toolpath_git/

lib.rs

#![doc = include_str!("../README.md")]

// ============================================================================
// Public configuration and types (available on all targets)
// ============================================================================

/// Configuration for deriving Toolpath documents from a git repository.
pub struct DeriveConfig {
    /// Remote name for URI generation (e.g., "origin").
    pub remote: String,
    /// Optional title for graph output.
    pub title: Option<String>,
    /// Global base commit override (overrides per-branch starts).
    pub base: Option<String>,
}

/// Parsed branch specification.
///
/// Branches can be specified as `"name"` or `"name:start"` where `start` is a
/// revision expression indicating where the path should begin.
#[derive(Debug, Clone)]
pub struct BranchSpec {
    pub name: String,
    pub start: Option<String>,
}

impl BranchSpec {
    /// Parse a branch specification string.
    ///
    /// Format: `"name"` or `"name:start"`.
    pub fn parse(s: &str) -> Self {
        if let Some((name, start)) = s.split_once(':') {
            BranchSpec {
                name: name.to_string(),
                start: Some(start.to_string()),
            }
        } else {
            BranchSpec {
                name: s.to_string(),
                start: None,
            }
        }
    }
}

/// Summary information about a local branch.
#[derive(Debug, Clone)]
pub struct BranchInfo {
    /// Branch name (e.g., "main", "feature/foo").
    pub name: String,
    /// Short (8-char) hex of the tip commit.
    pub head_short: String,
    /// Full hex OID of the tip commit.
    pub head: String,
    /// First line of the tip commit message.
    pub subject: String,
    /// Author name of the tip commit.
    pub author: String,
    /// ISO 8601 timestamp of the tip commit.
    pub timestamp: String,
}

// ============================================================================
// Public utility functions (pure, available on all targets)
// ============================================================================

/// Normalize a git remote URL to a canonical short form.
///
/// Converts common hosting URLs to compact identifiers:
/// - `git@github.com:org/repo.git` -> `github:org/repo`
/// - `https://github.com/org/repo.git` -> `github:org/repo`
/// - `git@gitlab.com:org/repo.git` -> `gitlab:org/repo`
/// - `https://gitlab.com/org/repo.git` -> `gitlab:org/repo`
///
/// # Examples
///
/// ```
/// use toolpath_git::normalize_git_url;
///
/// assert_eq!(normalize_git_url("git@github.com:org/repo.git"), "github:org/repo");
/// assert_eq!(normalize_git_url("https://gitlab.com/org/repo"), "gitlab:org/repo");
///
/// // Unknown hosts pass through unchanged
/// assert_eq!(
///     normalize_git_url("https://bitbucket.org/org/repo"),
///     "https://bitbucket.org/org/repo",
/// );
/// ```
pub fn normalize_git_url(url: &str) -> String {
    if let Some(rest) = url.strip_prefix("git@github.com:") {
        let repo = rest.trim_end_matches(".git");
        return format!("github:{}", repo);
    }

    if let Some(rest) = url.strip_prefix("https://github.com/") {
        let repo = rest.trim_end_matches(".git");
        return format!("github:{}", repo);
    }

    if let Some(rest) = url.strip_prefix("git@gitlab.com:") {
        let repo = rest.trim_end_matches(".git");
        return format!("gitlab:{}", repo);
    }

    if let Some(rest) = url.strip_prefix("https://gitlab.com/") {
        let repo = rest.trim_end_matches(".git");
        return format!("gitlab:{}", repo);
    }

    // Return as-is for other URLs
    url.to_string()
}

/// Create a URL-safe slug from a git author name and email.
///
/// Prefers the email username; falls back to the name.
///
/// # Examples
///
/// ```
/// use toolpath_git::slugify_author;
///
/// assert_eq!(slugify_author("Alex Smith", "asmith@example.com"), "asmith");
/// assert_eq!(slugify_author("Alex Smith", "unknown"), "alex-smith");
/// ```
pub fn slugify_author(name: &str, email: &str) -> String {
    // Try to extract username from email
    if let Some(username) = email.split('@').next()
        && !username.is_empty()
        && username != email
    {
        return username
            .to_lowercase()
            .chars()
            .map(|c| if c.is_alphanumeric() { c } else { '-' })
            .collect();
    }

