/*
 * Copyright (c) 2020 Manivannan Sadhasivam <mani@kernel.org>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <init.h>
#include <errno.h>
#include <lorawan/lorawan.h>
#include <zephyr.h>

#include "lw_priv.h"

#include <LoRaMac.h>

BUILD_ASSERT(!IS_ENABLED(CONFIG_LORAMAC_REGION_UNKNOWN),
	     "Unknown region specified for LoRaWAN in Kconfig");

#ifdef CONFIG_LORAMAC_REGION_AS923
	#define LORAWAN_REGION LORAMAC_REGION_AS923
#elif CONFIG_LORAMAC_REGION_AU915
	#define LORAWAN_REGION LORAMAC_REGION_AU915
#elif CONFIG_LORAMAC_REGION_CN470
	#define LORAWAN_REGION LORAMAC_REGION_CN470
#elif CONFIG_LORAMAC_REGION_CN779
	#define LORAWAN_REGION LORAMAC_REGION_CN779
#elif CONFIG_LORAMAC_REGION_EU433
	#define LORAWAN_REGION LORAMAC_REGION_EU433
#elif CONFIG_LORAMAC_REGION_EU868
	#define LORAWAN_REGION LORAMAC_REGION_EU868
#elif CONFIG_LORAMAC_REGION_KR920
	#define LORAWAN_REGION LORAMAC_REGION_KR920
#elif CONFIG_LORAMAC_REGION_IN865
	#define LORAWAN_REGION LORAMAC_REGION_IN865
#elif CONFIG_LORAMAC_REGION_US915
	#define LORAWAN_REGION LORAMAC_REGION_US915
#elif CONFIG_LORAMAC_REGION_RU864
	#define LORAWAN_REGION LORAMAC_REGION_RU864
#else
	#error "At least one LoRaWAN region should be selected"
#endif

/* Use version 1.0.3.0 for ABP */
#define LORAWAN_ABP_VERSION 0x01000300

#define LOG_LEVEL CONFIG_LORAWAN_LOG_LEVEL
#include <logging/log.h>
LOG_MODULE_REGISTER(lorawan);

K_SEM_DEFINE(mlme_confirm_sem, 0, 1);
K_SEM_DEFINE(mcps_confirm_sem, 0, 1);

K_MUTEX_DEFINE(lorawan_join_mutex);
K_MUTEX_DEFINE(lorawan_send_mutex);

/* We store both the default datarate requested through lorawan_set_datarate
 * and the current datarate so that we can use the default datarate for all
 * join requests, even as the current datarate changes due to ADR.
 */
static enum lorawan_datarate default_datarate;
static enum lorawan_datarate current_datarate;
static uint8_t lorawan_conf_msg_tries = 1;
static bool lorawan_adr_enable;

static sys_slist_t dl_callbacks;

static LoRaMacPrimitives_t macPrimitives;
static LoRaMacCallback_t macCallbacks;

static LoRaMacEventInfoStatus_t last_mcps_confirm_status;
static LoRaMacEventInfoStatus_t last_mlme_confirm_status;
static LoRaMacEventInfoStatus_t last_mcps_indication_status;
static LoRaMacEventInfoStatus_t last_mlme_indication_status;

static uint8_t (*getBatteryLevelUser)(void);
static void (*dr_change_cb)(enum lorawan_datarate dr);

static uint8_t getBatteryLevelLocal(void)
{
	if (getBatteryLevelUser != NULL) {
		return getBatteryLevelUser();
	}

	return 255;
}

static void OnMacProcessNotify(void)
{
	LoRaMacProcess();
}

static void datarate_observe(bool force_notification)
{
	MibRequestConfirm_t mibGet;

	mibGet.Type = MIB_CHANNELS_DATARATE;
	LoRaMacMibGetRequestConfirm(&mibGet);

	if ((mibGet.Param.ChannelsDatarate != current_datarate) ||
	    (force_notification)) {
		current_datarate = mibGet.Param.ChannelsDatarate;
		if (dr_change_cb) {
			dr_change_cb(current_datarate);
		}
		LOG_INF("Datarate changed: DR_%d", current_datarate);
	}
}

static void McpsConfirm(McpsConfirm_t *mcpsConfirm)
{
	LOG_DBG("Received McpsConfirm (for McpsRequest %d)",
		mcpsConfirm->McpsRequest);

	if (mcpsConfirm->Status != LORAMAC_EVENT_INFO_STATUS_OK) {
		LOG_ERR("McpsRequest failed : %s",
			lorawan_eventinfo2str(mcpsConfirm->Status));
	} else {
		LOG_DBG("McpsRequest success!");
	}

