// Copyright 2024 Aleo Network Foundation
// This file is part of the snarkOS library.

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at:

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use std::{fs::File, io::Read, path::Path};

use walkdir::WalkDir;

// The following license text that should be present at the beginning of every source file.
const EXPECTED_LICENSE_TEXT: &[u8] = include_bytes!(".resources/license_header");

// The following directories will be excluded from the license scan.
const DIRS_TO_SKIP: [&str; 8] = [".cargo", ".circleci", ".git", ".github", ".resources", "examples", "js", "target"];

fn check_file_licenses<P: AsRef<Path>>(path: P) {
    let path = path.as_ref();

    let mut iter = WalkDir::new(path).into_iter();
    while let Some(entry) = iter.next() {
        let entry = entry.unwrap();
        let entry_type = entry.file_type();

        // Skip the specified directories.
        if entry_type.is_dir() && DIRS_TO_SKIP.contains(&entry.file_name().to_str().unwrap_or("")) {
            iter.skip_current_dir();

            continue;
        }

        // Check all files with the ".rs" extension.
        if entry_type.is_file() && entry.file_name().to_str().unwrap_or("").ends_with(".rs") {
            let file = File::open(entry.path()).unwrap();
            let mut contents = Vec::with_capacity(EXPECTED_LICENSE_TEXT.len());
            file.take(EXPECTED_LICENSE_TEXT.len() as u64).read_to_end(&mut contents).unwrap();

            assert!(
                contents == EXPECTED_LICENSE_TEXT,
                "The license in \"{}\" is either missing or it doesn't match the expected string!",
                entry.path().display()
            );
        }
    }

    // Re-run upon any changes to the workspace.
    println!("cargo:rerun-if-changed=.");
}

// The build script; it currently only checks the licenses.
fn main() {
    // Check licenses in the current folder.
    check_file_licenses(".");
}