/*
 * Copyright (C) 2017 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
"use strict";

function inferTypesForCall(func, typeArguments, argumentTypes, returnType)
{
    if (typeArguments.length && typeArguments.length != func.typeParameters.length)
        return {failure: new OverloadResolutionFailure(func, "Wrong number of type arguments (passed " + typeArguments.length + ", require " + func.typeParameters.length + ")")};
    if (argumentTypes.length != func.parameters.length)
        return {failure: new OverloadResolutionFailure(func, "Wrong number of arguments (passed " + argumentTypes.length + ", require " + func.parameters.length + ")")};
    let unificationContext = new UnificationContext(func.typeParametersForCallResolution);
    for (let i = 0; i < typeArguments.length; ++i) {
        let argument = typeArguments[i];
        let parameter = func.typeParameters[i];
        if (!argument.unify(unificationContext, parameter))
            return {failure: new OverloadResolutionFailure(func, "Type argument #" + (i + 1) + " for parameter " + parameter.name + " does not match (passed " + argument + ", require " + parameter + ")")};
    }
    for (let i = 0; i < argumentTypes.length; ++i) {
        if (!argumentTypes[i])
            throw new Error("Null argument type at i = " + i);
        if (!argumentTypes[i].unify(unificationContext, func.parameters[i].type))
            return {failure: new OverloadResolutionFailure(func, "Argument #" + (i + 1) + " " + (func.parameters[i].name ? "for parameter " + func.parameters[i].name + " " : "") + "does not match (passed " + argumentTypes[i] + ", require " + func.parameters[i].type + ")")};
    }
    if (returnType && !returnType.unify(unificationContext, func.returnType))
        return {failure: new OverloadResolutionFailure(func, "Return type " + func.returnType + " does not match " + returnType)};
    let verificationResult = unificationContext.verify();
    if (!verificationResult.result)
        return {failure: new OverloadResolutionFailure(func, verificationResult.reason)};
    let shouldBuildTypeArguments = !typeArguments.length;
    if (shouldBuildTypeArguments)
        typeArguments = [];
    for (let typeParameter of func.typeParameters) {
        let typeArgument = unificationContext.find(typeParameter);
        if (typeArgument == typeParameter)
            return {failure: new OverloadResolutionFailure(func, "Type parameter " + typeParameter + " did not get assigned a type")};
        if (shouldBuildTypeArguments)
            typeArguments.push(typeArgument);
    }
    return {func, unificationContext, typeArguments};
}