/*
 *
 * 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 "rb_server.h"

#include <ruby/ruby.h>

#include <grpc/grpc.h>
#include <grpc/grpc_security.h>
#include "rb_call.h"
#include "rb_channel_args.h"
#include "rb_completion_queue.h"
#include "rb_server_credentials.h"
#include "rb_grpc.h"

/* grpc_rb_cServer is the ruby class that proxies grpc_server. */
static VALUE grpc_rb_cServer = Qnil;

/* id_at is the constructor method of the ruby standard Time class. */
static ID id_at;

/* grpc_rb_server wraps a grpc_server.  It provides a peer ruby object,
  'mark' to minimize copying when a server is created from ruby. */
typedef struct grpc_rb_server {
  /* Holder of ruby objects involved in constructing the server */
  VALUE mark;
  /* The actual server */
  grpc_server *wrapped;
} grpc_rb_server;

/* Destroys server instances. */
static void grpc_rb_server_free(void *p) {
  grpc_rb_server *svr = NULL;
  if (p == NULL) {
    return;
  };
  svr = (grpc_rb_server *)p;

  /* Deletes the wrapped object if the mark object is Qnil, which indicates
     that no other object is the actual owner. */
  /* grpc_server_shutdown does not exist. Change this to something that does
     or delete it */
  if (svr->wrapped != NULL && svr->mark == Qnil) {
    // grpc_server_shutdown(svr->wrapped);
    // Aborting to indicate a bug
    abort();
    grpc_server_destroy(svr->wrapped);
  }

  xfree(p);
}

/* Protects the mark object from GC */
static void grpc_rb_server_mark(void *p) {
  grpc_rb_server *server = NULL;
  if (p == NULL) {
    return;
  }
  server = (grpc_rb_server *)p;
  if (server->mark != Qnil) {
    rb_gc_mark(server->mark);
  }
}

static const rb_data_type_t grpc_rb_server_data_type = {
    "grpc_server",
    {grpc_rb_server_mark, grpc_rb_server_free, GRPC_RB_MEMSIZE_UNAVAILABLE,
     {NULL, NULL}},
    NULL,
    NULL,
    /* It is unsafe to specify RUBY_TYPED_FREE_IMMEDIATELY because the free function would block
     * and we might want to unlock GVL
     * TODO(yugui) Unlock GVL?
     */
    0};

/* Allocates grpc_rb_server instances. */
static VALUE grpc_rb_server_alloc(VALUE cls) {
  grpc_rb_server *wrapper = ALLOC(grpc_rb_server);
  wrapper->wrapped = NULL;
  wrapper->mark = Qnil;
  return TypedData_Wrap_Struct(cls, &grpc_rb_server_data_type, wrapper);
}

/*
  call-seq:
    cq = CompletionQueue.new
    server = Server.new(cq, {'arg1': 'value1'})

  Initializes server instances. */
static VALUE grpc_rb_server_init(VALUE self, VALUE cqueue, VALUE channel_args) {
  grpc_completion_queue *cq = NULL;
  grpc_rb_server *wrapper = NULL;
  grpc_server *srv = NULL;
  grpc_channel_args args;
  MEMZERO(&args, grpc_channel_args, 1);
  cq = grpc_rb_get_wrapped_completion_queue(cqueue);
  TypedData_Get_Struct(self, grpc_rb_server, &grpc_rb_server_data_type,
                       wrapper);
  grpc_rb_hash_convert_to_channel_args(channel_args, &args);
  srv = grpc_server_create(&args);

  if (args.args != NULL) {
    xfree(args.args); /* Allocated by grpc_rb_hash_convert_to_channel_args */
  }
  if (srv == NULL) {
    rb_raise(rb_eRuntimeError, "could not create a gRPC server, not sure why");
  }
  grpc_server_register_completion_queue(srv, cq);
  wrapper->wrapped = srv;

  /* Add the cq as the server's mark object. This ensures the ruby cq can't be
     GCed before the server */
  wrapper->mark = cqueue;
  return self;
}

/* Clones Server instances.

