/*
 * Copyright (C) 2011 Andrea Mazzoleni
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include "portable.h"

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

/****************************************************************************/
/* sync */

static int state_sync_process(struct snapraid_state* state, struct snapraid_parity* parity, struct snapraid_parity* qarity, block_off_t blockstart, block_off_t blockmax)
{
	struct snapraid_handle* handle;
	unsigned diskmax;
	block_off_t i;
	unsigned j;
	void* buffer_alloc;
	unsigned char* buffer_aligned;
	unsigned char** buffer;
	unsigned buffermax;
	data_off_t countsize;
	block_off_t countpos;
	block_off_t countmax;
	block_off_t autosavedone;
	block_off_t autosavelimit;
	block_off_t autosavemissing;
	int ret;
	unsigned unrecoverable_error;

	/* maps the disks to handles */
	handle = handle_map(state, &diskmax);

	/* we need disk + 1 for each parity level buffers */
	buffermax = diskmax + state->level;

	buffer_aligned = malloc_nofail_align(buffermax * state->block_size, &buffer_alloc);
	buffer = malloc_nofail(buffermax * sizeof(void*));
	for(i=0;i<buffermax;++i) {
		buffer[i] = buffer_aligned + i * state->block_size;
	}

	unrecoverable_error = 0;

	/* first count the number of blocks to process */
	countmax = 0;
	for(i=blockstart;i<blockmax;++i) {
		int one_invalid;
		int one_valid;

		/* for each disk */
		one_invalid = 0;
		one_valid = 0;
		for(j=0;j<diskmax;++j) {
			struct snapraid_block* block = BLOCK_EMPTY;
			if (handle[j].disk)
				block = disk_block_get(handle[j].disk, i);

			if (block_has_file(block)) {
				one_valid = 1;
			}
			if (block_has_invalid_parity(block)) {
				one_invalid = 1;
			}
		}

		/* if none valid or none invalid, we don't need to update */
		if (!one_invalid || !one_valid) {
			continue;
		}

		++countmax;
	}

	/* compute the autosave size for all disk, even if not read */
	/* this makes sense because the speed should be almost the same */
	/* if the disks are read in parallel */
	autosavelimit = state->autosave / (diskmax * state->block_size);
	autosavemissing = countmax; /* blocks to do */
	autosavedone = 0; /* blocks done */

	countsize = 0;
	countpos = 0;
	state_progress_begin(state, blockstart, blockmax, countmax);
	for(i=blockstart;i<blockmax;++i) {
		int one_invalid;
		int one_valid;
		int skip_this_block;
		int ret;

		/* for each disk */
		one_invalid = 0;
		one_valid = 0;
		for(j=0;j<diskmax;++j) {
			struct snapraid_block* block = BLOCK_EMPTY;
			if (handle[j].disk)
				block = disk_block_get(handle[j].disk, i);

			if (block_has_file(block)) {
				one_valid = 1;
			}
			if (block_has_invalid_parity(block)) {
				one_invalid = 1;
			}
		}

		/* if none valid or none invalid, we don't need to update */
		if (!one_invalid || !one_valid) {
			/* cleanup all the deleted blocks at this position */
			for(j=0;j<diskmax;++j) {
				struct snapraid_block* block = BLOCK_EMPTY;
				if (handle[j].disk)
					block = disk_block_get(handle[j].disk, i);

				/* if the block is deleted */
				if (block_state_get(block) == BLOCK_STATE_DELETED) {
					/* set it to empty */
					tommy_array_set(&handle[j].disk->blockarr, i, BLOCK_EMPTY);

					/* mark the state as needing write */
					state->need_write = 1;
				}
			}

			/* skip */
			continue;
		}

		/* one more block processed for autosave */
		++autosavedone;
		--autosavemissing;

		/* by default process the block, and skip it if something go wrong */
		skip_this_block = 0;

		/* for each disk, process the block */
		for(j=0;j<diskmax;++j) {
			int read_size;
			unsigned char hash[HASH_SIZE];
			struct snapraid_block* block;

