/**
 * Copyright (c) 2026 Dominic Masters
 *
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#pragma once
#include "error/error.h"
#include <stddef.h>

// Backed by SAVE.platform.dataBuffer (see savepsp.h) rather than owning its
// own memory - the buffer has to outlive a single saveFileWrite()/Load()
// call, since the actual save/load dialog it's handed to only completes
// several frames later.
typedef struct {
  uint8_t *buffer;
  size_t bufferSize;
  size_t position;
  size_t length;
} savestreampsp_t;

/**
 * Copies len bytes from the buffer at the current position into buf.
 *
 * @param p   Active stream.
 * @param buf Destination buffer.
 * @param len Number of bytes to read.
 * @return An error if the read would exceed the populated data length.
 */
errorret_t saveStreamReadBytesPSP(
  savestreampsp_t *p, void *buf, const size_t len
);

/**
 * Copies len bytes from buf into the buffer at the current position,
 * growing p->length if this write extends past it.
 *
 * @param p   Active stream.
 * @param buf Source buffer.
 * @param len Number of bytes to write.
 * @return An error if the write would exceed bufferSize.
 */
errorret_t saveStreamWriteBytesPSP(
  savestreampsp_t *p, const void *buf, const size_t len
);

/**
 * Sets the current read/write position within the buffer.
 *
 * @param p   Active stream.
 * @param pos Target byte offset from the start of the buffer.
 * @return An error if pos is out of range.
 */
errorret_t saveStreamSeekPSP(savestreampsp_t *p, const size_t pos);

/**
 * Gets the current read/write position within the buffer.
 *
 * @param p   Active stream.
 * @param out Receives the current position.
 * @return An error - always succeeds, matches saveStreamTellImpl's shape.
 */
errorret_t saveStreamTellPSP(savestreampsp_t *p, size_t *out);