package com.thoughtworks.seleniumtest.testhelper;



import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.util.ArrayList;

import java.util.Enumeration;

import java.util.List;

import java.util.Properties;



import org.apache.log4j.Logger;



public class OSEnvironment {



    private static final Logger LOG = Logger.getLogger(OSEnvironment.class);



    /**

     * Internal representation of the system environment

     */

    private Properties variables = new Properties();



    /**

     * Constructor

     *

     * Creates an instance of OSEnvironment, queries the OS to discover it's

     * environment variables and makes them available through the getter methods

     */

    public OSEnvironment() {

        parse();

    }



    /**

     * Parses the OS environment and makes the environment variables available

     * through the getter methods

     */

    private void parse() {



        String command;



        // Detemine the correct command to run based on OS name

        String os = System.getProperty("os.name").toLowerCase();

        if (isWindows9x(os)) {

            command = "command.com /c set";

        } else if ((os.indexOf("nt") > -1) || (os.indexOf("windows") > -1)

                || (os.indexOf("os/2") > -1)) {

            command = "cmd.exe /c set";

        } else {

            // should work for just about any Unix variant

            command = "env";

        }



        // Get our environment

        try {

            Process p = Runtime.getRuntime().exec(command);

            p.getOutputStream().close();



            // Capture the output of the command

            BufferedReader stdoutStream = new BufferedReader(new InputStreamReader(p.getInputStream()));

            BufferedReader stderrStream = new BufferedReader(new InputStreamReader(p.getErrorStream()));



            // Parse the output

            String line;

            String key = null;

            while ((line = stdoutStream.readLine()) != null) {

                int idx = line.indexOf('=');

                String value;

                if (idx == -1) {

                    if (key == null) {

                        continue;

                    }

                    // potential multi-line property. Let's rebuild it

                    value = variables.getProperty(key);

                    value += "\n" + line;

                } else {

                    key = line.substring(0, idx);

                    value = line.substring(idx + 1);

                }

                variables.setProperty(key, value);

            }



            // Close down our streams

            stdoutStream.close();

            stderrStream.close();



        } catch (Exception e) {

            LOG.error("Failed to parse the OS environment.", e);

        }

    }



    private boolean isWindows9x(String os) {

        return os.indexOf("windows 9") > -1;

    }



    /**

     * Gets the value of an environment variable. The variable name is case

     * sensitive.

     *

     * @param variable

     *            The variable for which you wish the value

     *

     * @return The value of the variable, or <code>null</code> if not found

     *

     * @see #getVariable(String variable, String defaultValue)

     */

    public String getVariable(String variable) {

        return variables.getProperty(variable);

    }



    /**

     * Gets the value of an environment variable. The variable name is case

     * sensitive.

     *

     * @param variable

     *            the variable for which you wish the value

     *

     * @param defaultValue

     *            The value to return if the variable is not set in the

     *            environment.

     *

     * @return The value of the variable. If the variable is not found, the

     *         defaultValue is returned.

     */

    public String getVariable(String variable, String defaultValue) {

        return variables.getProperty(variable, defaultValue);

    }



    /**

     * Gets the value of an environment variable. The variable name is NOT case

     * sensitive. If more than one variable matches the pattern provided, the

     * result is unpredictable. You are greatly encouraged to use

     * <code>getVariable()</code> instead.

     *

     * @param variable

     *            the variable for which you wish the value

     *

     * @see #getVariable(String variable)

     * @see #getVariable(String variable, String defaultValue)

     */

    public String getVariableIgnoreCase(String variable) {

        Enumeration keys = variables.keys();

        while (keys.hasMoreElements()) {

            String key = (String) keys.nextElement();

            if (key.equalsIgnoreCase(variable)) {

                return variables.getProperty(key);

            }

        }

        return null;

    }



    /**

     * Adds a variable to this representation of the environment. If the

     * variable already existed, the value will be replaced.

     *

     * @param variable

     *            the variable to set

     * @param value

     *            the value of the variable

     */

    public void add(String variable, String value) {

        variables.setProperty(variable, value);

    }



    /**

     * Returns all environment variables which were set at the time the class

     * was instantiated, as well as any which have been added programatically.

     *

     * @return a <code>List</code> of all environment variables. The

     *         <code>List</code> is made up of <code>String</code>s of the

     *         form "variable=value".

     *

     * @see #toArray()

     */

    public List getEnvironment() {

        List env = new ArrayList();

        Enumeration keys = variables.keys();

        while (keys.hasMoreElements()) {

            String key = (String) keys.nextElement();

            env.add(key + "=" + variables.getProperty(key));

        }

        return env;

    }



    /**

     * Returns all environment variables which were set at the time the class

     * was instantiated, as well as any which have been added programatically.

     *

     * @return a <code>String[]</code> containing all environment variables.

     *         The <code>String</code>s are of the form "variable=value".

     *         This is the format expected by

     *         <code>java.lang.Runtime.exec()</code>.

     *

     * @see java.lang.Runtime

     */

    public String[] toArray() {

        List list = getEnvironment();

        return (String[]) list.toArray(new String[list.size()]);

    }



    /**

     * Returns a <code>String<code> representation of the

     * environment.

     *

     * @return A <code>String<code> representation of the environment

     */

    public String toString() {

        return variables.toString();

    }

}