/* LICENSE BLOCK
Part of mde: a Modular D game-oriented Engine
Copyright © 2007-2008 Diggory Hardy

This program is free software; you can redistribute it and/or modify it under the terms of
the GNU General Public License, version 2, as published by the Free Software Foundation.

This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */

/// Contains the base class for all mde exceptions plus some exception classes.
module mde.exception;

/** Base class for all mde Exceptions.
 *
 * All packages should have their own base exception type extending this one, and for each package
 * level a CTOR taking a message should pass the message to the super.
 * A CTOR not taking a message and calling the super without a parameter may also be provided.
 *
 * The static string symbol
 * should be overriden as below so that it ends up as something like "mde.file" or
 * "mde.pkg.file.Class" describing where the exception was thrown. (Since only methods overload
 * correctly, symbol is made static and an overloadable method is used to access the correct symbol.)
 */
 class mdeException : Exception {
     /// Override in derived classes to name the module where the error occured.
    char[] getSymbol () {
        return "mde";
    }
    /// Prefix msg, e.g.: "mde.foo: message"
    char[] prefixedMsg () {
        return getSymbol() ~ ": " ~ msg;
    }
    this (char[] msg) {
        super(msg);
    }
    this () {			// No supplied error message.
        super("");
    }
}

/// Thrown when loading options fails.
class optionsLoadException : mdeException {
    char[] getSymbol () {
        return super.getSymbol ~ ".options";
    }
    
    this (char[] msg) {
        super(msg);
    }
}

/// Thrown when loading strings for the requested name and current locale fails.
class L10nLoadException : mdeException {
    char[] getSymbol () {
        return super.getSymbol ~ ".i18n.I18nTranslation";
    }
    
    this (char[] msg) {
        super(msg);
    }
}

debug (mdeUnitTest) {
    import tango.util.log.Log : Log, Logger;

    private Logger logger;
    static this() {
        logger = Log.getLogger ("mde.exception");
    }
    
    unittest {
        // Check message prepending works correctly.
        mdeException mE = new optionsLoadException("");
        assert (mE.getSymbol() == "mde.options", mE.getSymbol());
        try {
            throw new mdeException ("ABC");
            assert (false);
        } catch (Exception e) {
            assert (e.msg == "mde: ABC", e.msg);
        }
    
        logger.info ("Unittest complete.");
    }
}