/*
 * ModeShape (http://www.modeshape.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.modeshape.schematic.document;

import java.io.Serializable;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.UUID;
import java.util.regex.Pattern;
import org.modeshape.schematic.SchemaLibrary;

/**
 * Primary read-only interface for an in-memory representation of JSON/BSON objects.
 * 
 * @author Randall Hauch <rhauch@redhat.com> (C) 2011 Red Hat Inc.
 */
public interface Document extends Serializable {

    /**
     * Gets the value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The field value, if found, or null otherwise
     */
    Object get( String name );

    /**
     * Get the boolean value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The boolean field value, if found, or null if there is no such pair or if the value is not a boolean
     */
    Boolean getBoolean( String name );

    /**
     * Get the boolean value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a boolean
     * @return The boolean field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a
     *         boolean
     */
    boolean getBoolean( String name,
                        boolean defaultValue );

    /**
     * Get the integer value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The integer field value, if found, or null if there is no such pair or if the value is not an integer
     */
    Integer getInteger( String name );

    /**
     * Get the integer value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a integer
     * @return The integer field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a
     *         integer
     */
    int getInteger( String name,
                    int defaultValue );

    /**
     * Get the integer value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The long field value, if found, or null if there is no such pair or if the value is not a long value
     */
    Long getLong( String name );

    /**
     * Get the long value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a long value
     * @return The long field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a long
     *         value
     */
    long getLong( String name,
                  long defaultValue );

    /**
     * Get the double value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The double field value, if found, or null if there is no such pair or if the value is not a double
     */
    Double getDouble( String name );

    /**
     * Get the double value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a double
     * @return The double field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a
     *         double
     */
    double getDouble( String name,
                      double defaultValue );

    /**
     * Get the number value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The double field value, if found, or null if there is no such pair or if the value is not a number
     */
    Number getNumber( String name );

    /**
     * Get the number value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a number
     * @return The number field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a
     *         number
     */
    Number getNumber( String name,
                      Number defaultValue );

    /**
     * Get the string value in this document for the given field name. This method will return the string even if the actual value
     * is a {@link Symbol}.
     * 
     * @param name The name of the pair
     * @return The string field value, if found, or null if there is no such pair or if the value is not a string
     */
    String getString( String name );

    /**
     * Get the string value in this document for the given field name. This method will return the string even if the actual value
     * is a {@link Symbol}.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a string
     * @return The string field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not a
     *         string
     */
    String getString( String name,
                      String defaultValue );

    /**
     * Get the array value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The array field value (as a list), if found, or null if there is no such pair or if the value is not an array
     */
    List<?> getArray( String name );

    /**
     * Get the document value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The document field value, if found, or null if there is no such pair or if the value is not a document
     */
    Document getDocument( String name );

    /**
     * Determine whether this object has a pair with the given the name and the value is null. This is equivalent to calling:
     * 
     * <pre>
     * this.get(name) instanceof Null;
     * </pre>
     * 
     * @param name The name of the pair
     * @return <code>true</code> if the field has been set to a {@link Null} value, or false otherwise
     * @see #isNullOrMissing(String)
     */
    boolean isNull( String name );

    /**
     * Determine whether this object has a pair with the given the name and the value is null, or if this object has no field with
     * the given name. This is equivalent to calling:
     * 
     * <pre>
     * Null.matches(this.get(name));
     * </pre>
     * 
     * @param name The name of the pair
     * @return <code>true</code> if the field value for the name is null or if there is no such field.
     * @see #isNull(String)
     */
    boolean isNullOrMissing( String name );

    /**
     * Get the {@link MaxKey} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link MaxKey} field value, if found, or null if there is no such pair or if the value is not a {@link MaxKey}
     */
    MaxKey getMaxKey( String name );

    /**
     * Get the {@link MinKey} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link MinKey} field value, if found, or null if there is no such pair or if the value is not a {@link MinKey}
     */
    MinKey getMinKey( String name );

    /**
     * Get the {@link Code} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link Code} field value, if found, or null if there is no such pair or if the value is not a {@link Code}
     */
    Code getCode( String name );

