// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// OpenEthereum 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 General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with OpenEthereum.  If not, see <http://www.gnu.org/licenses/>.

//! Error utils

use std::fmt;

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
/// Error indicating an expected value was not found.
pub struct Mismatch<T> {
    /// Value expected.
    pub expected: T,
    /// Value found.
    pub found: T,
}

impl<T: fmt::Display> fmt::Display for Mismatch<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_fmt(format_args!(
            "Expected {}, found {}",
            self.expected, self.found
        ))
    }
}

#[derive(Debug, PartialEq, Eq, Clone, Copy)]
/// Error indicating value found is outside of a valid range.
pub struct OutOfBounds<T> {
    /// Minimum allowed value.
    pub min: Option<T>,
    /// Maximum allowed value.
    pub max: Option<T>,
    /// Value found.
    pub found: T,
}

impl<T> OutOfBounds<T> {
    pub fn map<F, U>(self, map: F) -> OutOfBounds<U>
    where
        F: Fn(T) -> U,
    {
        OutOfBounds {
            min: self.min.map(&map),
            max: self.max.map(&map),
            found: map(self.found),
        }
    }
}

impl<T: fmt::Display> fmt::Display for OutOfBounds<T> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let msg = match (self.min.as_ref(), self.max.as_ref()) {
            (Some(min), Some(max)) => format!("Min={}, Max={}", min, max),
            (Some(min), _) => format!("Min={}", min),
            (_, Some(max)) => format!("Max={}", max),
            (None, None) => "".into(),
        };

        f.write_fmt(format_args!("Value {} out of bounds. {}", self.found, msg))
    }
}