    // Fall back to name
    name.to_lowercase()
        .chars()
        .map(|c| if c.is_alphanumeric() { c } else { '-' })
        .collect::<String>()
        .trim_matches('-')
        .to_string()
}

// ============================================================================
// git2-dependent code (native targets only)
// ============================================================================

#[cfg(not(target_os = "emscripten"))]
mod native {
    use anyhow::{Context, Result};
    use chrono::{DateTime, Utc};
    use git2::{Commit, DiffOptions, Oid, Repository};
    use std::collections::HashMap;
    use toolpath::v1::{
        ActorDefinition, ArtifactChange, Base, Graph, GraphIdentity, GraphMeta, Identity, Path,
        PathIdentity, PathMeta, PathOrRef, Step, StepIdentity, StepMeta, VcsSource,
    };

    use super::{BranchInfo, BranchSpec, DeriveConfig};

    /// Derive a Toolpath [`Graph`] from the given repository and branch names.
    ///
    /// Branch strings are parsed as [`BranchSpec`]s (supporting `"name:start"` syntax).
    /// A single branch yields a single-path graph (one entry in `paths`); multiple
    /// branches yield a multi-path graph.
    pub fn derive(repo: &Repository, branches: &[String], config: &DeriveConfig) -> Result<Graph> {
        let branch_specs: Vec<BranchSpec> = branches.iter().map(|s| BranchSpec::parse(s)).collect();

        if branch_specs.len() == 1 {
            let path_doc = derive_path(repo, &branch_specs[0], config)?;
            Ok(Graph::from_path(path_doc))
        } else {
            derive_graph(repo, &branch_specs, config)
        }
    }

    /// Derive a Toolpath [`Path`] from a single branch specification.
    pub fn derive_path(
        repo: &Repository,
        spec: &BranchSpec,
        config: &DeriveConfig,
    ) -> Result<Path> {
        let repo_uri = get_repo_uri(repo, &config.remote)?;

        let branch_ref = repo
            .find_branch(&spec.name, git2::BranchType::Local)
            .with_context(|| format!("Branch '{}' not found", spec.name))?;
        let branch_commit = branch_ref.get().peel_to_commit()?;

        // Determine base commit
        let base_oid = if let Some(global_base) = &config.base {
            // Global base overrides per-branch
            let obj = repo
                .revparse_single(global_base)
                .with_context(|| format!("Failed to parse base ref '{}'", global_base))?;
            obj.peel_to_commit()?.id()
        } else if let Some(start) = &spec.start {
            // Per-branch start commit - resolve relative to the branch
            // e.g., "main:HEAD~5" means 5 commits before main's HEAD
            let start_ref = if let Some(rest) = start.strip_prefix("HEAD") {
                // Replace HEAD with the branch name for relative refs
                format!("{}{}", spec.name, rest)
            } else {
                start.clone()
            };
            let obj = repo.revparse_single(&start_ref).with_context(|| {
                format!(
                    "Failed to parse start ref '{}' (resolved to '{}') for branch '{}'",
                    start, start_ref, spec.name
                )
            })?;
            obj.peel_to_commit()?.id()
        } else {
            // Default: find merge-base with default branch
            find_base_for_branch(repo, &branch_commit)?
        };

        let base_commit = repo.find_commit(base_oid)?;

        // Collect commits from base to head
        let commits = collect_commits(repo, base_oid, branch_commit.id())?;

        // Generate steps and collect actor definitions
        let mut actors: HashMap<String, ActorDefinition> = HashMap::new();
        let steps = generate_steps(repo, &commits, base_oid, &mut actors)?;

        // Build path document
        let head_step_id = if steps.is_empty() {
            format!("step-{}", short_oid(branch_commit.id()))
        } else {
            steps.last().unwrap().step.id.clone()
        };

        Ok(Path {
            path: PathIdentity {
                id: format!("path-{}", spec.name.replace('/', "-")),
                base: Some(Base {
                    uri: repo_uri,
                    ref_str: Some(base_commit.id().to_string()),
                    branch: Some(spec.name.clone()),
                }),
                head: head_step_id,
                graph_ref: None,
            },
            steps,
            meta: Some(PathMeta {
                title: Some(format!("Branch: {}", spec.name)),
                actors: if actors.is_empty() {
                    None
                } else {
                    Some(actors)
                },
                ..Default::default()
            }),
        })
    }

