// SPDX-License-Identifier: GPL-3.0-or-later
// Copyright (C) 2013 Andrea Mazzoleni

#include "os/portable.h"

#include "util.h"
#include "elem.h"
#include "import.h"
#include "state.h"
#include "parity.h"
#include "handle.h"
#include "raid/raid.h"

/****************************************************************************/
/* rehash */

void state_rehash(struct snapraid_state* state)
{
	block_off_t blockmax;
	block_off_t i;
	int has_pending_dealloc = 0;

	blockmax = parity_allocated_size(state);

	/* check if a rehash is already in progress */
	if (state->prevhash != HASH_UNDEFINED) {
		/* LCOV_EXCL_START */
		log_tag("summary:exit:already_in_progress\n");
		log_fatal(EUSER, "You already have a rehash in progress.\n");
		exit(EXIT_FAILURE);
		/* LCOV_EXCL_STOP */
	}

	if (state->hash == state->besthash) {
		/* LCOV_EXCL_START */
		log_tag("summary:exit:not_required\n");
		log_fatal(EUSER, "You are already using the best hash for your platform.\n");
		exit(EXIT_FAILURE);
		/* LCOV_EXCL_STOP */
	}

	/* deleted-only positions are not counted in unsynced_blocks, but their hashes still need the current generation */
	for (tommy_node* node = state->disklist; node != 0; node = node->next) {
		struct snapraid_disk* disk = node->data;
		if (!tommy_list_empty(&disk->dealloclist)) {
			has_pending_dealloc = 1;
			break;
		}
	}

	/* a rehash can start only from a fully synchronized state */
	if (state->unsynced_blocks != 0 || has_pending_dealloc) {
		/* LCOV_EXCL_START */
		log_tag("summary:exit:sync_required\n");
		log_fatal(EUSER, "You cannot start a rehash with an incomplete sync.\n");
		log_fatal(EUSER, "Run 'snapraid sync' first.\n");
		exit(EXIT_FAILURE);
		/* LCOV_EXCL_STOP */
	}

	/* copy the present hash as previous one */
	state->prevhash = state->hash;
	memcpy(state->prevhashseed, state->hashseed, HASH_MAX);

	/* set the new hash and seed */
	state->hash = state->besthash;
	if (os_randomize(state->hashseed, HASH_MAX) != 0) {
		/* LCOV_EXCL_START */
		log_fatal(errno, "Failed to get random values.\n");
		exit(EXIT_FAILURE);
		/* LCOV_EXCL_STOP */
	}

	/* mark all the block for rehashing */
	for (i = 0; i < blockmax; ++i) {
		snapraid_info info;

		/* if it's unused */
		info = info_get(&state->infoarr, i);
		if (info == 0) {
			/* skip it */
			continue;
		}

		if (info_get_rehash(info)) {
			/* LCOV_EXCL_START */
			log_fatal(EINTERNAL, "Internal inconsistency for a rehash already in progress\n");
			os_abort();
			/* LCOV_EXCL_STOP */
		}

		/* enable the rehash */
		info = info_set_rehash(info);

		/* save it */
		info_set(&state->infoarr, i, info);
	}

	/* save the new content file */
	state->need_write = 1;

	msg_status("A rehash is now scheduled. It will take place progressively in the next\n");
	msg_status("'sync' and 'scrub' commands. You can check the rehash progress using the\n");
	msg_status("'status' command.\n");
	log_tag("summary:exit:scheduled\n");
}