/*
 * Copyright (C) 2011 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.ndk.internal.templates;

import java.io.IOException;
import java.io.InputStream;
import java.util.Map;

/**
 * Reads from a template substituting marked values from the supplied Map.
 */
public class TemplatedInputStream extends InputStream {

    private final InputStream mIn;
    private final Map<String, String> mMap;
    private char[] mSub;
    private int mPos;
    private int mMark;

    public TemplatedInputStream(InputStream in, Map<String, String> map) {
        this.mIn = in;
        this.mMap = map;
    }

    @Override
    public int read() throws IOException {
        // if from a mark, return the char
        if (mMark != 0) {
            int c = mMark;
            mMark = 0;
            return c;
        }

        // return char from sub layer if available
        if (mSub != null) {
            char c = mSub[mPos++];
            if (mPos >= mSub.length)
                mSub = null;
            return c;
        }

        int c = mIn.read();
        if (c == '%') {
            // check if it's a sub
            c = mIn.read();
            if (c == '{') {
                // it's a sub
                StringBuffer buff = new StringBuffer();
                for (c = mIn.read(); c != '}' && c >= 0; c = mIn.read())
                    buff.append((char) c);
                String str = mMap.get(buff.toString());
                if (str != null) {
                    mSub = str.toCharArray();
                    mPos = 0;
                }
                return read(); // recurse to get the real char
            } else {
                // not a sub
                mMark = c;
                return '%';
            }
        }

        return c;
    }

    @Override
    public void close() throws IOException {
        super.close();
        mIn.close();
    }

}