/* Copyright (c) 2006-2009 Dovecot authors, see the included COPYING file */

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

#include <stdlib.h>

#define SQUAT_FILE_PREFIX "dovecot.index.search"

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

struct squat_fts_backend_build_context {
	struct fts_backend_build_context ctx;
	struct squat_trie_build_context *build_ctx;
};

static void
fts_backend_squat_set(struct squat_fts_backend *backend, const char *str)
{
	const char *const *tmp;
	int len;

	for (tmp = t_strsplit_spaces(str, " "); *tmp != NULL; tmp++) {
		if (strncmp(*tmp, "partial=", 8) == 0) {
			len = atoi(*tmp + 8);
			if (len <= 0) {
				i_fatal("fts_squat: Invalid partial len: %s",
					*tmp + 8);
			}
			squat_trie_set_partial_len(backend->trie, len);
		} else if (strncmp(*tmp, "full=", 5) == 0) {
			len = atoi(*tmp + 5);
			if (len <= 0) {
				i_fatal("fts_squat: Invalid full len: %s",
					*tmp + 5);
			}
			squat_trie_set_full_len(backend->trie, len);
		} else {
			i_fatal("fts_squat: Invalid setting: %s", *tmp);
		}
	}
}

static struct fts_backend *fts_backend_squat_init(struct mailbox *box)
{
	struct squat_fts_backend *backend;
	struct mail_storage *storage;
	struct mailbox_status status;
	const char *path, *env;
	enum squat_index_flags flags = 0;

	storage = mailbox_get_storage(box);
	path = mail_storage_get_mailbox_index_dir(storage,
						  mailbox_get_name(box));
	if (*path == '\0') {
		/* in-memory indexes */
		if ((storage->flags & MAIL_STORAGE_FLAG_DEBUG) != 0)
			i_info("fts squat: Disabled with in-memory indexes");
		return NULL;
	}

	mailbox_get_status(box, STATUS_UIDVALIDITY, &status);
	if ((storage->flags & (MAIL_STORAGE_FLAG_MMAP_DISABLE |
			       MAIL_STORAGE_FLAG_MMAP_NO_WRITE)) != 0)
		flags |= SQUAT_INDEX_FLAG_MMAP_DISABLE;
	if ((storage->flags & MAIL_STORAGE_FLAG_NFS_FLUSH_INDEX) != 0)
		flags |= SQUAT_INDEX_FLAG_NFS_FLUSH;
	if ((storage->flags & MAIL_STORAGE_FLAG_DOTLOCK_USE_EXCL) != 0)
		flags |= SQUAT_INDEX_FLAG_DOTLOCK_USE_EXCL;

	backend = i_new(struct squat_fts_backend, 1);
	backend->backend = fts_backend_squat;
	backend->trie =
		squat_trie_init(t_strconcat(path, "/"SQUAT_FILE_PREFIX, NULL),
				status.uidvalidity, storage->lock_method,
				flags, box->file_create_mode,
				box->file_create_gid);

	env = getenv("FTS_SQUAT");
	if (env != NULL)
		fts_backend_squat_set(backend, env);
	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_deinit(&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;

	return squat_trie_get_last_uid(backend->trie, last_uid_r);
}

static int
fts_backend_squat_build_init(struct fts_backend *_backend, uint32_t *last_uid_r,
			     struct fts_backend_build_context **ctx_r)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;
	struct squat_fts_backend_build_context *ctx;
	struct squat_trie_build_context *build_ctx;

	if (squat_trie_build_init(backend->trie, last_uid_r, &build_ctx) < 0)
		return -1;

	ctx = i_new(struct squat_fts_backend_build_context, 1);
	ctx->ctx.backend = _backend;
	ctx->build_ctx = build_ctx;

