#pragma once

#include <atomic>

#include <map>

#include <memory>

#include "envoy/access_log/access_log.h"

#include "envoy/buffer/buffer.h"

#include "envoy/extensions/wasm/v3/wasm.pb.validate.h"

#include "envoy/http/filter.h"

#include "envoy/stats/sink.h"

#include "envoy/upstream/cluster_manager.h"

#include "source/common/common/assert.h"

#include "source/common/common/logger.h"

#include "source/extensions/common/wasm/plugin.h"

#include "source/extensions/filters/common/expr/cel_state.h"

#include "source/extensions/filters/common/expr/evaluator.h"

#include "eval/public/activation.h"

#include "include/proxy-wasm/wasm.h"

namespace Envoy {

namespace Extensions {

namespace Common {

namespace Wasm {

using proxy_wasm::BufferInterface;

using proxy_wasm::CloseType;

using proxy_wasm::ContextBase;

using proxy_wasm::Pairs;

using proxy_wasm::PairsWithStringValues;

using proxy_wasm::PluginBase;

using proxy_wasm::PluginHandleBase;

using proxy_wasm::SharedQueueDequeueToken;

using proxy_wasm::SharedQueueEnqueueToken;

using proxy_wasm::WasmBase;

using proxy_wasm::WasmBufferType;

using proxy_wasm::WasmHandleBase;

using proxy_wasm::WasmHeaderMapType;

using proxy_wasm::WasmResult;

using proxy_wasm::WasmStreamType;

using VmConfig = envoy::extensions::wasm::v3::VmConfig;

using CapabilityRestrictionConfig = envoy::extensions::wasm::v3::CapabilityRestrictionConfig;

using SanitizationConfig = envoy::extensions::wasm::v3::SanitizationConfig;

using GrpcService = envoy::config::core::v3::GrpcService;

class PluginHandle;

class Wasm;

using PluginBaseSharedPtr = std::shared_ptr<PluginBase>;

using PluginHandleBaseSharedPtr = std::shared_ptr<PluginHandleBase>;

using PluginHandleSharedPtr = std::shared_ptr<PluginHandle>;

using WasmHandleBaseSharedPtr = std::shared_ptr<WasmHandleBase>;

// Opaque context object.

class StorageObject {

public:

};

class Buffer : public proxy_wasm::BufferBase {

public:

  // proxy_wasm::BufferInterface

  size_t size() const override;

  WasmResult copyTo(WasmBase* wasm, size_t start, size_t length, uint64_t ptr_ptr,

                    uint64_t size_ptr) const override;

  WasmResult copyFrom(size_t start, size_t length, std::string_view data) override;

  // proxy_wasm::BufferBase

private:

  const ::Envoy::Buffer::Instance* const_buffer_instance_{};

  ::Envoy::Buffer::Instance* buffer_instance_{};

};

// A context which will be the target of callbacks for a particular session

// e.g. a handler of a stream.

class Context : public proxy_wasm::ContextBase,

                public Logger::Loggable<Logger::Id::wasm>,

                public AccessLog::Instance,

                public Http::StreamFilter,

                public Network::ConnectionCallbacks,

                public Network::Filter,

                public Filters::Common::Expr::StreamActivation,

                public std::enable_shared_from_this<Context> {

public:

  Context();                                          // Testing.

  Context(Wasm* wasm);                                // Vm Context.

  Context(Wasm* wasm, const PluginSharedPtr& plugin); // Root Context.

  Context(Wasm* wasm, uint32_t root_context_id,

          PluginHandleSharedPtr plugin_handle); // Stream context.

  ~Context() override;

  WasmBase* wasm() const override;

  Wasm* envoyWasm() const;

  Plugin* plugin() const;

  Context* rootContext() const;

  Upstream::ClusterManager& clusterManager() const;

  // proxy_wasm::ContextBase

  void error(std::string_view message) override;

  // Retrieves the stream info associated with the request (a.k.a active stream).

  // It selects a value based on the following order: encoder callback, decoder

  // callback, log callback, network read filter callback, network write filter

  // callback. As long as any one of the callbacks is invoked, the value should be

  // available.

  const StreamInfo::StreamInfo* getConstRequestStreamInfo() const;

  StreamInfo::StreamInfo* getRequestStreamInfo() const;

  // Retrieves the connection object associated with the request (a.k.a active stream).

