#pragma once

#include "source/extensions/filters/network/thrift_proxy/decoder.h"

#include "source/extensions/filters/network/thrift_proxy/filters/filter.h"

#include "source/extensions/filters/network/thrift_proxy/thrift_object.h"

namespace Envoy {

namespace Extensions {

namespace NetworkFilters {

namespace ThriftProxy {

/**

 * ThriftBase is a base class for decoding Thrift objects. It implements methods from

 * DecoderEventHandler to automatically delegate to an underlying ThriftBase so that, for example,

 * the fieldBegin call for a struct field nested within a list is automatically delegated down the

 * object hierarchy to the correct ThriftBase subclass.

 */

class ThriftBase : public DecoderEventHandler {

public:

  ThriftBase(ThriftBase* parent);

  ~ThriftBase() override = default;

  // DecoderEventHandler

  FilterStatus passthroughData(Buffer::Instance&) override { return FilterStatus::Continue; }

  FilterStatus transportBegin(MessageMetadataSharedPtr) override { return FilterStatus::Continue; }

  FilterStatus transportEnd() override { return FilterStatus::Continue; }

  FilterStatus messageBegin(MessageMetadataSharedPtr) override { return FilterStatus::Continue; }

  FilterStatus messageEnd() override { return FilterStatus::Continue; }

  FilterStatus structBegin(absl::string_view name) override;

  FilterStatus structEnd() override;

  FilterStatus fieldBegin(absl::string_view name, FieldType& field_type,

                          int16_t& field_id) override;

  FilterStatus fieldEnd() override;

  FilterStatus boolValue(bool& value) override;

  FilterStatus byteValue(uint8_t& value) override;

  FilterStatus int16Value(int16_t& value) override;

  FilterStatus int32Value(int32_t& value) override;

  FilterStatus int64Value(int64_t& value) override;

  FilterStatus doubleValue(double& value) override;

  FilterStatus stringValue(absl::string_view value) override;

  FilterStatus mapBegin(FieldType& key_type, FieldType& value_type, uint32_t& size) override;

  FilterStatus mapEnd() override;

  FilterStatus listBegin(FieldType& elem_type, uint32_t& size) override;

  FilterStatus listEnd() override;

  FilterStatus setBegin(FieldType& elem_type, uint32_t& size) override;

  FilterStatus setEnd() override;

  // Invoked when the current delegate is complete. Completion implies that the delegate is fully

  // specified (all list values processed, all struct fields processed, etc).

  virtual void delegateComplete();

protected:

  ThriftBase* parent_;

  ThriftBase* delegate_{nullptr};

};

/**

 * ThriftValueBase is a base class for all struct field values, list values, set values, map keys,

 * and map values.

 */

class ThriftValueBase : public ThriftValue, public ThriftBase {

public:

  ThriftValueBase(ThriftBase* parent, FieldType value_type)

      : ThriftBase(parent), value_type_(value_type) {}

  ~ThriftValueBase() override = default;

  // ThriftValue

  FieldType type() const override { return value_type_; }

protected:

  const FieldType value_type_;

};

class ThriftStructValueImpl;

/**

 * ThriftField represents a field in a thrift Struct. It always delegates DecoderEventHandler

 * methods to a subclass of ThriftValueBase.

 */

class ThriftFieldImpl : public ThriftField, public ThriftBase {

public:

  ThriftFieldImpl(ThriftStructValueImpl* parent, absl::string_view name, FieldType field_type,

                  int16_t field_id);

  // DecoderEventHandler

  FilterStatus fieldEnd() override;

  // ThriftField

  FieldType fieldType() const override { return field_type_; }

  int16_t fieldId() const override { return field_id_; }

  const ThriftValue& getValue() const override { return *value_; }

private:

  std::string name_;

  FieldType field_type_;

  int16_t field_id_;

  ThriftValuePtr value_;

};

/**

 * ThriftStructValueImpl implements ThriftStruct.

 */

class ThriftStructValueImpl : public ThriftStructValue, public ThriftValueBase {

public:

  ThriftStructValueImpl(ThriftBase* parent) : ThriftValueBase(parent, FieldType::Struct) {}

  // DecoderEventHandler

  FilterStatus structBegin(absl::string_view name) override;

  FilterStatus structEnd() override;

  FilterStatus fieldBegin(absl::string_view name, FieldType& field_type,

                          int16_t& field_id) override;

  // ThriftStructValue

  const ThriftFieldPtrList& fields() const override { return fields_; }

private:

  // ThriftValue

  const void* getValue() const override { return this; };

  ThriftFieldPtrList fields_;

};

/**

 * ThriftListValueImpl represents Thrift lists.

