url).or_else(|err| {
        if url.contains('@') && url.contains(':') && url.contains('/') {
            ssh_path_segments(url)
        } else {
            Err(err)
        }
    })
}

/// Returns the Remote from parsing the HTTPS format URL.
///
/// This function expects the URL to be in the following format:
///
/// ```text
/// https://hostname/query/path.git
/// ```
fn url_path_segments(url: &str) -> Result<Remote> {
    let parsed_url = Url::parse(url.strip_suffix(".git").unwrap_or(url))?;
    let segments: Vec<&str> = parsed_url
        .path_segments()
        .ok_or_else(|| Error::RepoError(String::from("failed to get URL segments")))?
        .rev()
        .collect();
    let [repo, owner, ..] = &segments[..] else {
        return Err(Error::RepoError(String::from(
            "failed to get the owner and repo",
        )));
    };
    Ok(Remote {
        owner: owner.to_string(),
        repo: repo.to_string(),
        token: None,
        is_custom: false,
        api_url: None,
        native_tls: None,
    })
}

/// Returns the Remote from parsing the SSH format URL.
///
/// This function expects the URL to be in the following format:
///
/// > git@hostname:owner/repo.git
fn ssh_path_segments(url: &str) -> Result<Remote> {
    let [_, owner_repo, ..] = url
        .strip_suffix(".git")
        .unwrap_or(url)
        .split(':')
        .collect::<Vec<_>>()[..]
    else {
        return Err(Error::RepoError(String::from(
            "failed to get the owner and repo from ssh remote (:)",
        )));
    };
    let [owner, repo] = owner_repo.split('/').collect::<Vec<_>>()[..] else {
        return Err(Error::RepoError(String::from(
            "failed to get the owner and repo from ssh remote (/)",
        )));
    };
    Ok(Remote {
        owner: owner.to_string(),
        repo: repo.to_string(),
        token: None,
        is_custom: false,
        api_url: None,
        native_tls: None,
    })
}

#[cfg(test)]
mod test {
    use std::process::Command;
    use std::{env, fs, io, str};

    use temp_dir::TempDir;

    use super::*;
    use crate::commit::Commit as AppCommit;

    fn get_last_commit_hash() -> Result<String> {
        Ok(str::from_utf8(
            Command::new("git")
                .args(["log", "--pretty=format:'%H'", "-n", "1"])
                .output()?
                .stdout
                .as_ref(),
        )?
        .trim_matches('\'')
        .to_string())
    }

    fn get_root_commit_hash() -> Result<String> {
        Ok(str::from_utf8(
            Command::new("git")
                .args(["rev-list", "--max-parents=0", "HEAD"])
                .output()?
                .stdout
                .as_ref(),
        )?
        .trim_ascii_end()
        .to_string())
    }

    fn get_last_tag() -> Result<String> {
        Ok(str::from_utf8(
            Command::new("git")
                .args(["describe", "--abbrev=0"])
                .output()?
                .stdout
                .as_ref(),
        )?
        .trim()
        .to_string())
    }

    fn get_repository() -> Result<Repository> {
        Repository::discover(
            PathBuf::from(env!("CARGO_MANIFEST_DIR"))
                .parent()
                .expect("parent directory not found")
                .to_path_buf(),
        )
    }

    #[test]
    fn http_url_repo_owner() -> Result<()> {
        let url = "https://hostname.com/bob/magic.git";
        let remote = find_remote(url)?;
        assert_eq!(remote.owner, "bob", "match owner");
        assert_eq!(remote.repo, "magic", "match repo");
        Ok(())
    }

    #[test]
    fn ssh_url_repo_owner() -> Result<()> {
        let url = "git@hostname.com:bob/magic.git";
        let remote = find_remote(url)?;
        assert_eq!(remote.owner, "bob", "match owner");
        assert_eq!(remote.repo, "magic", "match repo");
        Ok(())
    }

    #[test]
    fn get_latest_commit() -> Result<()> {
        let repository = get_repository()?;
        let commits = repository.commits(None, None, None, false)?;
        let last_commit = AppCommit::from(&commits.first().expect("no commits found").clone());
        assert_eq!(get_last_commit_hash()?, last_commit.id);
        Ok(())
    }

