/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2014  Intel Corporation.
 *  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
 *
 */

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

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

#include <bluetooth/bluetooth.h>

#include <glib.h>

#include "src/log.h"

#include "lib/uuid.h"
#include "src/shared/util.h"
#include "src/shared/uhid.h"

#include "attrib/att.h"
#include "attrib/gattrib.h"
#include "attrib/gatt.h"

#include "btio/btio.h"

#include "android/hog.h"

#define HOG_UUID		"00001812-0000-1000-8000-00805f9b34fb"

#define HOG_INFO_UUID		0x2A4A
#define HOG_REPORT_MAP_UUID	0x2A4B
#define HOG_REPORT_UUID		0x2A4D
#define HOG_PROTO_MODE_UUID	0x2A4E
#define HOG_CONTROL_POINT_UUID	0x2A4C

#define HOG_REPORT_TYPE_INPUT	1
#define HOG_REPORT_TYPE_OUTPUT	2
#define HOG_REPORT_TYPE_FEATURE	3

#define HOG_PROTO_MODE_BOOT    0
#define HOG_PROTO_MODE_REPORT  1

#define HOG_REPORT_MAP_MAX_SIZE        512
#define HID_INFO_SIZE			4
#define ATT_NOTIFICATION_HEADER_SIZE	3

struct bt_hog {
	int			ref_count;
	char			*name;
	uint16_t		vendor;
	uint16_t		product;
	uint16_t		version;
	struct gatt_primary	*primary;
	GAttrib			*attrib;
	GSList			*reports;
	struct bt_uhid		*uhid;
	gboolean		has_report_id;
	uint16_t		bcdhid;
	uint8_t			bcountrycode;
	uint16_t		proto_mode_handle;
	uint16_t		ctrlpt_handle;
	uint8_t			flags;
};

struct report {
	struct bt_hog		*hog;
	uint8_t			id;
	uint8_t			type;
	guint			notifyid;
	struct gatt_char	*decl;
};

static void report_value_cb(const guint8 *pdu, guint16 len, gpointer user_data)
{
	struct report *report = user_data;
	struct bt_hog *hog = report->hog;
	struct uhid_event ev;
	uint8_t *buf;
	int err;

	if (len < ATT_NOTIFICATION_HEADER_SIZE) {
		error("Malformed ATT notification");
		return;
	}

	pdu += ATT_NOTIFICATION_HEADER_SIZE;
	len -= ATT_NOTIFICATION_HEADER_SIZE;

	memset(&ev, 0, sizeof(ev));
	ev.type = UHID_INPUT;
	buf = ev.u.input.data;

	if (hog->has_report_id) {
		buf[0] = report->id;
		len = MIN(len, sizeof(ev.u.input.data) - 1);
		memcpy(buf + 1, pdu, len);
		ev.u.input.size = ++len;
	} else {
		len = MIN(len, sizeof(ev.u.input.data));
		memcpy(buf, pdu, len);
		ev.u.input.size = len;
	}

	err = bt_uhid_send(hog->uhid, &ev);
	if (err < 0) {
		error("bt_uhid_send: %s (%d)", strerror(-err), -err);
		return;
	}

	DBG("HoG report (%u bytes)", ev.u.input.size);
}

static void report_ccc_written_cb(guint8 status, const guint8 *pdu,
					guint16 plen, gpointer user_data)
{
	struct report *report = user_data;
	struct bt_hog *hog = report->hog;

	if (status != 0) {
		error("Write report characteristic descriptor failed: %s",
							att_ecode2str(status));
		return;
	}

	report->notifyid = g_attrib_register(hog->attrib,
					ATT_OP_HANDLE_NOTIFY,
					report->decl->value_handle,
					report_value_cb, report, NULL);

	DBG("Report characteristic descriptor written: notifications enabled");
}

static void write_ccc(uint16_t handle, gpointer user_data)
{
	struct report *report = user_data;
	struct bt_hog *hog = report->hog;
	uint8_t value[] = { 0x01, 0x00 };

	gatt_write_char(hog->attrib, handle, value, sizeof(value),
					report_ccc_written_cb, report);
}

static void report_reference_cb(guint8 status, const guint8 *pdu,
					guint16 plen, gpointer user_data)
{
	struct report *report = user_data;

	if (status != 0) {
		error("Read Report Reference descriptor failed: %s",
							att_ecode2str(status));
		return;
	}

	if (plen != 3) {
		error("Malformed ATT read response");
		return;
	}

	report->id = pdu[1];
	report->type = pdu[2];
	DBG("Report ID: 0x%02x Report type: 0x%02x", pdu[1], pdu[2]);
}

static void external_report_reference_cb(guint8 status, const guint8 *pdu,
					guint16 plen, gpointer user_data);


static void discover_descriptor_cb(uint8_t status, GSList *descs,
								void *user_data)
{
	struct report *report;
	struct bt_hog *hog;
	GAttrib *attrib = NULL;

	if (status != 0) {
		error("Discover all descriptors failed: %s",
							att_ecode2str(status));
		return;
	}