  // It selects a value based on the following order: encoder callback, decoder

  // callback. As long as any one of the callbacks is invoked, the value should be

  // available.

  const Network::Connection* getConnection() const;

  //

  // VM level down-calls into the Wasm code on Context(id == 0).

  //

  virtual bool validateConfiguration(std::string_view configuration,

                                     const std::shared_ptr<PluginBase>& plugin); // deprecated

  // AccessLog::Instance

  void log(const Formatter::Context& log_context, const StreamInfo::StreamInfo& info) override;

  uint32_t getLogLevel() override;

  // Network::ConnectionCallbacks

  void onEvent(Network::ConnectionEvent event) override;

  // Network::ReadFilter

  Network::FilterStatus onNewConnection() override;

  Network::FilterStatus onData(::Envoy::Buffer::Instance& data, bool end_stream) override;

  void initializeReadFilterCallbacks(Network::ReadFilterCallbacks& callbacks) override;

  // Network::WriteFilter

  Network::FilterStatus onWrite(::Envoy::Buffer::Instance& data, bool end_stream) override;

  void initializeWriteFilterCallbacks(Network::WriteFilterCallbacks& callbacks) override;

  // proxy_wasm::ContextBase

  void onDownstreamConnectionClose(CloseType) override;

  void onUpstreamConnectionClose(CloseType) override;

  // Http::StreamFilterBase. Note: This calls onDone() in Wasm.

  void onDestroy() override;

  // Http::StreamDecoderFilter

  Http::FilterHeadersStatus decodeHeaders(Http::RequestHeaderMap& headers,

                                          bool end_stream) override;

  Http::FilterDataStatus decodeData(::Envoy::Buffer::Instance& data, bool end_stream) override;

  Http::FilterTrailersStatus decodeTrailers(Http::RequestTrailerMap& trailers) override;

  Http::FilterMetadataStatus decodeMetadata(Http::MetadataMap& metadata_map) override;

  void setDecoderFilterCallbacks(Envoy::Http::StreamDecoderFilterCallbacks& callbacks) override;

  // Http::StreamEncoderFilter

  Http::Filter1xxHeadersStatus encode1xxHeaders(Http::ResponseHeaderMap&) override;

  Http::FilterHeadersStatus encodeHeaders(Http::ResponseHeaderMap& headers,

                                          bool end_stream) override;

  Http::FilterDataStatus encodeData(::Envoy::Buffer::Instance& data, bool end_stream) override;

  Http::FilterTrailersStatus encodeTrailers(Http::ResponseTrailerMap& trailers) override;

  Http::FilterMetadataStatus encodeMetadata(Http::MetadataMap& metadata_map) override;

  void setEncoderFilterCallbacks(Envoy::Http::StreamEncoderFilterCallbacks& callbacks) override;

  // VM calls out to host.

  // proxy_wasm::ContextBase

  // General

  WasmResult log(uint32_t level, std::string_view message) override;

  uint64_t getCurrentTimeNanoseconds() override;

  uint64_t getMonotonicTimeNanoseconds() override;

  std::string_view getConfiguration() override;

  std::pair<uint32_t, std::string_view> getStatus() override;

  // State accessors

  WasmResult getProperty(std::string_view path, std::string* result) override;

  WasmResult setProperty(std::string_view path, std::string_view value) override;

  WasmResult setEnvoyFilterState(std::string_view path, std::string_view value,

                                 StreamInfo::FilterState::LifeSpan life_span);

  WasmResult declareProperty(std::string_view path,

                             Filters::Common::Expr::CelStatePrototypeConstPtr state_prototype);

  // Continue

  WasmResult continueStream(WasmStreamType stream_type) override;

  WasmResult closeStream(WasmStreamType stream_type) override;

  void failStream(WasmStreamType stream_type) override;

  WasmResult sendLocalResponse(uint32_t response_code, std::string_view body_text,

                               Pairs additional_headers, uint32_t grpc_status,

                               std::string_view details) override;

  // Header/Trailer/Metadata Maps

  WasmResult addHeaderMapValue(WasmHeaderMapType type, std::string_view key,

                               std::string_view value) override;

  WasmResult getHeaderMapValue(WasmHeaderMapType type, std::string_view key,

                               std::string_view* value) override;

