package Torello.JSON;

import Torello.JavaDoc.Annotations.IntoHTMLTable;
import static Torello.JavaDoc.Annotations.IntoHTMLTable.Background.BlueDither;
import static Torello.JavaDoc.Annotations.IntoHTMLTable.Background.GreenDither;

import java.math.BigDecimal;
import java.util.function.Function;

import javax.json.JsonObject;
import javax.json.JsonArray;
import javax.json.JsonNumber;
import javax.json.JsonValue;

import static javax.json.JsonValue.ValueType.TRUE;
import static javax.json.JsonValue.ValueType.NUMBER;
import static javax.json.JsonValue.ValueType.NULL;

/**
 * Builds on the J2EE Standard Release JSON Parsing Tools by providing additional
 * help with converting JSON Data into <B STYLE='color: red'>Java Primitive-Types</B>
 * 
 * <EMBED CLASS='external-html' DATA-FILE-ID=ALL_CLASSES_NOTE>
 * <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_JSON>
 * <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_PTABLE>
 * <EMBED CLASS='external-html' DATA-CH=char DATA-FILE-ID=JAVA_LANG_CHAR>
 * 
 * @see JsonObject
 * @see JsonArray
 */
@Torello.JavaDoc.Annotations.StaticFunctional
public class ReadPrimJSON
{
    // This is a static class.  Has no program state.
    private ReadPrimJSON() { }


    // ********************************************************************************************
    // ********************************************************************************************
    // Read from a JsonArray
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * <EMBED CLASS='external-html' DATA-TYPE=int DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see JsonNumber#intValueExact()
     */
    @IntoHTMLTable(
        title="Extract a JsonNumber from a JsonArray, and Transform it to a Java 'int' Primitive",
        background=BlueDither
    )
    public static int getInt(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, int.class);

        try
            { return jn.intValueExact(); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, int.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=long DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see JsonNumber#longValueExact()
     */
    @IntoHTMLTable(
        title="Extract a JsonNumber from a JsonArray, and Transform it to a Java 'long' Primitive",
        background=GreenDither
    )
    public static long getLong(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, long.class);

        try
            { return jn.longValueExact(); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, long.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=short DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see JsonNumber#longValueExact()
     * @see RJInternal#SHORT_FROM_LONG(long)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonArray, and Transform it to a Java 'short' Primitive",
        background=BlueDither
    )
    public static short getShort(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, short.class);

        try
            { return RJInternal.SHORT_FROM_LONG(jn.longValueExact()); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, short.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=byte DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see JsonNumber#longValueExact()
     * @see RJInternal#BYTE_FROM_LONG(long)
     */
    @IntoHTMLTable(
        title="Extract a JsonNumber from a JsonArray, and Transform it to a Java 'byte' Primitive",
        background=GreenDither
    )
    public static byte getByte(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, byte.class);

        try
            { return RJInternal.BYTE_FROM_LONG(jn.longValueExact()); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, byte.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=double DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see RJInternal#DOUBLE_WITH_CHECK(BigDecimal)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonArray, and Transform it to a Java 'double' " +
            "Primitive",
        background=BlueDither
    )
    public static double getDouble(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, double.class);

        try
            { return RJInternal.DOUBLE_WITH_CHECK(jn.bigDecimalValue()); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, double.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=float DATA-FILE-ID=READ_PRIM_JA>
     * @see #GET(JsonArray, int, Class)
     * @see RJInternal#FLOAT_WITH_CHECK(BigDecimal)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonArray, and Transform it to a Java 'float' Primitive",
        background=GreenDither
    )
    public static float getFloat(final JsonArray ja, final int index)
    {
        final JsonNumber jn = GET(ja, index, float.class);

        try
            { return RJInternal.FLOAT_WITH_CHECK(jn.bigDecimalValue()); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticArrException(ae, ja, index, NUMBER, jn, float.class); }
    }

