package Torello.JSON;

import javax.json.*;

import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;

import java.math.*;

import static javax.json.JsonValue.ValueType.*;
import static Torello.JSON.JFlag.*;

import java.util.Objects;
import java.util.function.Function;

/**
 * Class which provides a series of helper functions for all JSON Type-Binding Reader 
 * Classes.
 * 
 * <BR /><BR /><DIV CLASS=JDHint>
 * 100% of the helper-methods that appear here are protected, and cannot be accessed
 * outside of this package.  They are included in the documentation solely for the purposes of
 * (<I>if you happen to be interested</I>) letting you know how the JSON-Tools work.  It is not
 * intended that programmers would ever need to invoke, directly, any of the methods in this
 * class!
 * </DIV>
 */
@Torello.JavaDoc.Annotations.StaticFunctional
public class RJInternal
{
    private RJInternal() { }


    // ********************************************************************************************
    // ********************************************************************************************
    // "Helpers for the Helpers for the Helpers"
    // ********************************************************************************************
    // ********************************************************************************************


    private static void throwAE_INFINITY
        (JsonNumber jn, String primTypeName, boolean positiveOrNegative)
    {
        throw new ArithmeticException(
            "When attempting to conver the JsonNumber [" + jn.toString() + "] to a " +
            primTypeName + " primitive, the number had a magnitude that was too large: " +
            (positiveOrNegative ? "Positive" : "Negative") + " Infinity was returned."
        );
    }

    private static void throwAE_INFINITY(BigDecimal bd, String primTypeName)
    {
        throw new ArithmeticException(
            "When attempting to conver the JsonNumber [" + bd.toString() + "] to a " +
            primTypeName + " primitive, the number had a magnitude that was infinite."
        );
    }

    private static void throwAE_PRECISION(BigDecimal bd, String primTypeName)
    {
        throw new ArithmeticException(
            "When attempting to conver the JsonNumber [" + bd.toString() + "] to a " +
            primTypeName + " primitive, the number had a loss of precision."
        );
    }

    /*
     * Converts a {@link JsonNumber} into a Java {@code double}
     * @param jn Any {@link JsonNumber}
     * @return java {@code double} primitive
     * @throws ArithmeticException If infinity is returned from the call to
     * {@code BigDecimal.doubleValue()}
     * @see JsonNumber#bigDecimalValue()
     */
    protected static double DOUBLE_WITH_CHECK(JsonNumber jn)
    { return DOUBLE_WITH_CHECK(jn.bigDecimalValue()); }

    /**
     * Converts a {@code BigDecimal} into a Java {@code double}
     * @param bd Any {@code BigDecimal}
     * @return Java {@code double} primitive
     * @throws ArithmeticException If infinity is returned from the call to
     * {@code code BigDecimal.doubleValue()}
     */
    protected static double DOUBLE_WITH_CHECK(BigDecimal bd)
    {
        double ret = bd.doubleValue();

        if (Double.isInfinite(ret)) throwAE_INFINITY(bd, "double");

        if (BigDecimal.valueOf(ret).compareTo(bd) != 0) throwAE_PRECISION(bd, "double");

        return ret;
    }

    /**
     * Converts a {@link JsonNumber} into a Java {@code float}
     * @param jn Any {@link JsonNumber}
     * @return java {@code float} primitive
     * @throws ArithmeticException If infinity is returned from the call to
     * {@code BigDecimal.floatValue()}
     * @see JsonNumber#bigDecimalValue()
     */
    protected static float FLOAT_WITH_CHECK(JsonNumber jn)
    { return FLOAT_WITH_CHECK(jn.bigDecimalValue()); }

    /**
     * Converts a {@code BigDecimal} into a Java {@code float}
     * @param bd Any {@code BigDecimal}
     * @return Java {@code float} primitive
     * @throws ArithmeticException If infinity is returned from the call to
     * {@code code BigDecimal.floatValue()}
     */
    protected static float FLOAT_WITH_CHECK(BigDecimal bd)
    {
        float ret = bd.floatValue();

        if (Float.isInfinite(ret)) throwAE_INFINITY(bd, "float");

        if (BigDecimal.valueOf(ret).compareTo(bd) != 0) throwAE_PRECISION(bd, "float");

        return ret;
    }

    /**
     * Converts a {@code long} into a Java {@code byte}
     * @param l A long that has been produced by {@link JsonNumber#longValueExact()}
     * @return A valid {@code byte} primitive
     * @throws ArithmeticException If the {@code long} doesn't fit into a {@code byte}
     */
    protected static byte BYTE_FROM_LONG(final long l)
    {
        if ((l < Byte.MIN_VALUE) || (l > Byte.MAX_VALUE))
            throw new ArithmeticException("byte out of range: " + l);

        return (byte) l;
    }

    /**
     * Converts a {@code long} into a Java {@code short}
     * @param l A long that has been produced by {@link JsonNumber#longValueExact()}
     * @return A valid {@code short} primitive
     * @throws ArithmeticException If the {@code long} doesn't fit into a {@code short}
     */
    protected static short SHORT_FROM_LONG(final long l)
    {
        if ((l < Short.MIN_VALUE) || (l > Short.MAX_VALUE))
            throw new ArithmeticException("short out of range: " + l);

        return (short) l;
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // FLAG-CHECKER METHODS another section of "Helpers for the Helpers ..."
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * Flag Checker for {@code IndexOutOfBoundsException}.
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code IndexOutOfBoundsException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws IndexOutOfBoundsException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_IOB
     * @see JFlag#RETURN_DEFVAL_ON_IOB
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T IOOBEX(JsonArray ja, int index, T defaultValue, int FLAGS)
    {
        if ((FLAGS & RETURN_NULL_ON_IOB) != 0)          return null;
        if ((FLAGS & RETURN_DEFVAL_ON_IOB) != 0)        return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        ja.get(index); // Throws an IndexOutOfBoundsException

