/*
 * Copyright (C) 2018 Intel Corporation
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <malloc.h>
#include <openssl/sha.h>
#include <signal.h>
#include <limits.h>
#include <stdlib.h>
#include "android_events.h"
#include "strutils.h"
#include "cmdutils.h"
#include "log_sys.h"
#include "fsutils.h"
#include "history.h"
#include "loop.h"
#include "vmrecord.h"

#define VM_WARNING_LINES 2000

#define ANDROID_DATA_PAR_NAME "data"
#define ANDROID_EVT_KEY_LEN 20

/* TODO: hardcoding the img path here means that only one Android Guest OS
 * is supoorted at this moment. To support multiple Android Guest OS, this
 * path should be moved to structure vm_t and configurable.
 */
static const char *android_img = "/data/android/android.img";
static const char *android_histpath = "logs/history_event";
char *loop_dev;

/* Find the next event that needs to be synced.
 * There is a history_event file in User VM side, it records User VM's events in
 * real-time. Generally, the cursor point to the first unsynchronized line.
 */
static char *next_vm_event(const char *cursor, const char *data,
			size_t dlen, const struct vm_t *vm)
{
	char *line_to_sync = (char *)~(0);
	const char *syncevent;
	int id;

	if (!cursor || !vm)
		return NULL;

	/* find all syncing types start from cursor,
	 * focus the event with smaller address.
	 */
	for_each_syncevent_vm(id, syncevent, vm) {
		char *p;
		char *new;
		char *type;
		int tlen;
		size_t len;

		if (!syncevent)
			continue;

		tlen = asprintf(&type, "\n%s ", syncevent);
		if (tlen == -1) {
			LOGE("out of memory\n");
			return NULL;
		}
		/* a sync event may be configured as type/subtype */
		p = strchr(type, '/');
		if (p) {
			char *subtype;
			int stlen;

			tlen = p - type;
			stlen = asprintf(&subtype, " %s", p + 1);
			if (stlen == -1) {
				free(type);
				LOGE("out of memory\n");
				return NULL;
			}
			new = get_line(subtype, (size_t)stlen, data, dlen,
				       cursor, &len);
			free(subtype);
			/*
			 * ignore the result if 'line' does not start with
			 * 'type'.
			 */
			if (!new || memcmp(new, type + 1, tlen - 1) ||
			    *(new + tlen - 1) != ' ') {
				free(type);
				continue;
			}
		} else {
			new = get_line(type, (size_t)tlen, data, dlen,
				       cursor, &len);
		}

		if (new)
			line_to_sync = MIN(line_to_sync, new);

		free(type);
	}

	if (line_to_sync == (char *)~(0))
		return NULL;

	return line_to_sync;
}

static int get_vms_history(const struct sender_t *sender)
{
	struct vm_t *vm;
	unsigned long size;
	int ret;
	int id;

	for_each_vm(id, vm, conf) {
		if (!vm)
			continue;

		if (e2fs_open(loop_dev, &vm->datafs) == -1)
			continue;

		if (e2fs_read_file_by_fpath(vm->datafs, android_histpath,
					    (void **)&vm->history_data,
					    &size) == -1) {
			LOGE("failed to get vm_history from (%s).\n", vm->name);
			vm->history_data = NULL;
			e2fs_close(vm->datafs);
			vm->datafs = NULL;
			continue;
		}

		e2fs_close(vm->datafs);
		vm->datafs = NULL;

		if (!size) {
			LOGE("empty vm_history from (%s).\n", vm->name);
			vm->history_data = NULL;
			continue;
		}

		/* warning large history file once */
		if (size == vm->history_size[sender->id])
			continue;

		ret = strcnt(vm->history_data, '\n');
		if (ret > VM_WARNING_LINES)
			LOGW("File too large, (%d) lines in (%s) of (%s)\n",
			     ret, android_histpath, vm->name);

		vm->history_size[sender->id] = size;
	}

	return 0;
}

/**
 * There are 2 stages in vm events sync.
 * Stage1: detect new vm events and record them into log_vmrecordid file.
 * Stage2: push the recorded events to event_queue, the senders will do
 *         the corresponding process.
 *
 * The design reason is giving User VM some time to get log stored.
 */
static void detect_new_events(struct sender_t *sender)
{
	int id;
	struct vm_t *vm;

	for_each_vm(id, vm, conf) {
		char *data;
		size_t data_size;
		char *start;
		char *last_key;
		char *line_to_sync;

		if (!vm || !vm->history_data)
			continue;

		data = vm->history_data;
		data_size = vm->history_size[sender->id];
		last_key = &vm->last_evt_detected[sender->id][0];
		if (*last_key) {
			start = strstr(data, last_key);
			if (start == NULL) {
				LOGW("no synced id (%s), sync from head\n",
				     last_key);
				start = data;
			} else {
				start = strchr(start, '\n');
			}
		} else {
			start = data;
		}