	/* Datarate may have changed due to a missed ADRACK */
	if (lorawan_adr_enable) {
		datarate_observe(false);
	}

	last_mcps_confirm_status = mcpsConfirm->Status;
	k_sem_give(&mcps_confirm_sem);
}

static void McpsIndication(McpsIndication_t *mcpsIndication)
{
	struct lorawan_downlink_cb *cb;

	LOG_DBG("Received McpsIndication %d", mcpsIndication->McpsIndication);

	if (mcpsIndication->Status != LORAMAC_EVENT_INFO_STATUS_OK) {
		LOG_ERR("McpsIndication failed : %s",
			lorawan_eventinfo2str(mcpsIndication->Status));
		return;
	}

	/* Datarate can change as result of ADR command from server */
	if (lorawan_adr_enable) {
		datarate_observe(false);
	}

	/* Iterate over all registered downlink callbacks */
	SYS_SLIST_FOR_EACH_CONTAINER(&dl_callbacks, cb, node) {
		if ((cb->port == LW_RECV_PORT_ANY) ||
		    (cb->port == mcpsIndication->Port)) {
			cb->cb(mcpsIndication->Port,
			       !!mcpsIndication->FramePending,
			       mcpsIndication->Rssi, mcpsIndication->Snr,
			       mcpsIndication->BufferSize,
			       mcpsIndication->Buffer);
		}
	}

	last_mcps_indication_status = mcpsIndication->Status;
}

static void MlmeConfirm(MlmeConfirm_t *mlmeConfirm)
{
	MibRequestConfirm_t mibGet;

	LOG_DBG("Received MlmeConfirm (for MlmeRequest %d)",
		mlmeConfirm->MlmeRequest);

	if (mlmeConfirm->Status != LORAMAC_EVENT_INFO_STATUS_OK) {
		LOG_ERR("MlmeConfirm failed : %s",
			lorawan_eventinfo2str(mlmeConfirm->Status));
		goto out_sem;
	}

	switch (mlmeConfirm->MlmeRequest) {
	case MLME_JOIN:
		mibGet.Type = MIB_DEV_ADDR;
		LoRaMacMibGetRequestConfirm(&mibGet);
		LOG_INF("Joined network! DevAddr: %08x", mibGet.Param.DevAddr);
		break;
	case MLME_LINK_CHECK:
		/* Not implemented */
		LOG_INF("Link check not implemented yet!");
		break;
	default:
		break;
	}

out_sem:
	last_mlme_confirm_status = mlmeConfirm->Status;
	k_sem_give(&mlme_confirm_sem);
}

static void MlmeIndication(MlmeIndication_t *mlmeIndication)
{
	LOG_DBG("Received MlmeIndication %d", mlmeIndication->MlmeIndication);
	last_mlme_indication_status = mlmeIndication->Status;
}

static LoRaMacStatus_t lorawan_join_otaa(
	const struct lorawan_join_config *join_cfg)
{
	MlmeReq_t mlme_req;
	MibRequestConfirm_t mib_req;

	mlme_req.Type = MLME_JOIN;
	mlme_req.Req.Join.Datarate = default_datarate;

	mib_req.Type = MIB_DEV_EUI;
	mib_req.Param.DevEui = join_cfg->dev_eui;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_JOIN_EUI;
	mib_req.Param.JoinEui = join_cfg->otaa.join_eui;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_NWK_KEY;
	mib_req.Param.NwkKey = join_cfg->otaa.nwk_key;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_APP_KEY;
	mib_req.Param.JoinEui = join_cfg->otaa.app_key;
	LoRaMacMibSetRequestConfirm(&mib_req);

	return LoRaMacMlmeRequest(&mlme_req);
}

static LoRaMacStatus_t lorawan_join_abp(
	const struct lorawan_join_config *join_cfg)
{
	MibRequestConfirm_t mib_req;

