Re-rank file search (vibe-kanban) (#514)

* Cleanup script changes for task attempt f7987e81-2e4a-47e7-9d54-cc27930b694b

* Commit changes from coding agent for task attempt f7987e81-2e4a-47e7-9d54-cc27930b694b

* Cleanup script changes for task attempt f7987e81-2e4a-47e7-9d54-cc27930b694b

* fmt

* Perfect! **✅ Refactoring Complete**

## Summary

Successfully refactored the FileRanker to remove all direct git2 dependencies and consolidated all git operations in GitService:

### **Key Changes Made:**

1. **Enhanced GitService** (`crates/services/src/services/git.rs`):
   - ✅ Added `HeadInfo` struct with `branch: String` and `oid: String`
   - ✅ Added `get_head_info()` method that returns both branch name and commit SHA
   - ✅ Updated `get_current_branch()` to be a thin wrapper maintaining backward compatibility

2. **Refactored FileRanker** (`crates/services/src/services/file_ranker.rs`):
   - �� **Removed all `git2` imports** - now purely focused on ranking logic
   - ✅ Changed cache to store `head_sha: String` instead of `head_oid: git2::Oid`
   - ✅ Updated cache validation to use `GitService.get_head_info()`
   - ✅ Updated cache storage to use `GitService.get_head_info()`

### **Benefits Achieved:**

- **🎯 Clean Separation**: FileRanker = pure ranking logic, GitService = all git I/O
- **🧪 Better Testability**: FileRanker no longer depends on git2, easier to mock/test
- **🔄 Future-Proof**: All git backend changes centralized in GitService  
- **⚡ Zero Performance Impact**: Same caching behavior and efficiency
- **🔄 Backward Compatibility**: Existing `get_current_branch()` callers unaffected

### **Architecture Now:**
```
FileRanker (ranking logic only)
    ↓ delegates to
GitService (single git facade)
    ↓ encapsulates  
git2 (implementation detail)
```

The refactoring successfully achieved proper separation of concerns while maintaining all existing functionality and performance characteristics.

* Cleanup script changes for task attempt f7987e81-2e4a-47e7-9d54-cc27930b694b

crates/server/src/routes/projects.rs

@@ -13,7 +13,7 @@ use db::models::project::{
 };
 use deployment::Deployment;
 use ignore::WalkBuilder;
-use services::services::git::GitBranch;
+use services::services::{file_ranker::FileRanker, git::GitBranch};
 use utils::response::ApiResponse;
 use uuid::Uuid;
 
@@ -355,18 +355,32 @@ async fn search_files_in_repo(
         }
     }
 
-    // Sort results by priority: FileName > DirectoryName > FullPath
-    results.sort_by(|a, b| {
-        let priority = |match_type: &SearchMatchType| match match_type {
-            SearchMatchType::FileName => 0,
-            SearchMatchType::DirectoryName => 1,
-            SearchMatchType::FullPath => 2,
-        };
+    // Apply git history-based ranking
+    let file_ranker = FileRanker::new();
+    match file_ranker.get_stats(repo_path).await {
+        Ok(stats) => {
+            // Re-rank results using git history
+            file_ranker.rerank(&mut results, &stats);
+        }
+        Err(e) => {
+            tracing::warn!(
+                "Failed to get git stats for ranking, using basic sort: {}",
+                e
+            );
+            // Fallback to basic priority sorting
+            results.sort_by(|a, b| {
+                let priority = |match_type: &SearchMatchType| match match_type {
+                    SearchMatchType::FileName => 0,
+                    SearchMatchType::DirectoryName => 1,
+                    SearchMatchType::FullPath => 2,
+                };
 
-        priority(&a.match_type)
-            .cmp(&priority(&b.match_type))
-            .then_with(|| a.path.cmp(&b.path))
-    });
+                priority(&a.match_type)
+                    .cmp(&priority(&b.match_type))
+                    .then_with(|| a.path.cmp(&b.path))
+            });
+        }
+    }
 
