Copyright (c) 2008, http://www.snakeyaml.org
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.
/**
 * Copyright (c) 2008, http://www.snakeyaml.org
 *
 * 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.yaml.snakeyaml.constructor;

import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TimeZone;
import java.util.TreeSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.yaml.snakeyaml.error.YAMLException;
import org.yaml.snakeyaml.external.biz.base64Coder.Base64Coder;
import org.yaml.snakeyaml.nodes.MappingNode;
import org.yaml.snakeyaml.nodes.Node;
import org.yaml.snakeyaml.nodes.NodeId;
import org.yaml.snakeyaml.nodes.NodeTuple;
import org.yaml.snakeyaml.nodes.ScalarNode;
import org.yaml.snakeyaml.nodes.SequenceNode;
import org.yaml.snakeyaml.nodes.Tag;

Construct standard Java classes
/**
 * Construct standard Java classes
 */
public class SafeConstructor extends BaseConstructor {

    public static final ConstructUndefined undefinedConstructor = new ConstructUndefined();

    public SafeConstructor() {
        this.yamlConstructors.put(Tag.NULL, new ConstructYamlNull());
        this.yamlConstructors.put(Tag.BOOL, new ConstructYamlBool());
        this.yamlConstructors.put(Tag.INT, new ConstructYamlInt());
        this.yamlConstructors.put(Tag.FLOAT, new ConstructYamlFloat());
        this.yamlConstructors.put(Tag.BINARY, new ConstructYamlBinary());
        this.yamlConstructors.put(Tag.TIMESTAMP, new ConstructYamlTimestamp());
        this.yamlConstructors.put(Tag.OMAP, new ConstructYamlOmap());
        this.yamlConstructors.put(Tag.PAIRS, new ConstructYamlPairs());
        this.yamlConstructors.put(Tag.SET, new ConstructYamlSet());
        this.yamlConstructors.put(Tag.STR, new ConstructYamlStr());
        this.yamlConstructors.put(Tag.SEQ, new ConstructYamlSeq());
        this.yamlConstructors.put(Tag.MAP, new ConstructYamlMap());
        this.yamlConstructors.put(null, undefinedConstructor);
        this.yamlClassConstructors.put(NodeId.scalar, undefinedConstructor);
        this.yamlClassConstructors.put(NodeId.sequence, undefinedConstructor);
        this.yamlClassConstructors.put(NodeId.mapping, undefinedConstructor);
    }

    protected void flattenMapping(MappingNode node) {
        // perform merging only on nodes containing merge node(s)
        processDuplicateKeys(node);
        if (node.isMerged()) {
            node.setValue(mergeNode(node, true, new HashMap<Object, Integer>(),
                    new ArrayList<NodeTuple>()));
        }
    }

    protected void processDuplicateKeys(MappingNode node) {
        List<NodeTuple> nodeValue = node.getValue();
        Map<Object, Integer> keys = new HashMap<Object, Integer>(nodeValue.size());
        TreeSet<Integer> toRemove = new TreeSet<Integer>();
        int i = 0;
        for (NodeTuple tuple : nodeValue) {
            Node keyNode = tuple.getKeyNode();
            if (!keyNode.getTag().equals(Tag.MERGE)) {
                Object key = constructObject(keyNode);
                if (key != null) {
                    try {
                        key.hashCode();// check circular dependencies
                    } catch (Exception e) {
                        throw new ConstructorException("while constructing a mapping",
                                node.getStartMark(), "found unacceptable key " + key,
                                tuple.getKeyNode().getStartMark(), e);
                    }
                }

                Integer prevIndex = keys.put(key, i);
                if (prevIndex != null) {
                    if (!isAllowDuplicateKeys()) {
                        throw new DuplicateKeyException(node.getStartMark(), key,
                                tuple.getKeyNode().getStartMark());
                    }
                    toRemove.add(prevIndex);
                }
            }
            i = i + 1;
        }

        Iterator<Integer> indicies2remove = toRemove.descendingIterator();
        while (indicies2remove.hasNext()) {
            nodeValue.remove(indicies2remove.next().intValue());
        }
    }

