package com.fasterxml.jackson.databind.ser.std;

import java.io.IOException;
import java.lang.reflect.Type;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.core.type.WritableTypeId;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonArrayFormatVisitor;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatTypes;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.node.ObjectNode;

Unlike other integral number array serializers, we do not just print out byte values
as numbers. Instead, we assume that it would make more sense to output content
as base64 encoded bytes (using default base64 encoding).

NOTE: since it is NOT serialized as an array, cannot use AsArraySerializer as base
 NOTE: since 2.6, has been a main-level class; earlier was embedded in StdArraySerializers. /**
 * Unlike other integral number array serializers, we do not just print out byte values
 * as numbers. Instead, we assume that it would make more sense to output content
 * as base64 encoded bytes (using default base64 encoding).
 *<p>
 * NOTE: since it is NOT serialized as an array, cannot use AsArraySerializer as base
 *<p>
 * NOTE: since 2.6, has been a main-level class; earlier was embedded in
 * {@link StdArraySerializers}.
 */
@JacksonStdImpl
public class ByteArraySerializer extends StdSerializer<byte[]>
{
    private static final long serialVersionUID = 1L;

    public ByteArraySerializer() {
        super(byte[].class);
    }
    
    @Override
    public boolean isEmpty(SerializerProvider prov, byte[] value) {
        return value.length == 0;
    }
    
    @Override
    public void serialize(byte[] value, JsonGenerator g, SerializerProvider provider)
        throws IOException
    {
        g.writeBinary(provider.getConfig().getBase64Variant(),
                value, 0, value.length);
    }

    @Override
    public void serializeWithType(byte[] value, JsonGenerator g, SerializerProvider provider,
            TypeSerializer typeSer)
        throws IOException
    {
        // most likely scalar
        WritableTypeId typeIdDef = typeSer.writeTypePrefix(g,
                typeSer.typeId(value, JsonToken.VALUE_EMBEDDED_OBJECT));
        g.writeBinary(provider.getConfig().getBase64Variant(),
                value, 0, value.length);
        typeSer.writeTypeSuffix(g, typeIdDef);

        /* OLD impl
        typeSer.writeTypePrefixForScalar(value, g);
        g.writeBinary(provider.getConfig().getBase64Variant(),
                value, 0, value.length);
        typeSer.writeTypeSuffixForScalar(value, g);
        */
    }

    @Override
    public JsonNode getSchema(SerializerProvider provider, Type typeHint)
    {
        ObjectNode o = createSchemaNode("array", true);
        ObjectNode itemSchema = createSchemaNode("byte"); //binary values written as strings?
        return o.set("items", itemSchema);
    }

    @Override
    public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint)
        throws JsonMappingException
    {
        // 14-Mar-2016, tatu: while logically (and within JVM) binary, gets encoded as Base64 String,
        // let's try to indicate it is array of Bytes... difficult, thanks to JSON Schema's
        // lackluster listing of types
        //
        // TODO: for 2.8, make work either as String/base64, or array of numbers,
        //   with a qualifier that can be used to determine it's byte[]
        JsonArrayFormatVisitor v2 = visitor.expectArrayFormat(typeHint);
        if (v2 != null) {
            v2.itemsFormat(JsonFormatTypes.INTEGER);
        }
    }
}