Add explicit image builder CLI commands

4 files changed, 137 insertions, 2 deletions

diff --git a/src/cli.rs b/src/cli.rs
new file mode 100644
index 0000000..de9404a
--- /dev/null
+++ b/src/cli.rs
@@ -0,0 +1,58 @@
+use std::path::PathBuf;
+
+use anyhow::{bail, Result};
+use clap::{Parser, Subcommand};
+
+use crate::{BuildPlan, ImageSpec};
+
+#[derive(Debug, Parser)]
+#[command(name = "alt-controller-image", about = "Native ALT image builder")]
+pub struct Cli {
+    #[command(subcommand)]
+    pub command: Command,
+}
+
+#[derive(Debug, Subcommand)]
+pub enum Command {
+    /// Validate an image specification and render its build intent.
+    Plan {
+        #[arg(long)]
+        spec: PathBuf,
+    },
+    /// Build an image from a specification.
+    Build {
+        #[arg(long)]
+        spec: PathBuf,
+        #[arg(long)]
+        workspace: PathBuf,
+        #[arg(long)]
+        output: PathBuf,
+    },
+    /// Inspect a built artifact.
+    Inspect {
+        #[arg(long)]
+        artifact: PathBuf,
+    },
+    /// Compare two built artifacts semantically.
+    Compare {
+        #[arg(long)]
+        left: PathBuf,
+        #[arg(long)]
+        right: PathBuf,
+    },
+}
+
+pub fn run(cli: Cli) -> Result<()> {
+    match cli.command {
+        Command::Plan { spec } => {
+            let plan = BuildPlan::compile(ImageSpec::load(&spec)?)?;
+            println!("target: {}", plan.spec().target.name);
+            println!("architecture: {}", plan.spec().target.architecture.as_str());
+            println!("format: tar");
+            Ok(())
+        }
+        Command::Build { .. } => bail!("build execution is not available yet"),
+        Command::Inspect { .. } => bail!("artifact inspection is not available yet"),
+        Command::Compare { .. } => bail!("artifact comparison is not available yet"),
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index a62cbde..52a875d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod cli;
 pub mod model;
 pub mod plan;
 
diff --git a/src/main.rs b/src/main.rs
index 1ca0cab..1e06263 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,9 @@
+use alt_controller_image::cli::{run, Cli};
+use clap::Parser;
+
 fn main() {
-    eprintln!("The command-line interface is not available yet. Use the library to load an ImageSpec.");
-    std::process::exit(2);
+    if let Err(error) = run(Cli::parse()) {
+        eprintln!("error: {error:#}");
+        std::process::exit(1);
+    }
 }
diff --git a/tests/cli.rs b/tests/cli.rs
new file mode 100644
index 0000000..b800e68
--- /dev/null
+++ b/tests/cli.rs
@@ -0,0 +1,71 @@
+use std::path::PathBuf;
+
+use alt_controller_image::cli::{Cli, Command};
+use clap::Parser;
+
+#[test]
+fn parses_plan_with_an_explicit_spec_path() {
+    let cli = Cli::try_parse_from(["alt-controller-image", "plan", "--spec", "image.toml"])
+        .expect("plan command parses");
+
+    assert!(matches!(
+        cli.command,
+        Command::Plan { spec } if spec == PathBuf::from("image.toml")
+    ));
+}
+
+#[test]
+fn parses_build_with_explicit_workspace_and_output_paths() {
+    let cli = Cli::try_parse_from([
+        "alt-controller-image",
+        "build",
+        "--spec",
+        "image.toml",
+        "--workspace",
+        "work",
+        "--output",
+        "out/image.tar",
+    ])
+    .expect("build command parses");
+
+    assert!(matches!(
+        cli.command,
+        Command::Build {
+            spec,
+            workspace,
+            output
+        } if spec == PathBuf::from("image.toml")
+            && workspace == PathBuf::from("work")
+            && output == PathBuf::from("out/image.tar")
+    ));
+}
+
+#[test]
+fn parses_inspect_with_an_explicit_artifact_path() {
+    let cli = Cli::try_parse_from(["alt-controller-image", "inspect", "--artifact", "out/image.tar"])
+        .expect("inspect command parses");
+
+    assert!(matches!(
+        cli.command,
+        Command::Inspect { artifact } if artifact == PathBuf::from("out/image.tar")
+    ));
+}
+
+#[test]
+fn parses_compare_with_explicit_artifact_paths() {
+    let cli = Cli::try_parse_from([
+        "alt-controller-image",
+        "compare",
+        "--left",
+        "legacy.tar",
+        "--right",
+        "native.tar",
+    ])
+    .expect("compare command parses");
+
+    assert!(matches!(
+        cli.command,
+        Command::Compare { left, right }
+            if left == PathBuf::from("legacy.tar") && right == PathBuf::from("native.tar")
+    ));
+}