feat 获取视频文件.

src/main.rs

@@ -1,7 +1,6 @@
 mod merge;
 
 use std::env;
-use std::error::Error;
 use std::io::Result;
 use std::path::PathBuf;
 

src/merge.rs

@@ -1,6 +1,30 @@
-use std::path::Path;
+use std::fs;
 use std::io::Result;
+use std::path::{Path, PathBuf};
+
+fn guess_video_path(path: &Path) -> Result<PathBuf> {
+    let mut largest_size = 0;
+    let mut largest_file = PathBuf::from(path);
+    for entry in fs::read_dir(path)? {
+        let entry_path = entry?.path().canonicalize()?;
+        if entry_path.is_dir() {
+            continue;
+        }
+
+        let size = entry_path.metadata()?.len();
+        if size > largest_size {
+            largest_size = size;
+            largest_file = entry_path.into();
+        }
+    }
+
+    Ok(largest_file)
+}
 
 pub fn merge_video_from_path(path: &Path) -> Result<()> {
+    let video_path = guess_video_path(path)?;
+    let video_name = video_path.file_name().unwrap();
+    println!("Merging video {:?}", video_name);
+
     Ok(())
 }