#![allow(unused)]

use std::convert::AsRef;
use std::env;
use std::ffi::OsString;
use std::path::{PathBuf, Path};
use std::process::Command;
use std::string::ToString;
use tar::Archive;
use flate2::read::GzDecoder;


///////////////////////////////////////////////////////////////////////////////
// UTILS - ENVIROMENT
///////////////////////////////////////////////////////////////////////////////

fn is_release_mode() -> bool {
    let value = std::env::var("PROFILE")
        .expect("missing PROFILE")
        .to_lowercase();
    &value == "release"
}

fn is_debug_mode() -> bool {
    let value = std::env::var("PROFILE")
        .expect("missing PROFILE")
        .to_lowercase();
    &value == "debug"
}

fn out_dir() -> PathBuf {
    PathBuf::from(std::env::var("OUT_DIR").expect("OUT_DIR env var"))
}

fn source_path() -> PathBuf {
    out_dir().join("x264-stable")
}

fn install_prefix() -> PathBuf {
    out_dir().join("build")
}

///////////////////////////////////////////////////////////////////////////////
// UTILS - BUILD
///////////////////////////////////////////////////////////////////////////////

pub fn extract_tar_file<P: AsRef<Path>, Q: AsRef<Path>>(tar_file: P, dest: Q) -> Result<(), String> {
    let source = std::fs::read(tar_file).expect("read tar file");
    let tar = GzDecoder::new(&source[..]);
    let mut archive = Archive::new(tar);
    // UNPACK ARCHIVE
    let tmp_source_dir: Option<PathBuf> = {
        archive
            .unpack(&dest)
            .map_err(|x| format!("[{:?}] failed to unpack tar file: {:?}", dest.as_ref(), x))?;
        let xs = std::fs::read_dir(&dest)
            .expect(&format!("unable to read dir {:?}", dest.as_ref()))
            .filter_map(Result::ok)
            .filter(|file| file.file_type().map(|x| x.is_dir()).unwrap_or(false))
            .collect::<Vec<std::fs::DirEntry>>();
        match &xs[..] {
            [x] => Some(x.path()),
            _ => None,
        }
    };
    Ok(())
}

pub fn lookup_newest(paths: Vec<PathBuf>) -> Option<PathBuf> {
    use std::time::{SystemTime, Duration};
    let mut newest: Option<(PathBuf, Duration)> = None;
    paths
        .clone()
        .into_iter()
        .filter_map(|x: PathBuf| {
            let timestamp = x
                .metadata()
                .ok()
                .and_then(|y| y.created().ok())
                .and_then(|x| x.duration_since(SystemTime::UNIX_EPOCH).ok());
            match timestamp {
                Some(y) => Some((x, y)),
                _ => None
            }
        })
        .for_each(|(x_path, x_created)| match &newest {
            None => {
                newest = Some((x_path, x_created));
            }
            Some((_, y_created)) => {
                if &x_created > y_created {
                    newest = Some((x_path, x_created));
                }
            }
        });
    // DONE
    newest.map(|(x, _)| x)
}

pub fn files_with_prefix(dir: &PathBuf, pattern: &str) -> Vec<PathBuf> {
    std::fs::read_dir(dir)
        .expect(&format!("get dir contents: {:?}", dir))
        .filter_map(Result::ok)
        .filter_map(|x| {
            let file_name = x
                .file_name()
                .to_str()?
                .to_owned();
            if file_name.starts_with(pattern) {
                Some(x.path())
            } else {
                None
            }
        })
        .collect::<Vec<_>>()
}

fn build_x264() {
    let source_path = source_path();

    let mut prefix_arg = OsString::from("--prefix=");
    prefix_arg.push(&install_prefix());

    let result = Command::new("bash")
        .arg("configure")
        .arg(prefix_arg)
        .arg("--disable-cli")
        .arg("--enable-static")
        .current_dir(&source_path)
        .status()
        .unwrap();

    if !result.success() {
        panic!("failed to configure x264");
    }

    let result = Command::new("make")
        .arg("-j")
        .arg(num_cpus::get().to_string())
        .arg("all")
        .arg("install")
        .current_dir(&source_path)
        .status()
        .unwrap();

    if !result.success() {
        panic!("Failed to build x264");
    }
}

fn cpy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) {
    std::fs::copy(&from, &to)
        .expect(&format!(
            "unable to cpy from {:?} to {:?}",
            from.as_ref(),
            to.as_ref(),
        ));
}

///////////////////////////////////////////////////////////////////////////////
// PATHS
///////////////////////////////////////////////////////////////////////////////

pub const STATIC_LIBS: &[(&str, &str)] = &[
    ("x264", "./libx264.a"),
];

pub const HEADERS: &[&str] = &[
    "x264.h",
];

///////////////////////////////////////////////////////////////////////////////
// BUILD PIPELINE
///////////////////////////////////////////////////////////////////////////////

fn build() {
    // SETUP
    extract_tar_file("archive/x264-stable.tar.gz", &out_dir());
    assert!(source_path().exists());
    // BUILD
    build_x264();
    // LINK
    println!("cargo:rustc-link-search=native={}", {
        install_prefix().join("lib").to_str().unwrap()
    });
    for (name, _) in STATIC_LIBS {
        println!("cargo:rustc-link-lib=static={}", name);
    }
    // CODEGEN
    let codegen = |file_name: &str, headers: &[&str]| {
        let codegen = bindgen::Builder::default();
        let codegen = codegen.header("include/prelude.h");
        let codegen = headers
            .iter()
            .fold(codegen, |codegen: bindgen::Builder, path: &&str| -> bindgen::Builder {
                let path: &str = path.clone();
                let path: PathBuf = install_prefix().join("include").join(path);
                let path: &str = path.to_str().expect("PathBuf to str");
                assert!(PathBuf::from(path).exists());
                codegen.header(path)
            });
        codegen
            .generate_comments(true)
            .generate()
            .expect("Unable to generate bindings")
            .write_to_file(out_dir().join(file_name))
            .expect("Couldn't write bindings!");
    };
    codegen("bindings_x264.rs", HEADERS);
    // CARGO METADATA
    println!("cargo:libs={}", install_prefix().join("lib").to_str().unwrap());
    println!("cargo:pkgconfig={}", install_prefix().join("lib").join("pkgconfig").to_str().unwrap());
}

///////////////////////////////////////////////////////////////////////////////
// MAIN
///////////////////////////////////////////////////////////////////////////////

fn main() {
    build();
}