/*
 * Copyright 2010-2017 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.ir.util

import org.jetbrains.kotlin.ir.IrProvider
import org.jetbrains.kotlin.ir.ObsoleteDescriptorBasedAPI
import org.jetbrains.kotlin.ir.symbols.IrSymbol

class ExternalDependenciesGenerator(
    private val symbolTable: SymbolTable,
    private val irProviders: List<IrProvider>
) {
    @OptIn(ObsoleteDescriptorBasedAPI::class)
    fun generateUnboundSymbolsAsDependencies() {
        // There should be at most one DeclarationStubGenerator (none in closed world?)
        irProviders.filterIsInstance<DeclarationStubGenerator>().singleOrNull()?.run { unboundSymbolGeneration = true }

        // Deserializing a reference may lead to new unbound references, so we loop until none are left.
        var unbound = emptySet<IrSymbol>()
        do {
            val prevUnbound = unbound
            unbound = symbolTable.descriptorExtension.allUnboundSymbols
            for (symbol in unbound) {
                // Symbol could get bound as a side effect of deserializing other symbols.
                if (!symbol.isBound) {
                    irProviders.firstNotNullOfOrNull { provider -> provider.getDeclaration(symbol) }
                }
            }
            // We wait for the unbound to stabilize on fake overrides.
        } while (unbound != prevUnbound)
    }
}
