/* Copyright (c) 2007-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "index-rebuild.h"
#include "mail-cache.h"
#include "sdbox-storage.h"
#include "sdbox-file.h"
#include "sdbox-sync.h"

#include <dirent.h>

static void sdbox_sync_set_uidvalidity(struct index_rebuild_context *ctx)
{
	uint32_t uid_validity;

	/* if uidvalidity is set in the old index, use it */
	uid_validity = mail_index_get_header(ctx->view)->uid_validity;
	if (uid_validity == 0)
		uid_validity = dbox_get_uidvalidity_next(ctx->box->list);

	mail_index_update_header(ctx->trans,
		offsetof(struct mail_index_header, uid_validity),
		&uid_validity, sizeof(uid_validity), TRUE);
}

static int
sdbox_sync_add_file_index(struct index_rebuild_context *ctx,
			  struct dbox_file *file, uint32_t uid, bool primary)
{
	uint32_t seq;
	bool deleted;
	int ret;

	if ((ret = dbox_file_open(file, &deleted)) > 0) {
		if (deleted)
			return 0;
		ret = dbox_file_seek(file, 0);
	}
	if (ret == 0) {
		if ((ret = dbox_file_fix(file, 0)) > 0)
			ret = dbox_file_seek(file, 0);
	}

	if (ret <= 0) {
		if (ret < 0)
			return -1;

		i_warning("sdbox: Skipping unfixable file: %s", file->cur_path);
		return 0;
	}

	if (!dbox_file_is_in_alt(file) && !primary) {
		/* we were supposed to open the file in alt storage, but it
		   exists in primary storage as well. skip it to avoid adding
		   it twice. */
		return 0;
	}

	mail_index_append(ctx->trans, uid, &seq);
	T_BEGIN {
		index_rebuild_index_metadata(ctx, seq, uid);
	} T_END;
	return 0;
}

static int
sdbox_sync_add_file(struct index_rebuild_context *ctx,
		    const char *fname, bool primary)
{
	struct sdbox_mailbox *mbox = SDBOX_MAILBOX(ctx->box);
	struct dbox_file *file;
	uint32_t uid;
	int ret;

	if (!str_begins(fname, SDBOX_MAIL_FILE_PREFIX))
		return 0;
	fname += strlen(SDBOX_MAIL_FILE_PREFIX);

	if (str_to_uint32(fname, &uid) < 0 || uid == 0) {
		i_warning("sdbox %s: Ignoring invalid filename %s",
			  mailbox_get_path(ctx->box), fname);
		return 0;
	}

	file = sdbox_file_init(mbox, uid);
	if (!primary)
		file->cur_path = file->alt_path;
	ret = sdbox_sync_add_file_index(ctx, file, uid, primary);
	dbox_file_unref(&file);
	return ret;
}

static int sdbox_sync_index_rebuild_dir(struct index_rebuild_context *ctx,
					const char *path, bool primary)
{
	DIR *dir;
	struct dirent *d;
	int ret = 0;

	dir = opendir(path);
	if (dir == NULL) {
		if (errno == ENOENT) {
			if (!primary) {
				/* alt directory doesn't exist, ignore */
				return 0;
			}
			return index_mailbox_fix_inconsistent_existence(ctx->box, path);
		}
		mailbox_set_critical(ctx->box, "opendir(%s) failed: %m", path);
		return -1;
	}
	do {
		errno = 0;
		if ((d = readdir(dir)) == NULL)
			break;

		ret = sdbox_sync_add_file(ctx, d->d_name, primary);
	} while (ret >= 0);
	if (errno != 0) {
		mailbox_set_critical(ctx->box, "readdir(%s) failed: %m", path);
		ret = -1;
	}

	if (closedir(dir) < 0) {
		mailbox_set_critical(ctx->box, "closedir(%s) failed: %m", path);
		ret = -1;
	}
	return ret;
}

static void sdbox_sync_update_header(struct index_rebuild_context *ctx)
{
	struct sdbox_mailbox *mbox = SDBOX_MAILBOX(ctx->box);
	struct sdbox_index_header hdr;
	bool need_resize;

	if (sdbox_read_header(mbox, &hdr, FALSE, &need_resize) < 0)
		i_zero(&hdr);
	if (guid_128_is_empty(hdr.mailbox_guid))
		guid_128_generate(hdr.mailbox_guid);
	if (++hdr.rebuild_count == 0)
		hdr.rebuild_count = 1;
	/* mailbox is being reset. this gets written directly there */
	mail_index_set_ext_init_data(ctx->box->index, mbox->hdr_ext_id,
				     &hdr, sizeof(hdr));
}

static int
sdbox_sync_index_rebuild_singles(struct index_rebuild_context *ctx)
{
	const char *path, *alt_path;
	int ret = 0;

	path = mailbox_get_path(ctx->box);
	if (mailbox_get_path_to(ctx->box, MAILBOX_LIST_PATH_TYPE_ALT_MAILBOX,
				&alt_path) < 0)
		return -1;

	sdbox_sync_set_uidvalidity(ctx);
	if (sdbox_sync_index_rebuild_dir(ctx, path, TRUE) < 0) {
		mailbox_set_critical(ctx->box, "sdbox: Rebuilding failed");
		ret = -1;
	} else if (alt_path != NULL) {
		if (sdbox_sync_index_rebuild_dir(ctx, alt_path, FALSE) < 0) {
			mailbox_set_critical(ctx->box,
				"sdbox: Rebuilding failed on alt path %s",
				alt_path);
			ret = -1;
		}
	}
	sdbox_sync_update_header(ctx);
	return ret;
}

int sdbox_sync_index_rebuild(struct sdbox_mailbox *mbox, bool force)
{
	struct index_rebuild_context *ctx;
	struct mail_index_view *view;
	struct mail_index_transaction *trans;
	struct sdbox_index_header hdr;
	bool need_resize;
	int ret;

	if (!force && sdbox_read_header(mbox, &hdr, FALSE, &need_resize) == 0) {
		if (hdr.rebuild_count != mbox->corrupted_rebuild_count &&
		    hdr.rebuild_count != 0) {
			/* already rebuilt by someone else */
			return 0;
		}
	}
	i_warning("sdbox %s: Rebuilding index", mailbox_get_path(&mbox->box));

	if (dbox_verify_alt_storage(mbox->box.list) < 0) {
		mailbox_set_critical(&mbox->box,
			"sdbox: Alt storage not mounted, "
			"aborting index rebuild");
		return -1;
	}

	view = mail_index_view_open(mbox->box.index);
	trans = mail_index_transaction_begin(view,
					MAIL_INDEX_TRANSACTION_FLAG_EXTERNAL);

	ctx = index_index_rebuild_init(&mbox->box, view, trans);
	ret = sdbox_sync_index_rebuild_singles(ctx);
	index_index_rebuild_deinit(&ctx, dbox_get_uidvalidity_next);

	if (ret < 0)
		mail_index_transaction_rollback(&trans);
	else {
		mail_index_unset_fscked(trans);
		ret = mail_index_transaction_commit(&trans);
	}
	mail_index_view_close(&view);
	mbox->corrupted_rebuild_count = 0;
	return ret;
}