/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwtx.jface.text.templates.TemplateContextType;

import dwtx.jface.text.templates.SimpleTemplateVariableResolver; // packageimport
import dwtx.jface.text.templates.TemplateBuffer; // packageimport
import dwtx.jface.text.templates.TemplateContext; // packageimport
import dwtx.jface.text.templates.Template; // packageimport
import dwtx.jface.text.templates.TemplateVariable; // packageimport
import dwtx.jface.text.templates.PositionBasedCompletionProposal; // packageimport
import dwtx.jface.text.templates.TemplateException; // packageimport
import dwtx.jface.text.templates.TemplateTranslator; // packageimport
import dwtx.jface.text.templates.DocumentTemplateContext; // packageimport
import dwtx.jface.text.templates.GlobalTemplateVariables; // packageimport
import dwtx.jface.text.templates.InclusivePositionUpdater; // packageimport
import dwtx.jface.text.templates.TemplateProposal; // packageimport
import dwtx.jface.text.templates.ContextTypeRegistry; // packageimport
import dwtx.jface.text.templates.JFaceTextTemplateMessages; // packageimport
import dwtx.jface.text.templates.TemplateCompletionProcessor; // packageimport
import dwtx.jface.text.templates.TextTemplateMessages; // packageimport
import dwtx.jface.text.templates.TemplateVariableType; // packageimport
import dwtx.jface.text.templates.TemplateVariableResolver; // packageimport


import dwt.dwthelper.utils;

import dwtx.dwtxhelper.Collection;






import dwtx.core.runtime.Assert;
import dwtx.jface.text.BadLocationException;
import dwtx.jface.text.Document;
import dwtx.jface.text.IDocument;
import dwtx.text.edits.MalformedTreeException;
import dwtx.text.edits.MultiTextEdit;
import dwtx.text.edits.RangeMarker;
import dwtx.text.edits.ReplaceEdit;
import dwtx.text.edits.TextEdit;


/**
 * A context type defines a context within which templates are resolved. It
 * stores a number of <code>TemplateVariableResolver</code>s. A
 * <code>TemplateBuffer</code> can be resolved in a
 * <code>TemplateContext</code> using the
 * {@link #resolve(TemplateBuffer, TemplateContext)} method.
 * <p>
 * Clients may extend this class.
 * </p>
 *
 * @since 3.0
 */
public class TemplateContextType {

    /** The id of the context type. */
    private /* final */ String fId= null;

    /** Variable resolvers used by this content type. */
    private const Map fResolvers= new HashMap();

    /** The name of the context type. */
    private String fName= null;

    /**
     * Creates a context type with an identifier. The identifier must be unique,
     * a qualified name is suggested. The id is also used as name.
     *
     * @param id the unique identifier of the context type
     */
    public this(String id) {
        this(id, id);
    }

    /**
     * Creates a context type with an identifier. The identifier must be unique, a qualified name is suggested.
     *
     * @param id the unique identifier of the context type
     * @param name the name of the context type
     */
    public this(String id, String name) {
        Assert.isNotNull(id);
        Assert.isNotNull(name);
        fId= id;
        fName= name;
    }

    /**
     * Returns the id of the context type.
     * 
     * @return the id of the receiver
     */
    public String getId() {
        return fId;
    }


    /**
     * Returns the name of the context type.
     *
     * @return the name of the context type
     */
    public String getName() {
        return fName;
    }

    /**
     * Creates a context type with a <code>null</code> identifier.
     * <p>
     * This is a framework-only constructor that exists only so that context
     * types can be contributed via an extension point and that should not be
     * called in client code except for subclass constructors; use
     * {@link #TemplateContextType(String)} instead.
     * </p>
     */
    public this() {
    }

    /**
     * Sets the id of this context.
     * <p>
     * This is a framework-only method that exists solely so that context types
     * can be contributed via an extension point and that should not be called
     * in client code; use {@link #TemplateContextType(String)} instead.
     * </p>
     *
     * @param id the identifier of this context
     * @throws RuntimeException an unspecified exception if the id has already
     *         been set on this context type
     */
    public final void setId(String id)  {
        Assert.isNotNull(id);
        Assert.isTrue(fId is null); // may only be called once when the context is instantiated
        fId= id;
    }

    /**
     * Sets the name of the context type.
     *
     * <p>
     * This is a framework-only method that exists solely so that context types
     * can be contributed via an extension point and that should not be called
     * in client code; use {@link #TemplateContextType(String, String)} instead.
     * </p>
     *
     * @param name the name of the context type
     */
    public final void setName(String name) {
        Assert.isTrue(fName is null); // only initialized by extension code
        fName= name;
    }

    /**
     * Adds a variable resolver to the context type. If there already is a resolver
     * for the same type, the previous one gets replaced by <code>resolver</code>.
     *
     * @param resolver the resolver to be added under its name
     */
    public void addResolver(TemplateVariableResolver resolver) {
        Assert.isNotNull(resolver);
        fResolvers.put(resolver.getType(), resolver);
    }