	*ctx_r = &ctx->ctx;
	return 0;
}

static int
fts_backend_squat_build_more(struct fts_backend_build_context *_ctx,
			     uint32_t uid, const unsigned char *data,
			     size_t size, bool headers)
{
	struct squat_fts_backend_build_context *ctx =
		(struct squat_fts_backend_build_context *)_ctx;
	enum squat_index_type squat_type;

	squat_type = headers ? SQUAT_INDEX_TYPE_HEADER :
		SQUAT_INDEX_TYPE_BODY;
	return squat_trie_build_more(ctx->build_ctx, uid, squat_type,
				     data, size);
}

static int get_all_msg_uids(struct mailbox *box, ARRAY_TYPE(seq_range) *uids)
{
	struct mailbox_transaction_context *t;
	struct mail_search_context *search_ctx;
	struct mail_search_args *search_args;
	struct mail *mail;
	int ret = 0;

	t = mailbox_transaction_begin(box, 0);
	mail = mail_alloc(t, 0, NULL);

	search_args = mail_search_build_init();
	mail_search_build_add_all(search_args);
	search_ctx = mailbox_search_init(t, search_args, NULL);
	mail_search_args_unref(&search_args);

	while ((ret = mailbox_search_next(search_ctx, mail)) > 0) {
		/* *2 because even/odd is for body/header */
		seq_range_array_add_range(uids, mail->uid * 2,
					  mail->uid * 2 + 1);
	}
	if (mailbox_search_deinit(&search_ctx) < 0)
		ret = -1;
	mail_free(&mail);
	(void)mailbox_transaction_commit(&t);
	return ret;
}

static int
fts_backend_squat_build_deinit(struct fts_backend_build_context *_ctx)
{
	struct squat_fts_backend_build_context *ctx =
		(struct squat_fts_backend_build_context *)_ctx;
	ARRAY_TYPE(seq_range) uids;
	int ret;

	i_array_init(&uids, 1024);
	if (get_all_msg_uids(ctx->ctx.backend->box, &uids) < 0)
		ret = squat_trie_build_deinit(&ctx->build_ctx, NULL);
	else {
		seq_range_array_invert(&uids, 2, (uint32_t)-2);
		ret = squat_trie_build_deinit(&ctx->build_ctx, &uids);
	}
	array_free(&uids);
	i_free(ctx);
	return ret;
}

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

static void
fts_backend_squat_expunge_finish(struct fts_backend *_backend ATTR_UNUSED,
				 struct mailbox *box ATTR_UNUSED,
				 bool committed ATTR_UNUSED)
{
	/* FIXME */
}

static int fts_backend_squat_lock(struct fts_backend *_backend)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;

	squat_trie_refresh(backend->trie);
	return 1;
}

static void fts_backend_squat_unlock(struct fts_backend *_backend ATTR_UNUSED)
{
}

static int
fts_backend_squat_lookup(struct fts_backend *_backend, const char *key,
			 enum fts_lookup_flags flags,
			 ARRAY_TYPE(seq_range) *definite_uids,
			 ARRAY_TYPE(seq_range) *maybe_uids)
{
	struct squat_fts_backend *backend =
		(struct squat_fts_backend *)_backend;
	enum squat_index_type squat_type = 0;

	i_assert((flags & FTS_LOOKUP_FLAG_INVERT) == 0);

	if ((flags & FTS_LOOKUP_FLAG_HEADER) != 0)
		squat_type |= SQUAT_INDEX_TYPE_HEADER;
	if ((flags & FTS_LOOKUP_FLAG_BODY) != 0)
		squat_type |= SQUAT_INDEX_TYPE_BODY;
	i_assert(squat_type != 0);

	return squat_trie_lookup(backend->trie, key, squat_type,
				 definite_uids, maybe_uids);
}

struct fts_backend fts_backend_squat = {
	MEMBER(name) "squat",
	MEMBER(flags) FTS_BACKEND_FLAG_SUBSTRING_LOOKUPS,

	{
		fts_backend_squat_init,
		fts_backend_squat_deinit,
		fts_backend_squat_get_last_uid,
		NULL,
		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_lock,
		fts_backend_squat_unlock,
		fts_backend_squat_lookup,
		NULL,
		NULL
	}
};