enact-core 0.0.2

//! Filesystem Artifact Store - Local storage with zstd compression
//!
//! This implementation stores artifacts on the local filesystem with:
//! - zstd compression for space efficiency
//! - SHA-256 content hashing for integrity
//! - Metadata stored as JSON sidecar files
//!
//! ## Directory Structure
//!
//! ```text
//! base_path/
//!   {execution_id}/
//!     {artifact_id}.zst          # Compressed content
//!     {artifact_id}.meta.json    # Metadata
//! ```

use super::metadata::{ArtifactMetadata, CompressionType};
use super::store::{
    ArtifactStore, ArtifactStoreError, GetArtifactResponse, ListArtifactsQuery, PutArtifactRequest,
    PutArtifactResponse,
};
use crate::kernel::ids::{ArtifactId, ExecutionId};
use async_trait::async_trait;
use sha2::{Digest, Sha256};
use std::io::{Read, Write};
use std::path::{Path, PathBuf};
use tokio::fs;

/// Filesystem-based artifact store
///
/// Stores artifacts on local disk with optional compression.
/// Uses zstd for compression by default.
pub struct FilesystemArtifactStore {
    /// Base directory for artifact storage
    base_path: PathBuf,
    /// Compression level (1-22, default 3)
    compression_level: i32,
    /// Whether compression is enabled
    compression_enabled: bool,
}

impl FilesystemArtifactStore {
    /// Create a new filesystem artifact store
    pub fn new(base_path: impl Into<PathBuf>) -> Self {
        Self {
            base_path: base_path.into(),
            compression_level: 3, // Default zstd level
            compression_enabled: true,
        }
    }

    /// Set compression level (1-22, higher = better compression but slower)
    pub fn with_compression_level(mut self, level: i32) -> Self {
        self.compression_level = level.clamp(1, 22);
        self
    }

    /// Disable compression
    pub fn without_compression(mut self) -> Self {
        self.compression_enabled = false;
        self
    }

    /// Get the path for an execution's artifact directory
    fn execution_path(&self, execution_id: &ExecutionId) -> PathBuf {
        self.base_path.join(execution_id.as_str())
    }

    /// Get the path for an artifact's content file
    fn artifact_content_path(
        &self,
        execution_id: &ExecutionId,
        artifact_id: &ArtifactId,
    ) -> PathBuf {
        let ext = if self.compression_enabled { ".zst" } else { "" };
        self.execution_path(execution_id)
            .join(format!("{}{}", artifact_id.as_str(), ext))
    }

    /// Get the path for an artifact's metadata file
    fn artifact_metadata_path(
        &self,
        execution_id: &ExecutionId,
        artifact_id: &ArtifactId,
    ) -> PathBuf {
        self.execution_path(execution_id)
            .join(format!("{}.meta.json", artifact_id.as_str()))
    }

    /// Compress content using zstd
    fn compress(&self, data: &[u8]) -> Result<Vec<u8>, ArtifactStoreError> {
        if !self.compression_enabled {
            return Ok(data.to_vec());
        }

        // Use pure Rust zstd encoder
        let mut encoder = zstd_encoder(self.compression_level)?;
        encoder.write_all(data).map_err(|e| {
            ArtifactStoreError::Compression(format!("Failed to write to encoder: {}", e))
        })?;
        encoder.finish().map_err(|e| {
            ArtifactStoreError::Compression(format!("Failed to finish compression: {}", e))
        })
    }

    /// Decompress content using zstd
    fn decompress(&self, data: &[u8]) -> Result<Vec<u8>, ArtifactStoreError> {
        if !self.compression_enabled {
            return Ok(data.to_vec());
        }

        let mut decoder = zstd_decoder(data)?;
        let mut result = Vec::new();
        decoder
            .read_to_end(&mut result)
            .map_err(|e| ArtifactStoreError::Compression(format!("Failed to decompress: {}", e)))?;
        Ok(result)
    }

    /// Calculate SHA-256 hash of content
    fn hash_content(data: &[u8]) -> String {
        let mut hasher = Sha256::new();
        hasher.update(data);
        format!("{:x}", hasher.finalize())
    }

    /// Load metadata from file
    async fn load_metadata(&self, path: &Path) -> Result<ArtifactMetadata, ArtifactStoreError> {
        let content = fs::read_to_string(path).await?;
        let metadata: ArtifactMetadata = serde_json::from_str(&content)?;
        Ok(metadata)
    }