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

		switch (desc->uuid16) {
		case GATT_CLIENT_CHARAC_CFG_UUID:
			report = user_data;
			attrib = report->hog->attrib;
			write_ccc(desc->handle, report);
			break;
		case GATT_REPORT_REFERENCE:
			report = user_data;
			attrib = report->hog->attrib;
			gatt_read_char(attrib, desc->handle,
						report_reference_cb, report);
			break;
		case GATT_EXTERNAL_REPORT_REFERENCE:
			hog = user_data;
			attrib = hog->attrib;
			gatt_read_char(attrib, desc->handle,
					external_report_reference_cb, hog);
			break;
		}
	}
}

static void discover_descriptor(GAttrib *attrib, uint16_t start, uint16_t end,
							gpointer user_data)
{
	if (start > end)
		return;

	gatt_discover_desc(attrib, start, end, NULL,
					discover_descriptor_cb, user_data);
}

static void external_service_char_cb(uint8_t status, GSList *chars,
								void *user_data)
{
	struct bt_hog *hog = user_data;
	struct gatt_primary *primary = hog->primary;
	struct report *report;
	GSList *l;

	if (status != 0) {
		const char *str = att_ecode2str(status);
		DBG("Discover external service characteristic failed: %s", str);
		return;
	}

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

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

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

		report = g_new0(struct report, 1);
		report->hog = hog;
		report->decl = g_memdup(chr, sizeof(*chr));
		hog->reports = g_slist_append(hog->reports, report);
		start = chr->value_handle + 1;
		end = (next ? next->handle - 1 : primary->range.end);
		discover_descriptor(hog->attrib, start, end, report);
	}
}

static void external_report_reference_cb(guint8 status, const guint8 *pdu,
					guint16 plen, gpointer user_data)
{
	struct bt_hog *hog = user_data;
	uint16_t uuid16;
	bt_uuid_t uuid;

	if (status != 0) {
		error("Read External Report Reference descriptor failed: %s",
							att_ecode2str(status));
		return;
	}

	if (plen != 3) {
		error("Malformed ATT read response");
		return;
	}

	uuid16 = get_le16(&pdu[1]);
	DBG("External report reference read, external report characteristic "
						"UUID: 0x%04x", uuid16);
	bt_uuid16_create(&uuid, uuid16);
	gatt_discover_char(hog->attrib, 0x00, 0xff, &uuid,
					external_service_char_cb, hog);
}

static int report_type_cmp(gconstpointer a, gconstpointer b)
{
	const struct report *report = a;
	uint8_t type = GPOINTER_TO_UINT(b);

	return report->type - type;
}

static void output_written_cb(guint8 status, const guint8 *pdu,
					guint16 plen, gpointer user_data)
{
	if (status != 0) {
		error("Write output report failed: %s", att_ecode2str(status));
		return;
	}
}

static void forward_report(struct uhid_event *ev, void *user_data)
{
	struct bt_hog *hog = user_data;
	struct report *report;
	GSList *l;
	void *data;
	int size;
	guint type;

	if (hog->has_report_id) {
		data = ev->u.output.data + 1;
		size = ev->u.output.size - 1;
	} else {
		data = ev->u.output.data;
		size = ev->u.output.size;
	}

	switch (ev->type) {
	case UHID_OUTPUT:
		type = HOG_REPORT_TYPE_OUTPUT;
		break;
	case UHID_FEATURE:
		type = HOG_REPORT_TYPE_FEATURE;
		break;
	default:
		return;
	}

	l = g_slist_find_custom(hog->reports, GUINT_TO_POINTER(type),
							report_type_cmp);
	if (!l)
		return;

	report = l->data;

	DBG("Sending report type %d to handle 0x%X", type,
						report->decl->value_handle);

	if (hog->attrib == NULL)
		return;

	if (report->decl->properties & GATT_CHR_PROP_WRITE)
		gatt_write_char(hog->attrib, report->decl->value_handle,
				data, size, output_written_cb, hog);
	else if (report->decl->properties & GATT_CHR_PROP_WRITE_WITHOUT_RESP)
		gatt_write_cmd(hog->attrib, report->decl->value_handle,
						data, size, NULL, NULL);
}

static bool get_descriptor_item_info(uint8_t *buf, ssize_t blen, ssize_t *len,
								bool *is_long)
{
	if (!blen)
		return false;

