/*
* Copyright 2020 sysmocom - s.f.m.c. GmbH <info@sysmocom.de>
* Author: Pau Espin Pedrol <pespin@sysmocom.de>
*
* SPDX-License-Identifier: 0BSD
*
* Permission to use, copy, modify, and/or distribute this software for any purpose
* with or without fee is hereby granted.THE SOFTWARE IS PROVIDED "AS IS" AND THE
* AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
* BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
* CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE
* USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#include <stdint.h>
#include <stddef.h>
#include <osmocom/core/talloc.h>

#include "shm.h"

#define ENCDECDEBUG(...) //fprintf(stderr, __VA_ARGS__)

/* Convert offsets to pointers */
struct ipc_shm_stream *ipc_shm_decode_stream(void *tall_ctx, struct ipc_shm_raw_region *root_raw,
					     struct ipc_shm_raw_stream *stream_raw)
{
	unsigned int i;
	struct ipc_shm_stream *stream;
	stream = talloc_zero(tall_ctx, struct ipc_shm_stream);
	stream = talloc_zero_size(tall_ctx, sizeof(struct ipc_shm_stream) +
						    sizeof(struct ipc_shm_raw_smpl_buf *) * stream_raw->num_buffers);
	if (!stream)
		return NULL;
	stream->num_buffers = stream_raw->num_buffers;
	stream->buffer_size = stream_raw->buffer_size;
	stream->raw = stream_raw;
	for (i = 0; i < stream->num_buffers; i++) {
		ENCDECDEBUG("decode: smpl_buf %d at offset %u\n", i, stream_raw->buffer_offset[i]);
		stream->buffers[i] =
			(struct ipc_shm_raw_smpl_buf *)(((uint8_t *)root_raw) + stream_raw->buffer_offset[i]);
	}
	return stream;
}

struct ipc_shm_channel *ipc_shm_decode_channel(void *tall_ctx, struct ipc_shm_raw_region *root_raw,
					       struct ipc_shm_raw_channel *chan_raw)
{
	struct ipc_shm_channel *chan;
	chan = talloc_zero(tall_ctx, struct ipc_shm_channel);
	if (!chan)
		return NULL;
	ENCDECDEBUG("decode: streams at offset %u and %u\n", chan_raw->dl_buf_offset, chan_raw->ul_buf_offset);
	chan->dl_stream = ipc_shm_decode_stream(
		chan, root_raw, (struct ipc_shm_raw_stream *)(((uint8_t *)root_raw) + chan_raw->dl_buf_offset));
	chan->ul_stream = ipc_shm_decode_stream(
		chan, root_raw, (struct ipc_shm_raw_stream *)(((uint8_t *)root_raw) + chan_raw->ul_buf_offset));
	return chan;
}
struct ipc_shm_region *ipc_shm_decode_region(void *tall_ctx, struct ipc_shm_raw_region *root_raw)
{
	unsigned int i;
	struct ipc_shm_region *root;
	root = talloc_zero_size(tall_ctx,
				sizeof(struct ipc_shm_region) + sizeof(struct ipc_shm_channel *) * root_raw->num_chans);
	if (!root)
		return NULL;

	root->num_chans = root_raw->num_chans;
	for (i = 0; i < root->num_chans; i++) {
		ENCDECDEBUG("decode: channel %d at offset %u\n", i, root_raw->chan_offset[i]);
		root->channels[i] = ipc_shm_decode_channel(
			root, root_raw,
			(struct ipc_shm_raw_channel *)(((uint8_t *)root_raw) + root_raw->chan_offset[i]));
	}
	return root;
}

unsigned int ipc_shm_encode_smpl_buf(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_smpl_buf *smpl_buf_raw,
				     uint32_t buffer_size)
{
	unsigned int offset = sizeof(struct ipc_shm_raw_smpl_buf);
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
	ENCDECDEBUG("encode: smpl_buf at offset %u\n", offset);
	offset += buffer_size * sizeof(uint16_t) * 2; /* samples */
	return offset;
}

unsigned int ipc_shm_encode_stream(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_stream *stream_raw,
				   uint32_t num_buffers, uint32_t buffer_size)
{
	unsigned int i;
	ptrdiff_t start = (ptrdiff_t)stream_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_stream) + sizeof(uint32_t) * num_buffers;
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
	ENCDECDEBUG("encode: stream at offset %lu\n", (start - (ptrdiff_t)root_raw));
	if (root_raw) {
		stream_raw->num_buffers = num_buffers;
		stream_raw->buffer_size = buffer_size;
		stream_raw->read_next = 0;
		stream_raw->write_next = 0;
	}
	for (i = 0; i < num_buffers; i++) {
		if (root_raw)
			stream_raw->buffer_offset[i] = (start + offset - (ptrdiff_t)root_raw);
		offset +=
			ipc_shm_encode_smpl_buf(root_raw, (struct ipc_shm_raw_smpl_buf *)(start + offset), buffer_size);
	}
	return offset;
}
unsigned int ipc_shm_encode_channel(struct ipc_shm_raw_region *root_raw, struct ipc_shm_raw_channel *chan_raw,
				    uint32_t num_buffers, uint32_t buffer_size)
{
	uint8_t *start = (uint8_t *)chan_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_channel);
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);
	ENCDECDEBUG("encode: channel at offset %lu\n", (start - (uint8_t *)root_raw));
	if (root_raw)
		chan_raw->dl_buf_offset = (start + offset - (uint8_t *)root_raw);
	offset += ipc_shm_encode_stream(root_raw, (struct ipc_shm_raw_stream *)(start + offset), num_buffers,
					buffer_size);
	if (root_raw)
		chan_raw->ul_buf_offset = (start + offset - (uint8_t *)root_raw);
	offset += ipc_shm_encode_stream(root_raw, (struct ipc_shm_raw_stream *)(start + offset), num_buffers,
					buffer_size);
	return offset;
}
/* if root_raw is NULL, then do a dry run, aka only calculate final offset */
unsigned int ipc_shm_encode_region(struct ipc_shm_raw_region *root_raw, uint32_t num_chans, uint32_t num_buffers,
				   uint32_t buffer_size)
{
	unsigned i;
	uintptr_t start = (uintptr_t)root_raw;
	unsigned int offset = sizeof(struct ipc_shm_raw_region) + sizeof(uint32_t) * num_chans;
	offset = (((uintptr_t)offset + 7) & ~0x07ULL);

	if (root_raw)
		root_raw->num_chans = num_chans;
	for (i = 0; i < num_chans; i++) {
		if (root_raw)
			root_raw->chan_offset[i] = (start + offset - (uintptr_t)root_raw);
		ENCDECDEBUG("encode: channel %d chan_offset[i]=%lu\n", i, start + offset - (uintptr_t)root_raw);
		offset += ipc_shm_encode_channel(root_raw, (struct ipc_shm_raw_channel *)(start + offset), num_buffers,
						 buffer_size);
	}
	//TODO: pass maximum size and verify we didn't go through
	return offset;
}