/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2014	Google, Inc.  (edjames@google.com)
 *  Copyright (C) 2012	Marcel Holtmann <marcel@holtmann.org>
 *  Copyright (C) 2012	Nordic Semiconductor Inc.
 *  Copyright (C) 2012	Instituto Nokia de Tecnologia - INdT
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

/* much lifted from input/hog.c */

/* OAD - over air download of firmware to devices */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <stdbool.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>
#include <unistd.h>
#include <glib.h>

#include "lib/bluetooth.h"
#include "lib/sdp.h"
#include "lib/uuid.h"

#include "src/adapter.h"
#include "src/device.h"
#include "src/log.h"
#include "src/plugin.h"
#include "src/profile.h"
#include "src/service.h"
#include "attrib/att.h"
#include "attrib/gattrib.h"
#include "src/attio.h"
#include "attrib/gatt.h"
#include "src/shared/util.h"

#define OAD_UUID		"f000ffc0-0451-4000-b000-000000000000"
#define OAD_IMG_IDENTITY_UUID	"f000ffc1-0451-4000-b000-000000000000"
#define OAD_IMG_BLOCK_UUID	"f000ffc2-0451-4000-b000-000000000000"

#define OAD_MAJOR_VERSION(x)	((x) >> 8)
#define OAD_MINOR_VERSION(x)	((x) & 0xff)

/* these codes may be returned instead of GP versions */
#define OAD_VERSION_BAD		0xfefe
#define OAD_VERSION_BUSY	0xffff

/* remote has 2 processors, 2 firmwares. */
#define OAD_GP_FIRMWARE_GFRM200		"gfrm200.gp.bin"
#define OAD_TI_FIRMWARE_GFRM200		"gfrm200.ti.bin"
#define OAD_GP_FIRMWARE_GFRM210		"gfrm210.gp.bin"
#define OAD_TI_FIRMWARE_GFRM210		"gfrm210.ti.bin"

/* remote checks in every 15 minutes */
#define OAD_UPGRADE_DELAY_SECS		1		// delay between wake and upgrade check
#define OAD_DELAY_NO_UPGRADE		(8*60*60)	// check for new ACS files (not likely)
#define OAD_DELAY_NO_UPGRADE_DEBUG	150		// check faster when /tmp firmware exists
#define OAD_DELAY_UPGRADING		60		// recheck in 1 minute (in case of 2 firmware update)

#define OAD_HEADER_LEN			8		// on-disk header.  See OAD_Formatv7.xlsx

enum OAD_Status {
	OADSTATUS_None            = 0,
	OADSTATUS_DataTransfer    = 1,
	OADSTATUS_TransferSuccess = 2,
	OADSTATUS_TIActive        = 0x81,	// maybe flashing
	OADSTATUS_GPActive        = 0x82,	// maybe rebooting
	OADSTATUS_CRCError        = 0xE0,
	OADSTATUS_LVD             = 0xE1,	// low voltage detection
	OADSTATUS_KeyPress        = 0xE2,	// user interrupted (not idle)
	OADSTATUS_GPWrite         = 0xE3,	// GP write failed?
	OADSTATUS_Bootloader      = 0xE5,	// Bootloader rejected?
	OADSTATUS_ImageError      = 0xE6,	// Image format error?
};

enum OAD_Action {
	OADACTION_GetRemoteInfo   = 0,
	OADACTION_TransferOADData = 1,
	OADACTION_StartUpdate     = 2,
};

/* firmware is upgraded in this order */
enum OAD_FirmwareType {
	OADFW_Unknown = -1,
	OADFW_TI = 0,
	OADFW_GP = 1,
	OADFW_Total = 2,
};

struct oad_fwinfo {
	uint16_t		version;
	uint32_t		size;
	uint8_t			header[OAD_HEADER_LEN];
	char			file[MAXPATHLEN];
};

struct oad_service {
	guint			attio_id;
	uint16_t		ccc_handle;
	uint16_t		value_handle;
	int			notify_enabled;
};

struct oad_device {
	uint16_t		id;
	struct btd_device	*device;
	GAttrib			*attrib;
	guint			attioid;
	struct gatt_primary	*oad_primary;

	struct oad_service	identity;
	struct oad_service	block;

	time_t			nextCheck;
	struct oad_fwinfo	disk[OADFW_Total];
	struct oad_fwinfo	remote[OADFW_Total];