    /// Derive a Toolpath [`Graph`] from multiple branch specifications.
    pub fn derive_graph(
        repo: &Repository,
        branch_specs: &[BranchSpec],
        config: &DeriveConfig,
    ) -> Result<Graph> {
        // Find the default branch name
        let default_branch = find_default_branch(repo);

        // If the default branch is included without an explicit start, compute the earliest
        // merge-base among all other branches to use as its starting point
        let default_branch_start =
            compute_default_branch_start(repo, branch_specs, &default_branch)?;

        // Generate paths for each branch with its own base
        let mut paths = Vec::new();
        for spec in branch_specs {
            // Check if this is the default branch and needs special handling
            let effective_spec = if default_branch_start.is_some()
                && spec.start.is_none()
                && default_branch.as_ref() == Some(&spec.name)
            {
                BranchSpec {
                    name: spec.name.clone(),
                    start: default_branch_start.clone(),
                }
            } else {
                spec.clone()
            };
            let path_doc = derive_path(repo, &effective_spec, config)?;
            paths.push(PathOrRef::Path(Box::new(path_doc)));
        }

        // Create graph ID from branch names
        let branch_names: Vec<&str> = branch_specs.iter().map(|s| s.name.as_str()).collect();
        let graph_id = if branch_names.len() <= 3 {
            format!(
                "graph-{}",
                branch_names
                    .iter()
                    .map(|b| b.replace('/', "-"))
                    .collect::<Vec<_>>()
                    .join("-")
            )
        } else {
            format!("graph-{}-branches", branch_names.len())
        };

        let title = config
            .title
            .clone()
            .unwrap_or_else(|| format!("Branches: {}", branch_names.join(", ")));

        Ok(Graph {
            graph: GraphIdentity { id: graph_id },
            paths,
            meta: Some(GraphMeta {
                title: Some(title),
                ..Default::default()
            }),
        })
    }

    /// Get the repository URI from a remote, falling back to a file:// URI.
    pub fn get_repo_uri(repo: &Repository, remote_name: &str) -> Result<String> {
        if let Ok(remote) = repo.find_remote(remote_name)
            && let Some(url) = remote.url()
        {
            return Ok(super::normalize_git_url(url));
        }

        // Fall back to file path
        if let Some(path) = repo.path().parent() {
            return Ok(format!("file://{}", path.display()));
        }

        Ok("file://unknown".to_string())
    }

    /// List local branches with summary metadata.
    pub fn list_branches(repo: &Repository) -> Result<Vec<BranchInfo>> {
        let mut branches = Vec::new();

        for branch_result in repo.branches(Some(git2::BranchType::Local))? {
            let (branch, _) = branch_result?;
            let name = branch.name()?.unwrap_or("<invalid utf-8>").to_string();

            let commit = branch.get().peel_to_commit()?;

            let author = commit.author();
            let author_name = author.name().unwrap_or("unknown").to_string();

            let time = commit.time();
            let timestamp = DateTime::<Utc>::from_timestamp(time.seconds(), 0)
                .map(|dt| dt.format("%Y-%m-%dT%H:%M:%SZ").to_string())
                .unwrap_or_else(|| "1970-01-01T00:00:00Z".to_string());

            let subject = commit
                .message()
                .unwrap_or("")
                .lines()
                .next()
                .unwrap_or("")
                .to_string();

            branches.push(BranchInfo {
                name,
                head_short: short_oid(commit.id()),
                head: commit.id().to_string(),
                subject,
                author: author_name,
                timestamp,
            });
        }

        branches.sort_by(|a, b| a.name.cmp(&b.name));
        Ok(branches)
    }

    // ========================================================================
    // Private helpers
    // ========================================================================

    fn compute_default_branch_start(
        repo: &Repository,
        branch_specs: &[BranchSpec],
        default_branch: &Option<String>,
    ) -> Result<Option<String>> {
        let default_name = match default_branch {
            Some(name) => name,
            None => return Ok(None),
        };