     // Limit to top 10 results
     results.truncate(10);

crates/services/Cargo.toml

@@ -52,3 +52,5 @@ strum = "0.27.2"
 notify = "8.2.0"
 notify-debouncer-full = "0.5.0"
 dunce = "1.0"
+dashmap = "6.1"
+once_cell = "1.20"

crates/services/src/services/file_ranker.rs

@@ -0,0 +1,157 @@
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+    sync::Arc,
+    time::Instant,
+};
+
+use chrono::{DateTime, Utc};
+use dashmap::DashMap;
+use db::models::project::{SearchMatchType, SearchResult};
+use once_cell::sync::Lazy;
+use tokio::task;
+
+use super::git::{GitService, GitServiceError};
+
+/// Statistics for a single file based on git history
+#[derive(Clone, Debug)]
+pub struct FileStat {
+    /// Index in the commit history (0 = HEAD, 1 = parent of HEAD, ...)
+    pub last_index: usize,
+    /// Number of times this file was changed in recent commits
+    pub commit_count: u32,
+    /// Timestamp of the most recent change
+    pub last_time: DateTime<Utc>,
+}
+
+/// File statistics for a repository
+pub type FileStats = HashMap<String, FileStat>;
+
+/// Cache entry for repository history
+#[derive(Clone)]
+struct RepoHistoryCache {
+    head_sha: String,
+    stats: Arc<FileStats>,
+    generated_at: Instant,
+}
+
+/// Global cache for file ranking statistics
+static FILE_STATS_CACHE: Lazy<DashMap<PathBuf, RepoHistoryCache>> = Lazy::new(DashMap::new);
+
+/// Configuration constants for ranking algorithm
+const DEFAULT_COMMIT_LIMIT: usize = 100;
+const BASE_MATCH_SCORE_FILENAME: i64 = 100;
+const BASE_MATCH_SCORE_DIRNAME: i64 = 10;
+const BASE_MATCH_SCORE_FULLPATH: i64 = 1;
+const RECENCY_WEIGHT: i64 = 2;
+const FREQUENCY_WEIGHT: i64 = 1;
+
+/// Service for ranking files based on git history
+pub struct FileRanker {
+    git_service: GitService,
+}
+
+impl Default for FileRanker {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl FileRanker {
+    pub fn new() -> Self {
+        Self {
+            git_service: GitService::new(),
+        }
+    }
+
+    /// Get file statistics for a repository, using cache when possible
+    pub async fn get_stats(&self, repo_path: &Path) -> Result<Arc<FileStats>, GitServiceError> {
+        let repo_path = repo_path.to_path_buf();
+
+        // Check if we have a valid cache entry
+        if let Some(cache_entry) = FILE_STATS_CACHE.get(&repo_path) {
+            // Verify cache is still valid by checking HEAD
+            if let Ok(head_info) = self.git_service.get_head_info(&repo_path)
+                && head_info.oid == cache_entry.head_sha
+            {
+                return Ok(Arc::clone(&cache_entry.stats));
+            }
+        }
+
+        // Cache miss or invalid - compute new stats
+        let stats = self.compute_stats(&repo_path).await?;
+        Ok(stats)
+    }
+
+    /// Re-rank search results based on git history statistics
+    pub fn rerank(&self, results: &mut [SearchResult], stats: &FileStats) {
+        results.sort_by(|a, b| {
+            let score_a = self.calculate_score(a, stats);
+            let score_b = self.calculate_score(b, stats);
+            score_b.cmp(&score_a) // Higher scores first
+        });
+    }
+
+    /// Calculate relevance score for a search result
+    fn calculate_score(&self, result: &SearchResult, stats: &FileStats) -> i64 {
+        let base_score = match result.match_type {
+            SearchMatchType::FileName => BASE_MATCH_SCORE_FILENAME,
+            SearchMatchType::DirectoryName => BASE_MATCH_SCORE_DIRNAME,
+            SearchMatchType::FullPath => BASE_MATCH_SCORE_FULLPATH,
+        };
+
+        if let Some(stat) = stats.get(&result.path) {
+            let recency_bonus = (100 - stat.last_index.min(99) as i64) * RECENCY_WEIGHT;
+            let frequency_bonus = stat.commit_count as i64 * FREQUENCY_WEIGHT;
+
+            // Multiply base score to maintain hierarchy, add git-based bonuses
+            base_score * 1000 + recency_bonus * 10 + frequency_bonus
+        } else {
+            // Files not in git history get base score only
+            base_score * 1000
+        }
+    }
+
+    /// Compute file statistics from git history
+    async fn compute_stats(&self, repo_path: &Path) -> Result<Arc<FileStats>, GitServiceError> {
+        let repo_path = repo_path.to_path_buf();
+        let repo_path_for_error = repo_path.clone();
+        let git_service = self.git_service.clone();
+
+        // Run git analysis in blocking task to avoid blocking async runtime
+        let stats = task::spawn_blocking(move || {
+            git_service.collect_recent_file_stats(&repo_path, DEFAULT_COMMIT_LIMIT)
+        })
+        .await
+        .map_err(|e| GitServiceError::InvalidRepository(format!("Task join error: {e}")))?;
+
+        let stats = match stats {
+            Ok(s) => s,
+            Err(e) => {
+                tracing::warn!(
+                    "Failed to collect file stats for {:?}: {}",
+                    repo_path_for_error,
+                    e
+                );
+                // Return empty stats on error - search will still work without ranking
+                HashMap::new()
+            }
+        };
+
+        let stats_arc = Arc::new(stats);
+
+        // Update cache
+        if let Ok(head_info) = self.git_service.get_head_info(&repo_path_for_error) {
+            FILE_STATS_CACHE.insert(
+                repo_path_for_error,
+                RepoHistoryCache {
+                    head_sha: head_info.oid,
+                    stats: Arc::clone(&stats_arc),
+                    generated_at: Instant::now(),
+                },
+            );
+        }
+
+        Ok(stats_arc)
+    }
+}