    #[test]
    fn commit_search() -> Result<()> {
        let repository = get_repository()?;
        assert!(
            repository
                .find_commit("e936ed571533ea6c41a1dd2b1a29d085c8dbada5")
                .is_some()
        );
        Ok(())
    }

    #[test]
    fn get_latest_tag() -> Result<()> {
        let repository = get_repository()?;
        let tags = repository.tags(&None, false, false)?;
        let latest = tags.last().expect("no tags found").1.name.clone();
        assert_eq!(get_last_tag()?, latest);

        let current = repository.current_tag().expect("a current tag").name;
        assert!(current.contains(&latest));
        Ok(())
    }

    #[test]
    fn git_tags() -> Result<()> {
        let repository = get_repository()?;
        let tags = repository.tags(&None, true, false)?;
        assert_eq!(
            tags.get("2b8b4d3535f29231e05c3572e919634b9af907b6")
                .expect("the commit hash does not exist in the repository (tag v0.1.0)")
                .name,
            "v0.1.0"
        );
        assert_eq!(
            tags.get("4ddef08debfff48117586296e49d5caa0800d1b5")
                .expect("the commit hash does not exist in the repository (tag v0.1.0-beta.4)")
                .name,
            "v0.1.0-beta.4"
        );
        let tags = repository.tags(
            &Some(Regex::new("^v[0-9]+\\.[0-9]+\\.[0-9]$").expect("the regex is not valid")),
            true,
            false,
        )?;
        assert_eq!(
            tags.get("2b8b4d3535f29231e05c3572e919634b9af907b6")
                .expect("the commit hash does not exist in the repository (tag v0.1.0)")
                .name,
            "v0.1.0"
        );
        assert!(!tags.contains_key("4ddef08debfff48117586296e49d5caa0800d1b5"));
        Ok(())
    }

    #[test]
    fn git_upstream_remote() -> Result<()> {
        let repository = get_repository()?;
        let remote = repository.upstream_remote()?;
        assert_eq!(
            Remote {
                owner: remote.owner.clone(),
                repo: String::from("git-cliff"),
                token: None,
                is_custom: false,
                api_url: remote.api_url.clone(),
                native_tls: None,
            },
            remote
        );
        Ok(())
    }

    #[test]
    fn resolves_existing_tag_with_name_and_message() -> Result<()> {
        let repository = get_repository()?;
        let tag = repository.resolve_tag("v0.2.3");
        assert_eq!(tag.name, "v0.2.3");
        assert_eq!(
            tag.message,
            Some(
                "Release v0.2.3\n\nBug Fixes\n- Fetch the dependencies before copying the file to \
                 embed (9e29c95)"
                    .to_string()
            )
        );

        Ok(())
    }

    #[test]
    fn resolves_tag_when_no_tags_exist() -> Result<()> {
        let repository = get_repository()?;
        let tag = repository.resolve_tag("nonexistent-tag");
        assert_eq!(tag.name, "nonexistent-tag");
        assert_eq!(tag.message, None);
        Ok(())
    }

    #[test]
    fn includes_root_commit() -> Result<()> {
        let repository = get_repository()?;
        // a close descendant of the root commit
        let range = Some("eea3914c7ab07472841aa85c36d11bdb2589a234");
        let commits = repository.commits(range, None, None, false)?;
        let root_commit = AppCommit::from(&commits.last().expect("no commits found").clone());
        assert_eq!(get_root_commit_hash()?, root_commit.id);
        Ok(())
    }

    fn create_temp_repo() -> (Repository, TempDir) {
        let temp_dir = TempDir::with_prefix("git-cliff-").expect("failed to create temp dir");

        let output = Command::new("git")
            .args(["init"])
            .current_dir(temp_dir.path())
            .output()
            .expect("failed to execute git init");
        assert!(output.status.success(), "git init failed {output:?}");

        let repo =
            Repository::discover(temp_dir.path().to_path_buf()).expect("failed to init repo");
        let output = Command::new("git")
            .args(["config", "user.email", "test@gmail.com"])
            .current_dir(temp_dir.path())
            .output()
            .expect("failed to execute git config user.email");
        assert!(
            output.status.success(),
            "git config user.email failed {output:?}",
        );

        let output = Command::new("git")
            .args(["config", "user.name", "test"])
            .current_dir(temp_dir.path())
            .output()
            .expect("failed to execute git config user.name");
        assert!(
            output.status.success(),
            "git config user.name failed {output:?}",
        );