    /**
     * Removes a template variable from the context type.
     *
     * @param resolver the variable to be removed
     */
    public void removeResolver(TemplateVariableResolver resolver) {
        Assert.isNotNull(resolver);
        fResolvers.remove(resolver.getType());
    }

    /**
     * Removes all template variables from the context type.
     */
    public void removeAllResolvers() {
        fResolvers.clear();
    }

    /**
     * Returns an iterator for the variables known to the context type.
     *
     * @return an iterator over the variables in this context type
     */
    public Iterator resolvers() {
        return Collections.unmodifiableMap(fResolvers).values().iterator();
    }

    /**
     * Returns the resolver for the given type.
     *
     * @param type the type for which a resolver is needed
     * @return a resolver for the given type, or <code>null</code> if none is registered
     */
    protected TemplateVariableResolver getResolver(String type) {
        return cast(TemplateVariableResolver) fResolvers.get(type);
    }

    /**
     * Validates a pattern, a <code>TemplateException</code> is thrown if
     * validation fails.
     *
     * @param pattern the template pattern to validate
     * @throws TemplateException if the pattern is invalid
     */
    public void validate(String pattern)  {
        TemplateTranslator translator= new TemplateTranslator();
        TemplateBuffer buffer= translator.translate(pattern);
        validateVariables(buffer.getVariables());
    }

    /**
     * Validates the variables in this context type. If a variable is not valid,
     * e.g. if its type is not known in this context type, a
     * <code>TemplateException</code> is thrown.
     * <p>
     * The default implementation does nothing.
     * </p>
     *
     * @param variables the variables to validate
     * @throws TemplateException if one of the variables is not valid in this
     *         context type
     */
    protected void validateVariables(TemplateVariable[] variables)  {
    }

    /**
     * Resolves the variables in <code>buffer</code> within <code>context</code>
     * and edits the template buffer to reflect the resolved variables.
     *
     * @param buffer the template buffer
     * @param context the template context
     * @throws MalformedTreeException if the positions in the buffer overlap
     * @throws BadLocationException if the buffer cannot be successfully modified
     */
    public void resolve(TemplateBuffer buffer, TemplateContext context)  {
        Assert.isNotNull(context);
        TemplateVariable[] variables= buffer.getVariables();

        List positions= variablesToPositions(variables);
        List edits= new ArrayList(5);

        // iterate over all variables and try to resolve them
        for (int i= 0; i !is variables.length; i++) {
            TemplateVariable variable= variables[i];

            if (!variable.isResolved())
                resolve(variable, context);

            String value= variable.getDefaultValue();
            int[] offsets= variable.getOffsets();
            // update buffer to reflect new value
            for (int k= 0; k !is offsets.length; k++)
                edits.add(new ReplaceEdit(offsets[k], variable.getInitialLength(), value));

        }

        IDocument document= new Document(buffer.getString());
        MultiTextEdit edit= new MultiTextEdit(0, document.getLength());
        edit.addChildren((TextEdit[]) positions.toArray(new TextEdit[positions.size()]));
        edit.addChildren((TextEdit[]) edits.toArray(new TextEdit[edits.size()]));
        edit.apply(document, TextEdit.UPDATE_REGIONS);

        positionsToVariables(positions, variables);

        buffer.setContent(document.get(), variables);
    }

    /**
     * Resolves a single variable in a context. Resolving is delegated to the registered resolver.
     * 
     * @param variable the variable to resolve
     * @param context the context in which to resolve the variable
     * @since 3.3
     */
    public void resolve(TemplateVariable variable, TemplateContext context) {
        String type= variable.getType();
        TemplateVariableResolver resolver= cast(TemplateVariableResolver) fResolvers.get(type);
        if (resolver is null)
            resolver= new TemplateVariableResolver(type, ""); //$NON-NLS-1$
        resolver.resolve(variable, context);
    }

    private static List variablesToPositions(TemplateVariable[] variables) {
        List positions= new ArrayList(5);
        for (int i= 0; i !is variables.length; i++) {
            int[] offsets= variables[i].getOffsets();
            for (int j= 0; j !is offsets.length; j++)
                positions.add(new RangeMarker(offsets[j], 0));
        }

        return positions;
    }

    private static void positionsToVariables(List positions, TemplateVariable[] variables) {
        Iterator iterator= positions.iterator();

        for (int i= 0; i !is variables.length; i++) {
            TemplateVariable variable= variables[i];

            int[] offsets= new int[variable.getOffsets().length];
            for (int j= 0; j !is offsets.length; j++)
                offsets[j]= (cast(TextEdit) iterator.next()).getOffset();

            variable.setOffsets(offsets);
        }
    }
}