  WasmResult getHeaderMapPairs(WasmHeaderMapType type, Pairs* result) override;

  WasmResult setHeaderMapPairs(WasmHeaderMapType type, const Pairs& pairs) override;

  WasmResult removeHeaderMapValue(WasmHeaderMapType type, std::string_view key) override;

  WasmResult replaceHeaderMapValue(WasmHeaderMapType type, std::string_view key,

                                   std::string_view value) override;

  WasmResult getHeaderMapSize(WasmHeaderMapType type, uint32_t* size) override;

  // Buffer

  BufferInterface* getBuffer(WasmBufferType type) override;

  // TODO: use stream_type.

  // HTTP

  WasmResult httpCall(std::string_view cluster, const Pairs& request_headers,

                      std::string_view request_body, const Pairs& request_trailers,

                      int timeout_milliseconds, uint32_t* token_ptr) override;

  // Stats/Metrics

  WasmResult defineMetric(uint32_t type, std::string_view name, uint32_t* metric_id_ptr) override;

  WasmResult incrementMetric(uint32_t metric_id, int64_t offset) override;

  WasmResult recordMetric(uint32_t metric_id, uint64_t value) override;

  WasmResult getMetric(uint32_t metric_id, uint64_t* value_ptr) override;

  // gRPC

  WasmResult grpcCall(std::string_view grpc_service, std::string_view service_name,

                      std::string_view method_name, const Pairs& initial_metadata,

                      std::string_view request, std::chrono::milliseconds timeout,

                      uint32_t* token_ptr) override;

  WasmResult grpcStream(std::string_view grpc_service, std::string_view service_name,

                        std::string_view method_name, const Pairs& initial_metadat,

                        uint32_t* token_ptr) override;

  WasmResult grpcClose(uint32_t token) override;

  WasmResult grpcCancel(uint32_t token) override;

  WasmResult grpcSend(uint32_t token, std::string_view message, bool end_stream) override;

  // Envoy specific ABI

  void onResolveDns(uint32_t token, Envoy::Network::DnsResolver::ResolutionStatus status,

                    std::list<Envoy::Network::DnsResponse>&& response);

  void onStatsUpdate(Envoy::Stats::MetricSnapshot& snapshot);

  // CEL evaluation

  absl::optional<google::api::expr::runtime::CelValue>

  findValue(absl::string_view name, Protobuf::Arena* arena, bool last) const;

  absl::optional<google::api::expr::runtime::CelValue>

  FindValue(absl::string_view name, Protobuf::Arena* arena) const override;

  // Foreign function state

protected:

  friend class Wasm;

  void addAfterVmCallAction(std::function<void()> f);

  void onCloseTCP();

  struct AsyncClientHandler : public Http::AsyncClient::Callbacks {

    // Http::AsyncClient::Callbacks

    void onSuccess(const Http::AsyncClient::Request&,

    void onFailure(const Http::AsyncClient::Request&,

    void

    onBeforeFinalizeUpstreamSpan(Envoy::Tracing::Span& /* span */,

    Context* context_;

    uint32_t token_;

    Http::AsyncClient::Request* request_;

  };

  struct GrpcCallClientHandler : public Grpc::RawAsyncRequestCallbacks {

    // Grpc::AsyncRequestCallbacks

    void onFailure(Grpc::Status::GrpcStatus status, const std::string& message,

    Context* context_;

    uint32_t token_;

    Grpc::RawAsyncClientSharedPtr client_;

    Grpc::AsyncRequest* request_;

  };

  struct GrpcStreamClientHandler : public Grpc::RawAsyncStreamCallbacks {

    // Grpc::AsyncStreamCallbacks

    Context* context_;

    uint32_t token_;

    Grpc::RawAsyncClientSharedPtr client_;

    Grpc::RawAsyncStream* stream_;

    bool local_closed_ = false;

    bool remote_closed_ = false;

