// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_
#define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_

#include <memory>
#include <utility>

#include "base/bind.h"
#include "base/callback.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/memory/ptr_util.h"
#include "base/memory/ref_counted.h"
#include "base/single_thread_task_runner.h"
#include "mojo/public/cpp/bindings/associated_group.h"
#include "mojo/public/cpp/bindings/interface_endpoint_client.h"
#include "mojo/public/cpp/bindings/interface_id.h"
#include "mojo/public/cpp/bindings/interface_ptr.h"
#include "mojo/public/cpp/bindings/interface_ptr_info.h"
#include "mojo/public/cpp/bindings/interface_request.h"
#include "mojo/public/cpp/bindings/lib/filter_chain.h"
#include "mojo/public/cpp/bindings/lib/multiplex_router.h"
#include "mojo/public/cpp/bindings/lib/router.h"
#include "mojo/public/cpp/bindings/message_header_validator.h"
#include "mojo/public/cpp/bindings/scoped_interface_endpoint_handle.h"
#include "mojo/public/cpp/system/core.h"

namespace mojo {
namespace internal {

template <typename Interface, bool use_multiplex_router>
class BindingState;

// Uses a single-threaded, dedicated router. If |Interface| doesn't have any
// methods to pass associated interface pointers or requests, there won't be
// multiple interfaces running on the underlying message pipe. In that case, we
// can use this specialization to reduce cost.
template <typename Interface>
class BindingState<Interface, false> {
 public:
  explicit BindingState(Interface* impl) : impl_(impl) {
    stub_.set_sink(impl_);
  }

  ~BindingState() { Close(); }

  void Bind(ScopedMessagePipeHandle handle,
            scoped_refptr<base::SingleThreadTaskRunner> runner) {
    DCHECK(!router_);
    internal::FilterChain filters;
    filters.Append<MessageHeaderValidator>(Interface::Name_);
    filters.Append<typename Interface::RequestValidator_>();

    router_ =
        new internal::Router(std::move(handle), std::move(filters),
                             Interface::HasSyncMethods_, std::move(runner));
    router_->set_incoming_receiver(&stub_);
    router_->set_connection_error_handler(
        base::Bind(&BindingState::RunConnectionErrorHandler,
                   base::Unretained(this)));
  }

  bool HasAssociatedInterfaces() const { return false; }

  void PauseIncomingMethodCallProcessing() {
    DCHECK(router_);
    router_->PauseIncomingMethodCallProcessing();
  }
  void ResumeIncomingMethodCallProcessing() {
    DCHECK(router_);
    router_->ResumeIncomingMethodCallProcessing();
  }

  bool WaitForIncomingMethodCall(
      MojoDeadline deadline = MOJO_DEADLINE_INDEFINITE) {
    DCHECK(router_);
    return router_->WaitForIncomingMessage(deadline);
  }

  void Close() {
    if (!router_)
      return;

    router_->CloseMessagePipe();
    DestroyRouter();
  }

  InterfaceRequest<Interface> Unbind() {
    InterfaceRequest<Interface> request =
        MakeRequest<Interface>(router_->PassMessagePipe());
    DestroyRouter();
    return std::move(request);
  }

  void set_connection_error_handler(const base::Closure& error_handler) {
    DCHECK(is_bound());
    connection_error_handler_ = error_handler;
  }

  Interface* impl() { return impl_; }

  bool is_bound() const { return !!router_; }

  MessagePipeHandle handle() const {
    DCHECK(is_bound());
    return router_->handle();
  }

  AssociatedGroup* associated_group() { return nullptr; }

  void EnableTestingMode() {
    DCHECK(is_bound());
    router_->EnableTestingMode();
  }

 private:
  void DestroyRouter() {
    router_->set_connection_error_handler(base::Closure());
    delete router_;
    router_ = nullptr;
    connection_error_handler_.Reset();
  }

  void RunConnectionErrorHandler() {
    if (!connection_error_handler_.is_null())
      connection_error_handler_.Run();
  }

  internal::Router* router_ = nullptr;
  typename Interface::Stub_ stub_;
  Interface* impl_;
  base::Closure connection_error_handler_;

  DISALLOW_COPY_AND_ASSIGN(BindingState);
};

// Uses a multiplexing router. If |Interface| has methods to pass associated
// interface pointers or requests, this specialization should be used.
template <typename Interface>
class BindingState<Interface, true> {
 public:
  explicit BindingState(Interface* impl) : impl_(impl) {
    stub_.set_sink(impl_);
  }

  ~BindingState() { Close(); }

  void Bind(ScopedMessagePipeHandle handle,
            scoped_refptr<base::SingleThreadTaskRunner> runner) {
    DCHECK(!router_);

    router_ = new internal::MultiplexRouter(false, std::move(handle), runner);
    router_->SetMasterInterfaceName(Interface::Name_);
    stub_.serialization_context()->group_controller = router_;

    endpoint_client_.reset(new InterfaceEndpointClient(
        router_->CreateLocalEndpointHandle(kMasterInterfaceId),
        &stub_, base::WrapUnique(new typename Interface::RequestValidator_()),
        Interface::HasSyncMethods_, std::move(runner)));

    endpoint_client_->set_connection_error_handler(
        base::Bind(&BindingState::RunConnectionErrorHandler,
                   base::Unretained(this)));
  }

  bool HasAssociatedInterfaces() const {
    return router_ ? router_->HasAssociatedEndpoints() : false;
  }

  void PauseIncomingMethodCallProcessing() {
    DCHECK(router_);
    router_->PauseIncomingMethodCallProcessing();
  }
  void ResumeIncomingMethodCallProcessing() {
    DCHECK(router_);
    router_->ResumeIncomingMethodCallProcessing();
  }

  bool WaitForIncomingMethodCall(
      MojoDeadline deadline = MOJO_DEADLINE_INDEFINITE) {
    DCHECK(router_);
    return router_->WaitForIncomingMessage(deadline);
  }

  void Close() {
    if (!router_)
      return;

    endpoint_client_.reset();
    router_->CloseMessagePipe();
    router_ = nullptr;
    connection_error_handler_.Reset();
  }

  InterfaceRequest<Interface> Unbind() {
    endpoint_client_.reset();
    InterfaceRequest<Interface> request =
        MakeRequest<Interface>(router_->PassMessagePipe());
    router_ = nullptr;
    connection_error_handler_.Reset();
    return request;
  }

  void set_connection_error_handler(const base::Closure& error_handler) {
    DCHECK(is_bound());
    connection_error_handler_ = error_handler;
  }

  Interface* impl() { return impl_; }

  bool is_bound() const { return !!router_; }

  MessagePipeHandle handle() const {
    DCHECK(is_bound());
    return router_->handle();
  }

  AssociatedGroup* associated_group() {
    return endpoint_client_ ? endpoint_client_->associated_group() : nullptr;
  }

  void EnableTestingMode() {
    DCHECK(is_bound());
    router_->EnableTestingMode();
  }

 private:
  void RunConnectionErrorHandler() {
    if (!connection_error_handler_.is_null())
      connection_error_handler_.Run();
  }

  scoped_refptr<internal::MultiplexRouter> router_;
  std::unique_ptr<InterfaceEndpointClient> endpoint_client_;

  typename Interface::Stub_ stub_;
  Interface* impl_;
  base::Closure connection_error_handler_;

  DISALLOW_COPY_AND_ASSIGN(BindingState);
};

}  // namesapce internal
}  // namespace mojo

#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_