    /** <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_JA_BOOL> */
    @IntoHTMLTable(
        title=
            "Extract Json-True or False from a JsonArray, and Transform it to a Java " +
            "'boolean' Primitive",
        background=BlueDither
    )
    public static boolean getBoolean(final JsonArray ja, final int index)
    {
        final JsonValue jv = ja.get(index);

        switch (jv.getValueType()) // throws IOB if necessary
        {
            case NULL: throw new JsonNullPrimitiveArrException
                (ja, index, TRUE, boolean.class);

            case TRUE:  return true;
            case FALSE: return false;

            default: throw new JsonTypeArrException
                (ja, index, TRUE, jv, boolean.class);
        }
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Internal GET
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * This is an internal helper method for retrieving an element from a {@link JsonArray},
     * and converting it to one of the standard <B STYLE='color: red;'>Java Types</B>.
     * 
     * @param ja                Any instance of {@link JsonArray}
     * @param index             Any index into the array which holds a {@link JsonNumber}
     * @param primitiveClass    <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_PCLASS>
     * 
     * @return The extracted {@link JsonNumber}.
     * 
     * @throws JsonNullPrimitiveArrException If the array element at {@code 'index'} contains
     *                                       <B STYLE='color: red'>Json-Null</B>
     * @throws JsonTypeArrException         If the array element at {@code 'index'} doesn't contain
     *                                      {@link JsonNumber}
     * @throws JsonArithmeticArrException   If there are any arithmetic problems during conversion
     * @throws IndexOutOfBoundsException    If {@code 'index'} is out of the bounds of {@code 'ja'}
     * 
     * @see #getInt(JsonArray, int)
     * @see #getLong(JsonArray, int)
     * @see #getShort(JsonArray, int)
     * @see #getByte(JsonArray, int)
     * @see #getDouble(JsonArray, int)
     * @see #getFloat(JsonArray, int)
     */
    protected static <T> JsonNumber GET(
            final JsonArray ja,
            final int       index,
            final Class<T>  primitiveClass
        )
    {
        // This will throw an IndexOutOfBoundsException if the index is out of bounds.
        final JsonValue jv = ja.get(index);

        switch (jv.getValueType())
        {
            case NULL: throw new JsonNullPrimitiveArrException
                (ja, index, NUMBER, primitiveClass);

            case NUMBER: return (JsonNumber) jv;

            default: throw new JsonTypeArrException
                (ja, index, NUMBER, jv, primitiveClass);
        }
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // Read from a JsonObject
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * <EMBED CLASS='external-html' DATA-TYPE=int DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see JsonNumber#intValueExact()
     */
    @IntoHTMLTable(
        title="Extract a JsonNumber from a JsonObject, and Transform it to a Java 'int' Primitive",
        background=GreenDither
    )
    public static int getInt(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, int.class);

        try
            { return jn.intValueExact(); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, int.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=long DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see JsonNumber#longValueExact()
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonObject, and Transform it to a Java 'long' Primitive",
        background=BlueDither
    )
    public static long getLong(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, long.class);

        try
            { return jn.longValueExact(); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, long.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=short DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see JsonNumber#longValueExact()
     * @see RJInternal#SHORT_FROM_LONG(long)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonObject, and Transform it to a Java 'short' Primitive",
        background=GreenDither
    )
    public static short getShort(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, short.class);

        try
            { return RJInternal.SHORT_FROM_LONG(jn.longValueExact()); }

        catch (ArithmeticException ae)
        {
            throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, short.class);
        }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=byte DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see JsonNumber#longValueExact()
     * @see RJInternal#BYTE_FROM_LONG(long)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonObject, and Transform it to a Java 'byte' Primitive",
        background=BlueDither
    )
    public static byte getByte(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, byte.class);

        try
            { return RJInternal.BYTE_FROM_LONG(jn.longValueExact()); }

        catch (ArithmeticException ae)
            { throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, byte.class); }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=double DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see RJInternal#DOUBLE_WITH_CHECK(BigDecimal)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonObject, and Transform it to a Java 'double' " +
            "Primitive",
        background=GreenDither
    )
    public static double getDouble(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, double.class);

        try
            { return RJInternal.DOUBLE_WITH_CHECK(jn.bigDecimalValue()); }

        catch (ArithmeticException ae)
        {
            throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, double.class);
        }
    }

