feat(exporters): add build() and available_names() factory

Cargo.toml

@@ -8,3 +8,4 @@ thiserror = "2.0.18"
 tracing = "0.1.44"
 tracing-subscriber = { version = "0.3.23", features = ["env-filter"] }
 serde = { version = "1.0.228", features = ["derive"] }
+serde_json = "1"

crates/exporters/Cargo.toml

@@ -11,3 +11,6 @@ anyhow = { workspace = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
 serde = { workspace = true }
+
+[dev-dependencies]
+serde_json = { workspace = true }

crates/exporters/src/lib.rs

@@ -1,5 +1,60 @@
 mod litematica;
 mod mcfunction;
 
+use lib::{BlockPalette, StructureExporter};
+
 pub use litematica::LitematicaExporter;
 pub use mcfunction::McFunctionExporter;
+
+pub fn available_names() -> &'static [&'static str] {
+    &["mcfunction", "litematica"]
+}
+
+pub fn build(name: &str, palette: &BlockPalette) -> Option<Box<dyn StructureExporter>> {
+    match name {
+        "mcfunction" => Some(Box::new(McFunctionExporter::new(palette))),
+        "litematica" => Some(Box::new(LitematicaExporter::new(palette))),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn dummy_palette() -> BlockPalette {
+        serde_json::from_str(r#"{
+            "name": "test",
+            "blocks": {
+                "body": "minecraft:stone",
+                "outline": "minecraft:cobblestone",
+                "shadow": "minecraft:gravel"
+            }
+        }"#).unwrap()
+    }
+
+    #[test]
+    fn build_mcfunction_returns_some() {
+        let p = dummy_palette();
+        assert!(build("mcfunction", &p).is_some());
+    }
+
+    #[test]
+    fn build_litematica_returns_some() {
+        let p = dummy_palette();
+        assert!(build("litematica", &p).is_some());
+    }
+
+    #[test]
+    fn build_unknown_returns_none() {
+        let p = dummy_palette();
+        assert!(build("foo", &p).is_none());
+    }
+
+    #[test]
+    fn available_names_contains_both() {
+        let names = available_names();
+        assert!(names.contains(&"mcfunction"));
+        assert!(names.contains(&"litematica"));
+    }
+}