//
// imag - the personal information management suite for the commandline
// Copyright (C) 2015-2019 Matthias Beyer <mail@beyermatthias.de> and contributors
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; version
// 2.1 of the License.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

use chrono::naive::NaiveDateTime;

use failure::Fallible as Result;
use failure::err_msg;

/// A Range between two dates
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct DateTimeRange(NaiveDateTime, NaiveDateTime);

impl DateTimeRange {

    /// Create a new DateTimeRange object
    ///
    /// # Return value
    ///
    /// Ok(DateTimeRange) if start is before end,
    /// else Err(DateTimeRangeError)
    ///
    pub fn new(start: NaiveDateTime, end: NaiveDateTime) -> Result<DateTimeRange> {
        if start < end {
            Ok(DateTimeRange(start, end))
        } else {
            Err(err_msg("End date before start date"))
        }
    }

}

#[cfg(test)]
mod tests {

    use chrono::naive::NaiveDateTime;
    use chrono::naive::NaiveDate;
    use chrono::naive::NaiveTime;

    use super::DateTimeRange;

    #[test]
    fn test_new_returns_error_if_start_after_end_date() {
        #[allow(clippy::zero_prefixed_literal)]
        let start = NaiveDateTime::new(
            NaiveDate::from_ymd(2000, 02, 02),
            NaiveTime::from_hms(12, 00, 02)
        );

        #[allow(clippy::zero_prefixed_literal)]
        let end = NaiveDateTime::new(
            NaiveDate::from_ymd(2000, 02, 02),
            NaiveTime::from_hms(12, 00, 01)
        );

        let res = DateTimeRange::new(start, end);

        assert!(res.is_err());
    }

    #[test]
    fn test_new_returns_ok_if_start_is_before_end() {
        #[allow(clippy::zero_prefixed_literal)]
        let start = NaiveDateTime::new(
            NaiveDate::from_ymd(2000, 02, 02),
            NaiveTime::from_hms(12, 00, 01)
        );

        #[allow(clippy::zero_prefixed_literal)]
        let end = NaiveDateTime::new(
            NaiveDate::from_ymd(2000, 02, 02),
            NaiveTime::from_hms(12, 00, 02)
        );

        let res = DateTimeRange::new(start, end);

        assert!(res.is_ok());
    }
}