	mib_req.Type = MIB_ABP_LORAWAN_VERSION;
	mib_req.Param.AbpLrWanVersion.Value = LORAWAN_ABP_VERSION;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_NET_ID;
	mib_req.Param.NetID = 0;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_DEV_ADDR;
	mib_req.Param.DevAddr = join_cfg->abp.dev_addr;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_F_NWK_S_INT_KEY;
	mib_req.Param.FNwkSIntKey = join_cfg->abp.nwk_skey;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_S_NWK_S_INT_KEY;
	mib_req.Param.SNwkSIntKey = join_cfg->abp.nwk_skey;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_NWK_S_ENC_KEY;
	mib_req.Param.NwkSEncKey = join_cfg->abp.nwk_skey;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_APP_S_KEY;
	mib_req.Param.AppSKey = join_cfg->abp.app_skey;
	LoRaMacMibSetRequestConfirm(&mib_req);

	mib_req.Type = MIB_NETWORK_ACTIVATION;
	mib_req.Param.NetworkActivation = ACTIVATION_TYPE_ABP;
	LoRaMacMibSetRequestConfirm(&mib_req);

	return LORAMAC_STATUS_OK;
}

int lorawan_join(const struct lorawan_join_config *join_cfg)
{
	MibRequestConfirm_t mib_req;
	LoRaMacStatus_t status;
	int ret = 0;

	k_mutex_lock(&lorawan_join_mutex, K_FOREVER);

	/* MIB_PUBLIC_NETWORK powers on the radio and does not turn it off */
	mib_req.Type = MIB_PUBLIC_NETWORK;
	mib_req.Param.EnablePublicNetwork = true;
	LoRaMacMibSetRequestConfirm(&mib_req);

	if (join_cfg->mode == LORAWAN_ACT_OTAA) {
		status = lorawan_join_otaa(join_cfg);
		if (status != LORAMAC_STATUS_OK) {
			LOG_ERR("OTAA join failed: %s",
				lorawan_status2str(status));
			ret = lorawan_status2errno(status);
			goto out;
		}

		LOG_DBG("Network join request sent!");

		/*
		 * We can be sure that the semaphore will be released for
		 * both success and failure cases after a specific time period.
		 * So we can use K_FOREVER and no need to check the return val.
		 */
		k_sem_take(&mlme_confirm_sem, K_FOREVER);
		if (last_mlme_confirm_status != LORAMAC_EVENT_INFO_STATUS_OK) {
			ret = lorawan_eventinfo2errno(last_mlme_confirm_status);
			goto out;
		}
	} else if (join_cfg->mode == LORAWAN_ACT_ABP) {
		status = lorawan_join_abp(join_cfg);
		if (status != LORAMAC_STATUS_OK) {
			LOG_ERR("ABP join failed: %s",
				lorawan_status2str(status));
			ret = lorawan_status2errno(status);
			goto out;
		}
	} else {
		ret = -EINVAL;
	}

out:
	/* If the join succeeded */
	if (ret == 0) {
		/*
		 * Several regions (AS923, AU915, US915) overwrite the
		 * datarate as part of the join process. Reset the datarate
		 * to the value requested (and validated) in
		 * lorawan_set_datarate so that the MAC layer is aware of the
		 * set datarate for LoRaMacQueryTxPossible. This is only
		 * performed when ADR is disabled as it the network servers
		 * responsibility to increase datarates when ADR is enabled.
		 */
		if (!lorawan_adr_enable) {
			MibRequestConfirm_t mib_req;

			mib_req.Type = MIB_CHANNELS_DATARATE;
			mib_req.Param.ChannelsDatarate = default_datarate;
			LoRaMacMibSetRequestConfirm(&mib_req);
		}