        let default_in_list = branch_specs
            .iter()
            .any(|s| &s.name == default_name && s.start.is_none());
        if !default_in_list {
            return Ok(None);
        }

        let default_ref = repo.find_branch(default_name, git2::BranchType::Local)?;
        let default_commit = default_ref.get().peel_to_commit()?;

        let mut earliest_base: Option<Oid> = None;

        for spec in branch_specs {
            if &spec.name == default_name {
                continue;
            }

            let branch_ref = match repo.find_branch(&spec.name, git2::BranchType::Local) {
                Ok(r) => r,
                Err(_) => continue,
            };
            let branch_commit = match branch_ref.get().peel_to_commit() {
                Ok(c) => c,
                Err(_) => continue,
            };

            if let Ok(merge_base) = repo.merge_base(default_commit.id(), branch_commit.id()) {
                match earliest_base {
                    None => earliest_base = Some(merge_base),
                    Some(current) => {
                        if repo.merge_base(merge_base, current).ok() == Some(merge_base)
                            && merge_base != current
                        {
                            earliest_base = Some(merge_base);
                        }
                    }
                }
            }
        }

        if let Some(base_oid) = earliest_base
            && let Ok(base_commit) = repo.find_commit(base_oid)
            && base_commit.parent_count() > 0
            && let Ok(parent) = base_commit.parent(0)
        {
            if parent.parent_count() > 0
                && let Ok(grandparent) = parent.parent(0)
            {
                return Ok(Some(grandparent.id().to_string()));
            }
            return Ok(Some(parent.id().to_string()));
        }

        Ok(earliest_base.map(|oid| oid.to_string()))
    }

    fn find_base_for_branch(repo: &Repository, branch_commit: &Commit) -> Result<Oid> {
        if let Some(default_branch) = find_default_branch(repo)
            && let Ok(default_ref) = repo.find_branch(&default_branch, git2::BranchType::Local)
            && let Ok(default_commit) = default_ref.get().peel_to_commit()
            && default_commit.id() != branch_commit.id()
            && let Ok(merge_base) = repo.merge_base(default_commit.id(), branch_commit.id())
            && merge_base != branch_commit.id()
        {
            return Ok(merge_base);
        }

        let mut walker = repo.revwalk()?;
        walker.push(branch_commit.id())?;
        walker.set_sorting(git2::Sort::TOPOLOGICAL | git2::Sort::REVERSE)?;

        if let Some(Ok(oid)) = walker.next() {
            return Ok(oid);
        }

        Ok(branch_commit.id())
    }

    fn find_default_branch(repo: &Repository) -> Option<String> {
        for name in &["main", "master", "trunk", "develop"] {
            if repo.find_branch(name, git2::BranchType::Local).is_ok() {
                return Some(name.to_string());
            }
        }
        None
    }

    fn collect_commits<'a>(
        repo: &'a Repository,
        base_oid: Oid,
        head_oid: Oid,
    ) -> Result<Vec<Commit<'a>>> {
        let mut walker = repo.revwalk()?;
        walker.push(head_oid)?;
        walker.hide(base_oid)?;
        walker.set_sorting(git2::Sort::TOPOLOGICAL | git2::Sort::REVERSE)?;

        let mut commits = Vec::new();
        for oid_result in walker {
            let oid = oid_result?;
            let commit = repo.find_commit(oid)?;
            commits.push(commit);
        }

        Ok(commits)
    }

    fn generate_steps(
        repo: &Repository,
        commits: &[Commit],
        base_oid: Oid,
        actors: &mut HashMap<String, ActorDefinition>,
    ) -> Result<Vec<Step>> {
        let mut steps = Vec::new();

        for commit in commits {
            let step = commit_to_step(repo, commit, base_oid, actors)?;
            steps.push(step);
        }

