feat(template): Add template for singleton protocols.

Separate templates and add one for protocols with only a single contract.

substreams/ethereum-template-singleton/build.rs

@@ -0,0 +1,49 @@
+use anyhow::Result;
+use std::{fs, io::Write};
+use substreams_ethereum::Abigen;
+
+fn main() -> Result<()> {
+    let abi_folder = "abi";
+    let output_folder = "src/abi";
+
+    let abis = fs::read_dir(abi_folder)?;
+
+    let mut files = abis.collect::<Result<Vec<_>, _>>()?;
+
+    // Sort the files by their name
+    files.sort_by_key(|a| a.file_name());
+
+    let mut mod_rs_content = String::new();
+    mod_rs_content.push_str("#![allow(clippy::all)]\n");
+
+    for file in files {
+        let file_name = file.file_name();
+        let file_name = file_name.to_string_lossy();
+
+        if !file_name.ends_with(".json") {
+            continue;
+        }
+
+        let contract_name = file_name.split('.').next().unwrap();
+
+        let input_path = format!("{}/{}", abi_folder, file_name);
+        let output_path = format!("{}/{}.rs", output_folder, contract_name);
+
+        mod_rs_content.push_str(&format!("pub mod {};\n", contract_name));
+
+        if std::path::Path::new(&output_path).exists() {
+            continue;
+        }
+
+        Abigen::new(contract_name, &input_path)?
+            .generate()?
+            .write_to_file(&output_path)?;
+    }
+
+    let mod_rs_path = format!("{}/mod.rs", output_folder);
+    let mut mod_rs_file = fs::File::create(mod_rs_path)?;
+
+    mod_rs_file.write_all(mod_rs_content.as_bytes())?;
+
+    Ok(())
+}