use std::path::{Path, PathBuf, Component};
use std::error::Error;
use std::fs::{self, metadata, File};

/// This is copied from the rust source code until Path_ Ext stabilizes.
/// You can use it, but be aware that it will be removed when those features go to rust stable
pub trait PathExt {
    fn exists(&self) -> bool;
    fn is_file(&self) -> bool;
    fn is_dir(&self) -> bool;
}

impl PathExt for Path {
    fn exists(&self) -> bool {
        metadata(self).is_ok()
    }

    fn is_file(&self) -> bool {
       metadata(self).map(|s| s.is_file()).unwrap_or(false)
    }

    fn is_dir(&self) -> bool {
       metadata(self).map(|s| s.is_dir()).unwrap_or(false)
    }
}

/// Takes a path and returns a path containing just enough `../` to point to the root of the given path.
///
/// This is mostly interesting for a relative path to point back to the directory from where the
/// path starts.
///
/// ```ignore
/// let mut path = Path::new("some/relative/path");
///
/// println!("{}", path_to_root(&path));
/// ```
///
/// **Outputs**
///
/// ```text
/// "../../"
/// ```
///
/// **note:** it's not very fool-proof, if you find a situation where it doesn't return the correct
/// path. Consider [submitting a new issue](https://github.com/azerupi/mdBook/issues) or a
/// [pull-request](https://github.com/azerupi/mdBook/pulls) to improve it.

pub fn path_to_root(path: &Path) -> String {
    debug!("[fn]: path_to_root");
    // Remove filename and add "../" for every directory

    path.to_path_buf().parent().expect("")
        .components().fold(String::new(), |mut s, c| {
            match c {
                Component::Normal(_) => s.push_str("../"),
                _ => {
                    debug!("[*]: Other path component... {:?}", c);
                }
            }
            s
        })
}

/// This function checks for every component in a path if the directory exists,
/// if it does not it is created.

pub fn create_path(path: &Path) -> Result<(), Box<Error>> {
    debug!("[fn]: create_path");

    // Create directories if they do not exist
    let mut constructed_path = PathBuf::new();

    for component in path.components() {

        let mut dir;
        match component {
            Component::Normal(_) => { dir = PathBuf::from(component.as_os_str()); },
            Component::RootDir => {
                debug!("[*]: Root directory");
                // This doesn't look very compatible with Windows...
                constructed_path.push("/");
                continue
            },
            _ => continue,
        }

        constructed_path.push(&dir);
        debug!("[*]: {:?}", constructed_path);

        if !constructed_path.exists() || !constructed_path.is_dir() {
            try!(fs::create_dir(&constructed_path));
            debug!("[*]: Directory created {:?}", constructed_path);
        } else {
            debug!("[*]: Directory exists {:?}", constructed_path);
            continue
        }

    }

    debug!("[*]: Constructed path: {:?}", constructed_path);

    Ok(())
}

/// This function creates a file and returns it. But before creating the file it checks every
/// directory in the path to see if it exists, and if it does not it will be created.

pub fn create_file(path: &Path) -> Result<File, Box<Error>> {
    debug!("[fn]: create_file");

    // Construct path
    if let Some(p) = path.parent() {
        try!(create_path(p));
    }

    debug!("[*]: Create file: {:?}", path);
    let f = try!(File::create(path));

    Ok(f)
}

/// Removes all the content of a directory but not the directory itself

pub fn remove_dir_content(dir: &Path) -> Result<(), Box<Error>> {
    for item in try!(fs::read_dir(dir)) {
        if let Ok(item) = item {
            let item = item.path();
            if item.is_dir() { try!(fs::remove_dir_all(item)); } else { try!(fs::remove_file(item)); }
        }
    }
    Ok(())
}

/// **Untested!**
///
/// Copies all files of a directory to another one except the files with the extensions given in the
/// `ext_blacklist` array

pub fn copy_files_except_ext(from: &Path, to: &Path, recursive: bool, ext_blacklist: &[String]) -> Result<(), Box<Error>> {

    // Check that from and to are different
    if from == to { return Ok(()) }

    for entry in try!(fs::read_dir(from)) {
        let entry = try!(entry);
        let metadata = try!(entry.metadata());

        // If the entry is a dir and the recursive option is enabled, call itself
        if metadata.is_dir() && recursive {
            try!(copy_files_except_ext(
                &from.join(entry.file_name()),
                &to.join(entry.file_name()),
                true,
                ext_blacklist
            ));
        } else if metadata.is_file() {

            // Check if it is in the blacklist
            if let Some(ext) = entry.path().extension() {
                if ext_blacklist.contains(&String::from(ext.to_str().unwrap())) { continue }

                try!(fs::copy(entry.path(), &to.join(entry.path().file_name().expect("a file should have a file name..."))));
            }
        }
    }
    Ok(())
}