fetch chain specs from Acala repo

.gitignore

@@ -14,4 +14,8 @@ target/
 #  be found at https://github.com/github/gitignore/blob/main/Global/JetBrains.gitignore
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
-#.idea/
+#.idea/
+
+
+# fetched by build.rs
+chainspecs

Cargo.toml

@@ -18,6 +18,7 @@ sc-cli = { git = "https://github.com/paritytech/polkadot-sdk", branch = "stable2
 [build-dependencies]
 substrate-build-script-utils = "11.0.0"
 orml-build-script-utils = "1.0.0"
+ureq = "2.12.1"
 
 [profile.release]
 lto = true

build.rs

@@ -16,7 +16,34 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
+use std::fs;
+use std::path::Path;
+
 fn main() {
     substrate_build_script_utils::generate_cargo_keys();
     orml_build_script_utils::check_file_licenses("./src", include_bytes!("./HEADER-GPL3"), &[]);
+
+    let out_dir = "chainspecs";
+    fs::create_dir_all(out_dir).expect("Failed to create chainspecs directory");
+
+    let files = [
+        (
+            "acala-dist.json",
+            "https://github.com/AcalaNetwork/Acala/raw/refs/heads/master/resources/acala-dist.json",
+        ),
+        (
+            "karura-dist.json",
+            "https://github.com/AcalaNetwork/Acala/raw/refs/heads/master/resources/karura-dist.json",
+        ),
+    ];
+
+    for (filename, url) in files.iter() {
+        let path = Path::new(out_dir).join(filename);
+        if !path.exists() {
+            let response = ureq::get(url).call().expect("Failed to fetch chainspec");
+            let mut file = fs::File::create(&path).expect("Failed to create file");
+            let mut reader = response.into_reader();
+            std::io::copy(&mut reader, &mut file).expect("Failed to copy data");
+        }
+    }
 }