#ifndef VIRTUAL_STORAGE_H
#define VIRTUAL_STORAGE_H

#include "seq-range-array.h"
#include "index-storage.h"

#define VIRTUAL_STORAGE_NAME "virtual"
#define VIRTUAL_SUBSCRIPTION_FILE_NAME ".virtual-subscriptions"
#define VIRTUAL_CONFIG_FNAME "dovecot-virtual"

#define VIRTUAL_CONTEXT(obj) \
	MODULE_CONTEXT(obj, virtual_storage_module)

struct virtual_save_context;

struct virtual_mail_index_header {
	/* Increased by one each time the header is modified */
	uint32_t change_counter;
	/* Number of mailbox records following this header. Mailbox names
	   follow the mailbox records - they have neither NUL terminator nor
	   padding. */
	uint32_t mailbox_count;
	/* Highest used mailbox ID. IDs are never reused. */
	uint32_t highest_mailbox_id;
	/* CRC32 of all the search parameters. If it changes, the mailbox is
	   rebuilt. */
	uint32_t search_args_crc32;
};

struct virtual_mail_index_mailbox_record {
	/* Unique mailbox ID used as mailbox_id in records. */
	uint32_t id;
	/* Length of this mailbox's name. */
	uint32_t name_len;
	/* Synced UID validity value */
	uint32_t uid_validity;
	/* Next unseen UID */
	uint32_t next_uid;
	/* Synced highest modseq value */
	uint64_t highest_modseq;
};

struct virtual_mail_index_record {
	uint32_t mailbox_id;
	uint32_t real_uid;
};

struct virtual_storage {
	struct mail_storage storage;

	/* List of mailboxes while a virtual mailbox is being opened.
	   Used to track loops. */
	ARRAY_TYPE(const_string) open_stack;

	unsigned int max_open_mailboxes;
};

struct virtual_backend_uidmap {
	uint32_t real_uid;
	/* can be 0 temporarily while syncing before the UID is assigned */
	uint32_t virtual_uid;
};

struct virtual_backend_box {
	union mailbox_module_context module_ctx;
	struct virtual_mailbox *virtual_mbox;

	/* linked list for virtual_mailbox->open_backend_boxes_{head,tail} */
	struct virtual_backend_box *prev_open, *next_open;

	/* Initially zero, updated by syncing */
	uint32_t mailbox_id;
	const char *name;

	unsigned int sync_mailbox_idx;
	uint32_t sync_uid_validity;
	uint32_t sync_next_uid;
	uint64_t sync_highest_modseq;
	/* this value is either 0 or same as sync_highest_modseq. it's kept 0
	   when there are pending removes that have yet to be expunged */
	uint64_t ondisk_highest_modseq;

	struct mail_search_args *search_args;
	struct mail_search_result *search_result;

	struct mailbox *box;
	/* Messages currently included in the virtual mailbox,
	   sorted by real_uid */
	ARRAY(struct virtual_backend_uidmap) uids;

	/* temporary mail used while syncing */
	struct mail *sync_mail;
	/* pending removed UIDs */
	ARRAY_TYPE(seq_range) sync_pending_removes;
	/* another process expunged these UIDs. they need to be removed on
	   next sync. */
	ARRAY_TYPE(seq_range) sync_outside_expunges;

	/* name contains a wildcard, this is a glob for it */
	struct imap_match_glob *glob;
	struct mail_namespace *ns;

	unsigned int open_tracked:1;
	unsigned int open_failed:1;
	unsigned int sync_seen:1;
	unsigned int wildcard:1;
	unsigned int clear_recent:1;
	unsigned int uids_nonsorted:1;
	unsigned int search_args_initialized:1;
};
ARRAY_DEFINE_TYPE(virtual_backend_box, struct virtual_backend_box *);

struct virtual_mailbox_vfuncs {
	/* convert backend UIDs to virtual UIDs. if some backend UID doesn't
	   exist in mailbox, it's simply ignored */
	void (*get_virtual_uids)(struct mailbox *box,
				 struct mailbox *backend_mailbox,
				 const ARRAY_TYPE(seq_range) *backend_uids,
				 ARRAY_TYPE(seq_range) *virtual_uids_r);
	/* like get_virtual_uids(), but if a backend UID doesn't exist,
	   convert it to 0. */
	void (*get_virtual_uid_map)(struct mailbox *box,
				    struct mailbox *backend_mailbox,
				    const ARRAY_TYPE(seq_range) *backend_uids,
				    ARRAY_TYPE(uint32_t) *virtual_uids_r);
	void (*get_virtual_backend_boxes)(struct mailbox *box,
					  ARRAY_TYPE(mailboxes) *mailboxes,
					  bool only_with_msgs);
};

struct virtual_mailbox {
	struct mailbox box;
	struct virtual_storage *storage;

	uint32_t virtual_ext_id;

	uint32_t prev_uid_validity;
	uint32_t prev_change_counter;
	uint32_t highest_mailbox_id;
	uint32_t search_args_crc32;

	struct virtual_backend_box *lookup_prev_bbox;
	uint32_t sync_virtual_next_uid;