        Ok(steps)
    }

    fn commit_to_step(
        repo: &Repository,
        commit: &Commit,
        base_oid: Oid,
        actors: &mut HashMap<String, ActorDefinition>,
    ) -> Result<Step> {
        let step_id = format!("step-{}", short_oid(commit.id()));

        let parents: Vec<String> = commit
            .parent_ids()
            .filter(|pid| *pid != base_oid)
            .map(|pid| format!("step-{}", short_oid(pid)))
            .collect();

        let author = commit.author();
        let author_name = author.name().unwrap_or("unknown");
        let author_email = author.email().unwrap_or("unknown");
        let actor = format!("human:{}", super::slugify_author(author_name, author_email));

        actors.entry(actor.clone()).or_insert_with(|| {
            let mut identities = Vec::new();
            if author_email != "unknown" {
                identities.push(Identity {
                    system: "email".to_string(),
                    id: author_email.to_string(),
                });
            }
            ActorDefinition {
                name: Some(author_name.to_string()),
                identities,
                ..Default::default()
            }
        });

        let time = commit.time();
        let timestamp = DateTime::<Utc>::from_timestamp(time.seconds(), 0)
            .map(|dt| dt.format("%Y-%m-%dT%H:%M:%SZ").to_string())
            .unwrap_or_else(|| "1970-01-01T00:00:00Z".to_string());

        let change = generate_diff(repo, commit)?;

        let message = commit.message().unwrap_or("").trim();
        let intent = if message.is_empty() {
            None
        } else {
            Some(message.lines().next().unwrap_or(message).to_string())
        };

        let source = VcsSource {
            vcs_type: "git".to_string(),
            revision: commit.id().to_string(),
            change_id: None,
            extra: HashMap::new(),
        };

        Ok(Step {
            step: StepIdentity {
                id: step_id,
                parents,
                actor,
                timestamp,
            },
            change,
            meta: Some(StepMeta {
                intent,
                source: Some(source),
                ..Default::default()
            }),
        })
    }

    fn generate_diff(
        repo: &Repository,
        commit: &Commit,
    ) -> Result<HashMap<String, ArtifactChange>> {
        let tree = commit.tree()?;

        let parent_tree = if commit.parent_count() > 0 {
            Some(commit.parent(0)?.tree()?)
        } else {
            None
        };

        let mut diff_opts = DiffOptions::new();
        diff_opts.context_lines(3);

        let diff =
            repo.diff_tree_to_tree(parent_tree.as_ref(), Some(&tree), Some(&mut diff_opts))?;

        let mut changes: HashMap<String, ArtifactChange> = HashMap::new();
        let mut current_file: Option<String> = None;
        let mut current_diff = String::new();

        diff.print(git2::DiffFormat::Patch, |delta, _hunk, line| {
            let file_path = delta
                .new_file()
                .path()
                .or_else(|| delta.old_file().path())
                .map(|p| p.to_string_lossy().to_string());

            if let Some(path) = file_path
                && current_file.as_ref() != Some(&path)
            {
                if let Some(prev_file) = current_file.take()
                    && !current_diff.is_empty()
                {
                    changes.insert(prev_file, ArtifactChange::raw(&current_diff));
                }
                current_file = Some(path);
                current_diff.clear();
            }

            let prefix = match line.origin() {
                '+' => "+",
                '-' => "-",
                ' ' => " ",
                '>' => ">",
                '<' => "<",
                'F' => "",
                'H' => "@",
                'B' => "",
                _ => "",
            };

            if line.origin() == 'H' {
                if let Ok(content) = std::str::from_utf8(line.content()) {
                    current_diff.push_str("@@");
                    current_diff.push_str(content.trim_start_matches('@'));
                }
            } else if (!prefix.is_empty() || line.origin() == ' ')
                && let Ok(content) = std::str::from_utf8(line.content())
            {
                current_diff.push_str(prefix);
                current_diff.push_str(content);
            }

            true
        })?;

        if let Some(file) = current_file
            && !current_diff.is_empty()
        {
            changes.insert(file, ArtifactChange::raw(&current_diff));
        }

        Ok(changes)
    }

    fn short_oid(oid: Oid) -> String {
        safe_prefix(&oid.to_string(), 8)
    }

    fn safe_prefix(s: &str, n: usize) -> String {
        s.chars().take(n).collect()
    }

    #[cfg(test)]
    mod tests {
        use super::*;

        #[test]
        fn test_safe_prefix_ascii() {
            assert_eq!(safe_prefix("abcdef12345", 8), "abcdef12");
        }

        #[test]
        fn test_safe_prefix_short_string() {
            assert_eq!(safe_prefix("abc", 8), "abc");
        }

