/*
 * Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package freemarker.core;

import java.util.Locale;

import freemarker.template.TemplateModelException;
import freemarker.template.TemplateNumberModel;
import freemarker.template.utility.NumberUtil;
import freemarker.template.utility.StringUtil;

public class BaseNTemplateNumberFormatFactory extends TemplateNumberFormatFactory {

    public static final BaseNTemplateNumberFormatFactory INSTANCE = new BaseNTemplateNumberFormatFactory();
    
    private BaseNTemplateNumberFormatFactory() {
        // Defined to decrease visibility
    }
    
    @Override
    public TemplateNumberFormat get(String params, Locale locale, Environment env)
            throws InvalidFormatParametersException {
        TemplateNumberFormat fallbackFormat;
        {
            int barIdx = params.indexOf('|');
            if (barIdx != -1) {
                String fallbackFormatStr = params.substring(barIdx + 1);
                params = params.substring(0, barIdx);
                try {
                    fallbackFormat = env.getTemplateNumberFormat(fallbackFormatStr, locale);
                } catch (InvalidFormatStringException e) {
                    throw new InvalidFormatParametersException(
                            "Couldn't get the fallback number format (specified after the \"|\"), "
                            + StringUtil.jQuote(fallbackFormatStr) + ". Reason: " + e.getMessage(),
                            e);
                }
            } else {
                fallbackFormat = null;
            }
        }
        
        int base;
        try {
            base = Integer.parseInt(params);
        } catch (NumberFormatException e) {
            if (params.length() == 0) {
                throw new InvalidFormatParametersException(
                        "A format parameter is required, which specifies the numerical system base.");
            }
            throw new InvalidFormatParametersException(
                    "The format paramter must be an integer, but was (shown quoted): " + StringUtil.jQuote(params));
        }
        return new BaseNTemplateNumberFormat(base, fallbackFormat);
    }

    private static class BaseNTemplateNumberFormat extends TemplateNumberFormat {

        private final int base;
        private final TemplateNumberFormat fallbackFormat;
        
        private BaseNTemplateNumberFormat(int base, TemplateNumberFormat fallbackFormat) {
            this.base = base;
            this.fallbackFormat = fallbackFormat;
        }
        
        @Override
        public String format(TemplateNumberModel numberModel)
                throws UnformattableNumberException, TemplateModelException {
            Number n = TemplateFormatUtil.getNonNullNumber(numberModel);
            try {
                return Integer.toString(NumberUtil.toIntExact(n), base);
            } catch (ArithmeticException e) {
                if (fallbackFormat == null) {
                    throw new UnformattableNumberException(
                            n + " doesn't fit into an int, and there was no fallback format specified.");
                } else {
                    return fallbackFormat.format(numberModel);
                }
            }
        }

        @Override
        public <MO extends TemplateMarkupOutputModel> MO format(TemplateNumberModel dateModel,
                MarkupOutputFormat<MO> outputFormat) throws UnformattableNumberException, TemplateModelException {
            return null;
        }

        @Override
        public boolean isLocaleBound() {
            return false;
        }

        @Override
        public String getDescription() {
            return "hexadecimal int";
        }
        
    }

}