package Torello.JavaDoc.Annotations;

import Torello.JDUInternal.Miscellaneous.EntityAnnotationData;

import Torello.JavaDoc.Messager.Messager;
import Torello.JavaDoc.Messager.MsgPrintTools;

import Torello.JDUInternal.Miscellaneous.Where.JDUAnnotations;

import Torello.Java.ReadOnly.ReadOnlyList;
import Torello.Java.ReadOnly.ROArrayListBuilder;
import Torello.Java.ReadOnly.ReadOnlyArrayList;

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

import java.util.List;

import com.sun.source.tree.Tree;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.MemberSelectTree;


/**
 * This class is intended to contain / hold a single mirror instance for each 
 * <B STYLE='color:red;'>Entity-Level Annotation</B> that has been placed on a single entity.
 * 
 * <BR /><BR />
 * See: {@link Torello.JavaDoc.Entity Entity} - Methods, Fields, Constructors,
 * Enumeration-Constants &amp; Annotation-Elements are referred to as "Entities" in JDU.
 * 
 * @see Torello.JavaDoc.Annotations.LinkJavaSource
 * @see Torello.JavaDoc.Annotations.IntoHTMLTable
 */
public class EntityAnnotationMirrors  
{
    // ********************************************************************************************
    // ********************************************************************************************
    // An Empty-Mirror Reference
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * If there are ZERO annotations that have been placed on a particular "Entity" (Method, Field,
     * Constructor, etc...), then there is no chance whatsoever that there are any JDU Annotations!
     * In such cases, the entire constructor is skipeed, and this "EMPTY_MIRROR" is assigned,
     * instead.
     */
    public static final EntityAnnotationMirrors EMPTY_MIRROR = new EntityAnnotationMirrors();

    @SuppressWarnings("unchecked")
    private EntityAnnotationMirrors()
    {
        this.ljsMirrors = ReadOnlyArrayList.emptyROAL();
        this.ihtMirror  = null;
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // The Actual Mirrors - as Fields of this class
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * {@code 'LinkJavaSource'} Data.
     * 
     * <BR /><BR />
     * This is a "Repeatable Annotation", and thus this is not a single reference, but rather a
     * "Read Only List" of references.  This pointer will never be null, instead if a particular
     * {@link Torello.JavaDoc.Entity Entity} has not been adorned with any
     * {@code '@LinkJavaSource'} annotations, then {@code 'ljsMirrors'} will be an empty list.
     * 
     * @see Torello.JavaDoc.Annotations.LinkJavaSource
     */
    public final ReadOnlyList<LJSMirror> ljsMirrors;

    /**
     * {@code 'IntoHTMLTable'} Data
     * @see Torello.JavaDoc.Annotations.IntoHTMLTable
     */
    public final IHTMirror ihtMirror;


    // ********************************************************************************************
    // ********************************************************************************************
    // Constructor: This is used (ONLY !) in class Torello.JavaDoc.Declaration
    // ********************************************************************************************
    // ********************************************************************************************


    @SuppressWarnings("unchecked")
    public EntityAnnotationMirrors(
            final List<AnnotationTree>  annotList,
            final String                signature,
            final EntityAnnotationData  ead
        )
    {
        // @LinkJavaSource is a @Repeatable Annotation ==> Keep Track of all of them
        ROArrayListBuilder<LJSMirror> ljsROALB = new ROArrayListBuilder<>();


        // @IntoHTMLTable is not *NOT* @Repeatable ==> it's an error to have more than one
        // This is declared as non-final, because it is also "Optional", and because it needs to 
        // be assigned to the actual final Instance-Field "ihtMirror".
        // 
        // NOTE: If you try to change this a third time, you are just goig to revert it back to the
        //       way it is right now...

        IHTMirror ihtMirror = null;

        TOP:
        for (AnnotationTree at : annotList)
        {
            Tree annotationType = at.getAnnotationType();

            // Say: "Thank-You ChatGPT"
            // That thing saved me a lot of time AND stress levels today.

            final String annotationClassName;

            if (annotationType instanceof IdentifierTree)
            {
                // This handles simple annotations, for instance: @SuppressWarnings and @Override
                // NOTE: Chat-GPT explained this whole thing - where there are 2 kinds of
                // "AnnotatinTypes" that are used by the Sun-Oracle Parser...
                // 
                // Unfortunately I forgot to write down what it said.  It was very right though !

                annotationClassName = ((IdentifierTree) annotationType).getName().toString();

                // System.out.println("\nIdentifierTree => annotationClassName: " + annotationClassName);
            }

            else if (annotationType instanceof MemberSelectTree)
            {
                // This handles fully qualified annotations like @java.lang.SuppressWarnings
                annotationClassName = ((MemberSelectTree) annotationType).getIdentifier().toString();

                // System.out.println("\nMemberSelectTree => annotationClassName: " + annotationClassName);
            }

            else
            {
                annotationClassName = null;

                throw Messager.assertFail(
                    BRED + "My Annotation Parser just bit the dust" + RESET + '\n' +
                    "Extracted instance of 'com.sun.source.tree.AnnotationTree' was neither an " +
                    "instance of 'IdentifierTree' nor 'MemberSelectTree'.\n" +
                    "This is not supposed to be possible / This is unreachable code.\n" +
                    "The returned Type / Class-Name was:\n" +
                    BRED + annotationType.getClass().getCanonicalName() + RESET,
                    JDUAnnotations.EntityAnnotationMirrors
                );
            }

            switch (annotationClassName)
            {
                case "LinkJavaSource" :

                    final LJSMirror ljsm = new LJSMirror(
                        at.toString(),
                        at.getArguments(),
                        signature,
                        ead.unParsedLJSFilesList,
                        ead.allPkgLJSHandlesList
                    );

                    // Skip the Annotation completely if there were errors
                    if (Messager.hadErrors()) break TOP;

                    // System.out.println(at.toString() + '\n' + m.toString());
                    ljsROALB.add(ljsm);

                    break;


                case "IntoHTMLTable" :

                    if (ihtMirror != null) throw Messager.assertFail(
                        "There appears to be a second instance of the @IntoHTMLTable " +
                            "Annotation.  However, this is not a @Repeatable Annotation." +
                        MsgPrintTools.annotationProcessingError(),
                        JDUAnnotations.EntityAnnotationMirrors
                    );


                    // The parsed arguments to to the Annotation
                    // final List<? extends ExpressionTree> arguments,
                    // 
                    // This is the Annotation, as a simple Java-String.  This is very useful for
                    // Error-Printing with the Messager.  That's the only purpose of it
                    // final String annotationAsStr,
                    //
                    // The Signature of the Detail-Entity onto which this "@LinkJavaSource"
                    // Annotation was placed.  Very important for error messages
                    // final String signature

                    ihtMirror = new IHTMirror(at.getArguments(), at.toString(), signature);

                    // Skip the Annotation completely if there were errors
                    if (Messager.hadErrors()) break TOP;

                    break;

                default: continue TOP;
            }
        }

        this.ljsMirrors = (Messager.hadErrors() || (ljsROALB.size() == 0))
            ? ReadOnlyArrayList.emptyROAL()
            : ljsROALB.build();

        this.ihtMirror = ihtMirror;
    }
};