implement initial cli

.gitignore

@@ -1,2 +1,3 @@
 /target
-.ignore
+.ignore
+fig

Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 block-padding = "0.3.3"
+clap = { version = "4.4.8", features = ["derive"] }
 image = "0.24.7"
 imageproc = "0.23.0"
 kdam = "0.5.0"

src/bin/fig.rs

@@ -1,27 +1,94 @@
 use std::{
     fs::{self, File},
-    io::{BufReader, Error},
+    io::{BufReader, Error, ErrorKind},
     path::Path,
 };
 
+use clap::{Args, Parser, Subcommand};
 use filegram::{decode, encode};
 use image::ImageFormat;
 
-fn main() -> Result<(), Error> {
-    {
-        let file = File::open(".ignore/file_large.txt")?;
-        let file_size = file.metadata().unwrap().len() as usize;
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    #[command(subcommand)]
+    command: Command,
+}
+
+impl Cli {
+    fn execute(self) -> Result<(), Error> {
+        let command: Box<dyn CommandTrait> = match self.command {
+            Command::Encode(encode) => Box::new(encode),
+            Command::Decode(decode) => Box::new(decode),
+        };
+        command.execute()
+    }
+}
+
+#[derive(Subcommand)]
+enum Command {
+    Encode(Encode),
+    Decode(Decode),
+}
+
+trait CommandTrait {
+    fn execute(&self) -> Result<(), Error>;
+    fn default_output(&self) -> String;
+}
+
+#[derive(Args)]
+struct Encode {
+    #[arg(short, long)]
+    file: String,
+    #[arg(short, long)]
+    output: Option<String>,
+}
+
+impl CommandTrait for Encode {
+    fn execute(&self) -> Result<(), Error> {
+        let output = self.output.clone().unwrap_or_else(|| self.default_output());
+        let file = File::open(self.file.clone())?;
+        let file_size = file.metadata()?.len() as usize;
         let mut file = BufReader::new(file);
         let rgb = encode::to_rgb(&mut file, file_size);
-        let path = Path::new("file_large.txt.png");
-        rgb.save(path).unwrap();
+        let path = Path::new(&output);
+        rgb.save(path)
+            .map_err(|err| Error::new(ErrorKind::Other, err))?;
+        Ok(())
+    }
+
+    fn default_output(&self) -> String {
+        self.file.clone() + ".png"
     }
+}
+
+#[derive(Args)]
+struct Decode {
+    #[arg(short, long)]
+    file: String,
+    #[arg(short, long)]
+    output: Option<String>,
+}
 
-    {
-        let file = File::open("file_large.txt.png")?;
+impl CommandTrait for Decode {
+    fn execute(&self) -> Result<(), Error> {
+        let output = self.output.clone().unwrap_or_else(|| self.default_output());
+        let file = File::open(self.file.clone())?;
         let data = decode::from_file(BufReader::new(file), ImageFormat::Png);
-        fs::write("file_large_decoded.txt", data)?;
+        fs::write(output, data)?;
+        Ok(())
     }
 
-    Ok(())
+    fn default_output(&self) -> String {
+        match self.file.strip_suffix(".png") {
+            Some(output) => output.to_string(),
+            None => self.file.clone() + ".decoded",
+        }
+    }
+}
+
+fn main() -> Result<(), Error> {
+    let cli = Cli::parse();
+
+    cli.execute()
 }