/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <string.h>

#include "src/core/lib/channel/channel_args.h"
#include "src/core/lib/security/context/security_context.h"
#include "src/core/lib/support/string.h"
#include "src/core/lib/surface/api_trace.h"
#include "src/core/lib/surface/call.h"

#include <grpc/grpc_security.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>

#ifndef NDEBUG
grpc_tracer_flag grpc_trace_auth_context_refcount =
    GRPC_TRACER_INITIALIZER(false, "auth_context_refcount");
#endif

/* --- grpc_call --- */

grpc_call_error grpc_call_set_credentials(grpc_call* call,
                                          grpc_call_credentials* creds) {
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
  grpc_client_security_context* ctx = nullptr;
  GRPC_API_TRACE("grpc_call_set_credentials(call=%p, creds=%p)", 2,
                 (call, creds));
  if (!grpc_call_is_client(call)) {
    gpr_log(GPR_ERROR, "Method is client-side only.");
    return GRPC_CALL_ERROR_NOT_ON_SERVER;
  }
  ctx = (grpc_client_security_context*)grpc_call_context_get(
      call, GRPC_CONTEXT_SECURITY);
  if (ctx == nullptr) {
    ctx = grpc_client_security_context_create();
    ctx->creds = grpc_call_credentials_ref(creds);
    grpc_call_context_set(call, GRPC_CONTEXT_SECURITY, ctx,
                          grpc_client_security_context_destroy);
  } else {
    grpc_call_credentials_unref(&exec_ctx, ctx->creds);
    ctx->creds = grpc_call_credentials_ref(creds);
  }
  grpc_exec_ctx_finish(&exec_ctx);
  return GRPC_CALL_OK;
}

grpc_auth_context* grpc_call_auth_context(grpc_call* call) {
  void* sec_ctx = grpc_call_context_get(call, GRPC_CONTEXT_SECURITY);
  GRPC_API_TRACE("grpc_call_auth_context(call=%p)", 1, (call));
  if (sec_ctx == nullptr) return nullptr;
  return grpc_call_is_client(call)
             ? GRPC_AUTH_CONTEXT_REF(
                   ((grpc_client_security_context*)sec_ctx)->auth_context,
                   "grpc_call_auth_context client")
             : GRPC_AUTH_CONTEXT_REF(
                   ((grpc_server_security_context*)sec_ctx)->auth_context,
                   "grpc_call_auth_context server");
}

void grpc_auth_context_release(grpc_auth_context* context) {
  GRPC_API_TRACE("grpc_auth_context_release(context=%p)", 1, (context));
  GRPC_AUTH_CONTEXT_UNREF(context, "grpc_auth_context_unref");
}

/* --- grpc_client_security_context --- */

grpc_client_security_context* grpc_client_security_context_create(void) {
  return (grpc_client_security_context*)gpr_zalloc(
      sizeof(grpc_client_security_context));
}

void grpc_client_security_context_destroy(void* ctx) {
  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
  grpc_client_security_context* c = (grpc_client_security_context*)ctx;
  grpc_call_credentials_unref(&exec_ctx, c->creds);
  GRPC_AUTH_CONTEXT_UNREF(c->auth_context, "client_security_context");
  if (c->extension.instance != nullptr && c->extension.destroy != nullptr) {
    c->extension.destroy(c->extension.instance);
  }
  gpr_free(ctx);
  grpc_exec_ctx_finish(&exec_ctx);
}

/* --- grpc_server_security_context --- */

grpc_server_security_context* grpc_server_security_context_create(void) {
  return (grpc_server_security_context*)gpr_zalloc(
      sizeof(grpc_server_security_context));
}

void grpc_server_security_context_destroy(void* ctx) {
  grpc_server_security_context* c = (grpc_server_security_context*)ctx;
  GRPC_AUTH_CONTEXT_UNREF(c->auth_context, "server_security_context");
  if (c->extension.instance != nullptr && c->extension.destroy != nullptr) {
    c->extension.destroy(c->extension.instance);
  }
  gpr_free(ctx);
}

/* --- grpc_auth_context --- */

static grpc_auth_property_iterator empty_iterator = {nullptr, 0, nullptr};

grpc_auth_context* grpc_auth_context_create(grpc_auth_context* chained) {
  grpc_auth_context* ctx =
      (grpc_auth_context*)gpr_zalloc(sizeof(grpc_auth_context));
  gpr_ref_init(&ctx->refcount, 1);
  if (chained != nullptr) {
    ctx->chained = GRPC_AUTH_CONTEXT_REF(chained, "chained");
    ctx->peer_identity_property_name =
        ctx->chained->peer_identity_property_name;
  }
  return ctx;
}