  };

  void onHttpCallSuccess(uint32_t token, Envoy::Http::ResponseMessagePtr&& response);

  void onHttpCallFailure(uint32_t token, Http::AsyncClient::FailureReason reason);

  void onGrpcCreateInitialMetadata(uint32_t token, Http::RequestHeaderMap& metadata);

  void onGrpcReceiveInitialMetadataWrapper(uint32_t token, Http::HeaderMapPtr&& metadata);

  void onGrpcReceiveWrapper(uint32_t token, ::Envoy::Buffer::InstancePtr response);

  void onGrpcReceiveTrailingMetadataWrapper(uint32_t token, Http::HeaderMapPtr&& metadata);

  void onGrpcCloseWrapper(uint32_t token, const Grpc::Status::GrpcStatus& status,

                          const std::string_view message);

  Http::HeaderMap* getMap(WasmHeaderMapType type);

  const Http::HeaderMap* getConstMap(WasmHeaderMapType type);

  const LocalInfo::LocalInfo* root_local_info_{nullptr}; // set only for root_context.

  PluginHandleSharedPtr plugin_handle_{nullptr};

  uint32_t next_http_call_token_ = 1;

  uint32_t next_grpc_token_ = 1; // Odd tokens are for Calls even for Streams.

  // Network callbacks.

  Network::ReadFilterCallbacks* network_read_filter_callbacks_{};

  Network::WriteFilterCallbacks* network_write_filter_callbacks_{};

  // HTTP callbacks.

  Envoy::Http::StreamDecoderFilterCallbacks* decoder_callbacks_{};

  Envoy::Http::StreamEncoderFilterCallbacks* encoder_callbacks_{};

  // Status.

  uint32_t status_code_{0};

  absl::string_view status_message_;

  // Network filter state.

  ::Envoy::Buffer::Instance* network_downstream_data_buffer_{};

  ::Envoy::Buffer::Instance* network_upstream_data_buffer_{};

  // HTTP filter state.

  Http::RequestHeaderMap* request_headers_{};

  Http::ResponseHeaderMap* response_headers_{};

  ::Envoy::Buffer::Instance* request_body_buffer_{};

  ::Envoy::Buffer::Instance* response_body_buffer_{};

  Http::RequestTrailerMap* request_trailers_{};

  Http::ResponseTrailerMap* response_trailers_{};

  Http::MetadataMap* request_metadata_{};

  Http::MetadataMap* response_metadata_{};

  // Only available during onHttpCallResponse.

  Envoy::Http::ResponseMessagePtr* http_call_response_{};

  Http::HeaderMapPtr grpc_receive_initial_metadata_;

  Http::HeaderMapPtr grpc_receive_trailing_metadata_;

  // Only available (non-nullptr) during onGrpcReceive.

  ::Envoy::Buffer::InstancePtr grpc_receive_buffer_;

  // Only available (non-nullptr) during grpcCall and grpcStream.

  Http::RequestHeaderMapPtr grpc_initial_metadata_;

  // Access log state.

  bool access_log_phase_ = false;

  const StreamInfo::StreamInfo* access_log_stream_info_{};

  const Http::RequestHeaderMap* access_log_request_headers_{};

  const Http::ResponseHeaderMap* access_log_response_headers_{};

  const Http::ResponseTrailerMap* access_log_response_trailers_{};

  // Temporary state.

  Buffer buffer_;

  bool buffering_request_body_ = false;

  bool buffering_response_body_ = false;

  bool end_of_stream_ = false;

  bool failure_local_reply_sent_ = false;

  // MB: must be a node-type map as we take persistent references to the entries.

  std::map<uint32_t, AsyncClientHandler> http_request_;

  std::map<uint32_t, GrpcCallClientHandler> grpc_call_request_;

  std::map<uint32_t, GrpcStreamClientHandler> grpc_stream_;

  // Opaque state.

  absl::flat_hash_map<std::string, std::unique_ptr<StorageObject>> data_storage_;

  // TCP State.

  bool upstream_closed_ = false;

  bool downstream_closed_ = false;

  bool tcp_connection_closed_ = false;

  // Filter state prototype declaration.

  absl::flat_hash_map<std::string, Filters::Common::Expr::CelStatePrototypeConstPtr>

      state_prototypes_;

  proxy_wasm::AbiVersion abi_version_{proxy_wasm::AbiVersion::Unknown};

};

using ContextSharedPtr = std::shared_ptr<Context>;

WasmResult serializeValue(Filters::Common::Expr::CelValue value, std::string* result);

} // namespace Wasm

} // namespace Common

} // namespace Extensions

} // namespace Envoy