extern crate num_cpus;

use std::fs::File;
use std::io::prelude::*;
use regex::RegexSet;
use gitignore::*;
use std::path::PathBuf;
use self::num_cpus::get;

pub fn mk_ignores(in_paths: &PathBuf, maybe_gitignore: &Option<RegexSet>) -> Option<RegexSet> {

    if let Some(ref gitignore) = *maybe_gitignore {
        Some(gitignore.to_owned())
    }
    else {
        if let (gitignore_path, Ok(mut file)) = { let mut gitignore_path = in_paths.clone() ; gitignore_path.push(".gitignore") ; (gitignore_path.clone(), File::open(gitignore_path)) } {
            let mut contents = String::new();
            file.read_to_string(&mut contents)
                .expect("File read failed.");
            Some(file_contents_to_regex(&contents, &gitignore_path))
        } else if let (darcs_path, Ok(mut file)) = { let mut darcs_path = in_paths.clone() ; darcs_path.push("_darcs/prefs/boring") ; (darcs_path.clone(), File::open(darcs_path)) } {
            let mut contents = String::new();
            file.read_to_string(&mut contents)
                .expect("File read failed.");
            Some(darcs_contents_to_regex(&contents, &darcs_path))
        } else if let (ignore_path, Ok(mut file)) = { let mut ignore_path = in_paths.clone(); ignore_path.push(".ignore") ; (ignore_path.clone(), File::open(ignore_path.clone())) } {
            let mut contents = String::new();
            file.read_to_string(&mut contents)
                .expect("File read failed.");
            Some(file_contents_to_regex(&contents, &ignore_path))
        } else {
            None
        }
    }

}

pub fn get_processors() -> usize {
    let n = get();
    if n > 1 { n - 1 } else { n }
}