/*
 * Copyright 2019 Google LLC. All Rights Reserved. This file and proprietary
 * source code may only be used and distributed under the Widevine Master
 * License Agreement.
 */

#ifndef ODKITEE_MESSAGE_H_
#define ODKITEE_MESSAGE_H_

#ifdef __cplusplus
extern "C" {
#endif

#include <stddef.h>
#include <stdint.h>

typedef struct _Message Message;

/*
 * TODO: there is a dangerous duplication of the MessageStatus
 * enum with odk/src/serialization_base.h. The two need to
 * be converged. Removing the random enum values here, since
 * a proper fix is outside the scope of the current CL. Opened
 * b/158603784.
 */
typedef enum {
  MESSAGE_STATUS_OK,
  MESSAGE_STATUS_UNKNOWN_ERROR,
  MESSAGE_STATUS_OVERFLOW_ERROR,
  MESSAGE_STATUS_UNDERFLOW_ERROR,
  MESSAGE_STATUS_PARSE_ERROR,
  MESSAGE_STATUS_NULL_POINTER_ERROR,
  MESSAGE_STATUS_API_VALUE_ERROR,
  MESSAGE_STATUS_INVALID_TAG_ERROR,
  MESSAGE_STATUS_END_OF_MESSAGE_ERROR,
  MESSAGE_STATUS_INVALID_ENUM_VALUE
} MessageStatus;

/*
 * Create a message from a buffer. The message structure consumes the first
 * sizeof(Message) bytes of the buffer. The caller is responsible for ensuring
 * that the buffer remains allocated for the lifetime of the message.
 */
Message* CreateMessage(uint8_t* buffer, size_t buffer_size);

/*
 * Initialize a message structure to reference a separate buffer. The caller
 * is responsible for ensuring that the buffer remains allocated for the
 * lifetime of the message.
 */
void InitMessage(Message* message, uint8_t* buffer, size_t capacity);

/*
 * Erase the contents of the message, set it
 * to an empty state.
 */
void ClearMessage(Message* message);

/*
 * Reset read pointer to the beginning of the
 * message and clear status
 */
void ResetMessage(Message* message);

/*
 * The message base is the start of the payload
 */
uint8_t* GetBase(Message* message);

/*
 * Get the maximum number of bytes the message
 * can hold.
 */
size_t GetCapacity(Message* message);

/*
 * Get the number of bytes currently in the
 * message
 */
size_t GetSize(Message* message);

/*
 * Return the status of the message
 */
MessageStatus GetStatus(Message* message);

/*
 * Set the message status to a specific value
 */
void SetStatus(Message* message, MessageStatus status);

/*
 * Set the size of the message to a value. This
 * may be needed after writing data into the payload.
 */
void SetSize(Message*message, size_t size);

#ifdef __cplusplus
}  // extern "C"
#endif

#endif  // ODKITEE_MESSAGE_H_