	int			force_upgrade;
	int			retries;
	int			num_blocks;
	int			progress;

	uint8_t			header[OAD_HEADER_LEN];
	int			fd;
	guint			tid;			// Timer id to delay starting upgrade
};

struct oad_characteristic {
	struct oad_device	*oaddev;
	char			uuid[MAX_LEN_UUID_STR + 1];
};

static GSList *oad_devices = NULL;

static struct oad_device *oad_new_device(struct btd_device *device, uint16_t id)
{
	struct oad_device *oaddev;

	oaddev = g_try_new0(struct oad_device, 1);
	if (!oaddev)
		return NULL;

	oaddev->id = id;
	oaddev->device = btd_device_ref(device);
	oaddev->fd = -1;

	return oaddev;
}

static void oad_free_device(struct oad_device *oaddev)
{
	if (oaddev->fd != -1) {
		close(oaddev->fd);
		oaddev->fd = -1;
	}
	btd_device_unref(oaddev->device);
	g_attrib_unref(oaddev->attrib);
	g_free(oaddev->oad_primary);
	g_free(oaddev);
}

static void oad_block_char_write_cb(guint8 status, const guint8 *pdu, guint16 len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;

	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		return;
	}
	oaddev->retries = 0;	// successful write
}

static void oad_identity_char_write_cb(guint8 status, const guint8 *pdu, guint16 len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;

	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		return;
	}
}

static void oad_start_transfer(struct oad_device* oaddev)
{
	uint8_t attr_val[OAD_HEADER_LEN+1];		// + 1 byte action

	memcpy(attr_val, oaddev->header, OAD_HEADER_LEN);
	attr_val[OAD_HEADER_LEN] = OADACTION_TransferOADData;	/* start OAD image transfer */

	gatt_write_char(oaddev->attrib, oaddev->identity.value_handle, attr_val,
			sizeof(attr_val), oad_identity_char_write_cb, oaddev);
}

static void oad_block_notify_handler(const uint8_t *pdu, uint16_t len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;
	int retry = 0;


	/* should be at least opcode (1b) + handle (7a00) */
	if (len < 3) {
		error("OAD Invalid PDU received");
		return;
	}

	// 2 bytes block_num + status byte
	if (len != 6) {
		error("OAD block notify format error: expected 6 bytes, got %d", len);
		return;
	}

	/* request for block */
	uint16_t block_num = get_le16(pdu + 3);
	enum OAD_Status status = (enum OAD_Status) pdu[5];

	switch (status) {
	case OADSTATUS_DataTransfer:		// send a block
		{
			uint8_t block[18];	// 2 bytes block_num + 16 data bytes

			memset(block, 0, sizeof block);
			put_le16(block_num, block);

			if (lseek(oaddev->fd, 16 * block_num, SEEK_SET) < 0) {
				perror("OAD firmware seek");
				goto error;
			}
			if (read(oaddev->fd, block+2, sizeof block - 2) < 0) {
				perror("OAD firmware read");
				goto error;
			}

			int progress = 0;
			if (oaddev->num_blocks > 0) progress = 100 * block_num / oaddev->num_blocks;
			if (oaddev->progress != progress) {
				oaddev->progress = progress;
				DBG("OAD sending block %d (%d%%)", block_num, progress);
			}
			gatt_write_char(oaddev->attrib, oaddev->block.value_handle, block,
				sizeof(block), oad_block_char_write_cb, oaddev);
		}
		break;
	case OADSTATUS_TransferSuccess:		// OK, successful transfer
		{
			DBG("OAD firmware transfer successful");
			close(oaddev->fd);
			oaddev->fd = -1;

			uint8_t attr_val[OAD_HEADER_LEN+1];		// + 1 byte action
			memcpy(attr_val, oaddev->header, OAD_HEADER_LEN);
			attr_val[OAD_HEADER_LEN] = OADACTION_StartUpdate;		/* commit fw image */
			DBG("OAD committing firmware");
			gatt_write_char(oaddev->attrib, oaddev->identity.value_handle, attr_val,
				sizeof(attr_val), oad_identity_char_write_cb, oaddev);
		}
		break;
	case OADSTATUS_GPActive:
		DBG("OAD GP is active (good)");
		break;
	case OADSTATUS_TIActive:
		DBG("OAD TI is active (good)");
		break;

