feat: implement robust format identification, plugin availability checks, and automatic conversion path rerouting on failure

src/pathfinder.rs

@@ -45,9 +45,13 @@ pub fn find_best_path<'a>(
     from_format: &'a str,
     to_format: &str,
     priority: &str,
+    banned_plugins: &[&str],
 ) -> Option<Vec<(&'a dyn Plugin, &'a str, &'a str)>> {
     let mut adj_list: HashMap<&str, Vec<&'a dyn Plugin>> = HashMap::new();
     for p in plugins {
+        if banned_plugins.contains(&p.name()) || !p.is_available() {
+            continue;
+        }
         for &from in &p.from_formats() {
             adj_list.entry(from).or_default().push(p.as_ref());
         }
@@ -243,7 +247,7 @@ mod tests {
             }),
         ];
 
-        let path = find_best_path(&plugins, "jpeg", "png", "fqs").unwrap();
+        let path = find_best_path(&plugins, "jpeg", "png", "fqs", &[]).unwrap();
         assert_eq!(path.len(), 1);
         assert_eq!(path[0].0.name(), "A");
     }
@@ -269,10 +273,10 @@ mod tests {
             }),
         ];
 
-        let path = find_best_path(&plugins, "jpeg", "png", "fqs").unwrap();
+        let path = find_best_path(&plugins, "jpeg", "png", "fqs", &[]).unwrap();
         assert_eq!(path[0].0.name(), "B");
 
-        let path = find_best_path(&plugins, "jpeg", "png", "qfs").unwrap();
+        let path = find_best_path(&plugins, "jpeg", "png", "qfs", &[]).unwrap();
         assert_eq!(path[0].0.name(), "A");
     }
 
@@ -339,7 +343,7 @@ mod tests {
                     }),
                 ];
 
-                let path = find_best_path(&plugins, $from, $to, $priority);
+                let path = find_best_path(&plugins, $from, $to, $priority, &[]);
                 if $expected_len == 0 {
                     assert!(path.is_none());
                 } else {
@@ -408,7 +412,7 @@ mod tests {
                         s: 10,
                     }),
                 ];
-                let path = find_best_path(&plugins, $from, $to, $priority);
+                let path = find_best_path(&plugins, $from, $to, $priority, &[]);
                 if $expected_len == 0 {
                     assert!(path.is_none());
                 } else {