/* Copyright (C) 2006 Timo Sirainen */

#include "lib.h"
#include "array.h"
#include "mail-storage.h"
#include "mail-search.h"
#include "squat-trie.h"
#include "fts-squat-plugin.h"

#define SQUAT_FILE_PREFIX "dovecot.index.search"

struct squat_fts_backend {
	struct fts_backend backend;
	struct squat_trie *trie;

	uint32_t last_uid;
};

static struct fts_backend *fts_backend_squat_init(struct mailbox *box)
{
	struct squat_fts_backend *backend;
	struct mail_storage *storage;
	const char *path;

	storage = mailbox_get_storage(box);
	path = mail_storage_get_mailbox_index_dir(storage,
						  mailbox_get_name(box));
	if (*path == '\0') {
		/* in-memory indexes */
		return NULL;
	}

	backend = i_new(struct squat_fts_backend, 1);
	backend->backend = fts_backend_squat;
	backend->trie =
		squat_trie_open(t_strconcat(path, "/"SQUAT_FILE_PREFIX, NULL));
	return &backend->backend;
}

static void fts_backend_squat_deinit(struct fts_backend *_backend)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;

	squat_trie_close(backend->trie);
	i_free(backend);
}

static int fts_backend_squat_get_last_uid(struct fts_backend *_backend,
					  uint32_t *last_uid_r)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;

	*last_uid_r = backend->last_uid;
	return 0;
}

static struct fts_backend_build_context *
fts_backend_squat_build_init(struct fts_backend *_backend, uint32_t *last_uid_r)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;
	struct fts_backend_build_context *ctx;

	*last_uid_r = backend->last_uid;

	ctx = i_new(struct fts_backend_build_context, 1);
	ctx->backend = _backend;
	return ctx;
}

static int
fts_backend_squat_build_more(struct fts_backend_build_context *ctx,
			     uint32_t uid, const unsigned char *data,
			     size_t size)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)ctx->backend;

	i_assert(uid >= backend->last_uid);
	backend->last_uid = uid;

	return squat_trie_add(backend->trie, uid, data, size);
}

static int
fts_backend_squat_build_deinit(struct fts_backend_build_context *ctx)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)ctx->backend;

	squat_trie_flush(backend->trie);
	i_free(ctx);
	return 0;
}

static void
fts_backend_squat_expunge(struct fts_backend *_backend __attr_unused__,
			  struct mail *mail __attr_unused__)
{
}

static int get_uids(struct mailbox *box, ARRAY_TYPE(seq_range) *uids,
		    unsigned int *message_count_r)
{
	struct mail_search_arg search_arg;
        struct mailbox_transaction_context *t;
	struct mail_search_context *ctx;
	struct mail *mail;
	unsigned int count = 0;
	int ret;

	memset(&search_arg, 0, sizeof(search_arg));
	search_arg.type = SEARCH_ALL;

	t = mailbox_transaction_begin(box, 0);
	ctx = mailbox_search_init(t, NULL, &search_arg, NULL);

	mail = mail_alloc(t, 0, NULL);
	while (mailbox_search_next(ctx, mail) > 0) {
		seq_range_array_add(uids, 0, mail->uid);
		count++;
	}
	mail_free(&mail);

	ret = mailbox_search_deinit(&ctx);
	mailbox_transaction_rollback(&t);

	*message_count_r = count;
	return ret;
}

static void
fts_backend_squat_expunge_finish(struct fts_backend *_backend,
				 struct mailbox *box, bool committed)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;
	ARRAY_TYPE(seq_range) uids = ARRAY_INIT;
	unsigned int count;

	if (!committed)
		return;

	t_push();
	t_array_init(&uids, 128);
	if (get_uids(box, &uids, &count) == 0) {
		(void)squat_trie_mark_having_expunges(backend->trie, &uids,
						      count);
	}
	t_pop();
}

static int
fts_backend_squat_lookup(struct fts_backend *_backend, const char *key,
			 ARRAY_TYPE(seq_range) *result)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;

	return squat_trie_lookup(backend->trie, result, key);
}

static int
fts_backend_squat_filter(struct fts_backend *_backend, const char *key,
			 ARRAY_TYPE(seq_range) *result)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;

	return squat_trie_filter(backend->trie, result, key);
}

struct fts_backend fts_backend_squat = {
	MEMBER(name) "squat",
	MEMBER(definite_lookups) FALSE,

	{
		fts_backend_squat_init,
		fts_backend_squat_deinit,
		fts_backend_squat_get_last_uid,
		fts_backend_squat_build_init,
		fts_backend_squat_build_more,
		fts_backend_squat_build_deinit,
		fts_backend_squat_expunge,
		fts_backend_squat_expunge_finish,
		fts_backend_squat_lookup,
		fts_backend_squat_filter
	}
};