	case OADSTATUS_CRCError:
		DBG("OAD firmware transfer checksum error");
		goto error;
	case OADSTATUS_LVD:
		DBG("OAD firmware upgrade low battery error");
		goto error;
	case OADSTATUS_KeyPress:
		DBG("OAD firmware upgrade user interrupted");
		goto error;
	case OADSTATUS_GPWrite:
		DBG("OAD firmware upgrade GP write error");
		goto error;
	case OADSTATUS_Bootloader:
		DBG("OAD firmware upgrade Bootloader error");
		goto error;
	case OADSTATUS_ImageError:
		DBG("OAD firmware upgrade Image error");
		goto error;

	default:
		/* 0xe0 or greater appear to be unrecoverable errors */
		if (status >= OADSTATUS_CRCError) {
			DBG("OAD unexpected block notify error 0x%02x", status);
			goto error;
		}
		DBG("OAD unexpected block notify status 0x%02x (ignoring)", status);
		break;
	}
	/* success so far*/
	return;

error:
	DBG("OAD upgrade stopping due to error %d", status);
	close(oaddev->fd);
	oaddev->fd = -1;
}

static time_t oad_wallclock(void)
{
	struct timespec ts;

	if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0) {
		return 0;
	}
	return ts.tv_sec;
}

static int oad_is_time_for_upgrade_check(struct oad_device* oaddev)
{
	time_t now = oad_wallclock();

	if (now < oaddev->nextCheck) {
		int next = oaddev->nextCheck - now;
		DBG("OAD not time for upgrade check yet (%d seconds left)", next);
		return 0;
	}
	DBG("OAD time for upgrade check");
	return 1;
}

static void oad_get_firmware_info(struct oad_device *oaddev, const char* file)
{
	uint8_t	header[OAD_HEADER_LEN];

	int fd = open(file, O_RDONLY);
	if (fd < 0) {
		error("OAD open: %s: %s", file, strerror(errno));
		return;
	}
	int len = read(fd, header, sizeof header);
	if (len < 0) {
		error("OAD read: %s: %s", file, strerror(errno));
		close(fd);
		return;
	}
	if (len < sizeof header) {
		error("OAD short read: %s: wanted %lu, got %d", file, sizeof header, len);
		close(fd);
		return;
	}
	close(fd);
	fd = -1;

	/* See OAD_Formatv7.xlsx, 'Image Info' tab.  8 bytes are:
	 * 2 bytes checksum
	 * 2 bytes version
	 * 3 bytes size
	 * 1 byte id: "T" TI image, "G" GP image
	 */
	uint16_t version = get_le16(header + 2);
	uint32_t size = get_le32(header+4) & 0x00ffffff;
	int id = header[7];
	enum OAD_FirmwareType type;

	switch(id) {
	case 'T':
	case 'U':
		type = OADFW_TI;
		break;
	case 'G':
	case 'H':
		type = OADFW_GP;
		break;
	default:
		type = OADFW_Unknown;
		break;
	}
	if (type == OADFW_Unknown) {
		error("OAD unknown firmware id '%c': file=%s version=%d.%d",
			id, file, OAD_MAJOR_VERSION(version), OAD_MINOR_VERSION(version));
		return;
	}
	int index = (int)type;
	if (version <= oaddev->disk[index].version) {
		error("OAD ignoring older firmware: file=%s type=%d version=%d.%d",
			file, type, OAD_MAJOR_VERSION(version), OAD_MINOR_VERSION(version));
		return;
	}
	if (strlen(file) >= sizeof oaddev->disk[index].file) {
		error("OAD firmware file name too long: %s", file);
		return;
	}

	oaddev->disk[index].version = version;
	oaddev->disk[index].size = size;
	memcpy(oaddev->disk[index].header, header, sizeof oaddev->disk[index].header);
	strncpy(oaddev->disk[index].file, file, sizeof oaddev->disk[index].file);
	oaddev->disk[index].file[sizeof oaddev->disk[index].file - 1] = '\0';
}

static const char* oad_firmware_type_string(enum OAD_FirmwareType type)
{
	switch (type) {
	case OADFW_GP:	return "GP";
	case OADFW_TI:	return "TI";
	}
	return "Unknown";
}

static void oad_find_firmware(struct oad_device *oaddev)
{
	char name[MAX_NAME_LENGTH + 1] = "";
	const char *tmp_gp;
	const char *tmp_ti;
	const char *etc_gp;
	const char *etc_ti;

