/*
 * Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies).
 * All rights reserved.
 * This component and the accompanying materials are made available
 * under the terms of the License "Eclipse Public License v1.0"
 * which accompanies this distribution, and is available
 * at the URL "http://www.eclipse.org/legal/epl-v10.html".
 *
 * Initial Contributors:
 * Nokia Corporation - initial contribution.
 *
 * Contributors:
 *
 * Description: 
 *
 */
package com.nokia.helium.synergy.ant.taskdefs;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

import org.apache.tools.ant.BuildException;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.Task;
import org.apache.tools.ant.taskdefs.Execute;
import org.apache.tools.ant.taskdefs.LogStreamHandler;
import org.apache.tools.ant.taskdefs.condition.Os;

import com.nokia.helium.core.FileUtils;

/**
 * <code>AbstractScmBaseTask</code> is an abstract class for GSCM related tasks
 * such as rebaseline and deconfigure.
 * 
 * @ant.task category="SCM"
 * 
 */
public abstract class AbstractScmBaseTask extends Task {

    // common attributes
    private String database; // -d dbname = Database name (or database path)
    private String password; // -U password = UNIX password
    private String ccmProject; // -p projectname = Project name (incompatible
    // with -B)

    private Integer verbosity;

    private StringBuffer commandString = new StringBuffer();
    private List<SCMCommandArgument> commands = new ArrayList<SCMCommandArgument>();

    /**
     * Return the Synergy project name.
     * 
     * @return the Synergy project name.
     */
    public String getCcmProject() {
        return ccmProject;
    }

    /**
     * Set Synergy Project Name to be used.
     * 
     * @param ccmProject
     *            is the Synergy project name to set
     * @ant.required
     */
    public void setCcmProject(String ccmProject) {
        this.ccmProject = ccmProject;
        log("Set ccmProject to " + ccmProject);
    }

    /**
     * Return the database name.
     * 
     * @return the database name.
     */
    public String getDatabase() {
        return database;
    }

    /**
     * Set Synergy Database name to be used.
     * 
     * @param database
     *            is the name of the Synergy database to set.
     * @ant.required
     */
    public void setDatabase(String database) {
        this.database = database;
        log("Set database to " + database);
    }

    /**
     * Return the Synergy password.
     * 
     * @return the Synergy password.
     */
    public String getPassword() {
        return password;
    }

    /**
     * Set Synergy Password to be used.
     * 
     * @param password
     *            is the password to set.
     * @ant.required
     */
    public void setPassword(String password) {
        this.password = password;
        log("Set password to ****** ");
    }

    /**
     * Return the verbosity.
     * 
     * @return the verbosity.
     */
    public Integer getVerbosity() {
        return verbosity;
    }

    /**
     * Set verbosity level to be used. Verbosity level ( 0 - quiet, 1 - verbose,
     * 2 - very verbose). Exception will be raised for any other value.
     * 
     * @param verbosity
     *            is the verbosity level to set.
     * @ant.not-required
     */
    public void setVerbosity(Integer verbosity) {
        this.verbosity = verbosity;
        log("Set verbosity to " + verbosity);
    }

    /**
     * Method executes the current task.
     * 
     */
    @Override
    public void execute() {
        // Set execution script
        String script = getExecutionScript();
        String systemPath = System.getenv("PATH");
        String[] pathDirs = systemPath.split(File.pathSeparator);
        if (Os.isFamily(Os.FAMILY_WINDOWS)) {
            // Under windows it is not in the path...
            String[] customPathDirs = new String[pathDirs.length + 1];
            System.arraycopy(pathDirs, 0, customPathDirs, 0, pathDirs.length);
            customPathDirs[customPathDirs.length - 1] = "C:\\apps\\base-apps\\bin";
            pathDirs = customPathDirs;
        } else {
            // Under Linux environment it is a perl script...
            script = script + ".pl";
        }
        
        File scriptFile = FileUtils
                .findExecutableOnPath(script, pathDirs);
        if (scriptFile == null) {
            throw new BuildException("Could not find " + script
                    + " application in the path.");
        }
        appendToCommandLine(scriptFile.getAbsolutePath());

