/*
 * Copyright (c) 2021 Demant
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr.h>
#include <sys/byteorder.h>

#include "util/mem.h"
#include "util/memq.h"
#include "util/mayfly.h"
#include "ticker/ticker.h"
#include "hal/ccm.h"
#include "hal/ticker.h"

#include "pdu.h"
#include "lll.h"
#include "lll_conn.h"
#include "ull_conn_types.h"
#include "lll_conn_iso.h"
#include "ull_conn_iso_types.h"
#include "ull_conn_internal.h"
#include "ull_conn_iso_internal.h"
#include "ull_internal.h"
#include "lll/lll_vendor.h"

#define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_HCI_DRIVER)
#define LOG_MODULE_NAME bt_ctlr_ull_conn_iso
#include "common/log.h"
#include "hal/debug.h"

#define LAST_VALID_CIS_HANDLE (CONFIG_BT_CTLR_CONN_ISO_STREAMS + LL_CIS_HANDLE_BASE - 1)

static int init_reset(void);
static void ticker_update_cig_op_cb(uint32_t status, void *param);
static void ticker_resume_op_cb(uint32_t status, void *param);
static void ticker_resume_cb(uint32_t ticks_at_expire, uint32_t ticks_drift,
			     uint32_t remainder, uint16_t lazy, uint8_t force,
			     void *param);
static void cis_disabled_cb(void *param);
static void ticker_stop_op_cb(uint32_t status, void *param);
static void cig_disable(void *param);
static void cig_disabled_cb(void *param);

static struct ll_conn_iso_stream cis_pool[CONFIG_BT_CTLR_CONN_ISO_STREAMS];
static void *cis_free;

static struct ll_conn_iso_group cig_pool[CONFIG_BT_CTLR_CONN_ISO_GROUPS];
static void *cig_free;

struct ll_conn_iso_group *ll_conn_iso_group_acquire(void)
{
	return mem_acquire(&cig_free);
}

void ll_conn_iso_group_release(struct ll_conn_iso_group *cig)
{
	mem_release(cig, &cig_free);
}

uint16_t ll_conn_iso_group_handle_get(struct ll_conn_iso_group *cig)
{
	return mem_index_get(cig, cig_pool, sizeof(struct ll_conn_iso_group));
}

struct ll_conn_iso_group *ll_conn_iso_group_get(uint16_t handle)
{
	return mem_get(cig_pool, sizeof(struct ll_conn_iso_group), handle);
}

struct ll_conn_iso_group *ll_conn_iso_group_get_by_id(uint8_t id)
{
	struct ll_conn_iso_group *cig;

	for (int h = 0; h < CONFIG_BT_CTLR_CONN_ISO_GROUPS; h++) {
		cig = ll_conn_iso_group_get(h);
		if (id == cig->cig_id) {
			return cig;
		}
	}

	return NULL;
}

struct ll_conn_iso_stream *ll_conn_iso_stream_acquire(void)
{
	return mem_acquire(&cis_free);
}

void ll_conn_iso_stream_release(struct ll_conn_iso_stream *cis)
{
	mem_release(cis, &cig_free);
}

uint16_t ll_conn_iso_stream_handle_get(struct ll_conn_iso_stream *cis)
{
	return mem_index_get(cis, cis_pool,
			     sizeof(struct ll_conn_iso_stream)) +
			     LL_CIS_HANDLE_BASE;
}

struct ll_conn_iso_stream *ll_conn_iso_stream_get(uint16_t handle)
{
	return mem_get(cis_pool, sizeof(struct ll_conn_iso_stream), handle -
		       LL_CIS_HANDLE_BASE);
}

struct ll_conn_iso_stream *ll_iso_stream_connected_get(uint16_t handle)
{
	struct ll_conn_iso_stream *cis;

	if (handle >= CONFIG_BT_CTLR_CONN_ISO_STREAMS +
		      LL_CIS_HANDLE_BASE) {
		return NULL;
	}

	cis = ll_conn_iso_stream_get(handle);
	if (cis->lll.handle != handle) {
		return NULL;
	}

	return cis;
}

struct ll_conn_iso_stream *ll_conn_iso_stream_get_by_acl(struct ll_conn *conn, uint16_t *cis_iter)
{
	uint8_t cis_iter_start = (cis_iter == NULL) || (*cis_iter) == UINT16_MAX;
	uint8_t cig_handle;