	device_get_name(oaddev->device, name, sizeof(name));
	if (g_strcmp0(name, "GFRM200") == 0) {
		tmp_gp = "/tmp/" OAD_GP_FIRMWARE_GFRM200;
		tmp_ti = "/tmp/" OAD_TI_FIRMWARE_GFRM200;
		etc_gp = "/etc/remote/" OAD_GP_FIRMWARE_GFRM200;
		etc_ti = "/etc/remote/" OAD_TI_FIRMWARE_GFRM200;
	} else if (g_strcmp0(name, "GFRM201") == 0 ||
			g_strcmp0(name, "GFRM210") == 0) {
		tmp_gp = "/tmp/" OAD_GP_FIRMWARE_GFRM210;
		tmp_ti = "/tmp/" OAD_TI_FIRMWARE_GFRM210;
		etc_gp = "/etc/remote/" OAD_GP_FIRMWARE_GFRM210;
		etc_ti = "/etc/remote/" OAD_TI_FIRMWARE_GFRM210;
	} else {
		error("OAD unknown model %s, skipping", name);
	}

	memset(oaddev->disk, 0, sizeof oaddev->disk);

	/* check in tmp first, to make debugging easier */
	if (access(tmp_gp, R_OK) == 0 || access(tmp_ti, R_OK) == 0) {
		DBG("OAD found firmware in /tmp, ignoring /etc/remote, enabling downgrade.");
		oaddev->force_upgrade = 1;	// allow downgrade
		oad_get_firmware_info(oaddev, tmp_gp);
		oad_get_firmware_info(oaddev, tmp_ti);
	} else {
		oaddev->force_upgrade = 0;
		oad_get_firmware_info(oaddev, etc_gp);
		oad_get_firmware_info(oaddev, etc_ti);
	}

	int i;
	for (i = 0; i < OADFW_Total; i++) {
		enum OAD_FirmwareType type = (enum OAD_FirmwareType) i;
		const char* typeStr = oad_firmware_type_string(type);
		if (strlen(oaddev->disk[type].file) == 0) {
			error("OAD no %s firmware found on disk", typeStr);
		} else {
			DBG("OAD found %s firmware: file=%s version=%d.%d",
				typeStr, oaddev->disk[i].file,
				OAD_MAJOR_VERSION(oaddev->disk[i].version),
				OAD_MINOR_VERSION(oaddev->disk[i].version));
		}
	}
}

static void oad_check_for_upgrade(struct oad_device *oaddev)
{
	if (!oad_is_time_for_upgrade_check(oaddev)) {
		return;
	}

	oad_find_firmware(oaddev);

	struct oad_fwinfo* fp = NULL;
	int i;
	for (i = 0; i < OADFW_Total; i++) {
		enum OAD_FirmwareType type = (enum OAD_FirmwareType) i;
		const char* typeStr = oad_firmware_type_string(type);
		if (strlen(oaddev->disk[i].file) == 0) {
			continue;
		}
		if (oaddev->disk[i].version == oaddev->remote[i].version ||
		    (!oaddev->force_upgrade &&
		     oaddev->disk[i].version < oaddev->remote[i].version &&
		     oaddev->remote[i].version != OAD_VERSION_BAD)) {
			DBG("OAD %s firmware is up to date", typeStr);
		} else {
			fp = &oaddev->disk[i];
			break;
		}
	}

	if (fp == NULL) {
		int next = oaddev->force_upgrade
				?  OAD_DELAY_NO_UPGRADE_DEBUG
				: OAD_DELAY_NO_UPGRADE;
		DBG("OAD next check is in %d seconds", next);
		oaddev->nextCheck = oad_wallclock() + next;
		return;
	}
	oaddev->nextCheck = oad_wallclock() + OAD_DELAY_UPGRADING;

	DBG("OAD starting upgrade with %s", fp->file);

	if (oaddev->fd != -1) {
		close(oaddev->fd);
	}
	oaddev->fd = open(fp->file, O_RDONLY);
	if (oaddev->fd < 0) {
		error("OAD open: %s: %s", fp->file, strerror(errno));
		return;
	}
	if (oaddev->tid) {
		g_source_remove(oaddev->tid);
		oaddev->tid = 0;
	}

	oaddev->progress = 0;
	oaddev->retries = 0;
	oaddev->num_blocks = (fp->size + 15) / 16;
	memcpy(oaddev->header, fp->header, sizeof oaddev->header);
	oad_start_transfer(oaddev);
}

static void oad_identity_notify_handler(const uint8_t *pdu, uint16_t len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;


