/*
 *
 * Copyright 2015, 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 "test/core/end2end/fixtures/proxy.h"

#include <string.h>

#include <grpc/support/alloc.h>
#include <grpc/support/host_port.h>
#include <grpc/support/log.h>
#include <grpc/support/sync.h>
#include <grpc/support/thd.h>
#include <grpc/support/useful.h>

#include "test/core/util/port.h"

struct grpc_end2end_proxy {
  gpr_thd_id thd;
  char *proxy_port;
  char *server_port;
  grpc_completion_queue *cq;
  grpc_server *server;
  grpc_channel *client;

  int shutdown;

  /* requested call */
  grpc_call *new_call;
  grpc_call_details new_call_details;
  grpc_metadata_array new_call_metadata;
};

typedef struct {
  void (*func)(void *arg, int success);
  void *arg;
} closure;

typedef struct {
  gpr_refcount refs;
  grpc_end2end_proxy *proxy;

  grpc_call *c2p;
  grpc_call *p2s;

  grpc_metadata_array c2p_initial_metadata;
  grpc_metadata_array p2s_initial_metadata;

  grpc_byte_buffer *c2p_msg;
  grpc_byte_buffer *p2s_msg;

  grpc_metadata_array p2s_trailing_metadata;
  grpc_status_code p2s_status;
  grpc_slice p2s_status_details;

  int c2p_server_cancelled;
} proxy_call;

static void thread_main(void *arg);
static void request_call(grpc_end2end_proxy *proxy);

grpc_end2end_proxy *grpc_end2end_proxy_create(const grpc_end2end_proxy_def *def,
                                              grpc_channel_args *client_args,
                                              grpc_channel_args *server_args) {
  gpr_thd_options opt = gpr_thd_options_default();
  int proxy_port = grpc_pick_unused_port_or_die();
  int server_port = grpc_pick_unused_port_or_die();

  grpc_end2end_proxy *proxy = gpr_malloc(sizeof(*proxy));
  memset(proxy, 0, sizeof(*proxy));

  gpr_join_host_port(&proxy->proxy_port, "localhost", proxy_port);
  gpr_join_host_port(&proxy->server_port, "localhost", server_port);

  gpr_log(GPR_DEBUG, "PROXY ADDR:%s BACKEND:%s", proxy->proxy_port,
          proxy->server_port);

  proxy->cq =
      grpc_completion_queue_create(GRPC_CQ_NEXT, GRPC_CQ_DEFAULT_POLLING, NULL);
  proxy->server = def->create_server(proxy->proxy_port, server_args);
  proxy->client = def->create_client(proxy->server_port, client_args);

  grpc_server_register_completion_queue(proxy->server, proxy->cq, NULL);
  grpc_server_start(proxy->server);

  grpc_call_details_init(&proxy->new_call_details);
  gpr_thd_options_set_joinable(&opt);
  GPR_ASSERT(gpr_thd_new(&proxy->thd, thread_main, proxy, &opt));

  request_call(proxy);

  return proxy;
}

static closure *new_closure(void (*func)(void *arg, int success), void *arg) {
  closure *cl = gpr_malloc(sizeof(*cl));
  cl->func = func;
  cl->arg = arg;
  return cl;
}

static void shutdown_complete(void *arg, int success) {
  grpc_end2end_proxy *proxy = arg;
  proxy->shutdown = 1;
  grpc_completion_queue_shutdown(proxy->cq);
}

void grpc_end2end_proxy_destroy(grpc_end2end_proxy *proxy) {
  grpc_server_shutdown_and_notify(proxy->server, proxy->cq,
                                  new_closure(shutdown_complete, proxy));
  gpr_thd_join(proxy->thd);
  gpr_free(proxy->proxy_port);
  gpr_free(proxy->server_port);
  grpc_server_destroy(proxy->server);
  grpc_channel_destroy(proxy->client);
  grpc_completion_queue_destroy(proxy->cq);
  grpc_call_details_destroy(&proxy->new_call_details);
  gpr_free(proxy);
}

static void unrefpc(proxy_call *pc, const char *reason) {
  if (gpr_unref(&pc->refs)) {
    grpc_call_destroy(pc->c2p);
    grpc_call_destroy(pc->p2s);
    grpc_metadata_array_destroy(&pc->c2p_initial_metadata);
    grpc_metadata_array_destroy(&pc->p2s_initial_metadata);
    grpc_metadata_array_destroy(&pc->p2s_trailing_metadata);
    grpc_slice_unref(pc->p2s_status_details);
    gpr_free(pc);
  }
}

static void refpc(proxy_call *pc, const char *reason) { gpr_ref(&pc->refs); }

static void on_c2p_sent_initial_metadata(void *arg, int success) {
  proxy_call *pc = arg;
  unrefpc(pc, "on_c2p_sent_initial_metadata");
}