	/* Find CIS associated with ACL conn */
	for (cig_handle = 0; cig_handle < CONFIG_BT_CTLR_CONN_ISO_GROUPS; cig_handle++) {
		struct ll_conn_iso_stream *cis;
		struct ll_conn_iso_group *cig;
		uint16_t handle_iter;
		int8_t cis_idx;

		cig = ll_conn_iso_group_get(cig_handle);
		if (!cig) {
			continue;
		}

		handle_iter = UINT16_MAX;

		for (cis_idx = 0; cis_idx < cig->lll.num_cis; cis_idx++) {
			cis = ll_conn_iso_stream_get_by_group(cig, &handle_iter);
			LL_ASSERT(cis);

			uint16_t cis_handle = cis->lll.handle;

			cis = ll_iso_stream_connected_get(cis_handle);
			if (!cis) {
				continue;
			}

			if (!cis_iter_start) {
				/* Look for iterator start handle */
				cis_iter_start = cis_handle == (*cis_iter);
			} else if (cis->lll.acl_handle == conn->lll.handle) {
				if (cis_iter) {
					(*cis_iter) = cis_handle;
				}
				return cis;
			}
		}
	}

	return NULL;
}

struct ll_conn_iso_stream *ll_conn_iso_stream_get_by_group(struct ll_conn_iso_group *cig,
							   uint16_t *handle_iter)
{
	struct ll_conn_iso_stream *cis;
	uint16_t handle_start;
	uint16_t handle;

	handle_start = (handle_iter == NULL) || ((*handle_iter) == UINT16_MAX) ?
			LL_CIS_HANDLE_BASE : (*handle_iter) + 1;

	for (handle = handle_start; handle <= LAST_VALID_CIS_HANDLE; handle++) {
		cis = ll_conn_iso_stream_get(handle);
		if (cis->group == cig) {
			if (handle_iter) {
				(*handle_iter) = handle;
			}
			return cis;
		}
	}

	return NULL;
}

void ull_conn_iso_cis_established(struct ll_conn_iso_stream *cis)
{
	struct node_rx_conn_iso_estab *est;
	struct node_rx_pdu *node_rx;

	node_rx = ull_pdu_rx_alloc();
	if (!node_rx) {
		/* No node available - try again later */
		return;
	}

	/* TODO: Send CIS_ESTABLISHED with status != 0 in error scenarios */
	node_rx->hdr.type = NODE_RX_TYPE_CIS_ESTABLISHED;
	node_rx->hdr.handle = 0xFFFF;
	node_rx->hdr.rx_ftr.param = cis;

	est = (void *)node_rx->pdu;
	est->status = 0;
	est->cis_handle = sys_le16_to_cpu(cis->lll.handle);

	ll_rx_put(node_rx->hdr.link, node_rx);
	ll_rx_sched();

	cis->established = 1;
}

void ull_conn_iso_done(struct node_rx_event_done *done)
{
	struct lll_conn_iso_group *lll;
	struct ll_conn_iso_group *cig;
	uint32_t ticks_drift_minus;
	uint32_t ticks_drift_plus;

	/* Get reference to ULL context */
	cig = CONTAINER_OF(done->param, struct ll_conn_iso_group, ull);
	lll = &cig->lll;

	/* Skip if CIG terminated by local host */
	if (unlikely(lll->handle == 0xFFFF)) {
		return;
	}

	ticks_drift_plus  = 0;
	ticks_drift_minus = 0;

	if (done->extra.trx_cnt) {
		if (IS_ENABLED(CONFIG_BT_CTLR_PERIPHERAL_ISO) && lll->role) {
			ull_drift_ticks_get(done, &ticks_drift_plus,
					    &ticks_drift_minus);
		}
	}

