/* BSD 2-Clause License - see OPAL/LICENSE for details. */
package org.opalj
package bi
package reader

import java.io.DataInputStream

/**
 * Generic parser for `RuntimeVisibleParameterAnnotations` attributes.
 */
trait RuntimeVisibleParameterAnnotations_attributeReader extends AttributeReader {

    //
    // TYPE DEFINITIONS AND FACTORY METHODS
    //

    type ParameterAnnotations
    type ParametersAnnotations <: IterableOnce[ParameterAnnotations]
    /**
     * Method that delegates to another reader to parse the annotations of the parameters.
     */
    def ParametersAnnotations(cp: Constant_Pool, in: DataInputStream): ParametersAnnotations

    type RuntimeVisibleParameterAnnotations_attribute >: Null <: Attribute

    def RuntimeVisibleParameterAnnotations_attribute(
        constant_pool:         Constant_Pool,
        ap_name_index:         Constant_Pool_Index,
        ap_descriptor_index:   Constant_Pool_Index,
        attribute_name_index:  Constant_Pool_Index,
        parameter_annotations: ParametersAnnotations
    ): RuntimeVisibleParameterAnnotations_attribute

    //
    // IMPLEMENTATION
    //

    /**
     * <pre>
     * RuntimeVisibleParameterAnnotations_attribute {
     *  u2 attribute_name_index;
     *  u4 attribute_length;
     *  u1 num_parameters;
     *  {
     *      u2 num_annotations;
     *      annotation annotations[num_annotations];
     *      } parameter_annotations[num_parameters];
     *  }
     * </pre>
     */
    private def parserFactory() = (
        cp:                   Constant_Pool,
        ap:                   AttributeParent,
        ap_name_index:        Constant_Pool_Index,
        ap_descriptor_index:  Constant_Pool_Index,
        attribute_name_index: Constant_Pool_Index,
        in:                   DataInputStream
    ) => {
        /*val attribute_length =*/
        in.readInt()
        val parameter_annotations = ParametersAnnotations(cp, in)
        if (parameter_annotations.iterator.nonEmpty || reifyEmptyAttributes) {
            RuntimeVisibleParameterAnnotations_attribute(
                cp,
                ap_name_index,
                ap_descriptor_index,
                attribute_name_index,
                parameter_annotations
            )
        } else {
            null
        }
    }

    registerAttributeReader(RuntimeVisibleParameterAnnotationsAttribute.Name -> parserFactory())

}