			/* if the disk position is not used */
			if (!handle[j].disk) {
				/* use an empty block */
				memset(buffer[j], 0, state->block_size);
				continue;
			}

			/* if the block is not used */
			block = disk_block_get(handle[j].disk, i);
			if (!block_has_file(block)) {
				/* use an empty block */
				memset(buffer[j], 0, state->block_size);
				continue;
			}

			/* if the file is different than the current one, close it */
			if (handle[j].file != block_file_get(block)) {
				ret = handle_close(&handle[j]);
				if (ret == -1) {
					/* This one is really an unexpected error, because we are only reading */
					/* and closing a descriptor should never fail */
					fprintf(stderr, "DANGER! Unexpected close error in a data disk, it isn't possible to sync.\n");
					printf("Stopping at block %u\n", i);
					++unrecoverable_error;
					goto bail;
				}
			}

			ret = handle_open(&handle[j], block_file_get(block));
			if (ret == -1) {
				if (errno == ENOENT) {
					fprintf(stderr, "Missing file '%s'.\n", handle[j].path);
					fprintf(stderr, "WARNING! You cannot modify data disk during a sync. Rerun the sync command when finished.\n");

					++unrecoverable_error;

					/* if the file is missing, it means that it was removed during sync */
					/* this isn't a serious error, so we skip this block, and continue with others */
					skip_this_block = 1;
					continue;
				} else if (errno == EACCES) {
					fprintf(stderr, "No access at file '%s'.\n", handle[j].path);
					fprintf(stderr, "WARNING! Please fix the access permission in the data disk.\n");
					printf("Stopping at block %u\n", i);
				} else {
					fprintf(stderr, "DANGER! Unexpected open error in a data disk, it isn't possible to sync.\n");
					printf("Stopping to allow recovery. Try with 'snapraid check'\n");
				}

				++unrecoverable_error;
				goto bail;
			}

			/* check if the file is changed */
			if (handle[j].st.st_size != block_file_get(block)->size
				|| handle[j].st.st_mtime != block_file_get(block)->mtime_sec
				|| STAT_NSEC(&handle[j].st) != block_file_get(block)->mtime_nsec
				|| handle[j].st.st_ino != block_file_get(block)->inode
			) {
				if (handle[j].st.st_size != block_file_get(block)->size)
					fprintf(stderr, "Unexpected size change at file '%s'.\n", handle[j].path);
				else if (handle[j].st.st_mtime != block_file_get(block)->mtime_sec
					|| STAT_NSEC(&handle[j].st) != block_file_get(block)->mtime_nsec)
					fprintf(stderr, "Unexpected time change at file '%s'.\n", handle[j].path);
				else
					fprintf(stderr, "Unexpected inode change from %"PRIu64" to %"PRIu64" at file '%s'.\n", block_file_get(block)->inode, (uint64_t)handle[j].st.st_ino, handle[j].path);
				fprintf(stderr, "WARNING! You cannot modify files during a sync. Rerun the sync command when finished.\n");

				++unrecoverable_error;

				/* if the file is changed, it means that it was modified during sync */
				/* this isn't a serious error, so we skip this block, and continue with others */
				skip_this_block = 1;
				continue;
			}

			read_size = handle_read(&handle[j], block, buffer[j], state->block_size);
			if (read_size == -1) {
				fprintf(stderr, "DANGER! Unexpected read error in a data disk, it isn't possible to sync.\n");
				printf("Stopping to allow recovery. Try with 'snapraid check'\n");
				++unrecoverable_error;
				goto bail;
			}

			countsize += read_size;

			/* now compute the hash */
			memhash(state->hash, hash, buffer[j], read_size);

			if (block_has_hash(block)) {
				/* compare the hash */
				if (memcmp(hash, block->hash, HASH_SIZE) != 0) {
					fprintf(stderr, "%u: Data error for file %s at position %u\n", i, block_file_get(block)->sub, block_file_pos(block));
					fprintf(stderr, "DANGER! Unexpected data error in a data disk, it isn't possible to sync.\n");
					printf("Stopping to allow recovery. Try with 'snapraid -s %u check'\n", i);
					++unrecoverable_error;
					goto bail;
				}
			} else {
				/* copy the hash, but doesn't mark the block as hashed */
				/* this allow on error to do not save the failed computation */
				memcpy(block->hash, hash, HASH_SIZE);
			}
		}