	/* Update CIG ticker to compensate for drift */
	if (ticks_drift_plus || ticks_drift_minus) {
		uint8_t ticker_id = TICKER_ID_CONN_ISO_BASE +
				    ll_conn_iso_group_handle_get(cig);
		struct ll_conn *conn = lll->hdr.parent;
		uint32_t ticker_status;

		ticker_status = ticker_update(TICKER_INSTANCE_ID_CTLR,
					      TICKER_USER_ID_ULL_HIGH,
					      ticker_id,
					      ticks_drift_plus,
					      ticks_drift_minus, 0, 0,
					      TICKER_NULL_LAZY, 0,
					      ticker_update_cig_op_cb,
					      cig);

		LL_ASSERT((ticker_status == TICKER_STATUS_SUCCESS) ||
			  (ticker_status == TICKER_STATUS_BUSY) ||
			  ((void *)conn == ull_disable_mark_get()));
	}
}

/**
 * @brief Stop and tear down a connected ISO stream
 * This function may be called to tear down a CIS. When the CIS teardown
 * has completed and the stream is released and callback is provided, the
 * cis_released_cb callback is invoked.
 *
 * @param cis		 Pointer to connected ISO stream to stop
 * @param cis_relased_cb Callback to invoke when the CIS has been released.
 *                       NULL to ignore.
 */
void ull_conn_iso_cis_stop(struct ll_conn_iso_stream *cis,
			   ll_iso_stream_released_cb_t cis_released_cb)
{
	struct ll_conn_iso_group *cig;
	struct ull_hdr *hdr;

	if (cis->teardown) {
		/* Teardown already started */
		return;
	}
	cis->teardown = 1;
	cis->released_cb = cis_released_cb;

	/* Check ref count to determine if any pending LLL events in pipeline */
	cig = cis->group;
	hdr = &cig->ull;
	if (ull_ref_get(hdr)) {
		static memq_link_t link;
		static struct mayfly mfy = {0, 0, &link, NULL, lll_disable};
		uint32_t ret;

		mfy.param = &cig->lll;

		/* Setup disabled callback to be called when ref count
		 * returns to zero.
		 */
		/* Event is active (prepare/done ongoing) - wait for done and
		 * continue CIS teardown from there. The disabled_cb cannot be
		 * reserved for other use.
		 */
		LL_ASSERT(!hdr->disabled_cb ||
			  (hdr->disabled_cb == cis_disabled_cb));
		hdr->disabled_param = mfy.param;
		hdr->disabled_cb = cis_disabled_cb;

		/* Trigger LLL disable */
		ret = mayfly_enqueue(TICKER_USER_ID_ULL_HIGH,
				     TICKER_USER_ID_LLL, 0, &mfy);
		LL_ASSERT(!ret);
	} else {
		/* No pending LLL events */

		/* Tear down CIS now in ULL_HIGH context. Ignore enqueue
		 * error (already enqueued) as all CISes marked for teardown
		 * will be handled in cis_disabled_cb. Use mayfly chaining to
		 * prevent recursive stop calls.
		 */
		cis_disabled_cb(&cig->lll);
	}
}

void ull_conn_iso_resume_ticker_start(struct lll_event *resume_event,
				      uint16_t cis_handle,
				      uint32_t ticks_anchor,
				      uint32_t resume_timeout)
{
	struct lll_conn_iso_group *cig;
	uint32_t ready_delay_us;
	uint32_t resume_delay_us;
	int32_t resume_offset_us;
	uint8_t ticker_id;
	uint32_t ret;

	cig = resume_event->prepare_param.param;
	ticker_id = TICKER_ID_CONN_ISO_RESUME_BASE + cig->handle;

	cig->resume_cis = cis_handle;