   Gives Server a consistent implementation of Ruby's object copy/dup
   protocol. */
static VALUE grpc_rb_server_init_copy(VALUE copy, VALUE orig) {
  grpc_rb_server *orig_srv = NULL;
  grpc_rb_server *copy_srv = NULL;

  if (copy == orig) {
    return copy;
  }

  /* Raise an error if orig is not a server object or a subclass. */
  if (TYPE(orig) != T_DATA ||
      RDATA(orig)->dfree != (RUBY_DATA_FUNC)grpc_rb_server_free) {
    rb_raise(rb_eTypeError, "not a %s", rb_obj_classname(grpc_rb_cServer));
  }

  TypedData_Get_Struct(orig, grpc_rb_server, &grpc_rb_server_data_type,
                       orig_srv);
  TypedData_Get_Struct(copy, grpc_rb_server, &grpc_rb_server_data_type,
                       copy_srv);

  /* use ruby's MEMCPY to make a byte-for-byte copy of the server wrapper
     object. */
  MEMCPY(copy_srv, orig_srv, grpc_rb_server, 1);
  return copy;
}

/* request_call_stack holds various values used by the
 * grpc_rb_server_request_call function */
typedef struct request_call_stack {
  grpc_call_details details;
  grpc_metadata_array md_ary;
} request_call_stack;

/* grpc_request_call_stack_init ensures the request_call_stack is properly
 * initialized */
static void grpc_request_call_stack_init(request_call_stack* st) {
  MEMZERO(st, request_call_stack, 1);
  grpc_metadata_array_init(&st->md_ary);
  grpc_call_details_init(&st->details);
  st->details.method = NULL;
  st->details.host = NULL;
}

/* grpc_request_call_stack_cleanup ensures the request_call_stack is properly
 * cleaned up */
static void grpc_request_call_stack_cleanup(request_call_stack* st) {
  grpc_metadata_array_destroy(&st->md_ary);
  grpc_call_details_destroy(&st->details);
}

/* call-seq:
   cq = CompletionQueue.new
   tag = Object.new
   timeout = 10
   server.request_call(cqueue, tag, timeout)

   Requests notification of a new call on a server. */
static VALUE grpc_rb_server_request_call(VALUE self, VALUE cqueue,
                                         VALUE tag_new, VALUE timeout) {
  grpc_rb_server *s = NULL;
  grpc_call *call = NULL;
  grpc_event ev;
  grpc_call_error err;
  request_call_stack st;
  VALUE result;
  TypedData_Get_Struct(self, grpc_rb_server, &grpc_rb_server_data_type, s);
  if (s->wrapped == NULL) {
    rb_raise(rb_eRuntimeError, "destroyed!");
    return Qnil;
  } else {
    grpc_request_call_stack_init(&st);
    /* call grpc_server_request_call, then wait for it to complete using
     * pluck_event */
    err = grpc_server_request_call(
        s->wrapped, &call, &st.details, &st.md_ary,
        grpc_rb_get_wrapped_completion_queue(cqueue),
        grpc_rb_get_wrapped_completion_queue(cqueue),
        ROBJECT(tag_new));
    if (err != GRPC_CALL_OK) {
      grpc_request_call_stack_cleanup(&st);
      rb_raise(grpc_rb_eCallError,
              "grpc_server_request_call failed: %s (code=%d)",
               grpc_call_error_detail_of(err), err);
      return Qnil;
    }
    ev = grpc_rb_completion_queue_pluck_event(cqueue, tag_new, timeout);
    if (ev.type == GRPC_QUEUE_TIMEOUT) {
      grpc_request_call_stack_cleanup(&st);
      return Qnil;
    }
    if (!ev.success) {
      grpc_request_call_stack_cleanup(&st);
      rb_raise(grpc_rb_eCallError, "request_call completion failed");
      return Qnil;
    }

    /* build the NewServerRpc struct result */
    result = rb_struct_new(
        grpc_rb_sNewServerRpc,
        rb_str_new2(st.details.method),
        rb_str_new2(st.details.host),
        rb_funcall(rb_cTime, id_at, 2, INT2NUM(st.details.deadline.tv_sec),
                   INT2NUM(st.details.deadline.tv_nsec)),
        grpc_rb_md_ary_to_h(&st.md_ary),
        grpc_rb_wrap_call(call),
        NULL);
    grpc_request_call_stack_cleanup(&st);
    return result;
  }
  return Qnil;
}

static VALUE grpc_rb_server_start(VALUE self) {
  grpc_rb_server *s = NULL;
  TypedData_Get_Struct(self, grpc_rb_server, &grpc_rb_server_data_type, s);
  if (s->wrapped == NULL) {
    rb_raise(rb_eRuntimeError, "destroyed!");
  } else {
    grpc_server_start(s->wrapped);
  }
  return Qnil;
}

/*
  call-seq:
    cq = CompletionQueue.new
    server = Server.new(cq, {'arg1': 'value1'})
    ... // do stuff with server
    ...
    ... // to shutdown the server
    server.destroy(cq)

    ... // to shutdown the server with a timeout
    server.destroy(cq, timeout)

  Destroys server instances. */
static VALUE grpc_rb_server_destroy(int argc, VALUE *argv, VALUE self) {
  VALUE cqueue = Qnil;
  VALUE timeout = Qnil;
  grpc_completion_queue *cq = NULL;
  grpc_event ev;
  grpc_rb_server *s = NULL;

