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

/// Takes a path to a file and try to read the file into a String

pub fn file_to_string(path: &Path) -> Result<String, Box<Error>> {
    let mut file = match File::open(path) {
        Ok(f) => f,
        Err(e) => {
            debug!("[*]: Failed to open {:?}", path);
            return Err(Box::new(e));
        },
    };

    let mut content = String::new();

    if let Err(e) = file.read_to_string(&mut content) {
        debug!("[*]: Failed to read {:?}", path);
        return Err(Box::new(e));
    }

    Ok(content)
}

/// 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.
///
/// ```rust
/// # extern crate mdbook;
/// #
/// # use std::path::Path;
/// # use mdbook::utils::fs::path_to_root;
/// #
/// # fn main() {
/// let path = Path::new("some/relative/path");
/// assert_eq!(path_to_root(path), "../../");
/// # }
/// ```
///
/// **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<P: Into<PathBuf>>(path: P) -> String {
    debug!("[fn]: path_to_root");
    // Remove filename and add "../" for every directory

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



/// 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) -> io::Result<File> {
    debug!("[fn]: create_file");

    // Construct path
    if let Some(p) = path.parent() {
        debug!("Parent directory is: {:?}", p);

        fs::create_dir_all(p)?;
    }

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

/// 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 fs::read_dir(dir)? {
        if let Ok(item) = item {
            let item = item.path();
            if item.is_dir() {
                fs::remove_dir_all(item)?;
            } else {
                fs::remove_file(item)?;
            }
        }
    }
    Ok(())
}

///
///
/// 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: &[&str])
                             -> Result<(), Box<Error>> {
    debug!("[fn] copy_files_except_ext");
    // Check that from and to are different
    if from == to {
        return Ok(());
    }
    debug!("[*] Loop");
    for entry in fs::read_dir(from)? {
        let entry = entry?;
        debug!("[*] {:?}", entry.path());
        let metadata = entry.metadata()?;

        // If the entry is a dir and the recursive option is enabled, call itself
        if metadata.is_dir() && recursive {
            if entry.path() == to.to_path_buf() {
                continue;
            }
            debug!("[*] is dir");

            // check if output dir already exists
            if !to.join(entry.file_name()).exists() {
                fs::create_dir(&to.join(entry.file_name()))?;
            }

            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(&ext.to_str().unwrap()) {
                    continue;
                }
            }
            debug!("[*] creating path for file: {:?}",
                   &to.join(entry
                                .path()
                                .file_name()
                                .expect("a file should have a file name...")));

            info!("[*] Copying file: {:?}\n    to {:?}",
                  entry.path(),
                  &to.join(entry
                               .path()
                               .file_name()
                               .expect("a file should have a file name...")));
            fs::copy(entry.path(),
                     &to.join(entry
                                  .path()
                                  .file_name()
                                  .expect("a file should have a file name...")))?;
        }
    }
    Ok(())
}


// ------------------------------------------------------------------------------------------------
// ------------------------------------------------------------------------------------------------

// tests

#[cfg(test)]
mod tests {
    extern crate tempdir;

    use super::copy_files_except_ext;
    use std::fs;

    #[test]
    fn copy_files_except_ext_test() {
        let tmp = match tempdir::TempDir::new("") {
            Ok(t) => t,
            Err(_) => panic!("Could not create a temp dir"),
        };

        // Create a couple of files
        if let Err(_) = fs::File::create(&tmp.path().join("file.txt")) {
            panic!("Could not create file.txt")
        }
        if let Err(_) = fs::File::create(&tmp.path().join("file.md")) {
            panic!("Could not create file.md")
        }
        if let Err(_) = fs::File::create(&tmp.path().join("file.png")) {
            panic!("Could not create file.png")
        }
        if let Err(_) = fs::create_dir(&tmp.path().join("sub_dir")) {
            panic!("Could not create sub_dir")
        }
        if let Err(_) = fs::File::create(&tmp.path().join("sub_dir/file.png")) {
            panic!("Could not create sub_dir/file.png")
        }
        if let Err(_) = fs::create_dir(&tmp.path().join("sub_dir_exists")) {
            panic!("Could not create sub_dir_exists")
        }
        if let Err(_) = fs::File::create(&tmp.path().join("sub_dir_exists/file.txt")) {
            panic!("Could not create sub_dir_exists/file.txt")
        }

        // Create output dir
        if let Err(_) = fs::create_dir(&tmp.path().join("output")) {
            panic!("Could not create output")
        }
        if let Err(_) = fs::create_dir(&tmp.path().join("output/sub_dir_exists")) {
            panic!("Could not create output/sub_dir_exists")
        }

        match copy_files_except_ext(&tmp.path(), &tmp.path().join("output"), true, &["md"]) {
            Err(e) => panic!("Error while executing the function:\n{:?}", e),
            Ok(_) => {},
        }

        // Check if the correct files where created
        if !(&tmp.path().join("output/file.txt")).exists() {
            panic!("output/file.txt should exist")
        }
        if (&tmp.path().join("output/file.md")).exists() {
            panic!("output/file.md should not exist")
        }
        if !(&tmp.path().join("output/file.png")).exists() {
            panic!("output/file.png should exist")
        }
        if !(&tmp.path().join("output/sub_dir/file.png")).exists() {
            panic!("output/sub_dir/file.png should exist")
        }
        if !(&tmp.path().join("output/sub_dir_exists/file.txt")).exists() {
            panic!("output/sub_dir/file.png should exist")
        }

    }
}