use std::path::PathBuf;
use std::io::Read;
use std::fs::File;

use util::{FileId, mkdir_existing};
use authentication::Credentials;

#[derive(Clone)]
pub struct Cache {
    root: PathBuf,
}

impl Cache {
    pub fn new(location: PathBuf) -> Cache {
        mkdir_existing(&location).unwrap();
        mkdir_existing(&location.join("files")).unwrap();

        Cache {
            root: location
        }
    }
}

impl Cache {
    fn credentials_path(&self) -> PathBuf {
        self.root.join("credentials.json")
    }

    pub fn credentials(&self) -> Option<Credentials> {
        let path = self.credentials_path();
        Credentials::from_file(path)
    }

    pub fn save_credentials(&self, cred: &Credentials) {
        let path = self.credentials_path();
        cred.save_to_file(&path);
    }
}

impl Cache {
    fn file_path(&self, file: FileId) -> PathBuf {
        let name = file.to_base16();
        self.root.join("files").join(&name[0..2]).join(&name[2..])
    }

    pub fn file(&self, file: FileId) -> Option<File> {
        File::open(self.file_path(file)).ok()
    }

    pub fn save_file(&self, file: FileId, contents: &mut Read) {
        let path = self.file_path(file);

        mkdir_existing(path.parent().unwrap()).unwrap();

        let mut cache_file = File::create(path).unwrap();
        ::std::io::copy(contents, &mut cache_file).unwrap();
    }
}