        #[test]
        fn test_safe_prefix_empty() {
            assert_eq!(safe_prefix("", 8), "");
        }

        #[test]
        fn test_safe_prefix_multibyte() {
            assert_eq!(safe_prefix("café", 3), "caf");
            assert_eq!(safe_prefix("日本語テスト", 3), "日本語");
        }

        #[test]
        fn test_short_oid() {
            let oid = Oid::from_str("abcdef1234567890abcdef1234567890abcdef12").unwrap();
            assert_eq!(short_oid(oid), "abcdef12");
        }

        fn init_temp_repo() -> (tempfile::TempDir, Repository) {
            let dir = tempfile::tempdir().unwrap();
            let repo = Repository::init(dir.path()).unwrap();

            let mut config = repo.config().unwrap();
            config.set_str("user.name", "Test User").unwrap();
            config.set_str("user.email", "test@example.com").unwrap();

            (dir, repo)
        }

        fn create_commit(
            repo: &Repository,
            message: &str,
            file_name: &str,
            content: &str,
            parent: Option<&git2::Commit>,
        ) -> Oid {
            let mut index = repo.index().unwrap();
            let file_path = repo.workdir().unwrap().join(file_name);
            std::fs::write(&file_path, content).unwrap();
            index.add_path(std::path::Path::new(file_name)).unwrap();
            index.write().unwrap();
            let tree_id = index.write_tree().unwrap();
            let tree = repo.find_tree(tree_id).unwrap();
            let sig = repo.signature().unwrap();
            let parents: Vec<&git2::Commit> = parent.into_iter().collect();
            repo.commit(Some("HEAD"), &sig, &sig, message, &tree, &parents)
                .unwrap()
        }

        #[test]
        fn test_list_branches_on_repo() {
            let (_dir, repo) = init_temp_repo();
            create_commit(&repo, "initial", "file.txt", "hello", None);

            let branches = list_branches(&repo).unwrap();
            assert!(!branches.is_empty());
            let names: Vec<&str> = branches.iter().map(|b| b.name.as_str()).collect();
            assert!(
                names.contains(&"main") || names.contains(&"master"),
                "Expected main or master in {:?}",
                names
            );
        }

        #[test]
        fn test_list_branches_sorted() {
            let (_dir, repo) = init_temp_repo();
            let oid = create_commit(&repo, "initial", "file.txt", "hello", None);
            let commit = repo.find_commit(oid).unwrap();

            repo.branch("b-beta", &commit, false).unwrap();
            repo.branch("a-alpha", &commit, false).unwrap();

            let branches = list_branches(&repo).unwrap();
            let names: Vec<&str> = branches.iter().map(|b| b.name.as_str()).collect();
            let mut sorted = names.clone();
            sorted.sort();
            assert_eq!(names, sorted);
        }

        #[test]
        fn test_get_repo_uri_no_remote() {
            let (_dir, repo) = init_temp_repo();
            let uri = get_repo_uri(&repo, "origin").unwrap();
            assert!(
                uri.starts_with("file://"),
                "Expected file:// URI, got {}",
                uri
            );
        }

        #[test]
        fn test_derive_single_branch() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "first commit", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();
            create_commit(&repo, "second commit", "file.txt", "v2", Some(&commit1));

            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: None,
                base: None,
            };

            let default = find_default_branch(&repo).unwrap_or("main".to_string());
            let graph = derive(&repo, &[default], &config).unwrap();
            let path = graph
                .single_path()
                .expect("single-branch derive yields a single-path graph");
            assert!(!path.steps.is_empty(), "Expected at least one step");
            assert!(path.path.base.is_some());
        }

        #[test]
        fn test_derive_multiple_branches_produces_graph() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "initial", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();
            let _oid2 = create_commit(&repo, "on default", "file.txt", "v2", Some(&commit1));

            let default_branch = find_default_branch(&repo).unwrap();

            repo.branch("feature", &commit1, false).unwrap();
            repo.set_head("refs/heads/feature").unwrap();
            repo.checkout_head(Some(git2::build::CheckoutBuilder::new().force()))
                .unwrap();
            let commit1_again = repo.find_commit(oid1).unwrap();
            create_commit(
                &repo,
                "feature work",
                "feature.txt",
                "feat",
                Some(&commit1_again),
            );

            repo.set_head(&format!("refs/heads/{}", default_branch))
                .unwrap();
            repo.checkout_head(Some(git2::build::CheckoutBuilder::new().force()))
                .unwrap();