	if (0) {
#if defined(CONFIG_BT_CTLR_PHY)
	} else {
		struct ll_conn_iso_stream *cis;
		struct ll_conn *acl;

		cis = ll_conn_iso_stream_get(cis_handle);
		acl = ll_conn_get(cis->lll.acl_handle);

		ready_delay_us = lll_radio_rx_ready_delay_get(acl->lll.phy_rx, 1);
#else
	} else {
		ready_delay_us = lll_radio_rx_ready_delay_get(0, 0);
#endif /* CONFIG_BT_CTLR_PHY */
	}

	resume_delay_us  = EVENT_OVERHEAD_START_US;
	resume_delay_us += EVENT_TICKER_RES_MARGIN_US;
	resume_delay_us += EVENT_JITTER_US;
	resume_delay_us += ready_delay_us;

	resume_offset_us = (int32_t)(resume_timeout - resume_delay_us);
	LL_ASSERT(resume_offset_us >= 0);

	/* Setup resume timeout as single-shot */
	ret = ticker_start(TICKER_INSTANCE_ID_CTLR,
			   TICKER_USER_ID_LLL,
			   ticker_id,
			   ticks_anchor,
			   HAL_TICKER_US_TO_TICKS(resume_offset_us),
			   TICKER_NULL_PERIOD,
			   TICKER_NULL_REMAINDER,
			   TICKER_NULL_LAZY,
			   TICKER_NULL_SLOT,
			   ticker_resume_cb, resume_event,
			   ticker_resume_op_cb, NULL);

	LL_ASSERT((ret == TICKER_STATUS_SUCCESS) ||
		  (ret == TICKER_STATUS_BUSY));
}

int ull_conn_iso_init(void)
{
	return init_reset();
}

int ull_conn_iso_reset(void)
{
	return init_reset();
}

static int init_reset(void)
{
	int err;

	/* Initialize CIS pool */
	mem_init(cis_pool, sizeof(struct ll_conn_iso_stream),
		 sizeof(cis_pool) / sizeof(struct ll_conn_iso_stream),
		 &cis_free);

	/* Initialize CIG pool */
	mem_init(cig_pool, sizeof(struct ll_conn_iso_group),
		 sizeof(cig_pool) / sizeof(struct ll_conn_iso_group),
		 &cig_free);

	for (int h = 0; h < CONFIG_BT_CTLR_CONN_ISO_GROUPS; h++) {
		ll_conn_iso_group_get(h)->cig_id = 0xFF;
	}

	/* Initialize LLL */
	err = lll_conn_iso_init();
	if (err) {
		return err;
	}

	return 0;
}

static void ticker_update_cig_op_cb(uint32_t status, void *param)
{
	/* CIG drift compensation succeeds, or it fails in a race condition
	 * when disconnecting (race between ticker_update and ticker_stop
	 * calls). TODO: Are the race-checks needed?
	 */
	LL_ASSERT(status == TICKER_STATUS_SUCCESS ||
		  param == ull_update_mark_get() ||
		  param == ull_disable_mark_get());
}

static void ticker_resume_op_cb(uint32_t status, void *param)
{
	ARG_UNUSED(param);

	LL_ASSERT(status == TICKER_STATUS_SUCCESS);
}

static void ticker_resume_cb(uint32_t ticks_at_expire, uint32_t ticks_drift,
			     uint32_t remainder, uint16_t lazy, uint8_t force,
			     void *param)
{
	static memq_link_t link;
	static struct mayfly mfy = {0, 0, &link, NULL, lll_resume};
	struct lll_event *resume_event;
	uint32_t ret;

	ARG_UNUSED(ticks_drift);
	LL_ASSERT(lazy == 0);

	resume_event = param;

	/* Append timing parameters */
	resume_event->prepare_param.ticks_at_expire = ticks_at_expire;
	resume_event->prepare_param.remainder = remainder;
	resume_event->prepare_param.lazy = 0;
	resume_event->prepare_param.force = force;
	mfy.param = resume_event;

