// Copyright (c) 2016  Sebastian Wiesner <swiesner@lunaryorn.com>

// 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.

extern crate bindgen;
extern crate hyper;

use std::env;
use std::fs::File;
use std::io;
use std::io::prelude::*;
use std::path::Path;

use hyper::Client;
use hyper::header::Connection;

fn generate_emacs_bindings(out_dir: &str) -> io::Result<()> {
    let origin_path = Path::new(&out_dir).join("emacs-module.h");
    //download header file first
    let client = Client::new();
    let mut response = client.get("https://github.com/emacs-mirror/emacs/raw/master/src/emacs-module.h").
        header(Connection::close()).send().unwrap();
    let mut content = String::new();
    response.read_to_string(&mut content).unwrap();
    //fix intmax_t for the moment
    content = content.replace("intmax_t","int");
    //write locally for bindgen
    let mut f = File::create(&origin_path).expect("Unable to create emacs-module.h file");
    f.write_all(content.as_bytes()).unwrap();

    //generate bindings from downloaded header
    let mut bindings = bindgen::Builder::new(origin_path.to_string_lossy().into_owned());
    let generated_bindings = bindings.builtins()
        .forbid_unknown_types()
        .generate()
        .expect("Failed to generate bindings");
    //and write them into the emacs.rs
    let dest_path = Path::new(out_dir).join("emacs.rs");
    let mut file = try!(File::create(dest_path));
    try!(file.write(b"pub mod emacs {\n"));
    try!(file.write(generated_bindings.to_string().as_bytes()));
    try!(file.write(b"\n}"));
    Ok(())
}

fn main() {
    let out_dir = env::var("OUT_DIR").unwrap();
    generate_emacs_bindings(&out_dir).unwrap();
}