feat: implement mode_diff function with diff command

src/main.rs

@@ -516,8 +516,35 @@ fn mode_diff(cmd: &mut Command, args: Args, ids: &mut Vec<i64>, tags: &mut Vec<S
 
             let compression_engine_b = compression::get_engine(compression_type_b).expect("Unable to get compression engine");
 
-            let program = "diff";
+            let (fd_a, path_a) = tempfile::NamedTempFile::new().unwrap();
-            let args = ["-u"];
+            let (fd_b, path_b) = tempfile::NamedTempFile::new().unwrap();
+
+            let mut stdout_a = io::stdout();
+            let mut stdout_b = io::stdout();
+
+            let mut stdout_a = stdout_a.duplicate().unwrap();
+            let mut stdout_b = stdout_b.duplicate().unwrap();
+
+            io::stdout().set_fd(fd_a.as_raw_fd()).unwrap();
+            compression_engine_a.cat(item_path_a.clone())?;
+            io::stdout().set_fd(stdout_a.as_raw_fd()).unwrap();
+
+            io::stdout().set_fd(fd_b.as_raw_fd()).unwrap();
+            compression_engine_b.cat(item_path_b.clone())?;
+            io::stdout().set_fd(stdout_b.as_raw_fd()).unwrap();
+
+            let output = std::process::Command::new("diff")
+                .arg("-u")
+                .arg(path_a)
+                .arg(path_b)
+                .output()
+                .expect("Failed to execute diff command");
+
+            if output.status.success() {
+                println!("{}", String::from_utf8_lossy(&output.stdout));
+            } else {
+                eprintln!("{}", String::from_utf8_lossy(&output.stderr));
+            }
 
             Ok(())
         } else {