/*
 *
 * Copyright 2014, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "src/core/surface/channel.h"

#include <stdlib.h>
#include <string.h>

#include "src/core/surface/call.h"
#include "src/core/surface/client.h"
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>

struct grpc_channel {
  int is_client;
  gpr_refcount refs;
  grpc_mdctx *metadata_context;
  grpc_mdstr *grpc_status_string;
  grpc_mdstr *grpc_message_string;
  grpc_mdstr *path_string;
  grpc_mdstr *authority_string;
};

#define CHANNEL_STACK_FROM_CHANNEL(c) ((grpc_channel_stack *)((c)+1))
#define CHANNEL_FROM_CHANNEL_STACK(channel_stack) (((grpc_channel *)(channel_stack)) - 1)
#define CHANNEL_FROM_TOP_ELEM(top_elem) \
  CHANNEL_FROM_CHANNEL_STACK(grpc_channel_stack_from_top_element(top_elem))

grpc_channel *grpc_channel_create_from_filters(
    const grpc_channel_filter **filters, size_t num_filters,
    const grpc_channel_args *args, grpc_mdctx *mdctx, int is_client) {
  size_t size =
      sizeof(grpc_channel) + grpc_channel_stack_size(filters, num_filters);
  grpc_channel *channel = gpr_malloc(size);
  channel->is_client = is_client;
  /* decremented by grpc_channel_destroy, and grpc_client_channel_closed if is_client */
  gpr_ref_init(&channel->refs, 1 + is_client);
  channel->metadata_context = mdctx;
  channel->grpc_status_string = grpc_mdstr_from_string(mdctx, "grpc-status");
  channel->grpc_message_string = grpc_mdstr_from_string(mdctx, "grpc-message");
  channel->path_string = grpc_mdstr_from_string(mdctx, ":path");
  channel->authority_string = grpc_mdstr_from_string(mdctx, ":authority");
  grpc_channel_stack_init(filters, num_filters, args, channel->metadata_context,
                          CHANNEL_STACK_FROM_CHANNEL(channel));
  return channel;
}

static void do_nothing(void *ignored, grpc_op_error error) {}

grpc_call *grpc_channel_create_call(grpc_channel *channel,
                                    grpc_completion_queue *cq,
                                    const char *method, const char *host,
                                    gpr_timespec absolute_deadline) {
  grpc_call *call;
  grpc_mdelem *path_mdelem;
  grpc_mdelem *authority_mdelem;
  grpc_call_op op;

  if (!channel->is_client) {
    gpr_log(GPR_ERROR, "Cannot create a call on the server.");
    return NULL;
  }

  call = grpc_call_create(channel, cq, NULL);

  /* Add :path and :authority headers. */
  /* TODO(klempner): Consider optimizing this by stashing mdelems for common
     values of method and host. */
  path_mdelem = grpc_mdelem_from_metadata_strings(
      channel->metadata_context, grpc_mdstr_ref(channel->path_string),
      grpc_mdstr_from_string(channel->metadata_context, method));
  op.type = GRPC_SEND_METADATA;
  op.dir = GRPC_CALL_DOWN;
  op.flags = 0;
  op.data.metadata = path_mdelem;
  op.done_cb = do_nothing;
  op.user_data = NULL;
  grpc_call_execute_op(call, &op);

  grpc_mdstr_ref(channel->authority_string);
  authority_mdelem = grpc_mdelem_from_metadata_strings(
      channel->metadata_context, channel->authority_string,
      grpc_mdstr_from_string(channel->metadata_context, host));
  op.data.metadata = authority_mdelem;
  grpc_call_execute_op(call, &op);

  if (0 != gpr_time_cmp(absolute_deadline, gpr_inf_future)) {
    op.type = GRPC_SEND_DEADLINE;
    op.dir = GRPC_CALL_DOWN;
    op.flags = 0;
    op.data.deadline = absolute_deadline;
    op.done_cb = do_nothing;
    op.user_data = NULL;
    grpc_call_execute_op(call, &op);
  }

  return call;
}

grpc_call *grpc_channel_create_call_old(grpc_channel *channel,
                                        const char *method, const char *host,
                                        gpr_timespec absolute_deadline) {
  return grpc_channel_create_call(channel, NULL, method, host,
                                  absolute_deadline);
}

void grpc_channel_internal_ref(grpc_channel *channel) {
  gpr_ref(&channel->refs);
}

void grpc_channel_internal_unref(grpc_channel *channel) {
  if (gpr_unref(&channel->refs)) {
    grpc_channel_stack_destroy(CHANNEL_STACK_FROM_CHANNEL(channel));
    grpc_mdstr_unref(channel->grpc_status_string);
    grpc_mdstr_unref(channel->grpc_message_string);
    grpc_mdstr_unref(channel->path_string);
    grpc_mdstr_unref(channel->authority_string);
    grpc_mdctx_orphan(channel->metadata_context);
    gpr_free(channel);
  }
}

void grpc_channel_destroy(grpc_channel *channel) {
  grpc_channel_op op;
  grpc_channel_element *elem;

  elem = grpc_channel_stack_element(CHANNEL_STACK_FROM_CHANNEL(channel), 0);

  op.type = GRPC_CHANNEL_GOAWAY;
  op.dir = GRPC_CALL_DOWN;
  op.data.goaway.status = GRPC_STATUS_OK;
  op.data.goaway.message = gpr_slice_from_copied_string("Client disconnect");
  elem->filter->channel_op(elem, NULL, &op);

  op.type = GRPC_CHANNEL_DISCONNECT;
  op.dir = GRPC_CALL_DOWN;
  elem->filter->channel_op(elem, NULL, &op);

  grpc_channel_internal_unref(channel);
}

void grpc_client_channel_closed(grpc_channel_element *elem) {
  grpc_channel_internal_unref(CHANNEL_FROM_TOP_ELEM(elem));
}

grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel) {
  return CHANNEL_STACK_FROM_CHANNEL(channel);
}

grpc_mdctx *grpc_channel_get_metadata_context(grpc_channel *channel) {
  return channel->metadata_context;
}

grpc_mdstr *grpc_channel_get_status_string(grpc_channel *channel) {
  return channel->grpc_status_string;
}

grpc_mdstr *grpc_channel_get_message_string(grpc_channel *channel) {
  return channel->grpc_message_string;
}