            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: Some("Test Graph".to_string()),
                base: None,
            };

            let graph = derive(&repo, &[default_branch, "feature".to_string()], &config).unwrap();
            assert_eq!(graph.paths.len(), 2);
            assert!(graph.meta.is_some());
            assert_eq!(graph.meta.unwrap().title.unwrap(), "Test Graph");
        }

        #[test]
        fn test_find_default_branch() {
            let (_dir, repo) = init_temp_repo();
            create_commit(&repo, "initial", "file.txt", "hello", None);

            let default = find_default_branch(&repo);
            assert!(default.is_some());
            let name = default.unwrap();
            assert!(name == "main" || name == "master");
        }

        #[test]
        fn test_branch_info_fields() {
            let (_dir, repo) = init_temp_repo();
            create_commit(&repo, "test subject line", "file.txt", "hello", None);

            let branches = list_branches(&repo).unwrap();
            let branch = &branches[0];

            assert!(!branch.head.is_empty());
            assert_eq!(branch.head_short.len(), 8);
            assert_eq!(branch.subject, "test subject line");
            assert_eq!(branch.author, "Test User");
            assert!(branch.timestamp.ends_with('Z'));
        }

        #[test]
        fn test_derive_with_global_base() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "first commit", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();
            let oid2 = create_commit(&repo, "second commit", "file.txt", "v2", Some(&commit1));
            let commit2 = repo.find_commit(oid2).unwrap();
            create_commit(&repo, "third commit", "file.txt", "v3", Some(&commit2));

            let default = find_default_branch(&repo).unwrap();
            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: None,
                base: Some(oid1.to_string()),
            };

            let graph = derive(&repo, &[default], &config).unwrap();
            let path = graph
                .single_path()
                .expect("single-branch derive yields a single-path graph");
            assert!(!path.steps.is_empty());
        }

        #[test]
        fn test_derive_path_with_branch_start() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "first", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();
            let oid2 = create_commit(&repo, "second", "file.txt", "v2", Some(&commit1));
            let commit2 = repo.find_commit(oid2).unwrap();
            create_commit(&repo, "third", "file.txt", "v3", Some(&commit2));

            let default = find_default_branch(&repo).unwrap();
            let spec = BranchSpec {
                name: default,
                start: Some(oid1.to_string()),
            };
            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: None,
                base: None,
            };

            let path = derive_path(&repo, &spec, &config).unwrap();
            assert!(!path.steps.is_empty());
        }

        #[test]
        fn test_generate_diff_initial_commit() {
            let (_dir, repo) = init_temp_repo();
            let oid = create_commit(&repo, "initial", "file.txt", "hello world", None);
            let commit = repo.find_commit(oid).unwrap();

            let changes = generate_diff(&repo, &commit).unwrap();
            assert!(!changes.is_empty());
            assert!(changes.contains_key("file.txt"));
        }

        #[test]
        fn test_collect_commits_range() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "first", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();
            let oid2 = create_commit(&repo, "second", "file.txt", "v2", Some(&commit1));
            let commit2 = repo.find_commit(oid2).unwrap();
            let oid3 = create_commit(&repo, "third", "file.txt", "v3", Some(&commit2));

            let commits = collect_commits(&repo, oid1, oid3).unwrap();
            assert_eq!(commits.len(), 2);
        }

        #[test]
        fn test_graph_id_many_branches() {
            let (_dir, repo) = init_temp_repo();
            let oid1 = create_commit(&repo, "initial", "file.txt", "v1", None);
            let commit1 = repo.find_commit(oid1).unwrap();

            repo.branch("b1", &commit1, false).unwrap();
            repo.branch("b2", &commit1, false).unwrap();
            repo.branch("b3", &commit1, false).unwrap();
            repo.branch("b4", &commit1, false).unwrap();