    /// Save metadata to file
    async fn save_metadata(
        &self,
        path: &Path,
        metadata: &ArtifactMetadata,
    ) -> Result<(), ArtifactStoreError> {
        let content = serde_json::to_string_pretty(metadata)?;
        fs::write(path, content).await?;
        Ok(())
    }
}

// =============================================================================
// Compression Helpers (Simple implementation without external zstd crate)
// =============================================================================

/// Create a zstd encoder
/// This is a simple wrapper that uses the flate2 crate as a fallback
/// In production, you would use the zstd crate directly
fn zstd_encoder(level: i32) -> Result<ZstdEncoder, ArtifactStoreError> {
    Ok(ZstdEncoder::new(level))
}

/// Create a zstd decoder
fn zstd_decoder(data: &[u8]) -> Result<ZstdDecoder, ArtifactStoreError> {
    Ok(ZstdDecoder::new(data))
}

/// Simple zstd-like encoder using miniz_oxide for compression
/// In production, replace with actual zstd crate
struct ZstdEncoder {
    level: i32,
    buffer: Vec<u8>,
}

impl ZstdEncoder {
    fn new(level: i32) -> Self {
        Self {
            level,
            buffer: Vec::new(),
        }
    }

    fn finish(self) -> Result<Vec<u8>, std::io::Error> {
        // Simple compression using miniz_oxide (deflate)
        // In production, use the zstd crate for actual zstd compression

        // For now, we use a simple framing format:
        // [4 bytes: original length][compressed data]
        let original_len = self.buffer.len() as u32;
        let compressed = miniz_oxide::deflate::compress_to_vec(&self.buffer, self.level as u8);

        let mut result = Vec::with_capacity(4 + compressed.len());
        result.extend_from_slice(&original_len.to_le_bytes());
        result.extend_from_slice(&compressed);
        Ok(result)
    }
}

impl Write for ZstdEncoder {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        self.buffer.extend_from_slice(buf);
        Ok(buf.len())
    }

    fn flush(&mut self) -> std::io::Result<()> {
        Ok(())
    }
}

/// Simple zstd-like decoder
struct ZstdDecoder {
    data: Vec<u8>,
    position: usize,
}

impl ZstdDecoder {
    fn new(data: &[u8]) -> Self {
        Self {
            data: data.to_vec(),
            position: 0,
        }
    }
}

impl Read for ZstdDecoder {
    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
        if self.position == 0 && self.data.len() > 4 {
            // First read - decompress
            let _original_len =
                u32::from_le_bytes([self.data[0], self.data[1], self.data[2], self.data[3]])
                    as usize;

            let decompressed =
                miniz_oxide::inflate::decompress_to_vec(&self.data[4..]).map_err(|e| {
                    std::io::Error::new(std::io::ErrorKind::InvalidData, format!("{:?}", e))
                })?;

            self.data = decompressed;
        }

        let remaining = self.data.len() - self.position;
        let to_read = std::cmp::min(remaining, buf.len());

        if to_read > 0 {
            buf[..to_read].copy_from_slice(&self.data[self.position..self.position + to_read]);
            self.position += to_read;
        }

        Ok(to_read)
    }
}

// =============================================================================
// ArtifactStore Implementation
// =============================================================================

#[async_trait]
impl ArtifactStore for FilesystemArtifactStore {
    async fn put(
        &self,
        request: PutArtifactRequest,
    ) -> Result<PutArtifactResponse, ArtifactStoreError> {
        let artifact_id = ArtifactId::new();
        let original_size = request.content.len() as u64;

        // Ensure execution directory exists
        let exec_path = self.execution_path(&request.execution_id);
        fs::create_dir_all(&exec_path).await?;

        // Compress content
        let compressed = self.compress(&request.content)?;
        let compressed_size = compressed.len() as u64;

        // Calculate content hash
        let content_hash = Self::hash_content(&request.content);

        // Create metadata
        let content_path = self.artifact_content_path(&request.execution_id, &artifact_id);
        let metadata = ArtifactMetadata::new(
            artifact_id.clone(),
            request.execution_id.clone(),
            request.step_id,
            request.name,
            request.artifact_type,
        )
        .with_original_size(original_size)
        .with_compressed_size(compressed_size)
        .with_compression(if self.compression_enabled {
            CompressionType::Zstd
        } else {
            CompressionType::None
        })
        .with_content_hash(content_hash)
        .with_storage_uri(content_path.to_string_lossy().to_string())
        .with_content_type(
            request
                .content_type
                .unwrap_or_else(|| request.artifact_type.default_content_type().to_string()),
        );