	*is_long = (buf[0] == 0xfe);

	if (*is_long) {
		if (blen < 3)
			return false;

		/*
		 * long item:
		 * byte 0 -> 0xFE
		 * byte 1 -> data size
		 * byte 2 -> tag
		 * + data
		 */

		*len = buf[1] + 3;
	} else {
		uint8_t b_size;

		/*
		 * short item:
		 * byte 0[1..0] -> data size (=0, 1, 2, 4)
		 * byte 0[3..2] -> type
		 * byte 0[7..4] -> tag
		 * + data
		 */

		b_size = buf[0] & 0x03;
		*len = (b_size ? 1 << (b_size - 1) : 0) + 1;
	}

	/* item length should be no more than input buffer length */
	return *len <= blen;
}

static char *item2string(char *str, uint8_t *buf, uint8_t len)
{
	char *p = str;
	int i;

	/*
	 * Since long item tags are not defined except for vendor ones, we
	 * just ensure that short items are printed properly (up to 5 bytes).
	 */
	for (i = 0; i < 6 && i < len; i++)
		p += sprintf(p, " %02x", buf[i]);

	/*
	 * If there are some data left, just add continuation mark to indicate
	 * this.
	 */
	if (i < len)
		sprintf(p, " ...");

	return str;
}

static void report_map_read_cb(guint8 status, const guint8 *pdu, guint16 plen,
							gpointer user_data)
{
	struct bt_hog *hog = user_data;
	uint8_t value[HOG_REPORT_MAP_MAX_SIZE];
	struct uhid_event ev;
	ssize_t vlen;
	char itemstr[20]; /* 5x3 (data) + 4 (continuation) + 1 (null) */
	int i, err;
	GError *gerr = NULL;

	if (status != 0) {
		error("Report Map read failed: %s", att_ecode2str(status));
		return;
	}

	vlen = dec_read_resp(pdu, plen, value, sizeof(value));
	if (vlen < 0) {
		error("ATT protocol error");
		return;
	}

	DBG("Report MAP:");
	for (i = 0; i < vlen;) {
		ssize_t ilen = 0;
		bool long_item = false;

		if (get_descriptor_item_info(&value[i], vlen - i, &ilen,
								&long_item)) {
			/* Report ID is short item with prefix 100001xx */
			if (!long_item && (value[i] & 0xfc) == 0x84)
				hog->has_report_id = TRUE;

			DBG("\t%s", item2string(itemstr, &value[i], ilen));

			i += ilen;
		} else {
			error("Report Map parsing failed at %d", i);

			/* Just print remaining items at once and break */
			DBG("\t%s", item2string(itemstr, &value[i], vlen - i));
			break;
		}
	}

	/* create uHID device */
	memset(&ev, 0, sizeof(ev));
	ev.type = UHID_CREATE;

	bt_io_get(g_attrib_get_channel(hog->attrib), &gerr,
			BT_IO_OPT_SOURCE, ev.u.create.phys,
			BT_IO_OPT_DEST, ev.u.create.uniq,
			BT_IO_OPT_INVALID);
	if (gerr) {
		error("Failed to connection details: %s", gerr->message);
		g_error_free(gerr);
		return;
	}

	strcpy((char *) ev.u.create.name, hog->name);
	ev.u.create.vendor = hog->vendor;
	ev.u.create.product = hog->product;
	ev.u.create.version = hog->version;
	ev.u.create.country = hog->bcountrycode;
	ev.u.create.bus = BUS_BLUETOOTH;
	ev.u.create.rd_data = value;
	ev.u.create.rd_size = vlen;

	err = bt_uhid_send(hog->uhid, &ev);
	if (err < 0) {
		error("bt_uhid_send: %s", strerror(-err));
		return;
	}

	bt_uhid_register(hog->uhid, UHID_OUTPUT, forward_report, hog);
	bt_uhid_register(hog->uhid, UHID_FEATURE, forward_report, hog);
}

static void info_read_cb(guint8 status, const guint8 *pdu, guint16 plen,
							gpointer user_data)
{
	struct bt_hog *hog = user_data;
	uint8_t value[HID_INFO_SIZE];
	ssize_t vlen;

	if (status != 0) {
		error("HID Information read failed: %s",
						att_ecode2str(status));
		return;
	}

	vlen = dec_read_resp(pdu, plen, value, sizeof(value));
	if (vlen != 4) {
		error("ATT protocol error");
		return;
	}

	hog->bcdhid = get_le16(&value[0]);
	hog->bcountrycode = value[2];
	hog->flags = value[3];

