/*
 * Copyright (C) 2013 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.loganalysis;

import com.android.loganalysis.item.BugreportItem;
import com.android.loganalysis.item.IItem;
import com.android.loganalysis.item.KernelLogItem;
import com.android.loganalysis.item.LogcatItem;
import com.android.loganalysis.parser.BugreportParser;
import com.android.loganalysis.parser.KernelLogParser;
import com.android.loganalysis.parser.LogcatParser;
import com.android.loganalysis.util.config.ArgsOptionParser;
import com.android.loganalysis.util.config.ConfigurationException;
import com.android.loganalysis.util.config.Option;

import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.Closeable;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

/**
 * A command line tool to parse a bugreport, logcat, or kernel log file and return the output.
 */
public class LogAnalyzer {

    private enum OutputFormat{
        // TODO: Add text output support.
        JSON;
    }

    @Option(name="bugreport", description="The path to the bugreport")
    private String mBugreportPath = null;

    @Option(name="logcat", description="The path to the logcat")
    private String mLogcatPath = null;

    @Option(name="kernel-log", description="The path to the kernel log")
    private String mKernelLogPath = null;

    @Option(name="output", description="The output format, currently only JSON")
    private OutputFormat mOutputFormat = OutputFormat.JSON;

    /**
     * Run the command line tool
     */
    public void run(String[] args) {
        try {
            initArgs(args);
        } catch (ConfigurationException e) {
            printUsage();
            return;
        }

        if (!checkPreconditions()) {
            printUsage();
            return;
        }

        BufferedReader reader = null;
        try {
            if (mBugreportPath != null) {
                reader = getBufferedReader(mBugreportPath);
                BugreportItem bugreport = new BugreportParser().parse(reader);
                printBugreport(bugreport);
                return;
            }

            if (mLogcatPath != null) {
                reader = getBufferedReader(mLogcatPath);
                LogcatItem logcat = new LogcatParser().parse(reader);
                printLogcat(logcat);
                return;
            }

            if (mKernelLogPath != null) {
                reader = getBufferedReader(mKernelLogPath);
                KernelLogItem kernelLog = new KernelLogParser().parse(reader);
                printKernelLog(kernelLog);
                return;
            }
        } catch (FileNotFoundException e) {
            System.err.println(e.getMessage());
        } catch (IOException e) {
            System.err.println(e.getMessage());
        } finally {
            close(reader);
        }

        // Should never reach here.
        printUsage();
    }

    /**
     * Print the bugreport to stdout.
     */
    private void printBugreport(BugreportItem bugreport) {
        if (OutputFormat.JSON.equals(mOutputFormat)) {
            printJson(bugreport);
        }
        // TODO: Print bugreport in human readable form.
    }

    /**
     * Print the logcat to stdout.
     */
    private void printLogcat(LogcatItem logcat) {
        if (OutputFormat.JSON.equals(mOutputFormat)) {
            printJson(logcat);
        }
        // TODO: Print logcat in human readable form.
    }

    /**
     * Print the kernel log to stdout.
     */
    private void printKernelLog(KernelLogItem kernelLog) {
        if (OutputFormat.JSON.equals(mOutputFormat)) {
            printJson(kernelLog);
        }
        // TODO: Print kernel log in human readable form.
    }

    /**
     * Print an {@link IItem} to stdout.
     */
    private void printJson(IItem item) {
        if (item != null && item.toJson() != null) {
            System.out.println(item.toJson().toString());
        } else {
            System.out.println(new JSONObject().toString());
        }
    }

    /**
     * Get a {@link BufferedReader} from a given filepath.
     * @param filepath the path to the file.
     * @return The {@link BufferedReader} containing the contents of the file.
     * @throws FileNotFoundException if the file could not be found.
     */
    private BufferedReader getBufferedReader(String filepath) throws FileNotFoundException {
        return new BufferedReader(new FileReader(new File(filepath)));
    }

    /**
     * Helper to close a {@link Closeable}.
     */
    private void close(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
                // Ignore
            }
        }
    }

    /**
     * Parse the command line options and set {@link Option} annotated fields.
     */
    private void initArgs(String[] args) throws ConfigurationException {
        ArgsOptionParser opt = new ArgsOptionParser(this);
        opt.parse(args);
    }

    /**
     * Checks the arguments to see if they are valid.
     *
     * @return true if they are valid, false if they are not.
     */
    private boolean checkPreconditions() {
        // Check to see that exactly one log is set.
        int logCount = 0;
        if (mBugreportPath != null) logCount++;
        if (mLogcatPath != null) logCount++;
        if (mKernelLogPath != null) logCount++;
        return (logCount == 1);
    }

    /**
     * Print the usage for the command.
     */
    private void printUsage() {
        System.err.println("Usage: loganalysis [--bugreport FILE|--logcat FILE|--kernel-log FILE]");
    }

    /**
     * Run the LogAnalyzer from the command line.
     */
    public static void main(String[] args) {
        LogAnalyzer analyzer = new LogAnalyzer();
        analyzer.run(args);
    }
}