    
Does merge for supplied mapping node.
Params:
node – 
           where to merge
isPreffered – 
           true if keys of node should take precedence over others...
key2index – 
           maps already merged keys to index from values
values – 
           collects merged NodeTuple
Returns:
list of the merged NodeTuple (to be set as value for the
        MappingNode)/**
     * Does merge for supplied mapping node.
     *
     * @param node
     *            where to merge
     * @param isPreffered
     *            true if keys of node should take precedence over others...
     * @param key2index
     *            maps already merged keys to index from values
     * @param values
     *            collects merged NodeTuple
     * @return list of the merged NodeTuple (to be set as value for the
     *         MappingNode)
     */
    private List<NodeTuple> mergeNode(MappingNode node, boolean isPreffered,
            Map<Object, Integer> key2index, List<NodeTuple> values) {
        Iterator<NodeTuple> iter = node.getValue().iterator();
        while (iter.hasNext()) {
            final NodeTuple nodeTuple = iter.next();
            final Node keyNode = nodeTuple.getKeyNode();
            final Node valueNode = nodeTuple.getValueNode();
            if (keyNode.getTag().equals(Tag.MERGE)) {
                iter.remove();
                switch (valueNode.getNodeId()) {
                case mapping:
                    MappingNode mn = (MappingNode) valueNode;
                    mergeNode(mn, false, key2index, values);
                    break;
                case sequence:
                    SequenceNode sn = (SequenceNode) valueNode;
                    List<Node> vals = sn.getValue();
                    for (Node subnode : vals) {
                        if (!(subnode instanceof MappingNode)) {
                            throw new ConstructorException("while constructing a mapping",
                                    node.getStartMark(),
                                    "expected a mapping for merging, but found "
                                            + subnode.getNodeId(),
                                    subnode.getStartMark());
                        }
                        MappingNode mnode = (MappingNode) subnode;
                        mergeNode(mnode, false, key2index, values);
                    }
                    break;
                default:
                    throw new ConstructorException("while constructing a mapping",
                            node.getStartMark(),
                            "expected a mapping or list of mappings for merging, but found "
                                    + valueNode.getNodeId(),
                            valueNode.getStartMark());
                }
            } else {
                // we need to construct keys to avoid duplications
                Object key = constructObject(keyNode);
                if (!key2index.containsKey(key)) { // 1st time merging key
                    values.add(nodeTuple);
                    // keep track where tuple for the key is
                    key2index.put(key, values.size() - 1);
                } else if (isPreffered) { // there is value for the key, but we
                                          // need to override it
                                          // change value for the key using saved position
                    values.set(key2index.get(key), nodeTuple);
                }
            }
        }
        return values;
    }

    @Override
    protected void constructMapping2ndStep(MappingNode node, Map<Object, Object> mapping) {
        flattenMapping(node);
        super.constructMapping2ndStep(node, mapping);
    }

    @Override
    protected void constructSet2ndStep(MappingNode node, Set<Object> set) {
        flattenMapping(node);
        super.constructSet2ndStep(node, set);
    }

    public class ConstructYamlNull extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            if (node != null) constructScalar((ScalarNode) node);
            return null;
        }
    }

    private final static Map<String, Boolean> BOOL_VALUES = new HashMap<String, Boolean>();
    static {
        BOOL_VALUES.put("yes", Boolean.TRUE);
        BOOL_VALUES.put("no", Boolean.FALSE);
        BOOL_VALUES.put("true", Boolean.TRUE);
        BOOL_VALUES.put("false", Boolean.FALSE);
        BOOL_VALUES.put("on", Boolean.TRUE);
        BOOL_VALUES.put("off", Boolean.FALSE);
    }

    public class ConstructYamlBool extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            String val = (String) constructScalar((ScalarNode) node);
            return BOOL_VALUES.get(val.toLowerCase());
        }
    }

    public class ConstructYamlInt extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            String value = constructScalar((ScalarNode) node).toString().replaceAll("_", "");
            int sign = +1;
            char first = value.charAt(0);
            if (first == '-') {
                sign = -1;
                value = value.substring(1);
            } else if (first == '+') {
                value = value.substring(1);
            }
            int base = 10;
            if ("0".equals(value)) {
                return Integer.valueOf(0);
            } else if (value.startsWith("0b")) {
                value = value.substring(2);
                base = 2;
            } else if (value.startsWith("0x")) {
                value = value.substring(2);
                base = 16;
            } else if (value.startsWith("0")) {
                value = value.substring(1);
                base = 8;
            } else if (value.indexOf(':') != -1) {
                String[] digits = value.split(":");
                int bes = 1;
                int val = 0;
                for (int i = 0, j = digits.length; i < j; i++) {
                    val += Long.parseLong(digits[j - i - 1]) * bes;
                    bes *= 60;
                }
                return createNumber(sign, String.valueOf(val), 10);
            } else {
                return createNumber(sign, value, 10);
            }
            return createNumber(sign, value, base);
        }
    }

    private Number createNumber(int sign, String number, int radix) {
        Number result;
        if (sign < 0) {
            number = "-" + number;
        }
        try {
            result = Integer.valueOf(number, radix);
        } catch (NumberFormatException e) {
            try {
                result = Long.valueOf(number, radix);
            } catch (NumberFormatException e1) {
                result = new BigInteger(number, radix);
            }
        }
        return result;
    }