#ifndef NDEBUG
grpc_auth_context* grpc_auth_context_ref(grpc_auth_context* ctx,
                                         const char* file, int line,
                                         const char* reason) {
  if (ctx == nullptr) return nullptr;
  if (GRPC_TRACER_ON(grpc_trace_auth_context_refcount)) {
    gpr_atm val = gpr_atm_no_barrier_load(&ctx->refcount.count);
    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
            "AUTH_CONTEXT:%p   ref %" PRIdPTR " -> %" PRIdPTR " %s", ctx, val,
            val + 1, reason);
  }
#else
grpc_auth_context* grpc_auth_context_ref(grpc_auth_context* ctx) {
  if (ctx == NULL) return NULL;
#endif
  gpr_ref(&ctx->refcount);
  return ctx;
}

#ifndef NDEBUG
void grpc_auth_context_unref(grpc_auth_context* ctx, const char* file, int line,
                             const char* reason) {
  if (ctx == nullptr) return;
  if (GRPC_TRACER_ON(grpc_trace_auth_context_refcount)) {
    gpr_atm val = gpr_atm_no_barrier_load(&ctx->refcount.count);
    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
            "AUTH_CONTEXT:%p unref %" PRIdPTR " -> %" PRIdPTR " %s", ctx, val,
            val - 1, reason);
  }
#else
void grpc_auth_context_unref(grpc_auth_context* ctx) {
  if (ctx == NULL) return;
#endif
  if (gpr_unref(&ctx->refcount)) {
    size_t i;
    GRPC_AUTH_CONTEXT_UNREF(ctx->chained, "chained");
    if (ctx->properties.array != nullptr) {
      for (i = 0; i < ctx->properties.count; i++) {
        grpc_auth_property_reset(&ctx->properties.array[i]);
      }
      gpr_free(ctx->properties.array);
    }
    gpr_free(ctx);
  }
}

const char* grpc_auth_context_peer_identity_property_name(
    const grpc_auth_context* ctx) {
  GRPC_API_TRACE("grpc_auth_context_peer_identity_property_name(ctx=%p)", 1,
                 (ctx));
  return ctx->peer_identity_property_name;
}

int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context* ctx,
                                                      const char* name) {
  grpc_auth_property_iterator it =
      grpc_auth_context_find_properties_by_name(ctx, name);
  const grpc_auth_property* prop = grpc_auth_property_iterator_next(&it);
  GRPC_API_TRACE(
      "grpc_auth_context_set_peer_identity_property_name(ctx=%p, name=%s)", 2,
      (ctx, name));
  if (prop == nullptr) {
    gpr_log(GPR_ERROR, "Property name %s not found in auth context.",
            name != nullptr ? name : "NULL");
    return 0;
  }
  ctx->peer_identity_property_name = prop->name;
  return 1;
}

int grpc_auth_context_peer_is_authenticated(const grpc_auth_context* ctx) {
  GRPC_API_TRACE("grpc_auth_context_peer_is_authenticated(ctx=%p)", 1, (ctx));
  return ctx->peer_identity_property_name == nullptr ? 0 : 1;
}

grpc_auth_property_iterator grpc_auth_context_property_iterator(
    const grpc_auth_context* ctx) {
  grpc_auth_property_iterator it = empty_iterator;
  GRPC_API_TRACE("grpc_auth_context_property_iterator(ctx=%p)", 1, (ctx));
  if (ctx == nullptr) return it;
  it.ctx = ctx;
  return it;
}

const grpc_auth_property* grpc_auth_property_iterator_next(
    grpc_auth_property_iterator* it) {
  GRPC_API_TRACE("grpc_auth_property_iterator_next(it=%p)", 1, (it));
  if (it == nullptr || it->ctx == nullptr) return nullptr;
  while (it->index == it->ctx->properties.count) {
    if (it->ctx->chained == nullptr) return nullptr;
    it->ctx = it->ctx->chained;
    it->index = 0;
  }
  if (it->name == nullptr) {
    return &it->ctx->properties.array[it->index++];
  } else {
    while (it->index < it->ctx->properties.count) {
      const grpc_auth_property* prop = &it->ctx->properties.array[it->index++];
      GPR_ASSERT(prop->name != nullptr);
      if (strcmp(it->name, prop->name) == 0) {
        return prop;
      }
    }
    /* We could not find the name, try another round. */
    return grpc_auth_property_iterator_next(it);
  }
}