    /**
     * <EMBED CLASS='external-html' DATA-TYPE=float DATA-FILE-ID=READ_PRIM_JO>
     * @see #GET(JsonObject, String, Class)
     * @see RJInternal#FLOAT_WITH_CHECK(BigDecimal)
     */
    @IntoHTMLTable(
        title=
            "Extract a JsonNumber from a JsonObject, and Transform it to a Java 'float' Primitive",
        background=BlueDither
    )
    public static float getFloat(final JsonObject jo, final String propertyName)
    {
        final JsonNumber jn = GET(jo, propertyName, float.class);

        try
            { return RJInternal.FLOAT_WITH_CHECK(jn.bigDecimalValue()); }

        catch (ArithmeticException ae)
        {
            throw new JsonArithmeticObjException(ae, jo, propertyName, NUMBER, jn, float.class);
        }
    }

    /** <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_JO_BOOL> */
    @IntoHTMLTable(
        title=
            "Extract Json-True or False from a JsonObject, and Transform it to a Java 'long' " +
            "Primitive",
        background=GreenDither
    )
    public static boolean getBoolean(final JsonObject jo, final String propertyName)
    {
        if (! jo.containsKey(propertyName)) throw new JsonPropMissingException
            (jo, propertyName, TRUE, boolean.class);

        final JsonValue jv = jo.get(propertyName);

        switch (jv.getValueType())
        {
            case NULL: throw new JsonNullPrimitiveObjException
                (jo, propertyName, TRUE, boolean.class);

            case TRUE:  return true;
            case FALSE: return false;

            default: throw new JsonTypeObjException
                (jo, propertyName, TRUE, jv, boolean.class);
        }
    }


    // ********************************************************************************************
    // ********************************************************************************************
    // The Internal Methods
    // ********************************************************************************************
    // ********************************************************************************************


    /**
     * This is an internal helper method for retrieving a property from a {@link JsonObject},
     * and converting it to one of the standard <B STYLE='color: red;'>Java Types</B>.
     * 
     * @param jo                Any instance of {@link JsonObject}
     * @param propertyName      Any property name contained by {@code 'jo'}
     * @param primitiveClass    <EMBED CLASS='external-html' DATA-FILE-ID=READ_PRIM_PCLASS>
     * 
     * @return The extracted {@link JsonNumber}.
     * 
     * @throws JsonNullPrimitiveObjException If the specified property contains
     *                                       <B STYLE='color: red'>Json-Null</B>
     * @throws JsonPropMissingException     If the property is missing, and {@code 'isOptional'}
     *                                      is {@code FALSE}.
     * @throws JsonTypeObjException         If the user specified property doesn't contain a
     *                                      {@link JsonNumber}
     * @throws JsonArithmeticObjException   If there any arithmetic problems during the conversion
     * 
     * @see #getInt(JsonObject, String)
     * @see #getLong(JsonObject, String)
     * @see #getShort(JsonObject, String)
     * @see #getByte(JsonObject, String)
     * @see #getDouble(JsonObject, String)
     * @see #getFloat(JsonObject, String)
     */
    protected static <T> JsonNumber GET(
            final JsonObject    jo,
            final String        propertyName,
            final Class<T>      primitiveClass
        )
    {
        // Here, a 'get' request was made for a property that isn't actually listed among the
        // properties in the provided JsonObject.  Since this internal 'GET' is used by methods
        // that are trying to return a Java Primitive (like 'int' or 'float'), then an exception
        // has to be thrown.  The option of returning 'null' isn't possible here!
    
        if (! jo.containsKey(propertyName)) throw new JsonPropMissingException
            (jo, propertyName, NUMBER, primitiveClass);

        final JsonValue jv = jo.get(propertyName);

        switch (jv.getValueType())
        {
            case NULL: throw new JsonNullPrimitiveObjException
                (jo, propertyName, NUMBER, primitiveClass);

            case NUMBER: return (JsonNumber) jv;

            // The JsonObject property does not contain a JsonNumber.
            default: throw new JsonTypeObjException
                (jo, propertyName, NUMBER, jv, primitiveClass);
        }
    }

}