Add very basic CLI.

src/main.rs

@@ -1,3 +1,66 @@
-fn main() {
-    println!("Hello, world!");
+use clap::Args;
+use clap::Parser;
+use clap::Subcommand;
+use std::path::PathBuf;
+use std::process::ExitCode;
+
+fn main() -> Result<ExitCode, Box<dyn std::error::Error>> {
+    let rt = tokio::runtime::Runtime::new()?;
+    rt.block_on(async {
+        let main_body_result = main_body().await;
+        main_body_result
+    })
+}
+
+async fn main_body() -> Result<ExitCode, Box<dyn std::error::Error>> {
+    let args = Cli::parse();
+    match args.command {
+        Commands::Init(_args) => {}
+        Commands::Build(_args) => {}
+        Commands::AddPost(_args) => {}
+    };
+    Ok(ExitCode::SUCCESS)
+}
+
+#[derive(Parser, Debug)]
+#[command(name = "Writer")]
+#[command(version = env!("CARGO_PKG_VERSION"))]
+#[command(about = "Generate a static site.", long_about = None)]
+#[command(propagate_version = true)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand, Debug)]
+enum Commands {
+    /// Initialize an empty website folder.
+    Init(InitArgs),
+
+    /// Build the static site.
+    Build(BuildArgs),
+
+    /// Add a blog post to the site.
+    AddPost(BuildArgs),
+}
+
+#[derive(Args, Debug)]
+struct InitArgs {
+    /// Path where you want the initial writer structure to be located.
+    #[arg(short, long)]
+    path: PathBuf,
+}
+
+#[derive(Args, Debug)]
+struct BuildArgs {
+    /// Path to the writer config file.
+    #[arg(short, long)]
+    config: PathBuf,
+}
+
+#[derive(Args, Debug)]
+struct AddPostArgs {
+    /// Path to the writer config file.
+    #[arg(short, long)]
+    config: PathBuf,
 }