/* Copyright (C) 2002-2003 Timo Sirainen */

#include "lib.h"
#include "buffer.h"
#include "ioloop.h"
#include "mail-index.h"
#include "index-storage.h"

#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>

#define DEFAULT_NEVER_CACHE_FIELDS "imap.envelope"

/* How many seconds to keep index opened for reuse after it's been closed */
#define INDEX_CACHE_TIMEOUT 10
/* How many closed indexes to keep */
#define INDEX_CACHE_MAX 3

#define LOCK_NOTIFY_INTERVAL 30

struct index_list {
	struct index_list *next;

	struct mail_index *index;
	char *mailbox_path;
	int refcount;

	dev_t index_dir_dev;
	ino_t index_dir_ino;

	time_t destroy_time;
};

static struct index_list *indexes = NULL;
static struct timeout *to_index = NULL;
static int index_storage_refcount = 0;

void index_storage_init(struct index_storage *storage __attr_unused__)
{
	index_storage_refcount++;
}

void index_storage_deinit(struct index_storage *storage)
{
	i_free(storage->storage.error);

	if (--index_storage_refcount > 0)
		return;

        index_storage_destroy_unrefed();
}

static void index_storage_add(struct mail_index *index,
			      const char *mailbox_path, struct stat *st)
{
	struct index_list *list;

	list = i_new(struct index_list, 1);
	list->refcount = 1;
	list->index = index;

	list->mailbox_path = i_strdup(mailbox_path);
	list->index_dir_dev = st->st_dev;
	list->index_dir_ino = st->st_ino;

	list->next = indexes;
	indexes = list;
}

static void index_list_free(struct index_list *list)
{
	mail_index_free(list->index);
	i_free(list->mailbox_path);
	i_free(list);
}

struct mail_index *
index_storage_alloc(const char *index_dir, const char *mailbox_path,
		    const char *prefix)
{
	struct index_list **list, *rec;
	struct mail_index *index;
	struct stat st;
	int destroy_count;

	if (index_dir == NULL || stat(index_dir, &st) < 0)
		memset(&st, 0, sizeof(st));

	/* compare index_dir inodes so we don't break even with symlinks.
	   for in-memory indexes compare just mailbox paths */
	destroy_count = 0; index = NULL;
	for (list = &indexes; *list != NULL;) {
		rec = *list;

		if ((index_dir != NULL && st.st_ino == rec->index_dir_ino &&
		     CMP_DEV_T(st.st_dev, rec->index_dir_dev)) ||
		    (index_dir == NULL && st.st_ino == 0 &&
		     strcmp(mailbox_path, rec->mailbox_path) == 0)) {
			rec->refcount++;
			index = rec->index;
		}

		if (rec->refcount == 0) {
			if (rec->destroy_time <= ioloop_time ||
			    destroy_count >= INDEX_CACHE_MAX) {
				*list = rec->next;
				index_list_free(rec);
				continue;
			} else {
				destroy_count++;
			}
		}

                list = &(*list)->next;
	}

	if (index == NULL) {
		index = mail_index_alloc(index_dir, prefix);
		index_storage_add(index, mailbox_path, &st);
	}

	return index;
}

static void destroy_unrefed(int all)
{
	struct index_list **list, *rec;

	for (list = &indexes; *list != NULL;) {
		rec = *list;

		if (rec->refcount == 0 &&
		    (all || rec->destroy_time <= ioloop_time)) {
			*list = rec->next;
			index_list_free(rec);
		} else {
			list = &(*list)->next;
		}
	}

	if (indexes == NULL && to_index != NULL) {
		timeout_remove(to_index);
		to_index = NULL;
	}
}

static void index_removal_timeout(void *context __attr_unused__)
{
	destroy_unrefed(FALSE);
}

void index_storage_unref(struct mail_index *index)
{
	struct index_list *list;

	for (list = indexes; list != NULL; list = list->next) {
		if (list->index == index)
			break;
	}

	i_assert(list != NULL);
	i_assert(list->refcount > 0);

	list->refcount--;
	list->destroy_time = ioloop_time + INDEX_CACHE_TIMEOUT;
	if (to_index == NULL)
		to_index = timeout_add(1000, index_removal_timeout, NULL);
}