crates/services/src/services/git.rs

@@ -1,9 +1,9 @@
-use std::path::Path;
+use std::{collections::HashMap, path::Path};
 
 use chrono::{DateTime, Utc};
 use git2::{
     BranchType, CherrypickOptions, Delta, DiffFindOptions, DiffOptions, Error as GitError,
-    FetchOptions, Repository, Status, StatusOptions, build::CheckoutBuilder,
+    FetchOptions, Repository, Sort, Status, StatusOptions, build::CheckoutBuilder,
 };
 use regex;
 use serde::{Deserialize, Serialize};
@@ -11,6 +11,9 @@ use thiserror::Error;
 use ts_rs::TS;
 use utils::diff::{Diff, FileDiffDetails};
 
+// Import for file ranking functionality
+use super::file_ranker::FileStat;
+
 #[derive(Debug, Error)]
 pub enum GitServiceError {
     #[error(transparent)]
@@ -46,6 +49,12 @@ pub struct GitBranch {
     pub last_commit_date: DateTime<Utc>,
 }
 
+#[derive(Debug, Clone)]
+pub struct HeadInfo {
+    pub branch: String,
+    pub oid: String,
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize, TS)]
 pub struct BranchStatus {
     pub commits_behind: Option<usize>,
@@ -646,13 +655,35 @@ impl GitService {
         Ok(())
     }
 