		/* if we have read all the data required, proceed with the parity */
		if (!skip_this_block) {

			/* compute the parity */
			raid_gen(state->level, buffer, diskmax, state->block_size);

			/* write the parity */
			ret = parity_write(parity, i, buffer[diskmax], state->block_size);
			if (ret == -1) {
				fprintf(stderr, "DANGER! Write error in the Parity disk, it isn't possible to sync.\n");
				printf("Stopping at block %u\n", i);
				++unrecoverable_error;
				goto bail;
			}

			/* write the qarity */
			if (state->level >= 2) {
				ret = parity_write(qarity, i, buffer[diskmax+1], state->block_size);
				if (ret == -1) {
					fprintf(stderr, "DANGER! Write error in the Q-Parity disk, it isn't possible to sync.\n");
					printf("Stopping at block %u\n", i);
					++unrecoverable_error;
					goto bail;
				}
			}

			/* for each disk, mark the blocks as processed */
			for(j=0;j<diskmax;++j) {
				struct snapraid_block* block = BLOCK_EMPTY;
				if (handle[j].disk)
					block = disk_block_get(handle[j].disk, i);

				if (block == BLOCK_EMPTY) {
					/* nothing to do */
					continue;
				}

				/* if it's a deleted block */
				if (block_state_get(block) == BLOCK_STATE_DELETED) {
					/* the parity is now updated without this block, so it's now empty */
					tommy_array_set(&handle[j].disk->blockarr, i, BLOCK_EMPTY);
					continue;
				}

				/* now all the blocks have the hash and the parity computed */
				block_state_set(block, BLOCK_STATE_BLK);
			}
		}

		/* mark the state as needing write */
		state->need_write = 1;

		/* count the number of processed block */
		++countpos;

		/* progress */
		if (state_progress(state, i, countpos, countmax, countsize)) {
			break;
		}

		/* autosave */
		if (state->autosave != 0
			&& autosavedone >= autosavelimit /* if we have reached the limit */
			&& autosavemissing >= autosavelimit /* if we have at least a full step to do */
		) {
			autosavedone = 0; /* restart the counter */

			state_progress_stop(state);

			printf("Autosaving...\n");
			state_write(state);

			state_progress_restart(state);
		}
	}

	state_progress_end(state, countpos, countmax, countsize);

bail:
	for(j=0;j<diskmax;++j) {
		ret = handle_close(&handle[j]);
		if (ret == -1) {
			fprintf(stderr, "DANGER! Unexpected close error in a data disk.\n");
			++unrecoverable_error;
			/* continue, as we are already exiting */
		}
	}

	free(handle);
	free(buffer_alloc);
	free(buffer);

	if (unrecoverable_error != 0)
		return -1;
	return 0;
}

int state_sync(struct snapraid_state* state, block_off_t blockstart, block_off_t blockcount)
{
	block_off_t blockmax;
	data_off_t loaded_size;
	data_off_t size;
	data_off_t out_size;
	tommy_node* i;
	int ret;
	struct snapraid_parity parity;
	struct snapraid_parity qarity;
	struct snapraid_parity* parity_ptr;
	struct snapraid_parity* qarity_ptr;
	unsigned unrecoverable_error;

	printf("Initializing...\n");

	blockmax = parity_size(state);
	size = blockmax * (data_off_t)state->block_size;
	loaded_size = state->loaded_blockmax * (data_off_t)state->block_size;

	/* remove all the deleted blocks over the new parity size */
	/* we know for sure that after the parity size, there is no used block */
	/* and then it's safe to lose any deleted block info */
	for(i=state->disklist;i!=0;i=i->next) {
		struct snapraid_disk* disk = i->data;
		block_off_t diskblockmax = tommy_array_size(&disk->blockarr);
		block_off_t block_pos;

		for(block_pos=blockmax;block_pos<diskblockmax;++block_pos) {
			struct snapraid_block* block = tommy_array_get(&disk->blockarr, block_pos);
			if (block_state_get(block) == BLOCK_STATE_DELETED) {
				tommy_array_set(&disk->blockarr, block_pos, BLOCK_EMPTY);

