/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *     https://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.
 */

#ifndef avro_Validating_hh__
#define avro_Validating_hh__

#include <cstdint>
#include <utility>
#include <vector>

#include "Config.hh"
#include "Types.hh"
#include "ValidSchema.hh"

namespace avro {

class AVRO_DECL NullValidator {
public:
    explicit NullValidator(const ValidSchema &) {}
    NullValidator() = default;

    NullValidator(const NullValidator &) = delete;
    NullValidator &operator=(const NullValidator &) = delete;

    void setCount(size_t) {}

    static bool typeIsExpected(Type) {
        return true;
    }

    static Type nextTypeExpected() {
        return AVRO_UNKNOWN;
    }

    static size_t nextSizeExpected() {
        return 0;
    }

    static bool getCurrentRecordName(std::string &) {
        return true;
    }

    static bool getNextFieldName(std::string &) {
        return true;
    }

    void checkTypeExpected(Type) {}
    void checkFixedSizeExpected(size_t) {}
};

/// This class is used by both the ValidatingSerializer and ValidationParser
/// objects.  It advances the parse tree (containing logic how to advance
/// through the various compound types, for example a record must advance
/// through all leaf nodes but a union only skips to one), and reports which
/// type is next.

class AVRO_DECL Validator {
public:
    explicit Validator(ValidSchema schema);

    Validator(const Validator &) = delete;
    Validator &operator=(const Validator &) = delete;

    void setCount(size_t val);

    bool typeIsExpected(Type type) const {
        return (expectedTypesFlag_ & typeToFlag(type)) != 0;
    }

    Type nextTypeExpected() const {
        return nextType_;
    }

    size_t nextSizeExpected() const;

    bool getCurrentRecordName(std::string &name) const;
    bool getNextFieldName(std::string &name) const;

    void checkTypeExpected(Type type) {
        if (!typeIsExpected(type)) {
            throw Exception("Type {} does not match schema {}", type, nextType_);
        }
        advance();
    }

    void checkFixedSizeExpected(size_t size) {
        if (nextSizeExpected() != size) {
            throw Exception("Wrong size for fixed, got {}, expected {}", size, nextSizeExpected());
        }
        checkTypeExpected(AVRO_FIXED);
    }

private:
    using flag_t = uint32_t;

    static flag_t typeToFlag(Type type) {
        flag_t flag = 1u << static_cast<flag_t>(type);
        return flag;
    }

    void setupOperation(const NodePtr &node);

    void setWaitingForCount();

    void advance();
    void doAdvance();

    void enumAdvance();
    bool countingSetup();
    void countingAdvance();
    void unionAdvance();
    void fixedAdvance();

    void setupFlag(Type type);

    const ValidSchema schema_;

    Type nextType_;
    flag_t expectedTypesFlag_;
    bool compoundStarted_;
    bool waitingForCount_;
    size_t count_;

    struct CompoundType {
        explicit CompoundType(NodePtr n) : node(std::move(n)), pos(0) {}
        NodePtr node; ///< save the node
        size_t pos;   ///< track the leaf position to visit
    };

    std::vector<CompoundType> compoundStack_;
    std::vector<size_t> counters_;
};

} // namespace avro

#endif