        // Build command argument list
        buildCommandList();

        // handle the command arguments
        handleCommandArguments();

        // configure verbosity
        configureVerbosity();

        // Execute the command-line launching as a separate process
        runCommand();
        log("Completed successfully.");
    }

    /**
     * Method appends the given prefix and the command to the command string if
     * the input cmd string is not null.
     * 
     * @param prefix
     *            is the prefix of the cmd string input.
     * @param cmd
     *            is the cmd string to be appended to main command string.
     */
    protected void appendToCommandLine(String prefix, Object cmd) {
        if (cmd != null) {
            commandString.append(prefix);
            commandString.append(" ");
            commandString.append(cmd);
            commandString.append(" ");
        }
    }

    /**
     * Method appends the given prefix to the command string if the boolean
     * value input is set true.
     * 
     * @param prefix
     *            is the prefix to be appended to the command string.
     * @param bool
     *            indicates whether to append the prefix or not.
     */
    protected void appendToCommandLine(String prefix, Boolean bool) {
        if (bool != null && bool) {
            appendToCommandLine(prefix);
        }
    }

    /**
     * Method appends the given cmd to the command string.
     * 
     * @param cmd
     *            is the command string to be appended.
     */
    protected void appendToCommandLine(String cmd) {
        commandString.append(cmd);
        commandString.append(" ");
    }

    /**
     * Add the given command argument to the command list.
     * 
     * @param fieldName
     *            is the name of the task field.
     * @param cmdArg
     *            is the command argument to be added to the command list.
     * @param required
     *            indicates whether the command argument is mandatory or not.
     * @param fieldValue
     *            is the value of the given field
     */
    protected void addCommandArg(String fieldName, String cmdArg,
            Boolean required, Object fieldValue) {
        SCMCommandArgument cmdObj = new SCMCommandArgument(fieldName, cmdArg,
                required, fieldValue);
        commands.add(cmdObj);
    }

    /**
     * Add the given command argument to the command list. By default, the input
     * command argument will be optional.
     * 
     * @param fieldName
     *            is the name of the task field.
     * @param cmdArg
     *            is the command argument to be added to the command list.
     * @param fieldValue
     *            is the value of the given field
     */
    protected void addCommandArg(String fieldName, String cmdArg,
            Object fieldValue) {
        addCommandArg(fieldName, cmdArg, false, fieldValue);
    }

    /**
     * Method validates the given arguments.
     */
    protected abstract void validateArguments();

    /**
     * Get the name of the script to execute
     * 
     * @return the script name to execute
     */
    protected abstract String getExecutionScript();

    /**
     * Build a command list consisting of all the required and optional command
     * arguments of the current task.
     */
    protected abstract void buildCommandList();

    /**
     * Method returns the correct verbosity level for the input choice.
     * 
     * @param choice
     *            is the verbosity choice set by user.
     * @return the verbosity level to set.
     */
    protected abstract String getVerbosity(int choice);

    // ----------------------------------- PRIVATE METHODS
    // --------------------------------------

    /**
     * Method returns the requested {@link Field} object from the input
     * {@link Class}. If the requested field is not found in the given
     * {@link Class} then all its super classes are searched recursively.
     * 
     * @param clazz
     *            is the {@link Class} of which the field is requested.
     * @param fieldName
     *            is the name of the requested field.
     * @return the requested field.
     */
    private Field getField(Class<?> clazz, String fieldName) {
        Field field = null;
        if (clazz != null) {
            try {
                field = clazz.getDeclaredField(fieldName);
            } catch (NoSuchFieldException nsfe) {
                field = getField(clazz.getSuperclass(), fieldName);
            }
        }
        return field;
    }

    /**
     * Method process the command arguments set in the command list.
     * 
     * @throws Exception
     *             if any error occurs while processing the command arguments.
     */
    private void handleCommandArguments() {
        StringBuffer missingArgs = new StringBuffer();
        Field field = null;
        for (SCMCommandArgument cmdObj : commands) {
            field = getField(getClass(), cmdObj.fieldName);
            if (field != null) {
                Object fieldValue = field.getType().cast(cmdObj.fieldValue);
                check4MandatoryCmdArguments(cmdObj, fieldValue, missingArgs);
                buildCommand(cmdObj, fieldValue);
            }
        }
        // handle missing args if any
        handleMissingArguments(missingArgs);
        validateArguments();
    }

