/** @file
  This library provides help functions for REST EX Protocol.

  (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include <Uefi.h>
#include <Library/BaseMemoryLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/NetLib.h>
#include <Library/UefiBootServicesTableLib.h>
#include <Protocol/Http.h>
#include <Protocol/RestEx.h>

#define REST_EX_CONFIG_DATA_LEN_UNKNOWN  0xff

/**
  This function allows the caller to create child handle for specific
  REST server.

  @param[in]  Image                The image handle used to open service.
  @param[in]  AccessMode           Access mode of REST server.
  @param[in]  ConfigType           Underlying configuration to communicate with REST server.
  @param[in]  ServiceType          REST service type.
  @param[out] ChildInstanceHandle  The handle to receive the create child.

  @retval  EFI_SUCCESS            Can't create the corresponding REST EX child instance.
  @retval  EFI_INVALID_PARAMETERS Any of input parameters is improper.

**/
EFI_STATUS
RestExLibCreateChild (
  IN EFI_HANDLE                       Image,
  IN EFI_REST_EX_SERVICE_ACCESS_MODE  AccessMode,
  IN EFI_REST_EX_CONFIG_TYPE          ConfigType,
  IN EFI_REST_EX_SERVICE_TYPE         ServiceType,
  OUT EFI_HANDLE                      *ChildInstanceHandle
  )
{
  EFI_STATUS                Status;
  UINTN                     NoBuffer;
  EFI_HANDLE                *Handle;
  EFI_HANDLE                ChildHandle;
  EFI_REST_EX_PROTOCOL      *RestEx;
  EFI_REST_EX_SERVICE_INFO  *RestExServiceInfo;
  UINT8                     LenOfConfig;

  if ((Image == NULL) ||
      (AccessMode >= EfiRestExServiceModeMax) ||
      (ConfigType >= EfiRestExConfigTypeMax) ||
      (ServiceType >= EfiRestExServiceTypeMax) ||
      (ChildInstanceHandle == NULL)
      )
  {
    return EFI_INVALID_PARAMETER;
  }

  *ChildInstanceHandle = NULL;
  //
  // Locate all REST EX binding service.
  //
  Handle   = NULL;
  NoBuffer = 0;
  Status   = gBS->LocateHandleBuffer (
                    ByProtocol,
                    &gEfiRestExServiceBindingProtocolGuid,
                    NULL,
                    &NoBuffer,
                    &Handle
                    );
  if (EFI_ERROR (Status) && (Status != EFI_BUFFER_TOO_SMALL)) {
    return Status;
  }

  Handle = (EFI_HANDLE *)AllocateZeroPool (sizeof (EFI_HANDLE) * NoBuffer);
  if (Handle == NULL) {
    return EFI_OUT_OF_RESOURCES;
  }

  Status = gBS->LocateHandleBuffer (
                  ByProtocol,
                  &gEfiRestExServiceBindingProtocolGuid,
                  NULL,
                  &NoBuffer,
                  &Handle
                  );
  if (EFI_ERROR (Status)) {
    FreePool (Handle);
    return Status;
  }

  //
  // Search for the proper REST EX instance.
  //
  while (NoBuffer != 0) {
    ChildHandle = NULL;
    Status      = NetLibCreateServiceChild (
                    *(Handle + (NoBuffer - 1)),
                    Image,
                    &gEfiRestExServiceBindingProtocolGuid,
                    &ChildHandle
                    );
    if (!EFI_ERROR (Status)) {
      Status = gBS->OpenProtocol (
                      ChildHandle,
                      &gEfiRestExProtocolGuid,
                      (VOID **)&RestEx,
                      Image,
                      NULL,
                      EFI_OPEN_PROTOCOL_GET_PROTOCOL
                      );
      if (EFI_ERROR (Status)) {
        goto ON_ERROR;
      }

      //
      // Get the information of REST service provided by this EFI REST EX driver
      //
      Status = RestEx->GetService (
                         RestEx,
                         &RestExServiceInfo
                         );
      if (EFI_ERROR (Status)) {
        goto ON_ERROR;
      }

      //
      // Check REST EX property.
      //
      switch (ConfigType) {
        case EfiRestExConfigHttp:
          LenOfConfig = sizeof (EFI_REST_EX_HTTP_CONFIG_DATA);
          break;

        case EfiRestExConfigUnspecific:
          LenOfConfig = REST_EX_CONFIG_DATA_LEN_UNKNOWN;
          break;

        default:
          goto ON_ERROR;
      }

      if ((RestExServiceInfo->EfiRestExServiceInfoV10.RestServiceAccessMode != AccessMode) ||
          (RestExServiceInfo->EfiRestExServiceInfoV10.RestServiceType != ServiceType) ||
          (RestExServiceInfo->EfiRestExServiceInfoV10.RestExConfigType != ConfigType) ||
          ((LenOfConfig != REST_EX_CONFIG_DATA_LEN_UNKNOWN) && (RestExServiceInfo->EfiRestExServiceInfoV10.RestExConfigDataLength != LenOfConfig)))
      {
        goto ON_ERROR;
      }
    }

    //
    // This is proper REST EX instance.
    //
    *ChildInstanceHandle = ChildHandle;
    FreePool (Handle);
    return EFI_SUCCESS;

ON_ERROR:;
    NetLibDestroyServiceChild (
      *(Handle + (NoBuffer - 1)),
      Image,
      &gEfiRestExServiceBindingProtocolGuid,
      ChildHandle
      );
    NoBuffer--;
  }

  FreePool (Handle);
  return EFI_NOT_FOUND;
}