	DBG("bcdHID: 0x%04X bCountryCode: 0x%02X Flags: 0x%02X",
			hog->bcdhid, hog->bcountrycode, hog->flags);
}

static void proto_mode_read_cb(guint8 status, const guint8 *pdu, guint16 plen,
							gpointer user_data)
{
	struct bt_hog *hog = user_data;
	uint8_t value;
	ssize_t vlen;

	if (status != 0) {
		error("Protocol Mode characteristic read failed: %s",
							att_ecode2str(status));
		return;
	}

	vlen = dec_read_resp(pdu, plen, &value, sizeof(value));
	if (vlen < 0) {
		error("ATT protocol error");
		return;
	}

	if (value == HOG_PROTO_MODE_BOOT) {
		uint8_t nval = HOG_PROTO_MODE_REPORT;

		DBG("HoG is operating in Boot Procotol Mode");

		gatt_write_cmd(hog->attrib, hog->proto_mode_handle, &nval,
						sizeof(nval), NULL, NULL);
	} else if (value == HOG_PROTO_MODE_REPORT)
		DBG("HoG is operating in Report Protocol Mode");
}

static void char_discovered_cb(uint8_t status, GSList *chars, void *user_data)
{
	struct bt_hog *hog = user_data;
	struct gatt_primary *primary = hog->primary;
	bt_uuid_t report_uuid, report_map_uuid, info_uuid;
	bt_uuid_t proto_mode_uuid, ctrlpt_uuid;
	struct report *report;
	GSList *l;
	uint16_t info_handle = 0, proto_mode_handle = 0;

	if (status != 0) {
		const char *str = att_ecode2str(status);
		DBG("Discover all characteristics failed: %s", str);
		return;
	}

	bt_uuid16_create(&report_uuid, HOG_REPORT_UUID);
	bt_uuid16_create(&report_map_uuid, HOG_REPORT_MAP_UUID);
	bt_uuid16_create(&info_uuid, HOG_INFO_UUID);
	bt_uuid16_create(&proto_mode_uuid, HOG_PROTO_MODE_UUID);
	bt_uuid16_create(&ctrlpt_uuid, HOG_CONTROL_POINT_UUID);

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

		bt_string_to_uuid(&uuid, chr->uuid);

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

		if (bt_uuid_cmp(&uuid, &report_uuid) == 0) {
			report = g_new0(struct report, 1);
			report->hog = hog;
			report->decl = g_memdup(chr, sizeof(*chr));
			hog->reports = g_slist_append(hog->reports,
								report);
			discover_descriptor(hog->attrib, start, end, report);
		} else if (bt_uuid_cmp(&uuid, &report_map_uuid) == 0) {
			gatt_read_char(hog->attrib, chr->value_handle,
						report_map_read_cb, hog);
			discover_descriptor(hog->attrib, start, end, hog);
		} else if (bt_uuid_cmp(&uuid, &info_uuid) == 0)
			info_handle = chr->value_handle;
		else if (bt_uuid_cmp(&uuid, &proto_mode_uuid) == 0)
			proto_mode_handle = chr->value_handle;
		else if (bt_uuid_cmp(&uuid, &ctrlpt_uuid) == 0)
			hog->ctrlpt_handle = chr->value_handle;
	}

	if (proto_mode_handle) {
		hog->proto_mode_handle = proto_mode_handle;
		gatt_read_char(hog->attrib, proto_mode_handle,
						proto_mode_read_cb, hog);
	}

	if (info_handle)
		gatt_read_char(hog->attrib, info_handle, info_read_cb,
									hog);
}

static void report_free(void *data)
{
	struct report *report = data;
	struct bt_hog *hog = report->hog;

	if (hog->attrib)
		g_attrib_unregister(hog->attrib, report->notifyid);

	g_free(report->decl);
	g_free(report);
}

static void hog_free(struct bt_hog *hog)
{
	bt_uhid_unref(hog->uhid);
	g_slist_free_full(hog->reports, report_free);
	g_attrib_unref(hog->attrib);
	g_free(hog->name);
	g_free(hog->primary);
	g_free(hog);
}

struct bt_hog *bt_hog_new(const char *name, uint16_t vendor, uint16_t product,
					uint16_t version, void *primary)
{
	struct bt_hog *hog;

	hog = g_try_new0(struct bt_hog, 1);
	if (!hog)
		return NULL;

	hog->uhid = bt_uhid_new_default();
	if (!hog->uhid) {
		hog_free(hog);
		return NULL;
	}

	hog->name = g_strdup(name);
	hog->vendor = vendor;
	hog->product = product;
	hog->version = version;

	if (primary)
		hog->primary = g_memdup(primary, sizeof(*hog->primary));

	return bt_hog_ref(hog);
}

struct bt_hog *bt_hog_ref(struct bt_hog *hog)
{
	if (!hog)
		return NULL;

