/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * 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 com.android.ide.eclipse.ddms.systrace;

import com.google.common.base.Charsets;
import com.google.common.io.Files;

import java.io.File;
import java.io.IOException;
import java.util.zip.DataFormatException;
import java.util.zip.Inflater;

/** {@link SystraceOutputParser} receives the output of atrace command run on the device,
 * parses it and generates html based on the trace */
public class SystraceOutputParser {
    private static final String TRACE_START = "TRACE:\n"; //$NON-NLS-1$

    private static final String HTML_PREFIX = "<!DOCTYPE HTML>\n"
            + "<html>\n"
            + "<head i18n-values=\"dir:textdirection;\">\n"
            + "<title>Android System Trace</title>\n"
            + "%s\n"
            + "%s\n"
            + "<script language=\"javascript\">\n"
            + "document.addEventListener('DOMContentLoaded', function() {\n"
            + "  if (!linuxPerfData)\n"
            + "    return;\n"
            + "  var m = new tracing.TimelineModel(linuxPerfData);\n"
            + "  var timelineViewEl = document.querySelector('.view');\n"
            + "  base.ui.decorate(timelineViewEl, tracing.TimelineView);\n"
            + "  timelineViewEl.model = m;\n"
            + "  timelineViewEl.tabIndex = 1;\n"
            + "  timelineViewEl.timeline.focusElement = timelineViewEl;\n"
            + "});\n"
            + "</script>\n"
            + "<style>\n"
            + "  .view {\n"
            + "    overflow: hidden;\n"
            + "    position: absolute;\n"
            + "    top: 0;\n"
            + "    bottom: 0;\n"
            + "    left: 0;\n"
            + "    right: 0;\n"
            + "  }\n"
            + "</style>\n"
            + "</head>\n"
            + "<body>\n"
            + "  <div class=\"view\">\n"
            + "  </div>\n"
            + "  <script>\n"
            + "  var linuxPerfData = \"\\\n";

    private static final String HTML_SUFFIX =
              "           dummy-0000  [000] 0.0: 0: trace_event_clock_sync: parent_ts=0.0\\n\";\n"
            + "  </script>\n"
            + "</body>\n"
            + "</html>\n";

    private final boolean mUncompress;
    private final String mJs;
    private final String mCss;

    private byte[] mAtraceOutput;
    private int mAtraceLength;
    private int mSystraceIndex = -1;

    /**
     * Constructs a atrace output parser.
     * @param compressedStream Is the input stream compressed using zlib?
     * @param systraceJs systrace javascript content
     * @param systraceCss systrace css content
     */
    public SystraceOutputParser(boolean compressedStream, String systraceJs, String systraceCss) {
        mUncompress = compressedStream;
        mJs = systraceJs;
        mCss = systraceCss;
    }

    /**
     * Parses the atrace output for systrace content.
     * @param atraceOutput output bytes from atrace
     */
    public void parse(byte[] atraceOutput) {
        mAtraceOutput = atraceOutput;
        mAtraceLength = atraceOutput.length;

        removeCrLf();

        // locate the trace start marker within the first hundred bytes
        String header = new String(mAtraceOutput, 0, Math.min(100, mAtraceLength));
        mSystraceIndex = locateSystraceData(header);

        if (mSystraceIndex < 0) {
            throw new RuntimeException("Unable to find trace start marker 'TRACE:':\n" + header);
        }
    }

    /** Replaces \r\n with \n in {@link #mAtraceOutput}. */
    private void removeCrLf() {
        int dst = 0;
        for (int src = 0; src < mAtraceLength - 1; src++, dst++) {
            byte copy;
            if (mAtraceOutput[src] == '\r' && mAtraceOutput[src + 1] == '\n') {
                copy = '\n';
                src++;
            } else {
                copy = mAtraceOutput[src];
            }
            mAtraceOutput[dst] = copy;
        }

        mAtraceLength = dst;
    }

    private int locateSystraceData(String header) {
        int index = header.indexOf(TRACE_START);
        if (index < 0) {
            return -1;
        } else {
            return index + TRACE_START.length();
        }
    }

    public String getSystraceHtml() {
        if (mSystraceIndex < 0) {
            return "";
        }

        String trace = "";
        if (mUncompress) {
            Inflater decompressor = new Inflater();
            decompressor.setInput(mAtraceOutput, mSystraceIndex, mAtraceLength - mSystraceIndex);

            byte[] buf = new byte[4096];
            int n;
            StringBuilder sb = new StringBuilder(1000);
            try {
                while ((n = decompressor.inflate(buf)) > 0) {
                    sb.append(new String(buf, 0, n));
                }
            } catch (DataFormatException e) {
                throw new RuntimeException(e);
            }
            decompressor.end();

            trace = sb.toString();
        } else {
            trace = new String(mAtraceOutput, mSystraceIndex, mAtraceLength - mSystraceIndex);
        }

        // each line should end with the characters \n\ followed by a newline
        String html_out = trace.replaceAll("\n", "\\\\n\\\\\n");
        String header = String.format(HTML_PREFIX, mCss, mJs);
        String footer = HTML_SUFFIX;
        return header + html_out + footer;
    }

    public static String getJs(File assetsFolder) {
        try {
            return String.format("<script language=\"javascript\">%s</script>",
                    Files.toString(new File(assetsFolder, "script.js"), Charsets.UTF_8));
        } catch (IOException e) {
            return "";
        }
    }

    public static String getCss(File assetsFolder) {
        try {
            return String.format("<style type=\"text/css\">%s</style>",
                    Files.toString(new File(assetsFolder, "style.css"), Charsets.UTF_8));
        } catch (IOException e) {
            return "";
        }
    }
}