    /**
     * Get the {@link CodeWithScope} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link CodeWithScope} field value, if found, or null if there is no such pair or if the value is not a
     *         {@link CodeWithScope}
     */
    CodeWithScope getCodeWithScope( String name );

    /**
     * Get the {@link ObjectId} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link ObjectId} field value, if found, or null if there is no such pair or if the value is not a
     *         {@link ObjectId}
     */
    ObjectId getObjectId( String name );

    /**
     * Get the {@link Binary} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link Binary} field value, if found, or null if there is no such pair or if the value is not a {@link Binary}
     */
    Binary getBinary( String name );
    /**
     * Get the {@link Date} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link Date} field value, if found, or null if there is no such pair or if the value is not a {@link Date}
     */
    Date getDate( String name );

    /**
     * Get the {@link Symbol} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link Symbol} field value, if found, or null if there is no such pair or if the value is not a {@link Symbol}
     */
    Symbol getSymbol( String name );

    /**
     * Get the {@link Pattern} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link Pattern} field value, if found, or null if there is no such pair or if the value is not a
     *         {@link Pattern}
     */
    Pattern getPattern( String name );

    /**
     * Get the {@link UUID} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @return The {@link UUID} field value, if found, or null if there is no such pair or if the value is not a {@link UUID}
     */
    UUID getUuid( String name );

    /**
     * Get the {@link UUID} value in this document for the given field name.
     * 
     * @param name The name of the pair
     * @param defaultValue the default value to return if there is no such pair or if the value is not a string
     * @return The {@link UUID} field value if found, or <code>defaultValue</code> if there is no such pair or if the value is not
     *         a UUID (or a string that is convertable from a UUID)
     */
    UUID getUuid( String name,
                  UUID defaultValue );

    /**
     * Get the {@link Bson.Type} constant that describes the type of value for the given field name.
     * 
     * @param name The name of the pair
     * @return the {@link Bson.Type} constant describing the value, or -1 if there is no field with the supplied name
     */
    int getType( String name );

    /**
     * Returns a map representing this BSONObject.
     * 
     * @return the map
     */
    Map<String, ?> toMap();

    /**
     * Obtain an iterator over the {@link Field}s in this object.
     * 
     * @return a field iterator; never null
     */
    Iterable<Field> fields();

    /**
     * Checks if this object contains a field with the given name.
     * 
     * @param name The name of the pair for which to check
     * @return true if this document contains a field with the supplied name, or false otherwise
     */
    boolean containsField( String name );

    /**
     * Checks if this object contains all of the fields in the supplied document.
     * 
     * @param document The document with the fields that should be in this document
     * @return true if this document contains all of the fields in the supplied document, or false otherwise
     */
    boolean containsAll( Document document );

    /**
     * Returns this object's fields' names
     * 
     * @return The names of the fields in this object
     */
    Set<String> keySet();

    /**
     * Return the number of name-value pairs in this object.
     * 
     * @return the number of name-value pairs; never negative
     */
    int size();

    /**
     * Return whether this document contains no fields and is therefore empty.
     * 
     * @return true if there are no fields in this document, or false if there is at least one.
     */
    boolean isEmpty();

    /**
     * Obtain a clone of this document.
     * 
     * @return the clone of this document; never null
     */
    Document clone();

    /**
     * Obtain a clone of this document, but with the supplied fields replaced.
     * 
     * @param changedFields the fields that should be changed; may be null
     * @return the clone of this document with the change fields, or this document if there are no changes
     */
    Document with( Map<String, Object> changedFields );

    /**
     * Obtain a clone of this document, but with the supplied fields replaced.
     * 
     * @param fieldName the name of the file that should be changed; may be null
     * @param value the new value for the field
     * @return the clone of this document with the change fields, or this document if there are no changes
     */
    Document with( String fieldName,
                   Object value );

    /**
     * Obtain a clone of this document, but with the field values transformed using the supplied {@link ValueTransformer}.
     * 
     * @param transformer the transformer that should be used to transform each field value; may not be null
     * @return the clone of this document with transformed fields, or this document if the transformer changed none of the values
     */
    Document with( ValueTransformer transformer );