grpc_auth_property_iterator grpc_auth_context_find_properties_by_name(
    const grpc_auth_context* ctx, const char* name) {
  grpc_auth_property_iterator it = empty_iterator;
  GRPC_API_TRACE("grpc_auth_context_find_properties_by_name(ctx=%p, name=%s)",
                 2, (ctx, name));
  if (ctx == nullptr || name == nullptr) return empty_iterator;
  it.ctx = ctx;
  it.name = name;
  return it;
}

grpc_auth_property_iterator grpc_auth_context_peer_identity(
    const grpc_auth_context* ctx) {
  GRPC_API_TRACE("grpc_auth_context_peer_identity(ctx=%p)", 1, (ctx));
  if (ctx == nullptr) return empty_iterator;
  return grpc_auth_context_find_properties_by_name(
      ctx, ctx->peer_identity_property_name);
}

static void ensure_auth_context_capacity(grpc_auth_context* ctx) {
  if (ctx->properties.count == ctx->properties.capacity) {
    ctx->properties.capacity =
        GPR_MAX(ctx->properties.capacity + 8, ctx->properties.capacity * 2);
    ctx->properties.array = (grpc_auth_property*)gpr_realloc(
        ctx->properties.array,
        ctx->properties.capacity * sizeof(grpc_auth_property));
  }
}

void grpc_auth_context_add_property(grpc_auth_context* ctx, const char* name,
                                    const char* value, size_t value_length) {
  grpc_auth_property* prop;
  GRPC_API_TRACE(
      "grpc_auth_context_add_property(ctx=%p, name=%s, value=%*.*s, "
      "value_length=%lu)",
      6,
      (ctx, name, (int)value_length, (int)value_length, value,
       (unsigned long)value_length));
  ensure_auth_context_capacity(ctx);
  prop = &ctx->properties.array[ctx->properties.count++];
  prop->name = gpr_strdup(name);
  prop->value = (char*)gpr_malloc(value_length + 1);
  memcpy(prop->value, value, value_length);
  prop->value[value_length] = '\0';
  prop->value_length = value_length;
}

void grpc_auth_context_add_cstring_property(grpc_auth_context* ctx,
                                            const char* name,
                                            const char* value) {
  grpc_auth_property* prop;
  GRPC_API_TRACE(
      "grpc_auth_context_add_cstring_property(ctx=%p, name=%s, value=%s)", 3,
      (ctx, name, value));
  ensure_auth_context_capacity(ctx);
  prop = &ctx->properties.array[ctx->properties.count++];
  prop->name = gpr_strdup(name);
  prop->value = gpr_strdup(value);
  prop->value_length = strlen(value);
}

void grpc_auth_property_reset(grpc_auth_property* property) {
  gpr_free(property->name);
  gpr_free(property->value);
  memset(property, 0, sizeof(grpc_auth_property));
}

static void auth_context_pointer_arg_destroy(grpc_exec_ctx* exec_ctx, void* p) {
  GRPC_AUTH_CONTEXT_UNREF((grpc_auth_context*)p, "auth_context_pointer_arg");
}

static void* auth_context_pointer_arg_copy(void* p) {
  return GRPC_AUTH_CONTEXT_REF((grpc_auth_context*)p,
                               "auth_context_pointer_arg");
}

static int auth_context_pointer_cmp(void* a, void* b) { return GPR_ICMP(a, b); }

static const grpc_arg_pointer_vtable auth_context_pointer_vtable = {
    auth_context_pointer_arg_copy, auth_context_pointer_arg_destroy,
    auth_context_pointer_cmp};

grpc_arg grpc_auth_context_to_arg(grpc_auth_context* p) {
  return grpc_channel_arg_pointer_create((char*)GRPC_AUTH_CONTEXT_ARG, p,
                                         &auth_context_pointer_vtable);
}

grpc_auth_context* grpc_auth_context_from_arg(const grpc_arg* arg) {
  if (strcmp(arg->key, GRPC_AUTH_CONTEXT_ARG) != 0) return nullptr;
  if (arg->type != GRPC_ARG_POINTER) {
    gpr_log(GPR_ERROR, "Invalid type %d for arg %s", arg->type,
            GRPC_AUTH_CONTEXT_ARG);
    return nullptr;
  }
  return (grpc_auth_context*)arg->value.pointer.p;
}

grpc_auth_context* grpc_find_auth_context_in_args(
    const grpc_channel_args* args) {
  size_t i;
  if (args == nullptr) return nullptr;
  for (i = 0; i < args->num_args; i++) {
    grpc_auth_context* p = grpc_auth_context_from_arg(&args->args[i]);
    if (p != nullptr) return p;
  }
  return nullptr;
}