// Copyright 2021 The Dawn Authors
//
// 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.

{% set impl_dir = metadata.impl_dir + "/" if metadata.impl_dir else "" %}
{% set native_namespace = Name(metadata.native_namespace).snake_case() %}
{% set native_dir = impl_dir + native_namespace %}
#include "{{native_dir}}/ChainUtils_autogen.h"

#include <unordered_set>

namespace {{native_namespace}} {

{% set namespace = metadata.namespace %}
{% for value in types["s type"].values %}
    {% if value.valid %}
        void FindInChain(const ChainedStruct* chain, const {{as_cppEnum(value.name)}}** out) {
            for (; chain; chain = chain->nextInChain) {
                if (chain->sType == {{namespace}}::SType::{{as_cppEnum(value.name)}}) {
                    *out = static_cast<const {{as_cppEnum(value.name)}}*>(chain);
                    break;
                }
            }
        }
    {% endif %}
{% endfor %}

MaybeError ValidateSTypes(const ChainedStruct* chain,
                          std::vector<std::vector<{{namespace}}::SType>> oneOfConstraints) {
    std::unordered_set<{{namespace}}::SType> allSTypes;
    for (; chain; chain = chain->nextInChain) {
        if (allSTypes.find(chain->sType) != allSTypes.end()) {
            return DAWN_VALIDATION_ERROR("Chain cannot have duplicate sTypes");
        }
        allSTypes.insert(chain->sType);
    }
    for (const auto& oneOfConstraint : oneOfConstraints) {
        bool satisfied = false;
        for ({{namespace}}::SType oneOfSType : oneOfConstraint) {
            if (allSTypes.find(oneOfSType) != allSTypes.end()) {
                if (satisfied) {
                    return DAWN_VALIDATION_ERROR("Unsupported sType combination");
                }
                satisfied = true;
                allSTypes.erase(oneOfSType);
            }
        }
    }
    if (!allSTypes.empty()) {
        return DAWN_VALIDATION_ERROR("Unsupported sType");
    }
    return {};
}

}  // namespace {{native_namespace}}