		while ((line_to_sync = next_vm_event(start, data, data_size,
						     vm))) {
			/* It's possible that log's content isn't ready
			 * at this moment, so we postpone the fn until
			 * the next loop
			 */
			//fn(line_to_sync, vm);
			char vmkey[ANDROID_WORD_LEN];
			ssize_t len;
			const char * const vm_format =
				IGN_ONEWORD ANDROID_KEY_FMT IGN_RESTS;

			len = strlinelen(line_to_sync,
					 data + data_size - line_to_sync);
			if (len == -1)
				break;

			start = strchr(line_to_sync, '\n');
			if (str_split_ere(line_to_sync, len + 1, vm_format,
					  strlen(vm_format), vmkey,
					  sizeof(vmkey)) != 1) {
				LOGE("get an invalid line from (%s), skip\n",
				     vm->name);
				continue;
			}

			if ((strnlen(vmkey, sizeof(vmkey)) !=
			     ANDROID_EVT_KEY_LEN) ||
			     !strcmp(vmkey, "00000000000000000000")) {
				LOGE("invalid key (%s) from (%s)\n",
				     vmkey, vm->name);
				continue;
			}

			LOGD("stage1 %s\n", vmkey);
			*(char *)(mempcpy(vm->last_evt_detected[sender->id],
					  vmkey, ANDROID_EVT_KEY_LEN)) = '\0';
			if (vmrecord_new(&sender->vmrecord, vm->name,
					  vmkey) == -1)
				LOGE("failed to new vm record\n");
		}
	}

}

static char *next_record(const struct mm_file_t *file, const char *fstart,
			size_t *len)
{
	const char *tag = " " VMRECORD_TAG_WAITING_SYNC;
	size_t tlen = strlen(tag);

	return get_line(tag, tlen, file->begin, file->size, fstart, len);
}

static void fire_detected_events(struct sender_t *sender,
			int (*fn)(const char*, size_t, const struct vm_t *))
{
	struct mm_file_t *recos;
	char *record;
	size_t recolen;

	pthread_mutex_lock(&sender->vmrecord.mtx);
	recos = mmap_file(sender->vmrecord.path);
	if (!recos) {
		LOGE("failed to mmap %s, %s\n", sender->vmrecord.path,
						strerror(errno));
		pthread_mutex_unlock(&sender->vmrecord.mtx);
		return;
	}
	if (!recos->size ||
	    mm_count_lines(recos) < VMRECORD_HEAD_LINES) {
		LOGE("(%s) invalid\n", sender->vmrecord.path);
		goto out;
	}

	sender->vmrecord.recos = recos;
	for (record = next_record(recos, recos->begin, &recolen); record;
	     record = next_record(recos, record + recolen, &recolen)) {
		const char * const record_fmt =
			VM_NAME_FMT ANDROID_KEY_FMT IGN_RESTS;
		char *hist_line;
		size_t len;
		char vm_name[32];
		char vmkey[ANDROID_WORD_LEN];
		struct vm_t *vm;
		int res;

		/* VMNAME xxxxxxxxxxxxxxxxxxxx <== */
		if (str_split_ere(record, recolen,
				  record_fmt, strlen(record_fmt),
				  vm_name, sizeof(vm_name),
				  vmkey, sizeof(vmkey)) != 2) {
			LOGE("failed to parse vm record\n");
			continue;
		}

		vm = get_vm_by_name((const char *)vm_name);
		if (!vm || !vm->history_data)
			continue;

		hist_line = get_line(vmkey, strnlen(vmkey, sizeof(vmkey)),
				     vm->history_data,
				     vm->history_size[sender->id],
				     vm->history_data, &len);
		if (!hist_line) {
			vmrecord_mark(&sender->vmrecord, vmkey,
				      strnlen(vmkey, sizeof(vmkey)), NOT_FOUND);
			continue;
		}

		res = fn(hist_line, len + 1, vm);
		if (res == VMEVT_HANDLED)
			vmrecord_mark(&sender->vmrecord, vmkey,
				      strnlen(vmkey, sizeof(vmkey)), ON_GOING);
	}

out:
	unmap_file(recos);
	pthread_mutex_unlock(&sender->vmrecord.mtx);
}

/* This function only for initialization */
static void get_last_evt_detected(struct sender_t *sender)
{
	int id;
	struct vm_t *vm;

	for_each_vm(id, vm, conf) {
		char vmkey[ANDROID_WORD_LEN];

		if (!vm)
			continue;

		/* generally only exec for each vm once */
		if (vm->last_evt_detected[sender->id][0])
			continue;

		if (vmrecord_last(&sender->vmrecord, vm->name, vm->name_len,
				  vmkey, sizeof(vmkey)) == -1)
			continue;

		if (strnlen(vmkey, sizeof(vmkey)) != ANDROID_EVT_KEY_LEN) {
			LOGE("get an invalid vm event (%s) in (%s)\n",
			     vmkey, sender->vmrecord.path);
			continue;
		}