				/* mark the state as needing write */
				state->need_write = 1;
			}
		}
	}

	if (blockstart > blockmax) {
		fprintf(stderr, "Error in the starting block %u. It's bigger than the parity size %u.\n", blockstart, blockmax);
		exit(EXIT_FAILURE);
	}

	/* adjust the number of block to process */
	if (blockcount != 0 && blockstart + blockcount < blockmax) {
		blockmax = blockstart + blockcount;
	}

	/* create the file and open for writing */
	parity_ptr = &parity;
	ret = parity_create(parity_ptr, state->parity, &out_size);
	if (ret == -1) {
		fprintf(stderr, "WARNING! Without an accessible Parity file, it isn't possible to sync.\n");
		exit(EXIT_FAILURE);
	}

	/* if the file is too small */
	if (out_size < loaded_size) {
		fprintf(stderr, "DANGER! The Parity file %s is smaller than the expected %" PRId64 ".\n", state->parity, loaded_size);
		exit(EXIT_FAILURE);
	}

	ret = parity_chsize(parity_ptr, size, &out_size);
	if (ret == -1) {
		parity_overflow(state, out_size);
		fprintf(stderr, "WARNING! Without an accessible Parity file, it isn't possible to sync.\n");
		exit(EXIT_FAILURE);
	}

	if (state->level >= 2) {
		qarity_ptr = &qarity;
		ret = parity_create(qarity_ptr, state->qarity, &out_size);
		if (ret == -1) {
			fprintf(stderr, "WARNING! Without an accessible Q-Parity file, it isn't possible to sync.\n");
			exit(EXIT_FAILURE);
		}

		/* if the file is too small */
		if (out_size < loaded_size) {
			fprintf(stderr, "DANGER! The Q-Parity file %s is smaller than the expected %" PRId64 ".\n", state->qarity, loaded_size);
			exit(EXIT_FAILURE);
		}

		ret = parity_chsize(qarity_ptr, size, &out_size);
		if (ret == -1) {
			parity_overflow(state, out_size);
			fprintf(stderr, "WARNING! Without an accessible Q-Parity file, it isn't possible to sync.\n");
			exit(EXIT_FAILURE);
		}
	} else {
		qarity_ptr = 0;
	}

	printf("Syncing...\n");

	unrecoverable_error = 0;

	/* skip degenerated cases of empty parity, or skipping all */
	if (blockstart < blockmax) {
		ret = state_sync_process(state, parity_ptr, qarity_ptr, blockstart, blockmax);
		if (ret == -1) {
			++unrecoverable_error;
			/* continue, as we are already exiting */
		}
	} else {
		printf("Nothing to do\n");
	}

	ret = parity_sync(parity_ptr);
	if (ret == -1) {
		fprintf(stderr, "DANGER! Unexpected sync error in Parity disk.\n");
		++unrecoverable_error;
		/* continue, as we are already exiting */
	}

	ret = parity_close(parity_ptr);
	if (ret == -1) {
		fprintf(stderr, "DANGER! Unexpected close error in Parity disk.\n");
		++unrecoverable_error;
		/* continue, as we are already exiting */
	}

	if (state->level >= 2) {
		ret = parity_sync(qarity_ptr);
		if (ret == -1) {
			fprintf(stderr, "DANGER! Unexpected sync error in Q-Parity disk.\n");
			++unrecoverable_error;
			/* continue, as we are already exiting */
		}

		ret = parity_close(qarity_ptr);
		if (ret == -1) {
			fprintf(stderr, "DANGER! Unexpected close error in Q-Parity disk.\n");
			++unrecoverable_error;
			/* continue, as we are already exiting */
		}
	}

	/* abort if required */
	if (unrecoverable_error != 0)
		return -1;
	return 0;
}