		/*
		 * Force a notification of the datarate on network join as the
		 * user may not have explicitly set a datarate to use.
		 */
		datarate_observe(true);
	}

	k_mutex_unlock(&lorawan_join_mutex);
	return ret;
}

int lorawan_set_class(enum lorawan_class dev_class)
{
	LoRaMacStatus_t status;
	MibRequestConfirm_t mib_req;

	mib_req.Type = MIB_DEVICE_CLASS;

	switch (dev_class) {
	case LORAWAN_CLASS_A:
		mib_req.Param.Class = CLASS_A;
		break;
	case LORAWAN_CLASS_B:
	case LORAWAN_CLASS_C:
		LOG_ERR("Device class not supported yet!");
		return -ENOTSUP;
	default:
		return -EINVAL;
	}

	status = LoRaMacMibSetRequestConfirm(&mib_req);
	if (status != LORAMAC_STATUS_OK) {
		LOG_ERR("Failed to set device class: %s",
			lorawan_status2str(status));
		return lorawan_status2errno(status);
	}

	return 0;
}

int lorawan_set_datarate(enum lorawan_datarate dr)
{
	MibRequestConfirm_t mib_req;

	/* Bail out if using ADR */
	if (lorawan_adr_enable) {
		return -EINVAL;
	}

	/* Notify MAC layer of the requested datarate */
	mib_req.Type = MIB_CHANNELS_DATARATE;
	mib_req.Param.ChannelsDatarate = dr;
	if (LoRaMacMibSetRequestConfirm(&mib_req) != LORAMAC_STATUS_OK) {
		/* Datarate is invalid for this region */
		return -EINVAL;
	}

	default_datarate = dr;
	current_datarate = dr;

	return 0;
}

void lorawan_get_payload_sizes(uint8_t *max_next_payload_size,
			       uint8_t *max_payload_size)
{
	LoRaMacTxInfo_t txInfo;

	/* QueryTxPossible cannot fail */
	(void)LoRaMacQueryTxPossible(0, &txInfo);

	*max_next_payload_size = txInfo.MaxPossibleApplicationDataSize;
	*max_payload_size = txInfo.CurrentPossiblePayloadSize;
}

enum lorawan_datarate lorawan_get_min_datarate(void)
{
	MibRequestConfirm_t mibGet;

	mibGet.Type = MIB_CHANNELS_MIN_TX_DATARATE;
	LoRaMacMibGetRequestConfirm(&mibGet);

	return mibGet.Param.ChannelsMinTxDatarate;
}

void lorawan_enable_adr(bool enable)
{
	MibRequestConfirm_t mib_req;

	if (enable != lorawan_adr_enable) {
		lorawan_adr_enable = enable;

		mib_req.Type = MIB_ADR;
		mib_req.Param.AdrEnable = lorawan_adr_enable;
		LoRaMacMibSetRequestConfirm(&mib_req);
	}
}

int lorawan_set_conf_msg_tries(uint8_t tries)
{
	lorawan_conf_msg_tries = tries;

	return 0;
}

int lorawan_send(uint8_t port, uint8_t *data, uint8_t len, uint8_t flags)
{
	LoRaMacStatus_t status;
	McpsReq_t mcpsReq;
	LoRaMacTxInfo_t txInfo;
	int ret = 0;
	bool empty_frame = false;

	if (data == NULL) {
		return -EINVAL;
	}

	k_mutex_lock(&lorawan_send_mutex, K_FOREVER);

	status = LoRaMacQueryTxPossible(len, &txInfo);
	if (status != LORAMAC_STATUS_OK) {
		/*
		 * If status indicates an error, then most likely the payload
		 * has exceeded the maximum possible length for the current
		 * region and datarate. We can't do much other than sending
		 * empty frame in order to flush MAC commands in stack and
		 * hoping the application to lower the payload size for
		 * next try.
		 */
		LOG_ERR("LoRaWAN Query Tx Possible Failed: %s",
			lorawan_status2str(status));
		empty_frame = true;
		mcpsReq.Type = MCPS_UNCONFIRMED;
		mcpsReq.Req.Unconfirmed.fBuffer = NULL;
		mcpsReq.Req.Unconfirmed.fBufferSize = 0;
		mcpsReq.Req.Unconfirmed.Datarate = DR_0;
	} else {
		if (flags & LORAWAN_MSG_CONFIRMED) {
			mcpsReq.Type = MCPS_CONFIRMED;
			mcpsReq.Req.Confirmed.fPort = port;
			mcpsReq.Req.Confirmed.fBuffer = data;
			mcpsReq.Req.Confirmed.fBufferSize = len;
			mcpsReq.Req.Confirmed.NbTrials = lorawan_conf_msg_tries;
			mcpsReq.Req.Confirmed.Datarate = current_datarate;
		} else {
			/* default message type */
			mcpsReq.Type = MCPS_UNCONFIRMED;
			mcpsReq.Req.Unconfirmed.fPort = port;
			mcpsReq.Req.Unconfirmed.fBuffer = data;
			mcpsReq.Req.Unconfirmed.fBufferSize = len;
			mcpsReq.Req.Unconfirmed.Datarate = current_datarate;
		}
	}