        // If you have reached this statment, this method was not applied properly
        throw new Torello.Java.UnreachableError();
    }

    /**
     * Flag Checker for {@link JsonPropMissingException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonPropMissingException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonPropMissingException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_MISSING
     * @see JFlag#RETURN_DEFVAL_ON_MISSING
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JPMEX(
            JsonObject jo, String propertyName, T defaultValue, int FLAGS,
            JsonValue.ValueType expectedType, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_MISSING) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_MISSING) != 0)    return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        throw new JsonPropMissingException(jo, propertyName, expectedType, returnClass);
    }

    /**
     * Flag Checker for {@link JsonNullArrException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonNullArrException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonNullArrException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_NULL
     * @see JFlag#RETURN_DEFVAL_ON_NULL
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JNAEX(
            JsonArray ja, int index, T defaultValue, int FLAGS, JsonValue.ValueType expectedType,
            Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_NULL) != 0)         return null;
        if ((FLAGS & RETURN_DEFVAL_ON_NULL) != 0)       return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        throw new JsonNullArrException(ja, index, expectedType, returnClass);
    }

    /**
     * Flag Checker for {@link JsonNullObjException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonNullObjException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonNullObjException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_NULL
     * @see JFlag#RETURN_DEFVAL_ON_NULL
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JNOEX(
            JsonObject jo, String propertyName, T defaultValue, int FLAGS,
            JsonValue.ValueType expectedType, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_NULL) != 0)         return null;
        if ((FLAGS & RETURN_DEFVAL_ON_NULL) != 0)       return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        throw new JsonNullObjException(jo, propertyName, expectedType, returnClass);
    }

    /**
     * Flag Checker for {@link JsonTypeArrException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonTypeArrException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonTypeArrException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_WRONG_JSONTYPE
     * @see JFlag#RETURN_DEFVAL_ON_WRONG_JSONTYPE
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JTAEX(
            JsonArray ja, int index, T defaultValue, int FLAGS, JsonValue.ValueType expectedType,
            JsonValue retrievedValue, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_WRONG_JSONTYPE) != 0)   return null;
        if ((FLAGS & RETURN_DEFVAL_ON_WRONG_JSONTYPE) != 0) return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)          return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)        return defaultValue;

        throw new JsonTypeArrException(ja, index, expectedType, retrievedValue, returnClass);
    }

    /**
     * Flag Checker for {@link JsonTypeObjException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonNullObjException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonNullObjException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_WRONG_JSONTYPE
     * @see JFlag#RETURN_DEFVAL_ON_WRONG_JSONTYPE
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JTOEX(
            JsonObject jo, String propertyName, T defaultValue, int FLAGS,
            JsonValue.ValueType expectedType, JsonValue retrievedValue, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_WRONG_JSONTYPE) != 0)   return null;
        if ((FLAGS & RETURN_DEFVAL_ON_WRONG_JSONTYPE) != 0) return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)          return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)        return defaultValue;

        throw new JsonTypeObjException
            (jo, propertyName, expectedType, retrievedValue, returnClass);
    }

    /**
     * Flag Checker for {@link JsonStrParseArrException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonStrParseArrException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonStrParseArrException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_SPEX
     * @see JFlag#RETURN_DEFVAL_ON_SPEX
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JSPAEX(
            Exception e, JsonArray ja, int index, T defaultValue, int FLAGS,
            JsonValue retrievedValue, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_SPEX) != 0)         return null;
        if ((FLAGS & RETURN_DEFVAL_ON_SPEX) != 0)       return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        throw new JsonStrParseArrException(e, ja, index, retrievedValue, returnClass);
    }

    /**
     * Flag Checker for {@link JsonStrParseObjException}
     * 
     * <BR /><BR />Checks whether the relevant flags were set in the users {@code FLAGS} parameter,
     * and either returns the appropriate value accordingly, or throws
     * {@code JsonStrParseObjException}.
     * 
     * <EMBED CLASS='external-html' DATA-FILE-ID=FLAG_PRECEDENCE>
     * 
     * @param <T> If requested, the default-value is returned, and this is its type.
     * 
     * @return Can return either the user-provided default-value, or null depending on whether a
     * match was found in the user's request settings ({@code 'FLAGS'}).
     * 
     * @throws JsonStrParseObjException If no flag was set specifying one of the two return-value
     * options.
     * 
     * @see JFlag#RETURN_NULL_ON_SPEX
     * @see JFlag#RETURN_DEFVAL_ON_SPEX
     * @see JFlag#RETURN_NULL_ON_ANY_ALL
     * @see JFlag#RETURN_DEFVAL_ON_ANY_ALL
     */
    protected static <T> T JSPOEX(
            Exception e, JsonObject jo, String propertyName, T defaultValue, int FLAGS,
            JsonValue retrievedValue, Class<T> returnClass
        )
    {
        if ((FLAGS & RETURN_NULL_ON_SPEX) != 0)         return null;
        if ((FLAGS & RETURN_DEFVAL_ON_SPEX) != 0)       return defaultValue;
        if ((FLAGS & RETURN_NULL_ON_ANY_ALL) != 0)      return null;
        if ((FLAGS & RETURN_DEFVAL_ON_ANY_ALL) != 0)    return defaultValue;

        throw new JsonStrParseObjException(e, jo, propertyName, retrievedValue, returnClass);
    }


}