/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
 *
 * 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 com.android.ide.eclipse.editors.layout;

import com.android.layoutlib.api.IXmlPullParser;

import org.xmlpull.v1.XmlPullParserException;

import java.io.InputStream;
import java.io.Reader;

/**
 * Base implementation of an {@link IXmlPullParser} for cases where the parser is not sitting
 * on top of an actual XML file.
 * <p/>It's designed to work on layout files, and will most likely not work on other resource
 * files.
 */
public abstract class BasePullParser implements IXmlPullParser {
    
    protected int mParsingState = START_DOCUMENT;
    
    public BasePullParser() {
    }
    
    // --- new methods to override ---
    
    public abstract void onNextFromStartDocument();
    public abstract void onNextFromStartTag();
    public abstract void onNextFromEndTag();
    
    // --- basic implementation of IXmlPullParser ---
    
    public void setFeature(String name, boolean state) throws XmlPullParserException {
        if (FEATURE_PROCESS_NAMESPACES.equals(name) && state) {
            return;
        }
        if (FEATURE_REPORT_NAMESPACE_ATTRIBUTES.equals(name) && state) {
            return;
        }
        throw new XmlPullParserException("Unsupported feature: " + name);
    }

    public boolean getFeature(String name) {
        if (FEATURE_PROCESS_NAMESPACES.equals(name)) {
            return true;
        }
        if (FEATURE_REPORT_NAMESPACE_ATTRIBUTES.equals(name)) {
            return true;
        }
        return false;
    }

    public void setProperty(String name, Object value) throws XmlPullParserException {
        throw new XmlPullParserException("setProperty() not supported");
    }

    public Object getProperty(String name) {
        return null;
    }

    public void setInput(Reader in) throws XmlPullParserException {
        throw new XmlPullParserException("setInput() not supported");
    }

    public void setInput(InputStream inputStream, String inputEncoding)
            throws XmlPullParserException {
        throw new XmlPullParserException("setInput() not supported");
    }

    public void defineEntityReplacementText(String entityName, String replacementText)
            throws XmlPullParserException {
        throw new XmlPullParserException("defineEntityReplacementText() not supported");
    }

    public String getNamespacePrefix(int pos) throws XmlPullParserException {
        throw new XmlPullParserException("getNamespacePrefix() not supported");
    }

    public String getInputEncoding() {
        return null;
    }

    public String getNamespace(String prefix) {
        throw new RuntimeException("getNamespace() not supported");
    }

    public int getNamespaceCount(int depth) throws XmlPullParserException {
        throw new XmlPullParserException("getNamespaceCount() not supported");
    }

    public String getNamespaceUri(int pos) throws XmlPullParserException {
        throw new XmlPullParserException("getNamespaceUri() not supported");
    }

    public int getColumnNumber() {
        return -1;
    }

    public int getLineNumber() {
        return -1;
    }

    public String getAttributeType(int arg0) {
        return "CDATA";
    }

    public int getEventType() {
        return mParsingState;
    }

    public String getText() {
        return null;
    }

    public char[] getTextCharacters(int[] arg0) {
        return null;
    }

    public boolean isAttributeDefault(int arg0) {
        return false;
    }

    public boolean isWhitespace() {
        return false;
    }
    
    public int next() throws XmlPullParserException {
        switch (mParsingState) {
            case END_DOCUMENT:
                throw new XmlPullParserException("Nothing after the end");
            case START_DOCUMENT:
                onNextFromStartDocument();
                break;
            case START_TAG:
                onNextFromStartTag();
                break;
            case END_TAG:
                onNextFromEndTag();
                break;
            case TEXT:
                // not used
                break;
            case CDSECT:
                // not used
                break;
            case ENTITY_REF:
                // not used
                break;
            case IGNORABLE_WHITESPACE:
                // not used
                break;
            case PROCESSING_INSTRUCTION:
                // not used
                break;
            case COMMENT:
                // not used
                break;
            case DOCDECL:
                // not used
                break;
        }
        
        return mParsingState;
    }

    public int nextTag() throws XmlPullParserException {
        int eventType = next();
        if (eventType != START_TAG && eventType != END_TAG) {
            throw new XmlPullParserException("expected start or end tag", this, null);
        }
        return eventType;
    }

    public String nextText() throws XmlPullParserException {
        if (getEventType() != START_TAG) {
            throw new XmlPullParserException("parser must be on START_TAG to read next text", this,
                    null);
        }
        int eventType = next();
        if (eventType == TEXT) {
            String result = getText();
            eventType = next();
            if (eventType != END_TAG) {
                throw new XmlPullParserException(
                        "event TEXT it must be immediately followed by END_TAG", this, null);
            }
            return result;
        } else if (eventType == END_TAG) {
            return "";
        } else {
            throw new XmlPullParserException("parser must be on START_TAG or TEXT to read text",
                    this, null);
        }
    }

    public int nextToken() throws XmlPullParserException {
        return next();
    }

    public void require(int type, String namespace, String name) throws XmlPullParserException {
        if (type != getEventType() || (namespace != null && !namespace.equals(getNamespace()))
                || (name != null && !name.equals(getName())))
            throw new XmlPullParserException("expected " + TYPES[type] + getPositionDescription());
    }
}