    public class ConstructYamlFloat extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            String value = constructScalar((ScalarNode) node).toString().replaceAll("_", "");
            int sign = +1;
            char first = value.charAt(0);
            if (first == '-') {
                sign = -1;
                value = value.substring(1);
            } else if (first == '+') {
                value = value.substring(1);
            }
            String valLower = value.toLowerCase();
            if (".inf".equals(valLower)) {
                return Double
                        .valueOf(sign == -1 ? Double.NEGATIVE_INFINITY : Double.POSITIVE_INFINITY);
            } else if (".nan".equals(valLower)) {
                return Double.valueOf(Double.NaN);
            } else if (value.indexOf(':') != -1) {
                String[] digits = value.split(":");
                int bes = 1;
                double val = 0.0;
                for (int i = 0, j = digits.length; i < j; i++) {
                    val += Double.parseDouble(digits[j - i - 1]) * bes;
                    bes *= 60;
                }
                return Double.valueOf(sign * val);
            } else {
                Double d = Double.valueOf(value);
                return Double.valueOf(d.doubleValue() * sign);
            }
        }
    }

    public class ConstructYamlBinary extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            // Ignore white spaces for base64 encoded scalar
            String noWhiteSpaces = constructScalar((ScalarNode) node).toString().replaceAll("\\s",
                    "");
            byte[] decoded = Base64Coder.decode(noWhiteSpaces.toCharArray());
            return decoded;
        }
    }

    private final static Pattern TIMESTAMP_REGEXP = Pattern.compile(
            "^([0-9][0-9][0-9][0-9])-([0-9][0-9]?)-([0-9][0-9]?)(?:(?:[Tt]|[ \t]+)([0-9][0-9]?):([0-9][0-9]):([0-9][0-9])(?:\\.([0-9]*))?(?:[ \t]*(?:Z|([-+][0-9][0-9]?)(?::([0-9][0-9])?)?))?)?$");
    private final static Pattern YMD_REGEXP = Pattern
            .compile("^([0-9][0-9][0-9][0-9])-([0-9][0-9]?)-([0-9][0-9]?)$");

    public static class ConstructYamlTimestamp extends AbstractConstruct {
        private Calendar calendar;

        public Calendar getCalendar() {
            return calendar;
        }

        @Override
        public Object construct(Node node) {
            ScalarNode scalar = (ScalarNode) node;
            String nodeValue = scalar.getValue();
            Matcher match = YMD_REGEXP.matcher(nodeValue);
            if (match.matches()) {
                String year_s = match.group(1);
                String month_s = match.group(2);
                String day_s = match.group(3);
                calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
                calendar.clear();
                calendar.set(Calendar.YEAR, Integer.parseInt(year_s));
                // Java's months are zero-based...
                calendar.set(Calendar.MONTH, Integer.parseInt(month_s) - 1); // x
                calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(day_s));
                return calendar.getTime();
            } else {
                match = TIMESTAMP_REGEXP.matcher(nodeValue);
                if (!match.matches()) {
                    throw new YAMLException("Unexpected timestamp: " + nodeValue);
                }
                String year_s = match.group(1);
                String month_s = match.group(2);
                String day_s = match.group(3);
                String hour_s = match.group(4);
                String min_s = match.group(5);
                // seconds and milliseconds
                String seconds = match.group(6);
                String millis = match.group(7);
                if (millis != null) {
                    seconds = seconds + "." + millis;
                }
                double fractions = Double.parseDouble(seconds);
                int sec_s = (int) Math.round(Math.floor(fractions));
                int usec = (int) Math.round((fractions - sec_s) * 1000);
                // timezone
                String timezoneh_s = match.group(8);
                String timezonem_s = match.group(9);
                TimeZone timeZone;
                if (timezoneh_s != null) {
                    String time = timezonem_s != null ? ":" + timezonem_s : "00";
                    timeZone = TimeZone.getTimeZone("GMT" + timezoneh_s + time);
                } else {
                    // no time zone provided
                    timeZone = TimeZone.getTimeZone("UTC");
                }
                calendar = Calendar.getInstance(timeZone);
                calendar.set(Calendar.YEAR, Integer.parseInt(year_s));
                // Java's months are zero-based...
                calendar.set(Calendar.MONTH, Integer.parseInt(month_s) - 1);
                calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(day_s));
                calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(hour_s));
                calendar.set(Calendar.MINUTE, Integer.parseInt(min_s));
                calendar.set(Calendar.SECOND, sec_s);
                calendar.set(Calendar.MILLISECOND, usec);
                return calendar.getTime();
            }
        }
    }

