#ifndef __IMAP_PARSER_H
#define __IMAP_PARSER_H

typedef enum {
	/* Set this flag if you wish to read only size of literal argument
	   and not convert literal into string. Useful when you need to deal
	   with large literal sizes. The literal must be the last read
	   parameter. */
	IMAP_PARSE_FLAG_LITERAL_SIZE	= 0x01,
	/* Don't remove '\' chars from string arguments */
	IMAP_PARSE_FLAG_NO_UNESCAPE	= 0x02,
} ImapParserFlags;

typedef enum {
	IMAP_ARG_NIL = 0,
	IMAP_ARG_ATOM,
	IMAP_ARG_STRING,
	IMAP_ARG_LITERAL_SIZE,
	IMAP_ARG_LIST,

	IMAP_ARG_EOL /* end of argument list */
} ImapArgType;

typedef struct _ImapParser ImapParser;
typedef struct _ImapArg ImapArg;
typedef struct _ImapArgList ImapArgList;

struct _ImapArg {
	ImapArgType type;
        ImapArg *parent; /* always of type IMAP_ARG_LIST */

	union {
		char *str;
		uoff_t literal_size;
		ImapArgList *list;
	} _data;
};

#define IMAP_ARG_STR(arg) \
	((arg)->type == IMAP_ARG_NIL ? NULL : \
	 (arg)->type == IMAP_ARG_ATOM || (arg)->type == IMAP_ARG_STRING ? \
	 (arg)->_data.str : _imap_arg_str_error(arg))

#define IMAP_ARG_LITERAL_SIZE(arg) \
	((arg)->type == IMAP_ARG_LITERAL_SIZE ? \
	 (arg)->_data.literal_size : _imap_arg_literal_size_error(arg))

#define IMAP_ARG_LIST(arg) \
	((arg)->type == IMAP_ARG_LIST ? \
	 (arg)->_data.list : _imap_arg_list_error(arg))

struct _ImapArgList {
	size_t size, alloc;
	ImapArg args[1]; /* variable size */
};

/* Create new IMAP argument parser. There's no limit in argument sizes, only
   the maximum buffer size of input stream limits it. max_literal_size limits
   the maximum size of internally handled literals (ie. FLAG_LITERAL_SIZE is
   unset). max_elements sets the number of elements we allow entirely so that
   user can't give huge lists or lists inside lists. output is used for sending
   command continuation requests for literals. */
ImapParser *imap_parser_create(IStream *input, OStream *output,
			       size_t max_literal_size, size_t max_elements);
void imap_parser_destroy(ImapParser *parser);

/* Reset the parser to initial state. */
void imap_parser_reset(ImapParser *parser);

/* Return the last error in parser. */
const char *imap_parser_get_error(ImapParser *parser);

/* Read a number of arguments. This function doesn't call i_stream_read(), you
   need to do that. Returns number of arguments read (may be less than count
   in case of EOL), -2 if more data is needed or -1 if error occured.

   count-sized array of arguments are stored into args when return value is
   0 or larger. If all arguments weren't read, they're set to NIL. count
   can be set to 0 to read all arguments in the line. Last element in
   args[size] is always of type IMAP_ARG_EOL. */
int imap_parser_read_args(ImapParser *parser, unsigned int count,
			  ImapParserFlags flags, ImapArg **args);

/* Read one word - used for reading tag and command name.
   Returns NULL if more data is needed. */
const char *imap_parser_read_word(ImapParser *parser);

/* Read the rest of the line. Returns NULL if more data is needed. */
const char *imap_parser_read_line(ImapParser *parser);

/* Returns the imap argument as string. NIL returns "" and list returns NULL. */
const char *imap_arg_string(ImapArg *arg);

/* Error functions */
char *_imap_arg_str_error(const ImapArg *arg);
uoff_t _imap_arg_literal_size_error(const ImapArg *arg);
ImapArgList *_imap_arg_list_error(const ImapArg *arg);

#endif