/*
 * Copyright 2010-2015 JetBrains s.r.o.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jetbrains.kotlin.backend.common

import org.jetbrains.kotlin.descriptors.FunctionDescriptor
import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
import org.jetbrains.kotlin.psi.KtClassOrObject
import org.jetbrains.kotlin.psi.KtObjectDeclaration
import org.jetbrains.kotlin.psi.KtParameter
import org.jetbrains.kotlin.resolve.BindingContext

/**
 * A platform-independent logic for generating data class synthetic methods.
 * TODO: data class with zero components gets no toString/equals/hashCode methods. This is inconsistent and should be
 * changed here with the platform backends adopted.
 */
abstract class DataClassMethodGenerator(
    declaration: KtClassOrObject,
    bindingContext: BindingContext
) : FunctionsFromAnyGenerator(declaration, bindingContext) {

    override fun generate() {
        if (declaration !is KtObjectDeclaration) {
            generateComponentFunctionsForDataClasses()
            generateCopyFunctionForDataClasses(primaryConstructorParameters)
        }

        super.generate()
    }

    protected abstract fun generateComponentFunction(function: FunctionDescriptor, parameter: ValueParameterDescriptor)

    protected abstract fun generateCopyFunction(function: FunctionDescriptor, constructorParameters: List<KtParameter>)

    private fun generateComponentFunctionsForDataClasses() {
        // primary constructor should exist for data classes
        // but when generating light-classes still need to check we have one
        val constructor = classDescriptor.unsubstitutedPrimaryConstructor ?: return

        for (parameter in constructor.valueParameters) {
            val function = bindingContext.get(BindingContext.DATA_CLASS_COMPONENT_FUNCTION, parameter)
            if (function != null) {
                generateComponentFunction(function, parameter)
            }
        }
    }

    private fun generateCopyFunctionForDataClasses(constructorParameters: List<KtParameter>) {
        val copyFunction = bindingContext.get(BindingContext.DATA_CLASS_COPY_FUNCTION, classDescriptor) ?: return
        generateCopyFunction(copyFunction, constructorParameters)
    }
}
