/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */


use cssparser::ast::{SyntaxError, SourceLocation};


pub struct ErrorLoggerIterator<I>(pub I);

impl<T, I: Iterator<Result<T, SyntaxError>>> Iterator<T> for ErrorLoggerIterator<I> {
    fn next(&mut self) -> Option<T> {
        let ErrorLoggerIterator(ref mut this) = *self;
        loop {
            match this.next() {
                Some(Ok(v)) => return Some(v),
                Some(Err(error)) => log_css_error(error.location,
                                                  format!("{:?}", error.reason).as_slice()),
                None => return None,
            }
        }
   }
}


/// Defaults to a no-op.
/// Set a `RUST_LOG=style::errors` environment variable
/// to log CSS parse errors to stderr.
pub fn log_css_error(location: SourceLocation, message: &str) {
    // TODO eventually this will got into a "web console" or something.
    info!("{:u}:{:u} {:s}", location.line, location.column, message)
}