refactoring hexagonal and clean architecture

src/application/ports/thumbnail_ports.rs

@@ -0,0 +1,91 @@
+//! Thumbnail Port - Application layer abstraction for thumbnail generation.
+//!
+//! This module defines the port (trait) for thumbnail operations,
+//! keeping the application and interface layers independent of specific
+//! image processing implementations.
+
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+use async_trait::async_trait;
+use bytes::Bytes;
+use crate::common::errors::DomainError;
+
+/// Thumbnail sizes supported by the system.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub enum ThumbnailSize {
+    /// Small icon for file listings (150×150)
+    Icon,
+    /// Medium preview for gallery view (400×400)
+    Preview,
+    /// Large preview for detail view (800×800)
+    Large,
+}
+
+impl ThumbnailSize {
+    /// Get the maximum dimension for this size.
+    pub fn max_dimension(&self) -> u32 {
+        match self {
+            ThumbnailSize::Icon => 150,
+            ThumbnailSize::Preview => 400,
+            ThumbnailSize::Large => 800,
+        }
+    }
+
+    /// Get the directory name for this size.
+    pub fn dir_name(&self) -> &'static str {
+        match self {
+            ThumbnailSize::Icon => "icon",
+            ThumbnailSize::Preview => "preview",
+            ThumbnailSize::Large => "large",
+        }
+    }
+
+    /// Get all thumbnail sizes.
+    pub fn all() -> &'static [ThumbnailSize] {
+        &[ThumbnailSize::Icon, ThumbnailSize::Preview, ThumbnailSize::Large]
+    }
+}
+
+/// Statistics about the thumbnail cache.
+#[derive(Debug, Clone)]
+pub struct ThumbnailStatsDto {
+    pub cached_thumbnails: usize,
+    pub cache_size_bytes: usize,
+    pub max_cache_bytes: usize,
+}
+
+/// Port for thumbnail generation and retrieval.
+///
+/// Implementations handle the actual image processing, caching,
+/// and storage of thumbnails, while the application layer only
+/// interacts through this abstraction.
+#[async_trait]
+pub trait ThumbnailPort: Send + Sync + 'static {
+    /// Check if a file is an image that can have thumbnails.
+    fn is_supported_image(&self, mime_type: &str) -> bool;
+
+    /// Get a thumbnail, generating it on-demand if needed.
+    ///
+    /// Returns the thumbnail bytes in WebP format.
+    async fn get_thumbnail(
+        &self,
+        file_id: &str,
+        size: ThumbnailSize,
+        original_path: &Path,
+    ) -> Result<Bytes, DomainError>;
+
+    /// Generate all thumbnail sizes for a file in the background.
+    ///
+    /// Called after file upload to pre-generate thumbnails.
+    fn generate_all_sizes_background(
+        self: Arc<Self>,
+        file_id: String,
+        original_path: PathBuf,
+    );
+
+    /// Delete all thumbnails for a file.
+    async fn delete_thumbnails(&self, file_id: &str) -> Result<(), DomainError>;
+
+    /// Get cache statistics.
+    async fn get_stats(&self) -> ThumbnailStatsDto;
+}