void index_storage_destroy_unrefed(void)
{
	destroy_unrefed(TRUE);
}

static void set_cache_decisions(const char *fields,
				enum mail_cache_decision_type dec)
{
	const char *const *arr;
	int i;

	if (fields == NULL || *fields == '\0')
		return;

	for (arr = t_strsplit_spaces(fields, " ,"); *arr != NULL; arr++) {
		for (i = 0; i < MAIL_CACHE_FIELD_COUNT; i++) {
			if (strcasecmp(cache_fields[i].name, *arr) == 0) {
				cache_fields[i].decision = dec;
				break;
			}
		}
		if (i == MAIL_CACHE_FIELD_COUNT) {
			i_error("Invalid cache field name '%s', ignoring ",
				*arr);
		}
	}
}

static void index_cache_register_defaults(struct mail_cache *cache)
{
	const char *never_env;

	never_env = getenv("MAIL_NEVER_CACHE_FIELDS");
	if (never_env == NULL)
		never_env = DEFAULT_NEVER_CACHE_FIELDS;

	set_cache_decisions(getenv("MAIL_CACHE_FIELDS"),
			    MAIL_CACHE_DECISION_TEMP);
	set_cache_decisions(never_env, MAIL_CACHE_DECISION_NO |
			    MAIL_CACHE_DECISION_FORCED);

	mail_cache_register_fields(cache, cache_fields,
				   MAIL_CACHE_FIELD_COUNT);
}

void index_storage_lock_notify(struct index_mailbox *ibox,
			       enum mailbox_lock_notify_type notify_type,
			       unsigned int secs_left)
{
	struct index_storage *storage = ibox->storage;
	const char *str;
	time_t now;

	if ((secs_left % 15) != 0) {
		/* update alarm() so that we get back here around the same
		   time we want the next notify. also try to use somewhat
		   rounded times. this affects only fcntl() locking, dotlock
		   and flock() calls should be calling us constantly */
		alarm(secs_left%15);
	}

	/* if notify type changes, print the message immediately */
	now = time(NULL);
	if (ibox->last_notify_type == MAILBOX_LOCK_NOTIFY_NONE ||
	    ibox->last_notify_type == notify_type) {
		if (ibox->last_notify_type == MAILBOX_LOCK_NOTIFY_NONE &&
		    notify_type == MAILBOX_LOCK_NOTIFY_MAILBOX_OVERRIDE) {
			/* first override notification, show it */
		} else {
			if (now < ibox->next_lock_notify || secs_left < 15)
				return;
		}
	}

	ibox->next_lock_notify = now + LOCK_NOTIFY_INTERVAL;
        ibox->last_notify_type = notify_type;

	switch (notify_type) {
	case MAILBOX_LOCK_NOTIFY_NONE:
		break;
	case MAILBOX_LOCK_NOTIFY_MAILBOX_ABORT:
		str = t_strdup_printf("Mailbox is locked, will abort in "
				      "%u seconds", secs_left);
		storage->callbacks->notify_no(&ibox->box, str,
					      storage->callback_context);
		break;
	case MAILBOX_LOCK_NOTIFY_MAILBOX_OVERRIDE:
		str = t_strdup_printf("Stale mailbox lock file detected, "
				      "will override in %u seconds", secs_left);
		storage->callbacks->notify_ok(&ibox->box, str,
					      storage->callback_context);
		break;
	}
}

void index_storage_lock_notify_reset(struct index_mailbox *ibox)
{
	ibox->next_lock_notify = time(NULL) + LOCK_NOTIFY_INTERVAL;
	ibox->last_notify_type = MAILBOX_LOCK_NOTIFY_NONE;
}

struct index_mailbox *
index_storage_mailbox_init(struct index_storage *storage, struct mailbox *box,
			   struct mail_index *index, const char *name,
			   enum mailbox_open_flags flags)
{
	struct index_mailbox *ibox;
	enum mail_index_open_flags index_flags;

	i_assert(name != NULL);