  /* "11" == 1 mandatory args, 1 (timeout) is optional */
  rb_scan_args(argc, argv, "11", &cqueue, &timeout);
  cq = grpc_rb_get_wrapped_completion_queue(cqueue);
  TypedData_Get_Struct(self, grpc_rb_server, &grpc_rb_server_data_type, s);

  if (s->wrapped != NULL) {
    grpc_server_shutdown_and_notify(s->wrapped, cq, NULL);
    ev = grpc_rb_completion_queue_pluck_event(cqueue, Qnil, timeout);

    if (!ev.success) {
      rb_warn("server shutdown failed, there will be a LEAKED object warning");
      return Qnil;
      /*
         TODO: renable the rb_raise below.

         At the moment if the timeout is INFINITE_FUTURE as recommended, the
         pluck blocks forever, even though

         the outstanding server_request_calls correctly fail on the other
         thread that they are running on.

         it's almost as if calls that fail on the other thread do not get
         cleaned up by shutdown request, even though it caused htem to
         terminate.

         rb_raise(rb_eRuntimeError, "grpc server shutdown did not succeed");
         return Qnil;

         The workaround is just to use a timeout and return without really
         shutting down the server, and rely on the grpc core garbage collection
         it down as a 'LEAKED OBJECT'.

      */
    }
    grpc_server_destroy(s->wrapped);
    s->wrapped = NULL;
  }
  return Qnil;
}

/*
  call-seq:
    // insecure port
    insecure_server = Server.new(cq, {'arg1': 'value1'})
    insecure_server.add_http2_port('mydomain:50051')

    // secure port
    server_creds = ...
    secure_server = Server.new(cq, {'arg1': 'value1'})
    secure_server.add_http_port('mydomain:50051', server_creds)

    Adds a http2 port to server */
static VALUE grpc_rb_server_add_http2_port(int argc, VALUE *argv, VALUE self) {
  VALUE port = Qnil;
  VALUE rb_creds = Qnil;
  grpc_rb_server *s = NULL;
  grpc_server_credentials *creds = NULL;
  int recvd_port = 0;

  /* "11" == 1 mandatory args, 1 (rb_creds) is optional */
  rb_scan_args(argc, argv, "11", &port, &rb_creds);

  TypedData_Get_Struct(self, grpc_rb_server, &grpc_rb_server_data_type, s);
  if (s->wrapped == NULL) {
    rb_raise(rb_eRuntimeError, "destroyed!");
    return Qnil;
  } else if (rb_creds == Qnil) {
    recvd_port = grpc_server_add_http2_port(s->wrapped, StringValueCStr(port));
    if (recvd_port == 0) {
      rb_raise(rb_eRuntimeError,
               "could not add port %s to server, not sure why",
               StringValueCStr(port));
    }
  } else {
    creds = grpc_rb_get_wrapped_server_credentials(rb_creds);
    recvd_port =
        grpc_server_add_secure_http2_port(s->wrapped, StringValueCStr(port),
                                          creds);
    if (recvd_port == 0) {
      rb_raise(rb_eRuntimeError,
               "could not add secure port %s to server, not sure why",
               StringValueCStr(port));
    }
  }
  return INT2NUM(recvd_port);
}

void Init_grpc_server() {
  grpc_rb_cServer =
      rb_define_class_under(grpc_rb_mGrpcCore, "Server", rb_cObject);

  /* Allocates an object managed by the ruby runtime */
  rb_define_alloc_func(grpc_rb_cServer, grpc_rb_server_alloc);

  /* Provides a ruby constructor and support for dup/clone. */
  rb_define_method(grpc_rb_cServer, "initialize", grpc_rb_server_init, 2);
  rb_define_method(grpc_rb_cServer, "initialize_copy",
                   grpc_rb_server_init_copy, 1);

  /* Add the server methods. */
  rb_define_method(grpc_rb_cServer, "request_call",
                   grpc_rb_server_request_call, 3);
  rb_define_method(grpc_rb_cServer, "start", grpc_rb_server_start, 0);
  rb_define_method(grpc_rb_cServer, "destroy", grpc_rb_server_destroy, -1);
  rb_define_alias(grpc_rb_cServer, "close", "destroy");
  rb_define_method(grpc_rb_cServer, "add_http2_port",
                   grpc_rb_server_add_http2_port,
                   -1);
  id_at = rb_intern("at");
}

/* Gets the wrapped server from the ruby wrapper */
grpc_server *grpc_rb_get_wrapped_server(VALUE v) {
  grpc_rb_server *wrapper = NULL;
  TypedData_Get_Struct(v, grpc_rb_server, &grpc_rb_server_data_type, wrapper);
  return wrapper->wrapped;
}