		*(char *)(mempcpy(vm->last_evt_detected[sender->id], vmkey,
				  ANDROID_EVT_KEY_LEN)) = '\0';

	}
}

static char *setup_loop_dev(void)
{

	/* Currently User VM image(/data/android/android.img) mounted by
	 * launch_UOS.sh, we need mount its data partition to loop device
	 */
	char loop_dev_tmp[32];
	int i;
	int res;
	int devnr;

	if (!file_exists(android_img)) {
		LOGW("img(%s) is not available\n", android_img);
		return NULL;
	}

	devnr = loopdev_num_get_free();
	if (devnr < 0) {
		LOGE("failed to get free loop device\n");
		return NULL;
	}

	for (i = 0; i < devnr; i++) {
		res = snprintf(loop_dev_tmp, ARRAY_SIZE(loop_dev_tmp),
			       "/dev/loop%d", i);
		if (s_not_expect(res, ARRAY_SIZE(loop_dev_tmp)))
			return NULL;

		if (loopdev_check_parname(loop_dev_tmp,
					  ANDROID_DATA_PAR_NAME)) {
			loop_dev = strdup(loop_dev_tmp);
			if (!loop_dev) {
				LOGE("out of memory\n");
				return NULL;
			}
			return loop_dev;
		}
	}

	res = asprintf(&loop_dev, "/dev/loop%d", devnr);
	if (res == -1) {
		LOGE("out of memory\n");
		return NULL;
	}

	res = loopdev_set_img_par(loop_dev, android_img, ANDROID_DATA_PAR_NAME);
	if (res == -1) {
		LOGE("failed to setup loopdev.\n");
		free(loop_dev);
		loop_dev = NULL;
		return NULL;
	}

	return loop_dev;
}

/* This function searches all android vms' new events and call the fn for
 * each event.
 *
 * Note that: fn should return VMEVT_HANDLED to indicate event has been handled.
 *	      fn will be called in a time loop if it returns VMEVT_DEFER.
 */
void refresh_vm_history(struct sender_t *sender,
		int (*fn)(const char*, size_t, const struct vm_t *))
{
	struct vm_t *vm;
	int id;

	if (!sender)
		return;

	if (!loop_dev) {
		loop_dev = setup_loop_dev();
		if (!loop_dev)
			return;
		LOGI("setup loop dev successful\n");
	}

	if (vmrecord_gen_ifnot_exists(&sender->vmrecord) == -1) {
		LOGE("failed to create vmrecord\n");
		return;
	}

	get_last_evt_detected(sender);
	get_vms_history(sender);

	/* read events from vmrecords and mark them as ongoing */
	fire_detected_events(sender, fn);

	/* add events to vmrecords */
	detect_new_events(sender);

	for_each_vm(id, vm, conf) {
		if (!vm)
			continue;
		if (vm->history_data) {
			free(vm->history_data);
			vm->history_data = NULL;
		}
	}
}

int android_event_analyze(const char *msg, size_t len, char **result,
			size_t *rsize)
{
	char *data;
	char *tail;
	size_t data_len;
	char event[ANDROID_WORD_LEN];
	char longtime[ANDROID_WORD_LEN];
	char type[ANDROID_WORD_LEN];
	char rest[PATH_MAX];
	char vmkey[ANDROID_WORD_LEN];
	const char * const format =
		ANDROID_ENEVT_FMT ANDROID_KEY_FMT ANDROID_LONGTIME_FMT
		ANDROID_TYPE_FMT ANDROID_LINE_REST_FMT;

	if (str_split_ere(msg, len, format, strlen(format), event,
			  sizeof(event), vmkey, sizeof(vmkey), longtime,
			  sizeof(longtime), type, sizeof(type), rest,
			  sizeof(rest)) != 5) {
		LOGE("try to analyze an invalid line (%s), skip\n", msg);
		return -1;
	}

	data_len = strnlen(vmkey, sizeof(vmkey)) + 1;
	data_len += strnlen(event, sizeof(event)) + 1;
	data_len += strnlen(type, sizeof(type)) + 1;
	data_len += strnlen(rest, sizeof(rest)) + 1;

	data = malloc(data_len);
	if (!data)
		return -1;
	tail = (char *)mempcpy(data, vmkey, strnlen(vmkey, sizeof(vmkey)));
	*(tail++) = '\0';
	tail = (char *)mempcpy(tail, event, strnlen(event, sizeof(event)));
	*(tail++) = '\0';
	tail = (char *)mempcpy(tail, type, strnlen(type, sizeof(type)));
	*(tail++) = '\0';
	*(char *)mempcpy(tail, rest, strnlen(rest, sizeof(rest))) = '\0';

	*result = data;
	*rsize = data_len;
	return 0;
}