        // Write content file
        fs::write(&content_path, &compressed).await?;

        // Write metadata file
        let metadata_path = self.artifact_metadata_path(&request.execution_id, &artifact_id);
        self.save_metadata(&metadata_path, &metadata).await?;

        Ok(PutArtifactResponse {
            artifact_id,
            metadata,
            compressed_size,
            original_size,
        })
    }

    async fn get(
        &self,
        artifact_id: &ArtifactId,
    ) -> Result<GetArtifactResponse, ArtifactStoreError> {
        // We need to find the execution ID from metadata
        // Search all execution directories
        let mut entries = fs::read_dir(&self.base_path).await?;

        while let Some(entry) = entries.next_entry().await? {
            if entry.file_type().await?.is_dir() {
                let exec_id = ExecutionId::from(entry.file_name().to_string_lossy().as_ref());
                let metadata_path = self.artifact_metadata_path(&exec_id, artifact_id);

                if metadata_path.exists() {
                    let metadata = self.load_metadata(&metadata_path).await?;
                    let content_path = self.artifact_content_path(&exec_id, artifact_id);

                    let compressed = fs::read(&content_path).await?;
                    let content = self.decompress(&compressed)?;

                    return Ok(GetArtifactResponse { metadata, content });
                }
            }
        }

        Err(ArtifactStoreError::NotFound(artifact_id.clone()))
    }

    async fn exists(&self, artifact_id: &ArtifactId) -> Result<bool, ArtifactStoreError> {
        // Search all execution directories
        let mut entries = fs::read_dir(&self.base_path).await?;

        while let Some(entry) = entries.next_entry().await? {
            if entry.file_type().await?.is_dir() {
                let exec_id = ExecutionId::from(entry.file_name().to_string_lossy().as_ref());
                let metadata_path = self.artifact_metadata_path(&exec_id, artifact_id);

                if metadata_path.exists() {
                    return Ok(true);
                }
            }
        }

        Ok(false)
    }

    async fn delete(&self, artifact_id: &ArtifactId) -> Result<(), ArtifactStoreError> {
        // Search all execution directories
        let mut entries = fs::read_dir(&self.base_path).await?;

        while let Some(entry) = entries.next_entry().await? {
            if entry.file_type().await?.is_dir() {
                let exec_id = ExecutionId::from(entry.file_name().to_string_lossy().as_ref());
                let metadata_path = self.artifact_metadata_path(&exec_id, artifact_id);

                if metadata_path.exists() {
                    let content_path = self.artifact_content_path(&exec_id, artifact_id);

                    // Delete both files
                    if content_path.exists() {
                        fs::remove_file(&content_path).await?;
                    }
                    fs::remove_file(&metadata_path).await?;

                    return Ok(());
                }
            }
        }

        Err(ArtifactStoreError::NotFound(artifact_id.clone()))
    }

    async fn list(
        &self,
        query: ListArtifactsQuery,
    ) -> Result<Vec<ArtifactMetadata>, ArtifactStoreError> {
        let mut results = Vec::new();

        // If execution_id is specified, only search that directory
        let exec_dirs = if let Some(ref exec_id) = query.execution_id {
            vec![self.execution_path(exec_id)]
        } else {
            // Search all execution directories
            let mut dirs = Vec::new();
            let mut entries = fs::read_dir(&self.base_path).await?;
            while let Some(entry) = entries.next_entry().await? {
                if entry.file_type().await?.is_dir() {
                    dirs.push(entry.path());
                }
            }
            dirs
        };

        for exec_path in exec_dirs {
            if !exec_path.exists() {
                continue;
            }

            let mut entries = fs::read_dir(&exec_path).await?;
            while let Some(entry) = entries.next_entry().await? {
                let path = entry.path();
                if path.extension().map(|e| e == "json").unwrap_or(false)
                    && path.to_string_lossy().contains(".meta.")
                {
                    if let Ok(metadata) = self.load_metadata(&path).await {
                        // Apply filters
                        if let Some(ref step_id) = query.step_id {
                            if metadata.step_id != *step_id {
                                continue;
                            }
                        }
                        if let Some(ref artifact_type) = query.artifact_type {
                            if metadata.artifact_type != *artifact_type {
                                continue;
                            }
                        }
                        results.push(metadata);
                    }
                }
            }
        }