    public class ConstructYamlOmap extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            // Note: we do not check for duplicate keys, because it's too
            // CPU-expensive.
            Map<Object, Object> omap = new LinkedHashMap<Object, Object>();
            if (!(node instanceof SequenceNode)) {
                throw new ConstructorException("while constructing an ordered map",
                        node.getStartMark(), "expected a sequence, but found " + node.getNodeId(),
                        node.getStartMark());
            }
            SequenceNode snode = (SequenceNode) node;
            for (Node subnode : snode.getValue()) {
                if (!(subnode instanceof MappingNode)) {
                    throw new ConstructorException("while constructing an ordered map",
                            node.getStartMark(),
                            "expected a mapping of length 1, but found " + subnode.getNodeId(),
                            subnode.getStartMark());
                }
                MappingNode mnode = (MappingNode) subnode;
                if (mnode.getValue().size() != 1) {
                    throw new ConstructorException("while constructing an ordered map",
                            node.getStartMark(), "expected a single mapping item, but found "
                                    + mnode.getValue().size() + " items",
                            mnode.getStartMark());
                }
                Node keyNode = mnode.getValue().get(0).getKeyNode();
                Node valueNode = mnode.getValue().get(0).getValueNode();
                Object key = constructObject(keyNode);
                Object value = constructObject(valueNode);
                omap.put(key, value);
            }
            return omap;
        }
    }

    public class ConstructYamlPairs extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            // Note: we do not check for duplicate keys, because it's too
            // CPU-expensive.
            if (!(node instanceof SequenceNode)) {
                throw new ConstructorException("while constructing pairs", node.getStartMark(),
                        "expected a sequence, but found " + node.getNodeId(), node.getStartMark());
            }
            SequenceNode snode = (SequenceNode) node;
            List<Object[]> pairs = new ArrayList<Object[]>(snode.getValue().size());
            for (Node subnode : snode.getValue()) {
                if (!(subnode instanceof MappingNode)) {
                    throw new ConstructorException("while constructingpairs", node.getStartMark(),
                            "expected a mapping of length 1, but found " + subnode.getNodeId(),
                            subnode.getStartMark());
                }
                MappingNode mnode = (MappingNode) subnode;
                if (mnode.getValue().size() != 1) {
                    throw new ConstructorException("while constructing pairs", node.getStartMark(),
                            "expected a single mapping item, but found " + mnode.getValue().size()
                                    + " items",
                            mnode.getStartMark());
                }
                Node keyNode = mnode.getValue().get(0).getKeyNode();
                Node valueNode = mnode.getValue().get(0).getValueNode();
                Object key = constructObject(keyNode);
                Object value = constructObject(valueNode);
                pairs.add(new Object[] { key, value });
            }
            return pairs;
        }
    }

    public class ConstructYamlSet implements Construct {
        @Override
        public Object construct(Node node) {
            if (node.isTwoStepsConstruction()) {
                return (constructedObjects.containsKey(node) ? constructedObjects.get(node)
                        : createDefaultSet(((MappingNode) node).getValue().size()));
            } else {
                return constructSet((MappingNode) node);
            }
        }

        @Override
        @SuppressWarnings("unchecked")
        public void construct2ndStep(Node node, Object object) {
            if (node.isTwoStepsConstruction()) {
                constructSet2ndStep((MappingNode) node, (Set<Object>) object);
            } else {
                throw new YAMLException("Unexpected recursive set structure. Node: " + node);
            }
        }
    }

    public class ConstructYamlStr extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            return constructScalar((ScalarNode) node);
        }
    }

    public class ConstructYamlSeq implements Construct {
        @Override
        public Object construct(Node node) {
            SequenceNode seqNode = (SequenceNode) node;
            if (node.isTwoStepsConstruction()) {
                return newList(seqNode);
            } else {
                return constructSequence(seqNode);
            }
        }

        @Override
        @SuppressWarnings("unchecked")
        public void construct2ndStep(Node node, Object data) {
            if (node.isTwoStepsConstruction()) {
                constructSequenceStep2((SequenceNode) node, (List<Object>) data);
            } else {
                throw new YAMLException("Unexpected recursive sequence structure. Node: " + node);
            }
        }
    }

    public class ConstructYamlMap implements Construct {
        @Override
        public Object construct(Node node) {
            MappingNode mnode = (MappingNode) node;
            if (node.isTwoStepsConstruction()) {
                return createDefaultMap(mnode.getValue().size());
            } else {
                return constructMapping(mnode);
            }
        }

        @Override
        @SuppressWarnings("unchecked")
        public void construct2ndStep(Node node, Object object) {
            if (node.isTwoStepsConstruction()) {
                constructMapping2ndStep((MappingNode) node, (Map<Object, Object>) object);
            } else {
                throw new YAMLException("Unexpected recursive mapping structure. Node: " + node);
            }
        }
    }

    public static final class ConstructUndefined extends AbstractConstruct {
        @Override
        public Object construct(Node node) {
            throw new ConstructorException(null, null,
                    "could not determine a constructor for the tag " + node.getTag(),
                    node.getStartMark());
        }
    }
}