	status = LoRaMacMcpsRequest(&mcpsReq);
	if (status != LORAMAC_STATUS_OK) {
		LOG_ERR("LoRaWAN Send failed: %s", lorawan_status2str(status));
		ret = lorawan_status2errno(status);
		goto out;
	}

	/*
	 * Always wait for MAC operations to complete.
	 * We can be sure that the semaphore will be released for
	 * both success and failure cases after a specific time period.
	 * So we can use K_FOREVER and no need to check the return val.
	 */
	k_sem_take(&mcps_confirm_sem, K_FOREVER);
	if (last_mcps_confirm_status != LORAMAC_EVENT_INFO_STATUS_OK) {
		ret = lorawan_eventinfo2errno(last_mcps_confirm_status);
	}

	/*
	 * Indicate to the application that the provided data was not sent and
	 * it has to resend the packet.
	 */
	if (empty_frame) {
		ret = -EAGAIN;
	}

out:
	k_mutex_unlock(&lorawan_send_mutex);
	return ret;
}

int lorawan_set_battery_level_callback(uint8_t (*battery_lvl_cb)(void))
{
	if (battery_lvl_cb == NULL) {
		return -EINVAL;
	}

	getBatteryLevelUser = battery_lvl_cb;

	return 0;
}

void lorawan_register_downlink_callback(struct lorawan_downlink_cb *cb)
{
	sys_slist_append(&dl_callbacks, &cb->node);
}

void lorawan_register_dr_changed_callback(void (*cb)(enum lorawan_datarate))
{
	dr_change_cb = cb;
}

int lorawan_start(void)
{
	LoRaMacStatus_t status;
	MibRequestConfirm_t mib_req;
	GetPhyParams_t phy_params;
	PhyParam_t phy_param;

	status = LoRaMacStart();
	if (status != LORAMAC_STATUS_OK) {
		LOG_ERR("Failed to start the LoRaMAC stack: %s",
			lorawan_status2str(status));
		return -EINVAL;
	}

	/* Retrieve the default TX datarate for selected region */
	phy_params.Attribute = PHY_DEF_TX_DR;
	phy_param = RegionGetPhyParam(LORAWAN_REGION, &phy_params);
	default_datarate = phy_param.Value;
	current_datarate = default_datarate;

	/* TODO: Move these to a proper location */
	mib_req.Type = MIB_SYSTEM_MAX_RX_ERROR;
	mib_req.Param.SystemMaxRxError = CONFIG_LORAWAN_SYSTEM_MAX_RX_ERROR;
	LoRaMacMibSetRequestConfirm(&mib_req);

	return 0;
}

static int lorawan_init(const struct device *dev)
{
	LoRaMacStatus_t status;

	sys_slist_init(&dl_callbacks);

	macPrimitives.MacMcpsConfirm = McpsConfirm;
	macPrimitives.MacMcpsIndication = McpsIndication;
	macPrimitives.MacMlmeConfirm = MlmeConfirm;
	macPrimitives.MacMlmeIndication = MlmeIndication;
	macCallbacks.GetBatteryLevel = getBatteryLevelLocal;
	macCallbacks.GetTemperatureLevel = NULL;
	macCallbacks.NvmContextChange = NULL;
	macCallbacks.MacProcessNotify = OnMacProcessNotify;

	status = LoRaMacInitialization(&macPrimitives, &macCallbacks,
				       LORAWAN_REGION);
	if (status != LORAMAC_STATUS_OK) {
		LOG_ERR("LoRaMacInitialization failed: %s",
			lorawan_status2str(status));
		return -EINVAL;
	}

	LOG_DBG("LoRaMAC Initialized");

	return 0;
}

SYS_INIT(lorawan_init, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);