static void on_p2s_recv_initial_metadata(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  memset(&op, 0, sizeof(op));
  if (!pc->proxy->shutdown) {
    op.op = GRPC_OP_SEND_INITIAL_METADATA;
    op.flags = 0;
    op.reserved = NULL;
    op.data.send_initial_metadata.count = pc->p2s_initial_metadata.count;
    op.data.send_initial_metadata.metadata = pc->p2s_initial_metadata.metadata;
    refpc(pc, "on_c2p_sent_initial_metadata");
    err = grpc_call_start_batch(
        pc->c2p, &op, 1, new_closure(on_c2p_sent_initial_metadata, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);
  }

  unrefpc(pc, "on_p2s_recv_initial_metadata");
}

static void on_p2s_sent_initial_metadata(void *arg, int success) {
  proxy_call *pc = arg;
  unrefpc(pc, "on_p2s_sent_initial_metadata");
}

static void on_c2p_recv_msg(void *arg, int success);

static void on_p2s_sent_message(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  grpc_byte_buffer_destroy(pc->c2p_msg);
  if (!pc->proxy->shutdown && success) {
    op.op = GRPC_OP_RECV_MESSAGE;
    op.flags = 0;
    op.reserved = NULL;
    op.data.recv_message.recv_message = &pc->c2p_msg;
    refpc(pc, "on_c2p_recv_msg");
    err = grpc_call_start_batch(pc->c2p, &op, 1,
                                new_closure(on_c2p_recv_msg, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);
  }

  unrefpc(pc, "on_p2s_sent_message");
}

static void on_p2s_sent_close(void *arg, int success) {
  proxy_call *pc = arg;
  unrefpc(pc, "on_p2s_sent_close");
}

static void on_c2p_recv_msg(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  if (!pc->proxy->shutdown && success) {
    if (pc->c2p_msg != NULL) {
      op.op = GRPC_OP_SEND_MESSAGE;
      op.flags = 0;
      op.reserved = NULL;
      op.data.send_message.send_message = pc->c2p_msg;
      refpc(pc, "on_p2s_sent_message");
      err = grpc_call_start_batch(pc->p2s, &op, 1,
                                  new_closure(on_p2s_sent_message, pc), NULL);
      GPR_ASSERT(err == GRPC_CALL_OK);
    } else {
      op.op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
      op.flags = 0;
      op.reserved = NULL;
      refpc(pc, "on_p2s_sent_close");
      err = grpc_call_start_batch(pc->p2s, &op, 1,
                                  new_closure(on_p2s_sent_close, pc), NULL);
      GPR_ASSERT(err == GRPC_CALL_OK);
    }
  }

  unrefpc(pc, "on_c2p_recv_msg");
}

static void on_p2s_recv_msg(void *arg, int success);

static void on_c2p_sent_message(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  grpc_byte_buffer_destroy(pc->p2s_msg);
  if (!pc->proxy->shutdown && success) {
    op.op = GRPC_OP_RECV_MESSAGE;
    op.flags = 0;
    op.reserved = NULL;
    op.data.recv_message.recv_message = &pc->p2s_msg;
    refpc(pc, "on_p2s_recv_msg");
    err = grpc_call_start_batch(pc->p2s, &op, 1,
                                new_closure(on_p2s_recv_msg, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);
  }

  unrefpc(pc, "on_c2p_sent_message");
}

static void on_p2s_recv_msg(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  if (!pc->proxy->shutdown && success && pc->p2s_msg) {
    op.op = GRPC_OP_SEND_MESSAGE;
    op.flags = 0;
    op.reserved = NULL;
    op.data.send_message.send_message = pc->p2s_msg;
    refpc(pc, "on_c2p_sent_message");
    err = grpc_call_start_batch(pc->c2p, &op, 1,
                                new_closure(on_c2p_sent_message, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);
  } else {
    grpc_byte_buffer_destroy(pc->p2s_msg);
  }
  unrefpc(pc, "on_p2s_recv_msg");
}

static void on_c2p_sent_status(void *arg, int success) {
  proxy_call *pc = arg;
  unrefpc(pc, "on_c2p_sent_status");
}

static void on_p2s_status(void *arg, int success) {
  proxy_call *pc = arg;
  grpc_op op;
  grpc_call_error err;

  if (!pc->proxy->shutdown) {
    GPR_ASSERT(success);
    op.op = GRPC_OP_SEND_STATUS_FROM_SERVER;
    op.flags = 0;
    op.reserved = NULL;
    op.data.send_status_from_server.trailing_metadata_count =
        pc->p2s_trailing_metadata.count;
    op.data.send_status_from_server.trailing_metadata =
        pc->p2s_trailing_metadata.metadata;
    op.data.send_status_from_server.status = pc->p2s_status;
    op.data.send_status_from_server.status_details = &pc->p2s_status_details;
    refpc(pc, "on_c2p_sent_status");
    err = grpc_call_start_batch(pc->c2p, &op, 1,
                                new_closure(on_c2p_sent_status, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);
  }

  unrefpc(pc, "on_p2s_status");
}

static void on_c2p_closed(void *arg, int success) {
  proxy_call *pc = arg;
  unrefpc(pc, "on_c2p_closed");
}

