// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of Open Ethereum.

// Open Ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Open Ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Open Ethereum.  If not, see <http://www.gnu.org/licenses/>.

extern crate rustc_version;
extern crate toml;
extern crate vergen;

use std::env;
use std::fs::File;
use std::io::Write;
use std::path::Path;
use vergen::{ConstantsFlags, generate_cargo_keys};

const ERROR_MSG: &'static str = "Failed to generate metadata files";

fn main() {
	let vergen_flags = ConstantsFlags::COMMIT_DATE |
		ConstantsFlags::SHA |
		ConstantsFlags::SHA_SHORT |
		ConstantsFlags::TARGET_TRIPLE |
		ConstantsFlags::REBUILD_ON_HEAD_CHANGE;
	generate_cargo_keys(vergen_flags).expect(ERROR_MSG);

	let version = rustc_version::version().expect(ERROR_MSG);

	let cargo: toml::Value = toml::from_str(include_str!("./Cargo.toml")).expect(ERROR_MSG);
	let track = cargo["package"]["metadata"]["track"].as_str().expect("'track' has to be a string!");

	create_file("meta.rs", format!("
			/// This versions track.
			#[allow(unused)]
			pub const TRACK: &str = {track:?};

			/// Returns compiler version.
			pub fn rustc_version() -> &'static str {{
				\"{version}\"
			}}
		",
		track = track,
		version = version,
	));
}

fn create_file(filename: &str, data: String) {
	let out_dir = env::var("OUT_DIR").expect(ERROR_MSG);
	let dest_path = Path::new(&out_dir).join(filename);
	let mut f = File::create(&dest_path).expect(ERROR_MSG);
	f.write_all(data.as_bytes()).expect(ERROR_MSG);
}