	__sync_fetch_and_add(&hog->ref_count, 1);

	return hog;
}

void bt_hog_unref(struct bt_hog *hog)
{
	if (!hog)
		return;

	if (__sync_sub_and_fetch(&hog->ref_count, 1))
		return;

	hog_free(hog);
}

static void find_included_cb(uint8_t status, GSList *services, void *user_data)
{
	struct bt_hog *hog = user_data;
	struct gatt_included *include;
	GSList *l;

	DBG("");

	if (hog->primary)
		return;

	if (status) {
		const char *str = att_ecode2str(status);
		DBG("Find included failed: %s", str);
		return;
	}

	if (!services) {
		DBG("No included service found");
		return;
	}

	for (l = services; l; l = l->next) {
		include = l->data;

		if (strcmp(include->uuid, HOG_UUID) == 0)
			break;
	}

	if (!l) {
		for (l = services; l; l = l->next) {
			include = l->data;

			gatt_find_included(hog->attrib, include->range.start,
				include->range.end, find_included_cb, hog);
		}
		return;
	}

	hog->primary = g_new0(struct gatt_primary, 1);
	memcpy(hog->primary->uuid, include->uuid, sizeof(include->uuid));
	memcpy(&hog->primary->range, &include->range, sizeof(include->range));

	gatt_discover_char(hog->attrib, hog->primary->range.start,
						hog->primary->range.end, NULL,
						char_discovered_cb, hog);
}

static void primary_cb(uint8_t status, GSList *services, void *user_data)
{
	struct bt_hog *hog = user_data;
	struct gatt_primary *primary;
	GSList *l;

	DBG("");

	if (status) {
		const char *str = att_ecode2str(status);
		DBG("Discover primary failed: %s", str);
		return;
	}

	if (!services) {
		DBG("No primary service found");
		return;
	}

	for (l = services; l; l = l->next) {
		primary = l->data;

		if (strcmp(primary->uuid, HOG_UUID) == 0)
			break;
	}

	if (!l) {
		for (l = services; l; l = l->next) {
			primary = l->data;

			gatt_find_included(hog->attrib, primary->range.start,
					primary->range.end, find_included_cb,
					hog);
		}
		return;
	}

	hog->primary = g_memdup(primary, sizeof(*primary));

	gatt_discover_char(hog->attrib, hog->primary->range.start,
						hog->primary->range.end, NULL,
						char_discovered_cb, hog);
}

bool bt_hog_attach(struct bt_hog *hog, void *gatt)
{
	struct gatt_primary *primary = hog->primary;
	GSList *l;

	if (hog->attrib)
		return false;

	hog->attrib = g_attrib_ref(gatt);

	if (!primary) {
		gatt_discover_primary(hog->attrib, NULL, primary_cb, hog);
		return true;
	}

	if (hog->reports == NULL) {
		gatt_discover_char(hog->attrib, primary->range.start,
						primary->range.end, NULL,
						char_discovered_cb, hog);
		return true;
	}

	for (l = hog->reports; l; l = l->next) {
		struct report *r = l->data;

		r->notifyid = g_attrib_register(hog->attrib,
					ATT_OP_HANDLE_NOTIFY,
					r->decl->value_handle,
					report_value_cb, r, NULL);
	}

	return true;
}

void bt_hog_detach(struct bt_hog *hog)
{
	GSList *l;

	if (!hog->attrib)
		return;

	for (l = hog->reports; l; l = l->next) {
		struct report *r = l->data;

		g_attrib_unregister(hog->attrib, r->notifyid);
	}

	g_attrib_unref(hog->attrib);
	hog->attrib = NULL;
}

int bt_hog_set_control_point(struct bt_hog *hog, bool suspend)
{
	uint8_t value = suspend ? 0x00 : 0x01;

	if (hog->attrib == NULL)
		return -ENOTCONN;

	if (hog->ctrlpt_handle == 0)
		return -ENOTSUP;

	gatt_write_cmd(hog->attrib, hog->ctrlpt_handle, &value,
					sizeof(value), NULL, NULL);

	return 0;
}