/**
 * Copyright 2007-2016, Kaazing Corporation. All rights reserved.
 *
 * 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 org.apache.mina.integration.beans;

import java.beans.PropertyEditor;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * A {@link PropertyEditor} which converts a {@link String} into
 * a {@link Collection} and vice versa.
 *
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public class MapEditor extends AbstractPropertyEditor {
    static final Pattern ELEMENT = Pattern.compile(
            "([,\\s]+)|" + // Entry delimiter
            "(\\s*=\\s*)|" + // Key-Value delimiter
            "(?<=\")((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^\"])*)(?=\")|" +
            "(?<=')((?:\\\\\"|\\\\'|\\\\\\\\|\\\\ |[^'])*)(?=')|" +
            "((?:[^\\\\\\s'\",]|\\\\ |\\\\\"|\\\\')+)");
    
    private final Class<?> keyType;
    private final Class<?> valueType;
    
    public MapEditor(Class<?> keyType, Class<?> valueType) {
        if (keyType == null) {
            throw new NullPointerException("keyType");
        }
        if (valueType == null) {
            throw new NullPointerException("valueType");
        }
        this.keyType = keyType;
        this.valueType = valueType;
        getKeyEditor();
        getValueEditor();
        setTrimText(false);
    }

    private PropertyEditor getKeyEditor() {
        PropertyEditor e = PropertyEditorFactory.getInstance(keyType);
        if (e == null) {
            throw new IllegalArgumentException(
                    "No key " + PropertyEditor.class.getSimpleName() + 
                    " found for " + keyType.getSimpleName() + '.');
        }
        return e;
    }

    private PropertyEditor getValueEditor() {
        PropertyEditor e = PropertyEditorFactory.getInstance(valueType);
        if (e == null) {
            throw new IllegalArgumentException(
                    "No value " + PropertyEditor.class.getSimpleName() + 
                    " found for " + valueType.getSimpleName() + '.');
        }
        return e;
    }

    @Override
    @SuppressWarnings("unchecked")
    protected final String toText(Object value) {
        StringBuilder buf = new StringBuilder();
        for (Object o: ((Map) value).entrySet()) {
            Map.Entry entry = (Map.Entry) o;
            Object ekey = entry.getKey();
            Object evalue = entry.getValue();
            
            PropertyEditor ekeyEditor = PropertyEditorFactory.getInstance(ekey);
            if (ekeyEditor == null) {
                throw new IllegalArgumentException(
                        "No key " + PropertyEditor.class.getSimpleName() + 
                        " found for " + ekey.getClass().getSimpleName() + '.');
            }
            ekeyEditor.setValue(ekey);
            
            PropertyEditor evalueEditor = PropertyEditorFactory.getInstance(evalue);
            if (evalueEditor == null) {
                throw new IllegalArgumentException(
                        "No value " + PropertyEditor.class.getSimpleName() + 
                        " found for " + evalue.getClass().getSimpleName() + '.');
            }
            ekeyEditor.setValue(ekey);
            evalueEditor.setValue(evalue);
            
            // TODO normalize.
            String keyString = ekeyEditor.getAsText();
            String valueString = evalueEditor.getAsText();
            buf.append(keyString);
            buf.append(" = ");
            buf.append(valueString);
            buf.append(", ");
        }
        
        // Remove the last delimiter.
        if (buf.length() >= 2) {
            buf.setLength(buf.length() - 2);
        }
        return buf.toString();
    }

    @Override
    protected final Object toValue(String text) throws IllegalArgumentException {
        PropertyEditor keyEditor = getKeyEditor();
        PropertyEditor valueEditor = getValueEditor();
        Map<Object, Object> answer = newMap();
        Matcher m = ELEMENT.matcher(text);
        TokenType lastTokenType = TokenType.ENTRY_DELIM;
        Object key = null;
        Object value;

        while (m.find()) {
            if (m.group(1) != null) {
                switch (lastTokenType) {
                case VALUE: case ENTRY_DELIM:
                    break;
                default:
                    throw new IllegalArgumentException(
                            "Unexpected entry delimiter: " + text);
                }
                
                lastTokenType = TokenType.ENTRY_DELIM;
                continue;
            }
            
            if (m.group(2) != null) {
                if (lastTokenType != TokenType.KEY) {
                    throw new IllegalArgumentException(
                            "Unexpected key-value delimiter: " + text);
                }
                
                lastTokenType = TokenType.KEY_VALUE_DELIM;
                continue;
            }
            
            
            // TODO escape here.
            String region = m.group();

            if (m.group(3) != null || m.group(4) != null) {
                // Skip the last '"'.
                m.region(m.end() + 1, m.regionEnd());
            }
            
            switch (lastTokenType) {
            case ENTRY_DELIM:
                keyEditor.setAsText(region);
                key = keyEditor.getValue();
                lastTokenType = TokenType.KEY;
                break;
            case KEY_VALUE_DELIM:
                valueEditor.setAsText(region);
                value = valueEditor.getValue();
                lastTokenType = TokenType.VALUE;
                answer.put(key, value);
                break;
            case KEY: case VALUE:
                throw new IllegalArgumentException(
                        "Unexpected key or value: " + text);
            }
        }
        
        return answer;
    }
    
    protected Map<Object, Object> newMap() {
        return new LinkedHashMap<>();
    }
    
    private enum TokenType {
        ENTRY_DELIM,
        KEY_VALUE_DELIM,
        KEY,
        VALUE,
    }
}