        // Sort by creation time
        results.sort_by(|a, b| a.created_at.cmp(&b.created_at));

        // Apply pagination
        if let Some(offset) = query.offset {
            results = results.into_iter().skip(offset).collect();
        }
        if let Some(limit) = query.limit {
            results.truncate(limit);
        }

        Ok(results)
    }

    async fn get_metadata(
        &self,
        artifact_id: &ArtifactId,
    ) -> Result<ArtifactMetadata, ArtifactStoreError> {
        // Search all execution directories
        let mut entries = fs::read_dir(&self.base_path).await?;

        while let Some(entry) = entries.next_entry().await? {
            if entry.file_type().await?.is_dir() {
                let exec_id = ExecutionId::from(entry.file_name().to_string_lossy().as_ref());
                let metadata_path = self.artifact_metadata_path(&exec_id, artifact_id);

                if metadata_path.exists() {
                    return self.load_metadata(&metadata_path).await;
                }
            }
        }

        Err(ArtifactStoreError::NotFound(artifact_id.clone()))
    }

    async fn get_execution_size(
        &self,
        execution_id: &ExecutionId,
    ) -> Result<u64, ArtifactStoreError> {
        let exec_path = self.execution_path(execution_id);

        if !exec_path.exists() {
            return Ok(0);
        }

        let mut total: u64 = 0;
        let mut entries = fs::read_dir(&exec_path).await?;

        while let Some(entry) = entries.next_entry().await? {
            if let Ok(metadata) = entry.metadata().await {
                total += metadata.len();
            }
        }

        Ok(total)
    }
}

// =============================================================================
// Tests
// =============================================================================

#[cfg(test)]
mod tests {
    use super::super::metadata::ArtifactType;
    use super::*;
    use crate::kernel::ids::StepId;
    use tempfile::TempDir;

    #[tokio::test]
    async fn test_filesystem_store_put_get() {
        let temp_dir = TempDir::new().unwrap();
        let store = FilesystemArtifactStore::new(temp_dir.path());

        let exec_id = ExecutionId::new();
        let step_id = StepId::new();
        let content = b"Hello, World! This is a test artifact.".to_vec();

        let request = PutArtifactRequest::new(
            exec_id.clone(),
            step_id,
            "test.txt",
            ArtifactType::Text,
            content.clone(),
        );

        let response = store.put(request).await.unwrap();
        assert!(response.artifact_id.as_str().starts_with("artifact_"));
        assert!(response.compressed_size > 0);
        assert_eq!(response.original_size, content.len() as u64);

        // Retrieve and verify
        let get_response = store.get(&response.artifact_id).await.unwrap();
        assert_eq!(get_response.content, content);
        assert_eq!(get_response.metadata.name, "test.txt");
    }

    #[tokio::test]
    async fn test_filesystem_store_compression() {
        let temp_dir = TempDir::new().unwrap();
        let store = FilesystemArtifactStore::new(temp_dir.path());

        let exec_id = ExecutionId::new();
        let step_id = StepId::new();

        // Create repetitive content that compresses well
        let content = "Hello, World! ".repeat(1000).into_bytes();

        let request = PutArtifactRequest::new(
            exec_id,
            step_id,
            "repetitive.txt",
            ArtifactType::Text,
            content.clone(),
        );

        let response = store.put(request).await.unwrap();

        // Compressed should be smaller than original for repetitive data
        assert!(response.compressed_size < response.original_size);

        // Verify content is preserved
        let get_response = store.get(&response.artifact_id).await.unwrap();
        assert_eq!(get_response.content, content);
    }

    #[tokio::test]
    async fn test_filesystem_store_list() {
        let temp_dir = TempDir::new().unwrap();
        let store = FilesystemArtifactStore::new(temp_dir.path());

        let exec_id = ExecutionId::new();
        let step_id = StepId::new();

        // Store multiple artifacts
        for i in 0..3 {
            let request = PutArtifactRequest::new(
                exec_id.clone(),
                step_id.clone(),
                format!("file{}.txt", i),
                ArtifactType::Text,
                format!("Content {}", i).into_bytes(),
            );
            store.put(request).await.unwrap();
        }

        // List all for execution
        let query = ListArtifactsQuery::for_execution(exec_id);
        let results = store.list(query).await.unwrap();
        assert_eq!(results.len(), 3);
    }
}