	/* Kick LLL resume */
	ret = mayfly_enqueue(TICKER_USER_ID_ULL_HIGH, TICKER_USER_ID_LLL,
			     0, &mfy);

	LL_ASSERT(!ret);
}

static void cis_disabled_cb(void *param)
{
	struct ll_conn_iso_group *cig;
	struct ll_conn_iso_stream *cis;
	uint32_t ticker_status;
	uint16_t handle_iter;
	uint8_t is_last_cis;
	uint8_t cis_idx;

	cig = HDR_LLL2ULL(param);
	is_last_cis = cig->lll.num_cis == 1;
	handle_iter = UINT16_MAX;

	/* Remove all CISes marked for teardown */
	for (cis_idx = 0; cis_idx < cig->lll.num_cis; cis_idx++) {
		cis = ll_conn_iso_stream_get_by_group(cig, &handle_iter);
		LL_ASSERT(cis);

		if (cis->teardown) {
			struct ll_conn *conn;
			ll_iso_stream_released_cb_t cis_released_cb;

			conn = ll_conn_get(cis->lll.acl_handle);
			cis_released_cb = cis->released_cb;

			ll_conn_iso_stream_release(cis);
			cig->lll.num_cis--;

			/* Check if removed CIS had an ACL disassociation callback. Invoke
			 * the callback to allow cleanup.
			 */
			if (cis_released_cb) {
				/* CIS removed - notify caller */
				cis_released_cb(conn);
			}
		}
	}

	if (is_last_cis && cig->lll.num_cis == 0) {
		/* This was the last CIS of the CIG. Initiate CIG teardown by
		 * stopping ticker.
		 */
		ticker_status = ticker_stop(TICKER_INSTANCE_ID_CTLR,
					    TICKER_USER_ID_ULL_HIGH,
					    TICKER_ID_CONN_ISO_BASE +
					    ll_conn_iso_group_handle_get(cig),
					    ticker_stop_op_cb,
					    cig);

		LL_ASSERT((ticker_status == TICKER_STATUS_SUCCESS) ||
			  (ticker_status == TICKER_STATUS_BUSY));
	}
}

static void ticker_stop_op_cb(uint32_t status, void *param)
{
	static memq_link_t link;
	static struct mayfly mfy = {0, 0, &link, NULL, cig_disable};
	uint32_t ret;

	/* Assert if race between thread and ULL */
	LL_ASSERT(status == TICKER_STATUS_SUCCESS);

	/* Check if any pending LLL events that need to be aborted */
	mfy.param = param;
	ret = mayfly_enqueue(TICKER_USER_ID_ULL_LOW,
			     TICKER_USER_ID_ULL_HIGH, 0, &mfy);
	LL_ASSERT(!ret);
}

static void cig_disable(void *param)
{
	struct ll_conn_iso_group *cig;
	struct ull_hdr *hdr;

	/* Check ref count to determine if any pending LLL events in pipeline */
	cig = param;
	hdr = &cig->ull;
	if (ull_ref_get(hdr)) {
		static memq_link_t link;
		static struct mayfly mfy = {0, 0, &link, NULL, lll_disable};
		uint32_t ret;

		mfy.param = &cig->lll;

		/* Setup disabled callback to be called when ref count
		 * returns to zero.
		 */
		LL_ASSERT(!hdr->disabled_cb);
		hdr->disabled_param = mfy.param;
		hdr->disabled_cb = cig_disabled_cb;

		/* Trigger LLL disable */
		ret = mayfly_enqueue(TICKER_USER_ID_ULL_HIGH,
				     TICKER_USER_ID_LLL, 0, &mfy);
		LL_ASSERT(!ret);
	} else {
		/* No pending LLL events */
		cig_disabled_cb(&cig->lll);
	}
}

static void cig_disabled_cb(void *param)
{
	struct ll_conn_iso_group *cig;

	cig = HDR_LLL2ULL(param);

	ll_conn_iso_group_release(cig);

	/* TODO: Flush pending TX in LLL */
}