extern crate users;
extern crate hex;

use std::io;
use std::fs;
use std::os::unix::fs::PermissionsExt;
use std::os::linux::fs::MetadataExt;
use std::io::prelude::*;

use walkdir::DirEntry;
use chrono::prelude::DateTime;
use chrono::{Utc};
use crypto_hash::{Algorithm, Hasher};


pub fn name(e: &DirEntry) -> String {
    e.path().to_string_lossy().to_string()
}


pub fn mtime(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    let mtime = meta.modified().unwrap();
    let datetime = DateTime::<Utc>::from(mtime);
    datetime.format("%Y-%m-%d %H:%M:%S.%f %z").to_string()
}


pub fn mode(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    let mode = meta.permissions().mode();
    format!("{:06o}", mode)
}


pub fn inode(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.st_ino())
}


pub fn dev(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.st_dev())
}


pub fn nlink(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.st_nlink())
}


pub fn size(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.len())
}


pub fn uid(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.st_uid())
}


pub fn gid(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    format!("{}", meta.st_gid())
}


pub fn username(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    if let Some(u) = users::get_user_by_uid(meta.st_uid()) {
        format!("{}", u.name())
    } else {
        format!("unknown user")
    }
}


pub fn group(e: &DirEntry) -> String {
    let meta = e.metadata().unwrap();
    if let Some(g) = users::get_group_by_gid(meta.st_gid()) {
        format!("{}", g.name())
    } else {
        format!("unknown group")
    }
}


pub fn sha256(e: &DirEntry) -> String {
    let mut ok = true;
    let mut hasher = Hasher::new(Algorithm::SHA256);
    if let Ok(file) = fs::File::open(e.path()) {
        let mut reader = io::BufReader::new(file);
        let mut buf = [0; 1024 * 1024];
        let mut done = false;
        while ok && !done{
            if let Ok(n) = reader.read(&mut buf) {
                if n == 0 {
                    done = true;
                } else if let Err(_) = hasher.write(&buf[0..n]) {
                    ok = false;
                }
            } else {
                ok = false;
            }
        }
    } else {
        ok = false;
    }
    if ok {
        let digest = hasher.finish();
        hex::encode(digest)
    } else {
        format!("can't read file")
    }
}