 */

class ThriftListValueImpl : public ThriftListValue, public ThriftValueBase {

public:

  ThriftListValueImpl(ThriftBase* parent) : ThriftValueBase(parent, FieldType::List) {}

  // DecoderEventHandler

  FilterStatus listBegin(FieldType& elem_type, uint32_t& size) override;

  FilterStatus listEnd() override;

  // ThriftListValue

  const ThriftValuePtrList& elements() const override { return elements_; }

  FieldType elementType() const override { return elem_type_; }

  void delegateComplete() override;

protected:

  // ThriftValue

  const void* getValue() const override { return this; };

  FieldType elem_type_{FieldType::Stop};

  uint32_t remaining_{0};

  ThriftValuePtrList elements_;

};

/**

 * ThriftSetValueImpl represents Thrift sets.

 */

class ThriftSetValueImpl : public ThriftSetValue, public ThriftValueBase {

public:

  ThriftSetValueImpl(ThriftBase* parent) : ThriftValueBase(parent, FieldType::Set) {}

  // DecoderEventHandler

  FilterStatus setBegin(FieldType& elem_type, uint32_t& size) override;

  FilterStatus setEnd() override;

  // ThriftSetValue

  const ThriftValuePtrList& elements() const override { return elements_; }

  FieldType elementType() const override { return elem_type_; }

  void delegateComplete() override;

protected:

  // ThriftValue

  const void* getValue() const override { return this; };

  FieldType elem_type_{FieldType::Stop};

  uint32_t remaining_{0};

  ThriftValuePtrList elements_; // maintain original order

};

/**

 * ThriftMapValueImpl represents Thrift maps.

 */

class ThriftMapValueImpl : public ThriftMapValue, public ThriftValueBase {

public:

  ThriftMapValueImpl(ThriftBase* parent) : ThriftValueBase(parent, FieldType::Map) {}

  // DecoderEventHandler

  FilterStatus mapBegin(FieldType& key_type, FieldType& elem_type, uint32_t& size) override;

  FilterStatus mapEnd() override;

  // ThriftMapValue

  const ThriftValuePtrPairList& elements() const override { return elements_; }

  FieldType keyType() const override { return key_type_; }

  FieldType valueType() const override { return elem_type_; }

  void delegateComplete() override;

protected:

  // ThriftValue

  const void* getValue() const override { return this; };

  FieldType key_type_{FieldType::Stop};

  FieldType elem_type_{FieldType::Stop};

  uint32_t remaining_{0};

  ThriftValuePtrPairList elements_; // maintain original order

};

/**

 * ThriftValueImpl represents primitive Thrift types, including strings.

 */

class ThriftValueImpl : public ThriftValueBase {

public:

  ThriftValueImpl(ThriftBase* parent, FieldType value_type) : ThriftValueBase(parent, value_type) {}

  // DecoderEventHandler

  FilterStatus boolValue(bool& value) override;

  FilterStatus byteValue(uint8_t& value) override;

  FilterStatus int16Value(int16_t& value) override;

  FilterStatus int32Value(int32_t& value) override;

  FilterStatus int64Value(int64_t& value) override;

  FilterStatus doubleValue(double& value) override;

  FilterStatus stringValue(absl::string_view value) override;

protected:

  // ThriftValue

  const void* getValue() const override;

private:

  union {

    bool bool_value_;

    uint8_t byte_value_;

    int16_t int16_value_;

    int32_t int32_value_;

    int64_t int64_value_;

    double double_value_;

  };

  std::string string_value_;

};

/**

 * ThriftObjectImpl is a generic representation of a Thrift struct.

 */

class ThriftObjectImpl : public ThriftObject,

                         public ThriftStructValueImpl,

                         public DecoderCallbacks {

public:

  ThriftObjectImpl(Transport& transport, Protocol& protocol);

  // DecoderCallbacks

  DecoderEventHandler& newDecoderEventHandler() override { return *this; }

  FilterStatus transportEnd() override {

    complete_ = true;

    return FilterStatus::Continue;

  }

  bool passthroughEnabled() const override { return false; }

  bool isRequest() const override { return false; }

  bool headerKeysPreserveCase() const override { return false; }

  // ThriftObject

  bool onData(Buffer::Instance& buffer) override;

  // ThriftStruct

  const ThriftFieldPtrList& fields() const override { return ThriftStructValueImpl::fields(); }

private:

  DecoderPtr decoder_;

  bool complete_{false};

};

} // namespace ThriftProxy

} // namespace NetworkFilters

} // namespace Extensions

} // namespace Envoy