    /**
     * Method checks for the mandatory command arguments.
     * 
     * @param cmdObj
     *            is the {@link SCMCommandArgument} used in verification
     * @param fieldValue
     *            is the field value to verify
     * @param missingArgs
     *            contains the mandatory command arguments which are missing.
     */
    private void check4MandatoryCmdArguments(SCMCommandArgument cmdObj,
            Object fieldValue, StringBuffer missingArgs) {
        if (cmdObj.required && fieldValue == null) {
            missingArgs.append(cmdObj.fieldName);
            missingArgs.append(" ");
        }
    }

    /**
     * Method is used to construct an executable command string.
     * 
     * @param cmdObj
     *            is the {@link SCMCommandArgument}
     * @param fieldValue
     *            is the fieldValue containing the actual command argument.
     */
    private void buildCommand(SCMCommandArgument cmdObj, Object fieldValue) {
        if (fieldValue instanceof Boolean) {
            appendToCommandLine(cmdObj.commandArgument, (Boolean)fieldValue);
        } else {
            appendToCommandLine(cmdObj.commandArgument, fieldValue);
        }
    }

    /**
     * Method throws a {@link BuildException} if any mandatory command arguments
     * are missing.
     * 
     * @param missingArgs
     *            is the {@link StringBuffer} consisting of mandatory command
     *            arguments which are missing.
     */
    private void handleMissingArguments(StringBuffer missingArgs) {
        if (missingArgs.length() > 0) {
            throw new BuildException("Error: mandatory attributes are not defined - "
                    + missingArgs.toString());
        }
    }

    /**
     * Configure the verbosity set by the user.
     */
    private void configureVerbosity() {
        if (verbosity != null) {
            appendToCommandLine(getVerbosity(verbosity));
        }
    }

    /**
     * Execute the specified command.
     * 
     * @throws Exception
     *             if execution fails or any error occurs while execution of the
     *             command.
     */
    private void runCommand() {
        String[] cmdline = commandString.toString().split(" ");
        /*
         * Note: static method call to Execute.runCommand does not run the given
         * script here due to the setting of vmLauncher which acutally
         * tries executing the script using Runtime.getRuntime().exec() method
         * and this method cannot run the script without reference to the cmd or
         * shell. (Similar with ExecTask)
         * 
         * So creating an instance of Execute class helps to disable the
         * vmLauncher and an OS dependent shellLauncher will be available for
         * the execution of the script.
         */
        // Make sure we replace the password on the command line before printing.
        log("Executing: " + commandString.toString().replace(" " + password + " ", " *** "));
        Execute exe = new Execute(new LogStreamHandler(this, Project.MSG_INFO,
                Project.MSG_ERR));
        exe.setAntRun(getProject());
        exe.setCommandline(cmdline);
        exe.setVMLauncher(false);
        try {
            int retval = exe.execute();
            if (Execute.isFailure(retval)) {
                throw new BuildException("Error: Script execution failure.");
            }
        } catch (IOException th) {
            th.printStackTrace();
            throw new BuildException("Error: Script execution failure.");
        }
    }

    // ************************************* PRIVATE CLASSES
    // ***************************************

    /**
     * <code>SCMCommandArgument</code> is a private class and represents a
     * normal java bean which is used to hold the information related to SCM
     * command arguments.
     */
    private class SCMCommandArgument {

        private String fieldName;
        private Object fieldValue;
        private String commandArgument;
        private Boolean required;

        /**
         * Create an instance of {@link SCMCommandArgument}.
         * 
         * @param fieldName
         *            is the name of the task field
         * @param commandArg
         *            is the SCM command argument
         * @param reqd
         *            indicates the input command argument is mandatory or not.
         */
        protected SCMCommandArgument(String fieldName, String commandArg,
                Boolean reqd, Object fieldValue) {
            this.fieldName = fieldName;
            this.commandArgument = commandArg;
            this.required = reqd;
            this.fieldValue = fieldValue;
        }
    }
}