	/* should be at least opcode (1b) + handle (76 00) */
	if (len < 3) {
		error("OAD Invalid PDU received");
		return;
	}

	/* See OAD_Formatv7.xlsx, 'Image Info' tab.  10 bytes are:
	 *	char gp_version[2];	// 09 00 is 0.9
	 * 	char gp_size[3];	// 00 00 01 is 0x010000 == 64k
	 *	char ti_version[2];	// 2a 00 is 0.42
	 * 	char ti_size[3];	// 00 00 01 is 0x010000 == 64k
	 */

	if (len != 13) {
		error("OAD identity data format error: expected 13 bytes, got %d", len);
		return;
	}

	oaddev->remote[OADFW_GP].version = get_le16(pdu+3);
	oaddev->remote[OADFW_GP].size = get_le32(pdu+5) & 0x00ffffff;

	oaddev->remote[OADFW_TI].version = get_le16(pdu+8);
	unsigned char size[4];
	memcpy(size, pdu+10, 3);
	size[3] = 0;				// need 4 bytes for get_le32
	oaddev->remote[OADFW_TI].size = get_le32(size) & 0x00ffffff;

	int i;
	for (i = 0; i < OADFW_Total; i++) {
		enum OAD_FirmwareType type = (enum OAD_FirmwareType) i;
		const char* typeStr = oad_firmware_type_string(type);
		DBG("OAD %s firmware on remote: version=%d.%d",
			typeStr, OAD_MAJOR_VERSION(oaddev->remote[i].version),
			OAD_MINOR_VERSION(oaddev->remote[i].version));
	}
	oad_check_for_upgrade(oaddev);
}

static void oad_check_fwversion(struct oad_device *oaddev)
{
	uint8_t attr_val[9];	// 8 byte header + 1 command byte (all zeros)

	if (!oaddev->identity.notify_enabled || !oaddev->block.notify_enabled) {
		return;
	}

	DBG("OAD sending fw version request");
	memset(attr_val, 0, sizeof attr_val);
	attr_val[8] = OADACTION_GetRemoteInfo;		/* trigger fw version notify */
	gatt_write_char(oaddev->attrib, oaddev->identity.value_handle, attr_val,
		sizeof(attr_val), oad_identity_char_write_cb, oaddev);
}

static void oad_ccc_char_write_identity_cb(guint8 status, const guint8 *pdu, guint16 len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;

	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		return;
	}
	oaddev->identity.notify_enabled = 1;

	oad_check_fwversion(oaddev);
}

static void oad_ccc_char_write_block_cb(guint8 status, const guint8 *pdu, guint16 len, gpointer user_data)
{
	struct oad_device *oaddev = user_data;

	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		return;
	}
	oaddev->block.notify_enabled = 1;

	oad_check_fwversion(oaddev);
}

static void oad_enable_notify(struct oad_device* oaddev)
{
	if (oaddev->identity.ccc_handle == 0 || oaddev->block.ccc_handle == 0 ||
	    oaddev->identity.value_handle == 0 || oaddev->block.value_handle == 0) {
	    	error("OAD discovery not complete, cannot enable notifiers");
		return;
	}

	oaddev->identity.attio_id =
		g_attrib_register(oaddev->attrib,
			ATT_OP_HANDLE_NOTIFY, oaddev->identity.value_handle,
			oad_identity_notify_handler, oaddev, NULL);
	oaddev->block.attio_id =
		g_attrib_register(oaddev->attrib,
			ATT_OP_HANDLE_NOTIFY, oaddev->block.value_handle,
			oad_block_notify_handler, oaddev, NULL);

	uint8_t attr_val[2];
	put_le16(GATT_CLIENT_CHARAC_CFG_NOTIF_BIT, attr_val);
	DBG("OAD enabling notify for OAD_IMG_IDENTITY_UUID");
	gatt_write_char(oaddev->attrib, oaddev->identity.ccc_handle, attr_val,
		sizeof(attr_val), oad_ccc_char_write_identity_cb, oaddev);
	DBG("OAD enabling notify for OAD_IMG_BLOCK_UUID");
	gatt_write_char(oaddev->attrib, oaddev->block.ccc_handle, attr_val,
		sizeof(attr_val), oad_ccc_char_write_block_cb, oaddev);
}

static gboolean oad_upgrade_timer(gpointer data)
{
	struct oad_device *oaddev = data;

	g_source_remove(oaddev->tid);
	oaddev->tid = 0;