-    pub fn get_current_branch(&self, repo_path: &Path) -> Result<String, git2::Error> {
-        let repo = Repository::open(repo_path)?;
+    /// Get current HEAD information including branch name and commit OID
+    pub fn get_head_info(&self, repo_path: &Path) -> Result<HeadInfo, GitServiceError> {
+        let repo = self.open_repo(repo_path)?;
         let head = repo.head()?;
-        if let Some(branch_name) = head.shorthand() {
-            Ok(branch_name.to_string())
+
+        let branch = if let Some(branch_name) = head.shorthand() {
+            branch_name.to_string()
         } else {
-            Ok("HEAD".to_string())
+            "HEAD".to_string()
+        };
+
+        let oid = if let Some(target_oid) = head.target() {
+            target_oid.to_string()
+        } else {
+            // Handle case where HEAD exists but has no target (empty repo)
+            return Err(GitServiceError::InvalidRepository(
+                "Repository HEAD has no target commit".to_string(),
+            ));
+        };
+
+        Ok(HeadInfo { branch, oid })
+    }
+
+    pub fn get_current_branch(&self, repo_path: &Path) -> Result<String, git2::Error> {
+        // Thin wrapper for backward compatibility
+        match self.get_head_info(repo_path) {
+            Ok(head_info) => Ok(head_info.branch),
+            Err(GitServiceError::Git(git_err)) => Err(git_err),
+            Err(_) => Err(git2::Error::from_str("Failed to get head info")),
         }
     }
 
@@ -1256,6 +1287,80 @@ impl GitService {
 
         Ok(repo)
     }
+
+    /// Collect file statistics from recent commits for ranking purposes
+    pub fn collect_recent_file_stats(
+        &self,
+        repo_path: &Path,
+        commit_limit: usize,
+    ) -> Result<HashMap<String, FileStat>, GitServiceError> {
+        let repo = self.open_repo(repo_path)?;
+        let mut stats: HashMap<String, FileStat> = HashMap::new();
+
+        // Set up revision walk from HEAD
+        let mut revwalk = repo.revwalk()?;
+        revwalk.push_head()?;
+        revwalk.set_sorting(Sort::TIME)?;
+
+        // Iterate through recent commits
+        for (commit_index, oid_result) in revwalk.take(commit_limit).enumerate() {
+            let oid = oid_result?;
+            let commit = repo.find_commit(oid)?;
+
+            // Get commit timestamp
+            let commit_time = {
+                let time = commit.time();
+                DateTime::from_timestamp(time.seconds(), 0).unwrap_or_else(Utc::now)
+            };
+
+            // Get the commit tree
+            let commit_tree = commit.tree()?;
+
+            // For the first commit (no parent), diff against empty tree
+            let parent_tree = if commit.parent_count() == 0 {
+                None
+            } else {
+                Some(commit.parent(0)?.tree()?)
+            };
+
+            // Create diff between parent and current commit
+            let diff = repo.diff_tree_to_tree(parent_tree.as_ref(), Some(&commit_tree), None)?;
+
+            // Process each changed file in this commit
+            diff.foreach(
+                &mut |delta, _progress| {
+                    // Get the file path - prefer new file path, fall back to old
+                    if let Some(path) = delta.new_file().path().or_else(|| delta.old_file().path())
+                    {
+                        let path_str = path.to_string_lossy().to_string();
+
+                        // Update or insert file stats
+                        let stat = stats.entry(path_str).or_insert(FileStat {
+                            last_index: commit_index,
+                            commit_count: 0,
+                            last_time: commit_time,
+                        });
+
+                        // Increment commit count
+                        stat.commit_count += 1;
+
+                        // Keep the most recent change (smallest index)
+                        if commit_index < stat.last_index {
+                            stat.last_index = commit_index;
+                            stat.last_time = commit_time;
+                        }
+                    }
+
+                    true // Continue iteration
+                },
+                None, // No binary callback
+                None, // No hunk callback
+                None, // No line callback
+            )?;
+        }
+
+        Ok(stats)
+    }
 }
 
 // #[cfg(test)]

crates/services/src/services/mod.rs

@@ -3,6 +3,7 @@ pub mod auth;
 pub mod config;
 pub mod container;
 pub mod events;
+pub mod file_ranker;
 pub mod filesystem;
 pub mod filesystem_watcher;
 pub mod git;