feat: Detect animation in image files for fetch_preview (#574)

* Implement animated metadata TODOs for database and thumbnailing.

Signed-off-by: Assisting <erik@eriklabine.com>

* Run linter for code changes

Signed-off-by: Assisting <erik@eriklabine.com>

---------

Signed-off-by: Assisting <erik@eriklabine.com>

crates/core/files/src/implementation/media_impl.rs

@@ -1,5 +1,5 @@
 use anyhow::Result;
-use image::{DynamicImage, ImageBuffer, ImageReader};
+use image::{AnimationDecoder, DynamicImage, ImageBuffer, ImageReader};
 use jxl_oxide::integration::JxlDecoder;
 use revolt_config::report_internal_error;
 use std::io::{BufRead, Read, Seek};
@@ -35,6 +35,31 @@ impl MediaRepository for MediaImpl {
         }
     }
 
+    fn is_animated(&self, f: &NamedTempFile, mime: &str) -> Option<bool> {
+        match mime {
+            // Current behaviour is to assume GIFs are animated, this checks for at least 2 frames
+            "image/gif" => {
+                let file = std::fs::File::open(f.path()).ok()?;
+                let reader = std::io::BufReader::new(file);
+                let decoder = image::codecs::gif::GifDecoder::new(reader).ok()?;
+                Some(decoder.into_frames().take(2).count() > 1)
+            }
+            "image/png" => {
+                let file = std::fs::File::open(f.path()).ok()?;
+                let reader = std::io::BufReader::new(file);
+                let decoder = image::codecs::png::PngDecoder::new(reader).ok()?;
+                decoder.is_apng().ok()
+            }
+            "image/webp" => {
+                let file = std::fs::File::open(f.path()).ok()?;
+                let reader = std::io::BufReader::new(file);
+                let decoder = image::codecs::webp::WebPDecoder::new(reader).ok()?;
+                Some(decoder.has_animation())
+            }
+            _ => Some(false),
+        }
+    }
+
     fn image_size_vec(&self, v: &[u8], mime: &str) -> Option<(usize, usize)> {
         match mime {
             "image/svg+xml" => {
@@ -171,9 +196,9 @@ impl MediaRepository for MediaImpl {
 
 #[cfg(test)]
 mod tests {
-    use std::io::Cursor;
-
     use crate::{MediaImpl, MediaRepository};
+    use std::io::{Cursor, Write};
+    use tempfile::NamedTempFile;
 
     #[tokio::test]
     async fn asset_test_jpeg() {
@@ -186,6 +211,15 @@ mod tests {
         media.create_thumbnail(image, "attachments");
     }
 
+    #[tokio::test]
+    async fn asset_test_jpeg_is_not_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/test.jpeg"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/jpeg"), Some(false));
+    }
+
     #[tokio::test]
     async fn asset_test_jpeg_extra_bytes() {
         let media = MediaImpl::from_config().await;
@@ -212,6 +246,15 @@ mod tests {
         media.create_thumbnail(image, "emojis");
     }
 
+    #[tokio::test]
+    async fn asset_test_png_is_not_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/test.png"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/png"), Some(false));
+    }
+
     #[tokio::test]
     async fn asset_test_png_extra_bytes() {
         let media = MediaImpl::from_config().await;
@@ -259,6 +302,15 @@ mod tests {
         media.create_thumbnail(image, "attachments");
     }
 
+    #[tokio::test]
+    async fn asset_test_animated_png_is_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/anim-icos.apng"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/png"), Some(true));
+    }
+
     #[tokio::test]
     async fn asset_test_jxl() {
         let media = MediaImpl::from_config().await;
@@ -292,6 +344,15 @@ mod tests {
         media.create_thumbnail(image, "attachments");
     }
 
+    #[tokio::test]
+    async fn asset_test_webp_is_not_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/dice.webp"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/webp"), Some(false));
+    }
+
     #[tokio::test]
     async fn asset_test_animated_webp() {
         let media = MediaImpl::from_config().await;
@@ -303,6 +364,15 @@ mod tests {
         media.create_thumbnail(image, "attachments");
     }
 
+    #[tokio::test]
+    async fn asset_test_animated_webp_is_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/anim-icos.webp"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/webp"), Some(true));
+    }
+
     #[tokio::test]
     async fn asset_test_animated_gif() {
         let media = MediaImpl::from_config().await;
@@ -313,4 +383,13 @@ mod tests {
         let image = media.decode_image(&mut reader, "image/gif").unwrap();
         media.create_thumbnail(image, "attachments");
     }
+
+    #[tokio::test]
+    async fn asset_test_animated_gif_is_animated() {
+        let media = MediaImpl::from_config().await;
+        let mut f = NamedTempFile::new().unwrap();
+        f.write_all(include_bytes!("../../tests/assets/anim-icos.gif"))
+            .unwrap();
+        assert_eq!(media.is_animated(&f, "image/gif"), Some(true));
+    }
 }