        (repo, temp_dir)
    }

    #[test]
    fn repository_path_not_found() {
        let path = PathBuf::from("/this/path/should/not/exist/123456789");
        let result = Repository::discover(path.clone());
        assert!(result.is_err());
        match result {
            Err(Error::IoError(err)) => {
                assert_eq!(err.kind(), io::ErrorKind::NotFound);
                assert!(err.to_string().contains("repository path not found"));
            }
            _ => panic!("expected IoError(NotFound)"),
        }
    }

    #[test]
    fn discover_jujutsu_repo() {
        let (repo, _temp_dir) = create_temp_repo();
        // working copy is the directory that contains the .git directory:
        let working_copy = repo.path;

        // Make the Git repository bare and set HEAD
        std::process::Command::new("git")
            .args(["config", "core.bare", "true"])
            .current_dir(&working_copy)
            .status()
            .expect("failed to make git repo non-bare");
        // Move the Git repo into jj
        let store = working_copy.join(".jj").join("repo").join("store");
        fs::create_dir_all(&store).expect("failed to create dir");
        fs::rename(working_copy.join(".git"), store.join("git")).expect("failed to move git repo");

        // Open repo from working copy, that contains the .jj directory
        let repo = Repository::discover(working_copy).expect("failed to init repo");

        // macOS canonical path for temp directories is in /private
        // libgit2 forces the path to be canonical regardless of what we pass in
        if repo.inner.path().starts_with("/private") {
            assert_eq!(
                repo.inner.path().strip_prefix("/private"),
                store.join("git").strip_prefix("/"),
                "open git repo in .jj/repo/store/"
            );
        } else {
            assert_eq!(
                repo.inner.path(),
                store.join("git"),
                "open git repo in .jj/repo/store/"
            );
        }
    }

    #[test]
    fn propagate_error_if_no_repo_found() {
        let temp_dir = TempDir::with_prefix("git-cliff-").expect("failed to create temp dir");

        let path = temp_dir.path().to_path_buf();

        let result = Repository::discover(path.clone());

        assert!(result.is_err());
        if let Err(error) = result {
            assert!(
                format!("{error:?}").contains(
                    format!("could not find repository at '{}'", path.display()).as_str()
                )
            )
        }
    }

    #[test]
    fn repository_path_does_not_exist() {
        let path = PathBuf::from("/this/path/should/not/exist/123456789");
        let result = Repository::init(path.clone());
        assert!(result.is_err());
        match result {
            Err(Error::IoError(err)) => {
                assert_eq!(err.kind(), io::ErrorKind::NotFound);
                assert!(err.to_string().contains("repository path not found"));
            }
            _ => panic!("expected IoError(NotFound)"),
        }
    }

    #[test]
    fn open_jujutsu_repo() {
        let (repo, _temp_dir) = create_temp_repo();
        // working copy is the directory that contains the .git directory:
        let working_copy = repo.path;

        // Make the Git repository bare and set HEAD
        Command::new("git")
            .args(["config", "core.bare", "true"])
            .current_dir(&working_copy)
            .status()
            .expect("failed to make git repo non-bare");

        // Move the Git repo into jj
        let store = working_copy.join(".jj").join("repo").join("store");
        fs::create_dir_all(&store).expect("failed to create dir");
        fs::rename(working_copy.join(".git"), store.join("git")).expect("failed to move git repo");

        // Open repo from working copy, that contains the .jj directory
        let repo = Repository::init(working_copy).expect("failed to init repo");

        // macOS canonical path for temp directories is in /private
        // libgit2 forces the path to be canonical regardless of what we pass in
        if repo.inner.path().starts_with("/private") {
            assert_eq!(
                repo.inner.path().strip_prefix("/private"),
                store.join("git").strip_prefix("/"),
                "open git repo in .jj/repo/store/"
            );
        } else {
            assert_eq!(
                repo.inner.path(),
                store.join("git"),
                "open git repo in .jj/repo/store/"
            );
        }
    }