	DBG("OAD timer fired");
	oad_enable_notify(oaddev);
}

static void oad_desc_discovered_cb(uint8_t status, GSList *descs, void* user_data)
{
	struct oad_characteristic *ch = user_data;
	struct oad_device *oaddev = ch->oaddev;
	struct GSList *list = NULL;

	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		goto done;
	}

	for (; descs; descs = descs->next) {
		struct gatt_desc *desc = descs->data;

		if (desc->uuid16 != GATT_CLIENT_CHARAC_CFG_UUID)
			continue;

		if (g_strcmp0(ch->uuid, OAD_IMG_IDENTITY_UUID) == 0) {
			DBG("OAD found OAD_IMG_IDENTITY_UUID ccc_handle=0x%04x", desc->handle);
			oaddev->identity.ccc_handle = desc->handle;

		} else if (g_strcmp0(ch->uuid, OAD_IMG_BLOCK_UUID) == 0) {
			DBG("OAD found OAD_IMG_BLOCK_UUID ccc_handle=0x%04x", desc->handle);
			oaddev->block.ccc_handle = desc->handle;
		}
	}
	if (oaddev->identity.ccc_handle && oaddev->block.ccc_handle)
		oaddev->tid = g_timeout_add_seconds(OAD_UPGRADE_DELAY_SECS, oad_upgrade_timer, oaddev);

done:
	g_free(ch);
}

static void oad_discover_desc(struct oad_device *oaddev, struct gatt_char *c, struct gatt_char *c_next)
{
	struct gatt_primary *prim = oaddev->oad_primary;
	struct oad_characteristic *ch;
	uint16_t start, end;

	start = c->value_handle + 1;

	if (c_next != NULL) {
		if (start == c_next->handle)
			return;
		end = c_next->handle - 1;
	} else if (c->value_handle != prim->range.end) {
		end = prim->range.end;
	} else {
		return;
	}

	ch = g_new0(struct oad_characteristic, 1);
	ch->oaddev = oaddev;
	memcpy(ch->uuid, c->uuid, sizeof(c->uuid));

	DBG("OAD discovering descriptors start=0x%04x end=0x%04x", start, end);

	gatt_discover_desc(oaddev->attrib, start, end, NULL, oad_desc_discovered_cb, ch);
}

static void oad_char_discovered_cb(uint8_t status, GSList *chars, void* user_data)
{
	struct oad_device *oaddev = user_data;
	struct gatt_primary *prim = oaddev->oad_primary;
	bt_uuid_t img_identity_uuid, img_block_uuid;
	GSList *l;
	uint16_t info_handle = 0, proto_mode_handle = 0;

	DBG("OAD inspecting characteristics");
	if (status != 0) {
		error("OAD %s failed: %s", __func__, att_ecode2str(status));
		return;
	}

	for (l = chars; l; l = g_slist_next(l)) {
		struct gatt_char *chr, *next;
		bt_uuid_t uuid;
		uint16_t start, end;

		chr = l->data;
		next = l->next ? l->next->data : NULL;

		DBG("OAD 0x%04x UUID: %s properties: %02x", chr->handle, chr->uuid, chr->properties);


		start = chr->value_handle + 1;
		end = (next ? next->handle - 1 : prim->range.end);

		if (g_strcmp0(chr->uuid, OAD_IMG_IDENTITY_UUID) == 0) {
			oaddev->identity.value_handle = chr->value_handle;
			DBG("OAD found OAD_IMG_IDENTITY_UUID value_handle=0x%04x", chr->value_handle);
			oad_discover_desc(oaddev, chr, next);
		} else if (g_strcmp0(chr->uuid, OAD_IMG_BLOCK_UUID) == 0) {
			oaddev->block.value_handle = chr->value_handle;
			DBG("OAD found OAD_IMG_BLOCK_UUID value_handle=0x%04x", chr->value_handle);
			oad_discover_desc(oaddev, chr, next);
		}

