package Torello.Java;

import Torello.Java.Additional.AppendableSafe;
import Torello.Java.Additional.BiAppendable;

import static Torello.Java.C.BGREEN;
import static Torello.Java.C.RESET;

import java.util.regex.Pattern;
import java.util.regex.MatchResult;
import java.util.function.Function;
import java.util.stream.Stream;

// This Configuration-Record is generated solely from the User-Input Method-Parameters which may be
// passed to the 8 variants that are offered by the Top-Level User-API Class 'SED'.  This 
// Data-Record Class does not have any methods whatsoever - it only has constructors.  Furthermore
// the fields in this Data-Class are fields which are strictly obtained (directly copied) from the
// User-Input Parameters obtained from the eight methods offered by class 'Torello.Java.SED'
// 
// ================================================================================================
// 
// The biggest benefit of looking at this is that *EVERY SINGLE ONE* of the following fields are 
// all declared 'final', and that means that when looking at the code inside of the various classes
// which do the processing for this Top-Level Dispatch-Class (Torello.Java.SED) you should be ssafe
// in knowing that instances of this class are strictly Data-Lookup, and therefore do not contain
// any fields which may be modified during the processing of a Text-File.  For some programmers, 
// especially me, this can be a somewhat non-trivial value when trying to understand what the hell
// these complicated for-loops and string-processing methods are even doing.
// 
// Note that this class has two variants for constructors.  One of the constructors is used for 
// SED-Replacement that involves Regular-Expressions, while the latter is used for direct 
// String-to-String replacements
// 
// Constructor-Variant ONE Parameters:
//      final String matchStr
//      final String replaceStr
//
// Constructor-Variant TWO Parameters:
//      final Pattern                       regEx,
//      final Function<MatchResult, String> replaceFunction
// 
// ================================================================================================
// 
// The second biggest benefit that this class provides is that because all of these fields are used
// sporadically throught he processing classes, it is more efficient to pass the parameters around 
// the internal methods used by SED.  Passing one single Record that contains all of the 
// Data-Fields (obtained from user parameters) to the methods means that their are fewer parameters
// or "arguments" to the various methods in SED.

class CONFIG_RECORD 
{
    // ********************************************************************************************
    // ********************************************************************************************
    // The two Data-Records
    // ********************************************************************************************
    // ********************************************************************************************


    // These two fields are only used when the User is doing a **REGULAR-EXPRESSION** Replacement
    final Pattern                       regEx;
    final Function<MatchResult, String> replaceFunction;

    // These two fields are only used when the User is doing a **STRING** Replacement
    final String matchStr;
    final String replaceStr;

    // This value is used repeatedly in this loop, so it is better left as a constant
    final int MATCH_STR_LEN;

    // These five fields are used when either of the two variants of SED are invoked
    final boolean               askFirst;
    final IOExceptionHandler    ioeh;
    final boolean               useUNIXColors;
    final Verbosity             verbosity;
    final Appendable            appendable;

    // Simple Print Loop Helpers ...
    final String HILITE_START;
    final String HILITE_END;


    // This Stream-Builder contains the list of FileNode's that are modified.  This Stream-Builder 
    // generates the Returned-Value from all of the SED methods which are offered by the Top-Level 
    // User-API SED-Class.

    final Stream.Builder<FileNode> ret = Stream.builder();


    // ********************************************************************************************
    // ********************************************************************************************
    // Two Constructors: One for the two Regular-Expression SED Methods, and one for String-Repl...
    // ********************************************************************************************
    // ********************************************************************************************


    // This Constructor is invoked by the two public SED methods which accept a Regular-Expression
    // Matcher along with a MatchResult Replacement-Function

    CONFIG_RECORD(
            final Pattern                       regEx, 
            final Function<MatchResult, String> replaceFunction, 
            final boolean                       askFirst,
            final IOExceptionHandler            ioeh,
            final boolean                       useUNIXColors, 
            final Verbosity                     verbosity,
            final Appendable                    outputSaver
        )
    {
        this.regEx              = regEx;
        this.replaceFunction    = replaceFunction;

        this.matchStr           = null;
        this.replaceStr         = null;
        this.MATCH_STR_LEN      = -1;

        this.askFirst           = askFirst;
        this.ioeh               = ioeh;
        this.useUNIXColors      = useUNIXColors;
        this.verbosity          = verbosity;
        this.appendable         = generateTheAppendable(outputSaver);

        this.HILITE_START       = useUNIXColors ? BGREEN  : "";
        this.HILITE_END         = useUNIXColors ? RESET   : "";
    }


    // This Constructor is (obviously!) invoked by the two SED methods which accept a Match-Sring 
    // and a Replacement-String as Configuration-Parameters.

    CONFIG_RECORD(
            final String                matchStr,
            final String                replaceStr,
            final boolean               askFirst,
            final IOExceptionHandler    ioeh,
            final boolean               useUNIXColors, 
            final Verbosity             verbosity,
            final Appendable            outputSaver
        )
    {
        this.regEx              = null;
        this.replaceFunction    = null;

        this.matchStr           = matchStr;
        this.replaceStr         = replaceStr;
        this.MATCH_STR_LEN      = matchStr.length();

        this.askFirst           = askFirst;
        this.ioeh               = ioeh;
        this.useUNIXColors      = useUNIXColors;
        this.verbosity          = verbosity;
        this.appendable         = generateTheAppendable(outputSaver);

        this.HILITE_START       = useUNIXColors ? BGREEN  : "";
        this.HILITE_END         = useUNIXColors ? RESET   : "";
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Very Short, Static, Constructor-Helper Method
    // ********************************************************************************************
    // ********************************************************************************************


    private static Appendable generateTheAppendable(final Appendable outputSaver)
    {
        return (outputSaver == null)

            // If no 'outputSaver' was provided, then just send text to Standard-Out
            ? System.out

            // This just allows for printing to **BOTH** System.out **AND** the 'outputSaver'
            : new BiAppendable
                (System.out, new AppendableSafe(outputSaver, AppendableSafe.USE_APPENDABLE_ERROR));
    }
}