#![crate_name = "uu_touch"]

// This file is part of the uutils coreutils package.
//
// (c) Nick Platt <platt.nicholas@gmail.com>
// (c) Jian Zeng <anonymousknight96 AT gmail.com>
//
// For the full copyright and license information, please view the LICENSE file
// that was distributed with this source code.
//

pub extern crate filetime;
extern crate getopts;
extern crate time;

#[macro_use]
extern crate uucore;

use filetime::*;
use std::fs::{self, File};
use std::io::Error;
use std::path::Path;

static NAME: &str = "touch";
static VERSION: &str = env!("CARGO_PKG_VERSION");

// Since touch's date/timestamp parsing doesn't account for timezone, the
// returned value from time::strptime() is UTC. We get system's timezone to
// localize the time.
macro_rules! to_local(
    ($exp:expr) => ({
        let mut tm = $exp;
        tm.tm_utcoff = time::now().tm_utcoff;
        tm
    })
);

macro_rules! local_tm_to_filetime(
    ($exp:expr) => ({
        let ts = $exp.to_timespec();
        FileTime::from_unix_time(ts.sec as i64, ts.nsec as u32)
    })
);

pub fn uumain(args: Vec<String>) -> i32 {
    let mut opts = getopts::Options::new();

    opts.optflag("a", "", "change only the access time");
    opts.optflag("c", "no-create", "do not create any files");
    opts.optopt(
        "d",
        "date",
        "parse argument and use it instead of current time",
        "STRING",
    );
    opts.optflag(
        "h",
        "no-dereference",
        "affect each symbolic link instead of any referenced file \
         (only for systems that can change the timestamps of a symlink)",
    );
    opts.optflag("m", "", "change only the modification time");
    opts.optopt(
        "r",
        "reference",
        "use this file's times instead of the current time",
        "FILE",
    );
    opts.optopt(
        "t",
        "",
        "use [[CC]YY]MMDDhhmm[.ss] instead of the current time",
        "STAMP",
    );
    opts.optopt(
        "",
        "time",
        "change only the specified time: \"access\", \"atime\", or \
         \"use\" are equivalent to -a; \"modify\" or \"mtime\" are \
         equivalent to -m",
        "WORD",
    );
    opts.optflag("h", "help", "display this help and exit");
    opts.optflag("V", "version", "output version information and exit");

    let matches = match opts.parse(&args[1..]) {
        Ok(m) => m,
        Err(e) => panic!("Invalid options\n{}", e),
    };

    if matches.opt_present("version") {
        println!("{} {}", NAME, VERSION);
        return 0;
    }

    if matches.opt_present("help") || matches.free.is_empty() {
        println!("{} {}", NAME, VERSION);
        println!("");
        println!("Usage: {} [OPTION]... FILE...", NAME);
        println!("");
        println!(
            "{}",
            opts.usage(
                "Update the access and modification times of \
                 each FILE to the current time."
            )
        );
        if matches.free.is_empty() {
            return 1;
        }
        return 0;
    }

    if matches.opt_present("date")
        && matches.opts_present(&["reference".to_owned(), "t".to_owned()])
        || matches.opt_present("reference")
            && matches.opts_present(&["date".to_owned(), "t".to_owned()])
        || matches.opt_present("t")
            && matches.opts_present(&["date".to_owned(), "reference".to_owned()])
    {
        panic!("Invalid options: cannot specify reference time from more than one source");
    }

    let (mut atime, mut mtime) = if matches.opt_present("reference") {
        stat(
            &matches.opt_str("reference").unwrap()[..],
            !matches.opt_present("no-dereference"),
        )
    } else if matches.opts_present(&["date".to_owned(), "t".to_owned()]) {
        let timestamp = if matches.opt_present("date") {
            parse_date(matches.opt_str("date").unwrap().as_ref())
        } else {
            parse_timestamp(matches.opt_str("t").unwrap().as_ref())
        };
        (timestamp, timestamp)
    } else {
        let now = local_tm_to_filetime!(time::now());
        (now, now)
    };

    for filename in &matches.free {
        let path = &filename[..];

        if !Path::new(path).exists() {
            // no-dereference included here for compatibility
            if matches.opts_present(&["no-create".to_owned(), "no-dereference".to_owned()]) {
                continue;
            }

            if let Err(e) = File::create(path) {
                show_warning!("cannot touch '{}': {}", path, e);
                continue;
            };

            // Minor optimization: if no reference time was specified, we're done.
            if !matches.opts_present(&["date".to_owned(), "reference".to_owned(), "t".to_owned()]) {
                continue;
            }
        }

        // If changing "only" atime or mtime, grab the existing value of the other.
        // Note that "-a" and "-m" may be passed together; this is not an xor.
        if matches.opts_present(&["a".to_owned(), "m".to_owned(), "time".to_owned()]) {
            let st = stat(path, !matches.opt_present("no-dereference"));
            let time = matches.opt_strs("time");

            if !(matches.opt_present("a") || time.contains(&"access".to_owned())
                || time.contains(&"atime".to_owned())
                || time.contains(&"use".to_owned()))
            {
                atime = st.0;
            }

            if !(matches.opt_present("m") || time.contains(&"modify".to_owned())
                || time.contains(&"mtime".to_owned()))
            {
                mtime = st.1;
            }
        }

        if matches.opt_present("h") {
            if let Err(e) = set_symlink_file_times(path, atime, mtime) {
                show_warning!("cannot touch '{}': {}", path, e);
            }
        } else {
            if let Err(e) = filetime::set_file_times(path, atime, mtime) {
                show_warning!("cannot touch '{}': {}", path, e);
            }
        }
    }

    0
}

fn stat(path: &str, follow: bool) -> (FileTime, FileTime) {
    let metadata = if follow {
        fs::symlink_metadata(path)
    } else {
        fs::metadata(path)
    };

    match metadata {
        Ok(m) => (
            FileTime::from_last_access_time(&m),
            FileTime::from_last_modification_time(&m),
        ),
        Err(_) => crash!(
            1,
            "failed to get attributes of '{}': {}",
            path,
            Error::last_os_error()
        ),
    }
}

fn parse_date(str: &str) -> FileTime {
    // This isn't actually compatible with GNU touch, but there doesn't seem to
    // be any simple specification for what format this parameter allows and I'm
    // not about to implement GNU parse_datetime.
    // http://git.savannah.gnu.org/gitweb/?p=gnulib.git;a=blob_plain;f=lib/parse-datetime.y
    match time::strptime(str, "%c") {
        Ok(tm) => local_tm_to_filetime!(to_local!(tm)),
        Err(e) => panic!("Unable to parse date\n{}", e),
    }
}

fn parse_timestamp(s: &str) -> FileTime {
    let now = time::now();
    let (format, ts) = match s.chars().count() {
        15 => ("%Y%m%d%H%M.%S", s.to_owned()),
        12 => ("%Y%m%d%H%M", s.to_owned()),
        13 => ("%y%m%d%H%M.%S", s.to_owned()),
        10 => ("%y%m%d%H%M", s.to_owned()),
        11 => ("%Y%m%d%H%M.%S", format!("{}{}", now.tm_year + 1900, s)),
        8 => ("%Y%m%d%H%M", format!("{}{}", now.tm_year + 1900, s)),
        _ => panic!("Unknown timestamp format"),
    };

    match time::strptime(&ts, format) {
        Ok(tm) => local_tm_to_filetime!(to_local!(tm)),
        Err(e) => panic!("Unable to parse timestamp\n{}", e),
    }
}