Add --latest flag (#67)

src/cli.rs

@@ -1,6 +1,6 @@
 use clap::Parser;
 
-use anyhow::bail;
+use anyhow::{bail, Context};
 use std::fs;
 use std::path::PathBuf;
 
@@ -11,6 +11,9 @@ use tlparse::{parse_path, ParseConfig};
 #[command(propagate_version = true)]
 pub struct Cli {
     path: PathBuf,
+    /// Parse most recent log
+    #[arg(long)]
+    latest: bool,
     /// Output directory, defaults to `tl_out`
     #[arg(short, default_value = "tl_out")]
     out: PathBuf,
@@ -42,7 +45,30 @@ pub struct Cli {
 
 fn main() -> anyhow::Result<()> {
     let cli = Cli::parse();
-    let path = cli.path;
+    let path = if cli.latest {
+        let input_path = cli.path;
+        // Path should be a directory
+        if !input_path.is_dir() {
+            bail!(
+                "Input path {} is not a directory (required when using --latest)",
+                input_path.display()
+            );
+        }
+
+        let last_modified_file = std::fs::read_dir(&input_path)
+            .with_context(|| format!("Couldn't access directory {}", input_path.display()))?
+            .flatten()
+            .filter(|f| f.metadata().unwrap().is_file())
+            .max_by_key(|x| x.metadata().unwrap().modified().unwrap());
+
+        let Some(last_modified_file) = last_modified_file else {
+            bail!("No files found in directory {}", input_path.display());
+        };
+        last_modified_file.path()
+    } else {
+        cli.path
+    };
+
     let out_path = cli.out;
 
     if out_path.exists() {