	}
}

static void oad_attio_connected_cb(GAttrib *attrib, gpointer user_data)
{
	struct oad_device *oaddev = user_data;
	struct gatt_primary *prim = oaddev->oad_primary;
	GSList *l;

	DBG("OAD connected");

	oaddev->attrib = g_attrib_ref(attrib);
	oaddev->identity.notify_enabled = 0;
	oaddev->block.notify_enabled = 0;

	if (oaddev->identity.ccc_handle == 0 || oaddev->block.ccc_handle == 0 ||
	    oaddev->identity.value_handle == 0 || oaddev->block.value_handle == 0) {
		DBG("OAD discovering characteristics");

		gatt_discover_char(oaddev->attrib, prim->range.start, prim->range.end, NULL,
			oad_char_discovered_cb, oaddev);
	} else {
		if (oad_is_time_for_upgrade_check(oaddev)) {
			oad_enable_notify(oaddev);
		}
	}
}

static void oad_attio_disconnected_cb(gpointer user_data)
{
	struct oad_device *oaddev = user_data;
	GSList *l;

	DBG("OAD disconnected");

	if (oaddev->identity.attio_id > 0) {
		g_attrib_unregister(oaddev->attrib, oaddev->identity.attio_id);
		oaddev->identity.attio_id = 0;
	}
	if (oaddev->block.attio_id > 0) {
		g_attrib_unregister(oaddev->attrib, oaddev->block.attio_id);
		oaddev->block.attio_id = 0;
	}
	if (oaddev->attrib)
		g_attrib_unref(oaddev->attrib);
	oaddev->attrib = NULL;
}

static struct oad_device *oad_register_device(struct btd_device *device, struct gatt_primary *prim)
{
	struct oad_device *oaddev;
	GIOCondition cond = G_IO_IN | G_IO_ERR | G_IO_NVAL;
	GIOChannel *io;

	oaddev = oad_new_device(device, prim->range.start);
	if (!oaddev)
		return NULL;

	oaddev->oad_primary = g_memdup(prim, sizeof(*prim));

	oaddev->attioid = btd_device_add_attio_callback(device,
		oad_attio_connected_cb, oad_attio_disconnected_cb, oaddev);

	return oaddev;
}

static int oad_unregister_device(struct oad_device *oaddev)
{
	if (oaddev->tid) {
		g_source_remove(oaddev->tid);
		oaddev->tid = 0;
	}
	btd_device_remove_attio_callback(oaddev->device, oaddev->attioid);
	oad_free_device(oaddev);

	return 0;
}

static int oad_probe(struct btd_service *service)
{
	struct btd_device *device = btd_service_get_device(service);
	const char *path = device_get_path(device);
	GSList *primaries, *l;

	DBG("OAD path %s", path);

	primaries = btd_device_get_primaries(device);
	if (primaries == NULL)
		return -EINVAL;

	for (l = primaries; l; l = g_slist_next(l)) {
		struct gatt_primary *prim = l->data;
		struct oad_device *oaddev;

		DBG("OAD uuid=%s", prim->uuid);
		if (strcmp(prim->uuid, OAD_UUID) != 0)
			continue;

		DBG("OAD matched OAD uuid");
		oaddev = oad_register_device(device, prim);
		if (oaddev == NULL)
			continue;

		oad_devices = g_slist_append(oad_devices, oaddev);
	}

	return 0;
}

static void oad_remove_device(gpointer a, gpointer b)
{
	struct oad_device *oaddev = a;
	struct btd_device *device = b;

	if (oaddev->device != device)
		return;

	oad_devices = g_slist_remove(oad_devices, oaddev);
	oad_unregister_device(oaddev);
}

static void oad_remove(struct btd_service *service)
{
	struct btd_device *device = btd_service_get_device(service);
	const char *path = device_get_path(device);

	DBG("OAD path %s", path);

	g_slist_foreach(oad_devices, oad_remove_device, device);
}

static struct btd_profile oad_profile = {
	.name		= "OAD",
	.remote_uuid	= OAD_UUID,
	.device_probe	= oad_probe,
	.device_remove	= oad_remove,
};

static int oad_init(void)
{
	int err;

	return btd_profile_register(&oad_profile);
}

static void oad_exit(void)
{
	btd_profile_unregister(&oad_profile);
}

BLUETOOTH_PLUGIN_DEFINE(oad, VERSION, BLUETOOTH_PLUGIN_PRIORITY_LOW, oad_init, oad_exit)