    /**
     * Obtain a clone of this document, but with all variables in string field values replaced with the referenced values from the
     * supplied properties.
     * <p>
     * Variables may appear anywhere within a string value, and multiple variables can be used within the same value. Variables
     * take the form:
     * 
     * <pre>
     *    variable := '${' variableNames [ ':' defaultValue ] '}'
     *    
     *    variableNames := variableName [ ',' variableNames ]
     *    
     *    variableName := /* any characters except ',' and ':' and '}'
     *    
     *    defaultValue := /* any characters except
     * </pre>
     * 
     * Note that <i>variableName</i> is the name used to look up the {@link Properties} property.
     * </p>
     * Notice that the syntax supports multiple <i>variables</i>. The logic will process the <i>variables</i> from let to right,
     * until an existing System property is found. And at that point, it will stop and will not attempt to find values for the
     * other <i>variables</i>.
     * <p>
     * 
     * @param properties the properties keyed by variable name
     * @return the clone of this document with variables in fields string values replaced with values from the properties object,
     *         or this document if no variables were found
     * @see #withVariablesReplacedWithSystemProperties()
     * @see #with(ValueTransformer)
     * @see SchemaLibrary#convertValues(Document, String)
     */
    Document withVariablesReplaced( Properties properties );

    /**
     * Obtain a clone of this document, but with all variables in string field values replaced with the referenced values from the
     * System properties.
     * <p>
     * Variables may appear anywhere within a string value, and multiple variables can be used within the same value. Variables
     * take the form:
     * 
     * <pre>
     *    variable := '${' variableNames [ ':' defaultValue ] '}'
     *    
     *    variableNames := variableName [ ',' variableNames ]
     *    
     *    variableName := /* any characters except ',' and ':' and '}'
     *    
     *    defaultValue := /* any characters except
     * </pre>
     * 
     * Note that <i>variableName</i> is the name used to look up a System property via {@link System#getProperty(String)}.
     * </p>
     * Notice that the syntax supports multiple <i>variables</i>. The logic will process the <i>variables</i> from let to right,
     * until an existing System property is found. And at that point, it will stop and will not attempt to find values for the
     * other <i>variables</i>.
     * <p>
     * <p>
     * Because only string values can contain variables, the resulting values are left as strings. This may not be valid according
     * to the document's JSON Schema, so see {@link SchemaLibrary#convertValues(Document, String)} to convert the string values
     * after variable substitution into the expected non-string types.
     * </p>
     * 
     * @return the clone of this document with variables in fields string values replaced with values from the System properties,
     *         or this document if no variables were found
     * @see #withVariablesReplaced(Properties)
     * @see #with(ValueTransformer)
     * @see SchemaLibrary#convertValues(Document, String)
     */
    Document withVariablesReplacedWithSystemProperties();

    /**
     * Obtains an editor for the supplied document. The editor allows the caller to make changes to the document and to obtain
     * these changes as a {@link Changes serializable memento} that can be applied to another document.
     * 
     * @return an {@link Editor} instance which can used to change the document; never {@code null} 
     */
    Editor edit(boolean clone);

    /**
     * Returns an editable view of the given document. Any changes will be reflected directly in the underlying document
     * 
     * @return a {@link EditableDocument} instance, never {@code null}
     */
    EditableDocument editable();

    /**
     * A component that can transform field values, via {@link Document#with(ValueTransformer)}. Implementations do not need to
     * worry about {@link Document} values, since the transformer is never called on such values.
     */
    interface ValueTransformer {
        /**
         * Transform the supplied field value.
         * 
         * @param name the name of the field; never null
         * @param value the existing value for the field
         * @return the transformed value; never null but may be the same <code>value</code> object if no transformation should be
         *         made
         */
        Object transform( String name,
                          Object value );
    }

    interface Field extends Comparable<Field> {

        /**
         * Get the name of the field
         * 
         * @return the field's name; never null
         */
        String getName();

        /**
         * Get the value of the field.
         * 
         * @return the field's value; may be null
         */
        Object getValue();

        String getValueAsString();

        Integer getValueAsInt();

        boolean getValueAsBoolean();

        Binary getValueAsBinary();

        Number getValueAsNumber();

        Pattern getValueAsPattern();

        Double getValueAsDouble();

        UUID getValueAsUuid();

        Document getValueAsDocument();
    }
}