package Torello.Java;

import java.io.File;
import java.util.Map;
import java.util.function.Consumer;

/**
 * This class allows for the user to provide redirects, environment variables, and output/error
 * unification (meaning the Standard-Output and Error-Output Streams are printed together, as if
 * they were being printed to the terminal).
 * 
 * <EMBED CLASS='external-html' DATA-FILE-ID=OSEXTRAS>
 */
@SuppressWarnings("overrides") // The 'equals(other) causes a warning about hashCode
public class OSExtras implements Cloneable
{
    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_CUR_WDIR> */
    public File currentWorkingDirectory = null;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_MERGE_IE> */
    public boolean mergeStdErrorAndStdOut = false;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_OUT_REDIR> */
    public ProcessBuilder.Redirect outputRedirect = null;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_INP_REDIR> */
    public ProcessBuilder.Redirect inputRedirect = null;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_ERR_REDIR> */
    public ProcessBuilder.Redirect errorRedirect = null;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_ENV_UPDT> */
    public Consumer<Map<String, String>> environmentVariableUpdater = null;

    /** <EMBED CLASS='external-html' DATA-FILE-ID=OSE_JAVA_PIPE> */
    public OSJavaPipe javaPipe = null;

    /** Builds a new instance of this class, and keeps the default values assigned. */
    public OSExtras() { }

    /**
     * Constructs an instance of this class
     * @param currentWorkingDirectory       <EMBED CLASS=external-html DATA-FILE-ID=OSE_CUR_WDIR>
     * @param mergeStdErrorAndStdOut        <EMBED CLASS=external-html DATA-FILE-ID=OSE_MERGE_IE>
     * @param outputRedirect                <EMBED CLASS=external-html DATA-FILE-ID=OSE_OUT_REDIR>
     * @param inputRedirect                 <EMBED CLASS=external-html DATA-FILE-ID=OSE_INP_REDIR>
     * @param errorRedirect                 <EMBED CLASS=external-html DATA-FILE-ID=OSE_ERR_REDIR>
     * @param environmentVariableUpdater    <EMBED CLASS=external-html DATA-FILE-ID=OSE_ENV_UPDT>
     * @param javaPipe                      <EMBED CLASS=external-html DATA-FILE-ID=OSE_JAVA_PIPE>
     * 
     * @throws IllegalArgumentException if {@code inputRedirect} and {@code javaPipe} are both
     * non-null.  Input may be redirected from only a single location.  Neither of these parameters
     * are required, but at most - <I>only one of these two parameters may be passed a non-null
     * value, otherwise this exception shall throw!</I>
     */
    public OSExtras(
           File                            currentWorkingDirectory,
           boolean                         mergeStdErrorAndStdOut,
           ProcessBuilder.Redirect         outputRedirect,
           ProcessBuilder.Redirect         inputRedirect,
           ProcessBuilder.Redirect         errorRedirect,
           Consumer<Map<String, String>>   environmentVariableUpdater,
           OSJavaPipe                      javaPipe
        )
    {
        this.currentWorkingDirectory    = currentWorkingDirectory;
        this.mergeStdErrorAndStdOut     = mergeStdErrorAndStdOut;
        this.outputRedirect             = outputRedirect;
        this.inputRedirect              = inputRedirect;
        this.errorRedirect              = errorRedirect;
        this.environmentVariableUpdater = environmentVariableUpdater;
        this.javaPipe                   = javaPipe;

        if ((this.javaPipe != null) && (this.inputRedirect != null))

            throw new IllegalArgumentException(
                "You have passed non-null Object-References to both parameters [inputRedirect] " +
                "and to [javaPipe], but this is not allowed.  Neither of these parameter are " +
                "actually required, and at most, only one of them are permitted non-null values."
            );
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Object & Cloneable Methods
    // ********************************************************************************************
    // ********************************************************************************************


    private static String toStrApp(Object a)
    { return (a == null) ? "null\n" : (a.getClass().getName() + '\n'); }

    /**
     * Generates a {@code String} this class.  The returned {@code String} merely encodes the
     * class-names of the non-null fields.
     *     
     * @return A simple representation of this class, as a {@code java.lang.String}
     */
    public String toString()
    {
        // private static String toStrApp(Appendable a)
        // { return (a == null) ? "null\n" : (a.getClass().getName() + '\n'); }

        return
            "currentWorkingDirectory:    " + toStrApp(this.currentWorkingDirectory) +
            "mergeStdErrorAndStdOut:     " + this.mergeStdErrorAndStdOut + '\n' +
            "outputRedirect:             " + toStrApp(this.outputRedirect) +
            "inputRedirect:              " + toStrApp(this.inputRedirect) +
            "errorRedirect:              " + toStrApp(this.errorRedirect) +
            "environmentVariableUpdater: " + toStrApp(this.environmentVariableUpdater) +
            "javaPipe:                   " + ((this.javaPipe == null) ? "null\n" : StrPrint.abbrev
                                                (this.javaPipe.toString(), 30, true, null, 60));
    }

    /**
     * Checks for equality based on whether two instances have identical references.
     *
     * @param other Any Java Object.  Only a valid sub-class of {@code OSExtras} could possibly
     * produce a {@code TRUE} return value
     *
     * @return {@code TRUE} if and only if each of the {@code OSExtras} fields are <I>identical
     * references in both {@code 'this'} and {@code 'other'}</I>.
     */
    public boolean equals(Object other)
    {
        if (other == null) return false;

        if (! OSExtras.class.isAssignableFrom(other.getClass())) return false;

        OSExtras o = (OSExtras) other;

        return 
                (this.currentWorkingDirectory       == o.currentWorkingDirectory)
            &&  (this.mergeStdErrorAndStdOut        == o.mergeStdErrorAndStdOut)
            &&  (this.outputRedirect                == o.outputRedirect)
            &&  (this.inputRedirect                 == o.inputRedirect)
            &&  (this.errorRedirect                 == o.errorRedirect)
            &&  (this.environmentVariableUpdater    == o.environmentVariableUpdater)
            &&  (this.javaPipe                      == o.javaPipe);
    }

    /**
     * Makes a copy of {@code 'this'} instance and returns it.
     * @return a clone of {@code 'this'} instance
     */
    public Object clone()
    {
        return new OSExtras(
            this.currentWorkingDirectory,
            this.mergeStdErrorAndStdOut,
            this.outputRedirect,
            this.inputRedirect,
            this.errorRedirect,
            this.environmentVariableUpdater,
            this.javaPipe
        );
    }
}