package Torello.JavaDoc.Annotations;

import Torello.Java.StrSource;
import Torello.Java.StrCh;
import Torello.Java.StringParse;

import Torello.Java.Additional.EffectivelyFinal;

import javax.annotation.processing.Messager;

import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.AnnotationValue;

import javax.tools.Diagnostic;

import java.util.List;
import java.util.Arrays;

import java.util.stream.Stream;

// EXPORTS:
//      public Background background() default Background.Blue;
//      public String title() default "";
//      public String divCSSClass() default "";
//      public String tableCSSClass() default "";
// 
// 
// The following files are relatedf to this 'javac' Annotation-Processor:
// 
// * Torello.JDUInternal.SimpleFeatures.IntoHTMLTableProc
//      This is the primary or "Work Horse" Method for Generating the HTML-Table that is inserted
//      into the Detail-Entry "description()" section.
// 
// * User-Annotations.css
//      For the CSS Color Choices/Options/Definitions
//      Since there are a suite of Color-Choices which have been presented to the user


@Torello.JavaDoc.Annotations.JDHeaderBackgroundImg(EmbedTagFileID="ANNOT_PROC_JDHBI")
public class IHTProcessor
{
    private IHTProcessor() { }

    // This is used by the Error-Message Printer
    private static final String IHT_NAME =
        Torello.JavaDoc.Annotations.IntoHTMLTable.class.getSimpleName();

    // @IntoHTMLTable Annotation:
    // 
    // EXPORTS:
    //      public Background background() default Background.Blue;
    //      public String title() default "";
    //      public String divCSSClass() default "";
    //      public String tableCSSClass() default "";

    static boolean process(
            Element             ciet,
            AnnotationMirror    am,
            javax.annotation.processing.Messager messager
        )
    {
        EffectivelyFinal<Boolean> errors = new EffectivelyFinal<>(false);

        am.getElementValues().forEach((ExecutableElement ee, AnnotationValue av) ->
        {
            // Understanding the 'terminology' in Annotations and Annotation-Processor's is half of
            // the work in using it.

            final Object val  = av.getValue();

            switch (ee.toString())
            {
                case "background()" :
                    break;

                case "title()" :
                    errors.f |= checkTitleAE(messager, ciet, (String) val);
                    break;

                case "divCSSClass()" :
                    errors.f |= checkCSSClassAE(messager, ciet, "divCSSClass()", (String) val);
                    break;

                case "tableCSSClass()" :
                    errors.f |= checkCSSClassAE(messager, ciet, "divCSSClass()", (String) val);
                    break;

                default: 

                    // This should be UNREACHABLE-CODE.  The Java-Compiler, itself, should do the
                    // complaining that the user supplied an Annotation-Element name that is not
                    // among those listed above.  Unless 'javac' changes, this cannot execute.

                    throw new InternalError(
                        "There was an annotation parameter whose name wasn't recognized: " +
                        ee.toString() + "\n" +
                        "The only parameter's that may be passed to @IntoHTMLTable are:\n" +
                        "'background()', 'title()', 'divCSSClass()' and 'tableCSSClass()'"
                    );
            }
        });        

        return errors.f;
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Checks both the "name()" and "handle()" Annotation-Elements
    // ********************************************************************************************
    // ********************************************************************************************


    private static boolean checkTitleAE(
            javax.annotation.processing.Messager messager,
            Element ciet,
            String  aeValAsStr
        )
    {
        // THIS TEST IS BLOCK-COPIED IDENTICAL TO THE TEST THAT IS LOCATED INSIDE
        // "Torello.JDUInternal.Annotations.EntityAnnotations.Mirror.IHTErrorCheck"

        final boolean test =
                (! StrCh.containsOR(aeValAsStr, '\t', '\n', '\r'))
            &&  (aeValAsStr.length() <= 300);

        if (test) return true;

        // NOTE: Torello.JDUInternal.Messager **DOES NOT** ALLOW '\t'
        messager.printMessage(
            Diagnostic.Kind.ERROR,
            HELPER.LOCATION(ciet, IHT_NAME) +
            "\tString Annotation-Parameter 'title()' was passed " +
                "[" + aeValAsStr + "]\n" +
            "\tHowever, this String may not contain the characters: '\\t', '\\n', '\\r'\n" +
            "\tNor may it be more than 300 Characters long."
        );

        return false;
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Checks the "typeName()" Annotation-Elements
    // ********************************************************************************************
    // ********************************************************************************************


    private static boolean checkCSSClassAE(
            final javax.annotation.processing.Messager messager,
            final Element   ciet,
            final String    aeName,
            final String    aeValAsStr
        )
    {
        if (aeValAsStr.length() == 0) return true;

        final String[] cssClasses = aeValAsStr.split("\\s");

        final Stream.Builder<String> b = Stream.builder();

        boolean errors = false;

        for (final String cssClass : cssClasses)

            if (! StrSource.isCSSClassName(cssClass))
            {
                b.accept(cssClass);
                errors = true;
            }

        if (! errors) return true;

        messager.printMessage(
            Diagnostic.Kind.ERROR,
            HELPER.LOCATION(ciet, IHT_NAME) +

            // NOTE: Torello.JDUInternal.Messager **DOES NOT** ALLOW '\t'
            "\tString Annotation-Parameter " + aeName + " was passed " +
                "[" + aeValAsStr + "]\n" +
            "\tHowever, the following CSS-Classes are invalid CSS Class-Names:\n" +
            Arrays.toString(b.build().toArray())
        );

        return false;
    }
}