            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: None,
                base: Some(oid1.to_string()),
            };

            let g = derive(
                &repo,
                &[
                    "b1".to_string(),
                    "b2".to_string(),
                    "b3".to_string(),
                    "b4".to_string(),
                ],
                &config,
            )
            .unwrap();

            assert!(g.graph.id.contains("4-branches"));
        }

        #[test]
        fn test_commit_to_step_creates_actor() {
            let (_dir, repo) = init_temp_repo();
            let oid = create_commit(&repo, "a commit", "file.txt", "content", None);
            let commit = repo.find_commit(oid).unwrap();

            let mut actors = HashMap::new();
            let step = commit_to_step(&repo, &commit, Oid::zero(), &mut actors).unwrap();

            assert!(step.step.actor.starts_with("human:"));
            assert!(!actors.is_empty());
            let actor_def = actors.values().next().unwrap();
            assert_eq!(actor_def.name.as_deref(), Some("Test User"));
        }

        #[test]
        fn test_derive_config_fields() {
            let config = DeriveConfig {
                remote: "origin".to_string(),
                title: Some("My Graph".to_string()),
                base: None,
            };
            assert_eq!(config.remote, "origin");
            assert_eq!(config.title.as_deref(), Some("My Graph"));
            assert!(config.base.is_none());
        }
    }
}

// Re-export native-only functions at crate root for API compatibility
#[cfg(not(target_os = "emscripten"))]
pub use native::{derive, derive_graph, derive_path, get_repo_uri, list_branches};

#[cfg(test)]
mod tests {
    use super::*;

    // ── normalize_git_url ──────────────────────────────────────────────

    #[test]
    fn test_normalize_github_ssh() {
        assert_eq!(
            normalize_git_url("git@github.com:org/repo.git"),
            "github:org/repo"
        );
    }

    #[test]
    fn test_normalize_github_https() {
        assert_eq!(
            normalize_git_url("https://github.com/org/repo.git"),
            "github:org/repo"
        );
    }

    #[test]
    fn test_normalize_github_https_no_suffix() {
        assert_eq!(
            normalize_git_url("https://github.com/org/repo"),
            "github:org/repo"
        );
    }

    #[test]
    fn test_normalize_gitlab_ssh() {
        assert_eq!(
            normalize_git_url("git@gitlab.com:org/repo.git"),
            "gitlab:org/repo"
        );
    }

    #[test]
    fn test_normalize_gitlab_https() {
        assert_eq!(
            normalize_git_url("https://gitlab.com/org/repo.git"),
            "gitlab:org/repo"
        );
    }

    #[test]
    fn test_normalize_unknown_url_passthrough() {
        let url = "https://bitbucket.org/org/repo.git";
        assert_eq!(normalize_git_url(url), url);
    }

    // ── slugify_author ─────────────────────────────────────────────────

    #[test]
    fn test_slugify_prefers_email_username() {
        assert_eq!(slugify_author("Alex Smith", "asmith@example.com"), "asmith");
    }

    #[test]
    fn test_slugify_falls_back_to_name() {
        assert_eq!(slugify_author("Alex Smith", "unknown"), "alex-smith");
    }

    #[test]
    fn test_slugify_lowercases() {
        assert_eq!(slugify_author("Alex", "Alex@example.com"), "alex");
    }

    #[test]
    fn test_slugify_replaces_special_chars() {
        assert_eq!(slugify_author("A.B", "a.b@example.com"), "a-b");
    }

    #[test]
    fn test_slugify_empty_email_username() {
        assert_eq!(slugify_author("Test User", "noreply"), "test-user");
    }

    // ── BranchSpec::parse ──────────────────────────────────────────────

    #[test]
    fn test_branch_spec_simple() {
        let spec = BranchSpec::parse("main");
        assert_eq!(spec.name, "main");
        assert!(spec.start.is_none());
    }

    #[test]
    fn test_branch_spec_with_start() {
        let spec = BranchSpec::parse("feature:HEAD~5");
        assert_eq!(spec.name, "feature");
        assert_eq!(spec.start.as_deref(), Some("HEAD~5"));
    }

    #[test]
    fn test_branch_spec_with_commit_start() {
        let spec = BranchSpec::parse("main:abc1234");
        assert_eq!(spec.name, "main");
        assert_eq!(spec.start.as_deref(), Some("abc1234"));
    }
}