	/* Mailboxes this virtual mailbox consists of, sorted by mailbox_id */
	ARRAY_TYPE(virtual_backend_box) backend_boxes;
	/* backend mailbox where to save messages when saving to this mailbox */
	struct virtual_backend_box *save_bbox;

	/* linked list of open backend mailboxes. head will contain the oldest
	   accessed mailbox, tail will contain the newest. */
	struct virtual_backend_box *open_backend_boxes_head;
	struct virtual_backend_box *open_backend_boxes_tail;
	/* number of backend mailboxes that are open currently. */
	unsigned int backends_open_count;

	ARRAY_TYPE(mailbox_virtual_patterns) list_include_patterns;
	ARRAY_TYPE(mailbox_virtual_patterns) list_exclude_patterns;

	struct virtual_mailbox_vfuncs vfuncs;

	unsigned int uids_mapped:1;
	unsigned int sync_initialized:1;
	unsigned int inconsistent:1;
	unsigned int have_guid_flags_set:1;
	unsigned int have_guids:1;
	unsigned int have_save_guids:1;
};

extern MODULE_CONTEXT_DEFINE(virtual_storage_module,
			     &mail_storage_module_register);

extern struct mail_storage virtual_storage;
extern struct mail_vfuncs virtual_mail_vfuncs;

int virtual_config_read(struct virtual_mailbox *mbox);
void virtual_config_free(struct virtual_mailbox *mbox);

int virtual_mailbox_ext_header_read(struct virtual_mailbox *mbox,
				    struct mail_index_view *view,
				    bool *broken_r);

struct virtual_backend_box *
virtual_backend_box_lookup_name(struct virtual_mailbox *mbox, const char *name);
struct virtual_backend_box *
virtual_backend_box_lookup(struct virtual_mailbox *mbox, uint32_t mailbox_id);

int virtual_backend_box_open(struct virtual_mailbox *mbox,
			     struct virtual_backend_box *bbox);
void virtual_backend_box_close(struct virtual_mailbox *mbox,
			       struct virtual_backend_box *bbox);
void virtual_backend_box_accessed(struct virtual_mailbox *mbox,
				  struct virtual_backend_box *bbox);
void virtual_backend_box_sync_mail_unset(struct virtual_backend_box *bbox);

struct mail_search_context *
virtual_search_init(struct mailbox_transaction_context *t,
		    struct mail_search_args *args,
		    const enum mail_sort_type *sort_program,
		    enum mail_fetch_field wanted_fields,
		    struct mailbox_header_lookup_ctx *wanted_headers);
int virtual_search_deinit(struct mail_search_context *ctx);
bool virtual_search_next_nonblock(struct mail_search_context *ctx,
				  struct mail **mail_r, bool *tryagain_r);
bool virtual_search_next_update_seq(struct mail_search_context *ctx);

struct mail *
virtual_mail_alloc(struct mailbox_transaction_context *t,
		   enum mail_fetch_field wanted_fields,
		   struct mailbox_header_lookup_ctx *wanted_headers);
struct mail *
virtual_mail_set_backend_mail(struct mail *mail,
			      struct virtual_backend_box *bbox);

struct mailbox_sync_context *
virtual_storage_sync_init(struct mailbox *box, enum mailbox_sync_flags flags);

struct mail_save_context *
virtual_save_alloc(struct mailbox_transaction_context *t);
int virtual_save_begin(struct mail_save_context *ctx, struct istream *input);
int virtual_save_continue(struct mail_save_context *ctx);
int virtual_save_finish(struct mail_save_context *ctx);
void virtual_save_cancel(struct mail_save_context *ctx);
void virtual_save_free(struct mail_save_context *ctx);

void virtual_box_copy_error(struct mailbox *dest, struct mailbox *src);

void virtual_backend_mailbox_allocated(struct mailbox *box);
void virtual_backend_mailbox_opened(struct mailbox *box);

#endif