	index_flags = MAIL_INDEX_OPEN_FLAG_CREATE;
	if ((flags & MAILBOX_OPEN_FAST) != 0)
		index_flags |= MAIL_INDEX_OPEN_FLAG_FAST;
	if (getenv("MMAP_DISABLE") != NULL)
		index_flags |= MAIL_INDEX_OPEN_FLAG_MMAP_DISABLE;
	if (getenv("MMAP_NO_WRITE") != NULL)
		index_flags |= MAIL_INDEX_OPEN_FLAG_MMAP_NO_WRITE;
	if (getenv("FCNTL_LOCKS_DISABLE") != NULL)
		index_flags |= MAIL_INDEX_OPEN_FLAG_FCNTL_LOCKS_DISABLE;

	do {
		ibox = i_new(struct index_mailbox, 1);
		ibox->box = *box;
		ibox->storage = storage;

		ibox->box.storage = &storage->storage;
		ibox->box.name = i_strdup(name);
		ibox->readonly = (flags & MAILBOX_OPEN_READONLY) != 0;
		ibox->keep_recent = (flags & MAILBOX_OPEN_KEEP_RECENT) != 0;

		ibox->index = index;

		ibox->next_lock_notify = time(NULL) + LOCK_NOTIFY_INTERVAL;
		ibox->commit_log_file_seq = 0;
		ibox->mail_read_mmaped = getenv("MAIL_READ_MMAPED") != NULL;

		if (mail_index_open(index, index_flags) < 0)
			break;

		ibox->cache = mail_index_get_cache(index);
		index_cache_register_defaults(ibox->cache);
		ibox->view = mail_index_view_open(index);
		return ibox;
	} while (0);

	mail_storage_set_index_error(ibox);
	index_storage_mailbox_free(&ibox->box);
	return NULL;
}

void index_storage_mailbox_free(struct mailbox *box)
{
	struct index_mailbox *ibox = (struct index_mailbox *) box;

	if (ibox->view != NULL)
		mail_index_view_close(ibox->view);

	index_mailbox_check_remove_all(ibox);
	if (ibox->index != NULL)
		index_storage_unref(ibox->index);
	i_free(ibox->path);
	i_free(ibox->control_dir);

	i_free(box->name);
	i_free(box);
}

int index_storage_is_readonly(struct mailbox *box)
{
	struct index_mailbox *ibox = (struct index_mailbox *) box;

	return ibox->readonly;
}

int index_storage_allow_new_keywords(struct mailbox *box)
{
	struct index_mailbox *ibox = (struct index_mailbox *) box;

	/* FIXME: return FALSE if we're full */
	return !ibox->readonly;
}

int index_storage_is_inconsistent(struct mailbox *box)
{
	struct index_mailbox *ibox = (struct index_mailbox *) box;

	return mail_index_view_is_inconsistent(ibox->view);
}

void index_storage_set_callbacks(struct mail_storage *_storage,
				 struct mail_storage_callbacks *callbacks,
				 void *context)
{
	struct index_storage *storage = (struct index_storage *) _storage;

	*storage->callbacks = *callbacks;
	storage->callback_context = context;
}

const char *index_storage_get_last_error(struct mail_storage *storage,
					 int *syntax_error_r)
{
	*syntax_error_r = storage->syntax_error;
	return storage->error;
}

int mail_storage_set_index_error(struct index_mailbox *ibox)
{
	switch (mail_index_get_last_error(ibox->index)) {
	case MAIL_INDEX_ERROR_NONE:
	case MAIL_INDEX_ERROR_INTERNAL:
		mail_storage_set_internal_error(ibox->box.storage);
		break;
	case MAIL_INDEX_ERROR_DISKSPACE:
		mail_storage_set_error(ibox->box.storage, "Out of disk space");
		break;
	}

	if (ibox->view != NULL)
		mail_index_view_unlock(ibox->view);
	mail_index_reset_error(ibox->index);
	return FALSE;
}

int index_mailbox_fix_keywords(struct index_mailbox *ibox,
			       enum mail_flags *flags,
			       const char *keywords[],
			       unsigned int keywords_count)
{
	/*FIXME:int ret;

	ret = mail_keywords_fix_list(ibox->index, flags, keywords,
				     keywords_count);
	switch (ret) {
	case 1:
		return TRUE;
	case 0:
		mail_storage_set_error(ibox->box.storage,
			"Maximum number of different keywords exceeded");
		return FALSE;
	default:
		return mail_storage_set_index_error(ibox);
	}*/
}