static void on_new_call(void *arg, int success) {
  grpc_end2end_proxy *proxy = arg;
  grpc_call_error err;

  if (success) {
    grpc_op op;
    memset(&op, 0, sizeof(op));
    proxy_call *pc = gpr_malloc(sizeof(*pc));
    memset(pc, 0, sizeof(*pc));
    pc->proxy = proxy;
    GPR_SWAP(grpc_metadata_array, pc->c2p_initial_metadata,
             proxy->new_call_metadata);
    pc->c2p = proxy->new_call;
    pc->p2s = grpc_channel_create_call(
        proxy->client, pc->c2p, GRPC_PROPAGATE_DEFAULTS, proxy->cq,
        proxy->new_call_details.method, &proxy->new_call_details.host,
        proxy->new_call_details.deadline, NULL);
    gpr_ref_init(&pc->refs, 1);

    op.reserved = NULL;

    op.op = GRPC_OP_RECV_INITIAL_METADATA;
    op.flags = 0;
    op.data.recv_initial_metadata.recv_initial_metadata =
        &pc->p2s_initial_metadata;
    refpc(pc, "on_p2s_recv_initial_metadata");
    err = grpc_call_start_batch(
        pc->p2s, &op, 1, new_closure(on_p2s_recv_initial_metadata, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    op.op = GRPC_OP_SEND_INITIAL_METADATA;
    op.flags = proxy->new_call_details.flags;
    op.data.send_initial_metadata.count = pc->c2p_initial_metadata.count;
    op.data.send_initial_metadata.metadata = pc->c2p_initial_metadata.metadata;
    refpc(pc, "on_p2s_sent_initial_metadata");
    err = grpc_call_start_batch(
        pc->p2s, &op, 1, new_closure(on_p2s_sent_initial_metadata, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    op.op = GRPC_OP_RECV_MESSAGE;
    op.flags = 0;
    op.data.recv_message.recv_message = &pc->c2p_msg;
    refpc(pc, "on_c2p_recv_msg");
    err = grpc_call_start_batch(pc->c2p, &op, 1,
                                new_closure(on_c2p_recv_msg, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    op.op = GRPC_OP_RECV_MESSAGE;
    op.flags = 0;
    op.data.recv_message.recv_message = &pc->p2s_msg;
    refpc(pc, "on_p2s_recv_msg");
    err = grpc_call_start_batch(pc->p2s, &op, 1,
                                new_closure(on_p2s_recv_msg, pc), NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    op.op = GRPC_OP_RECV_STATUS_ON_CLIENT;
    op.flags = 0;
    op.data.recv_status_on_client.trailing_metadata =
        &pc->p2s_trailing_metadata;
    op.data.recv_status_on_client.status = &pc->p2s_status;
    op.data.recv_status_on_client.status_details = &pc->p2s_status_details;
    refpc(pc, "on_p2s_status");
    err = grpc_call_start_batch(pc->p2s, &op, 1, new_closure(on_p2s_status, pc),
                                NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    op.op = GRPC_OP_RECV_CLOSE_ON_SERVER;
    op.flags = 0;
    op.data.recv_close_on_server.cancelled = &pc->c2p_server_cancelled;
    refpc(pc, "on_c2p_closed");
    err = grpc_call_start_batch(pc->c2p, &op, 1, new_closure(on_c2p_closed, pc),
                                NULL);
    GPR_ASSERT(err == GRPC_CALL_OK);

    request_call(proxy);

    grpc_call_details_destroy(&proxy->new_call_details);
    grpc_call_details_init(&proxy->new_call_details);

    unrefpc(pc, "init");
  } else {
    GPR_ASSERT(proxy->new_call == NULL);
  }
}

static void request_call(grpc_end2end_proxy *proxy) {
  proxy->new_call = NULL;
  GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
                                 proxy->server, &proxy->new_call,
                                 &proxy->new_call_details,
                                 &proxy->new_call_metadata, proxy->cq,
                                 proxy->cq, new_closure(on_new_call, proxy)));
}

static void thread_main(void *arg) {
  grpc_end2end_proxy *proxy = arg;
  closure *cl;
  for (;;) {
    grpc_event ev = grpc_completion_queue_next(
        proxy->cq, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL);
    switch (ev.type) {
      case GRPC_QUEUE_TIMEOUT:
        gpr_log(GPR_ERROR, "Should never reach here");
        abort();
      case GRPC_QUEUE_SHUTDOWN:
        return;
      case GRPC_OP_COMPLETE:
        cl = ev.tag;
        cl->func(cl->arg, ev.success);
        gpr_free(cl);
        break;
    }
  }
}

const char *grpc_end2end_proxy_get_client_target(grpc_end2end_proxy *proxy) {
  return proxy->proxy_port;
}

const char *grpc_end2end_proxy_get_server_port(grpc_end2end_proxy *proxy) {
  return proxy->server_port;
}