    #[test]
    fn propagate_error_if_no_repo_exist() {
        let temp_dir = TempDir::with_prefix("git-cliff-").expect("failed to create temp dir");

        let path = temp_dir.path().to_path_buf();

        let result = Repository::init(path.clone());

        assert!(result.is_err());
        if let Err(error) = result {
            assert!(
                format!("{error:?}").contains(
                    format!("could not find repository at '{}'", path.display()).as_str()
                )
            )
        }
    }

    fn create_commit_with_files<'a>(
        repo: &'a Repository,
        files: Vec<(&'a str, &'a str)>,
    ) -> Commit<'a> {
        for (path, content) in files {
            if let Some(parent) = repo.path.join(path).parent() {
                std::fs::create_dir_all(parent).expect("failed to create dir");
            }
            std::fs::write(repo.path.join(path), content).expect("failed to write file");
        }

        let output = Command::new("git")
            .args(["add", "."])
            .current_dir(&repo.path)
            .output()
            .expect("failed to execute git add");
        assert!(output.status.success(), "git add failed {output:?}");

        let output = Command::new("git")
            .args(["commit", "--no-gpg-sign", "-m", "test commit"])
            .current_dir(&repo.path)
            .output()
            .expect("failed to execute git commit");
        assert!(output.status.success(), "git commit failed {output:?}");

        repo.inner
            .head()
            .and_then(|head| head.peel_to_commit())
            .expect("failed to get the last commit")
    }

    #[test]
    fn test_should_retain_commit() {
        let (repo, _temp_dir) = create_temp_repo();

        let new_pattern = |input: &str| {
            Repository::normalize_pattern(Pattern::new(input).expect("valid pattern"))
        };

        let first_commit = create_commit_with_files(&repo, vec![
            ("initial.txt", "initial content"),
            ("dir/initial.txt", "initial content"),
        ]);

        {
            let retain =
                repo.should_retain_commit(&first_commit, &Some(vec![new_pattern("dir/")]), &None);
            assert!(retain, "include: dir/");
        }

        let commit = create_commit_with_files(&repo, vec![
            ("file1.txt", "content1"),
            ("file2.txt", "content2"),
            ("dir/file3.txt", "content3"),
            ("dir/subdir/file4.txt", "content4"),
        ]);

        {
            let retain = repo.should_retain_commit(&commit, &None, &None);
            assert!(retain, "no include/exclude patterns");
        }

        {
            let retain = repo.should_retain_commit(&commit, &Some(vec![new_pattern("./")]), &None);
            assert!(retain, "include: ./");
        }

        {
            let retain = repo.should_retain_commit(&commit, &Some(vec![new_pattern("**")]), &None);
            assert!(retain, "include: **");
        }

        {
            let retain = repo.should_retain_commit(&commit, &Some(vec![new_pattern("*")]), &None);
            assert!(retain, "include: *");
        }

        {
            let retain =
                repo.should_retain_commit(&commit, &Some(vec![new_pattern("dir/")]), &None);
            assert!(retain, "include: dir/");
        }

        {
            let retain =
                repo.should_retain_commit(&commit, &Some(vec![new_pattern("dir/*")]), &None);
            assert!(retain, "include: dir/*");
        }

        {
            let retain =
                repo.should_retain_commit(&commit, &Some(vec![new_pattern("file1.txt")]), &None);
            assert!(retain, "include: file1.txt");
        }

        {
            let retain =
                repo.should_retain_commit(&commit, &None, &Some(vec![new_pattern("file1.txt")]));
            assert!(retain, "exclude: file1.txt");
        }

        {
            let retain = repo.should_retain_commit(
                &commit,
                &Some(vec![new_pattern("file1.txt")]),
                &Some(vec![new_pattern("file2.txt")]),
            );
            assert!(retain, "include: file1.txt, exclude: file2.txt");
        }

        {
            let retain =
                repo.should_retain_commit(&commit, &None, &Some(vec![new_pattern("**/*.txt")]));
            assert!(!retain, "exclude: **/*.txt");
        }
    }
}
