/**\file expand.h

   Prototypes for string expansion functions. These functions perform
   several kinds of parameter expansion. There are a lot of issues
   with regards to memory allocation. Overall, these functions would
   benefit from using a more clever memory allocation scheme, perhaps
   an evil combination of talloc, string buffers and reference
   counting.

*/

#ifndef FISH_EXPAND_H
/**
   Header guard
*/
#define FISH_EXPAND_H

#include "config.h"                     // for __warn_unused

#include <wchar.h>
#include <string>                       // for string
#include <vector>                       // for vector

#include "common.h"
#include "parse_constants.h"

enum
{
    // Flag specifying that cmdsubst expansion should be skipped.
    EXPAND_SKIP_CMDSUBST = 1 << 0,
    // Flag specifying that variable expansion should be skipped.
    EXPAND_SKIP_VARIABLES = 1 << 1,
    // Flag specifying that wildcard expansion should be skipped.
    EXPAND_SKIP_WILDCARDS = 1 << 2,
    // The expansion is being done for tab or auto completions. Returned
    // completions may have the wildcard as a prefix instead of a match.
    EXPAND_FOR_COMPLETIONS = 1 << 3,
    // Only match files that are executable by the current user. Only
    // applicable together with ACCEPT_INCOMPLETE.
    EXECUTABLES_ONLY = 1 << 4,
    // Only match directories. Only applicable together with ACCEPT_INCOMPLETE.
    DIRECTORIES_ONLY = 1 << 5,
    // Don't generate descriptions.
    EXPAND_NO_DESCRIPTIONS = 1 << 6,
    // Don't expand jobs (but you can still expand processes). This is because
    // job expansion is not thread safe.
    EXPAND_SKIP_JOBS = 1 << 7,
    // Don't expand home directories.
    EXPAND_SKIP_HOME_DIRECTORIES = 1 << 8,
    // Allow fuzzy matching.
    EXPAND_FUZZY_MATCH = 1 << 9,
    // Disallow directory abbreviations like /u/l/b for /usr/local/bin. Only
    // applicable if EXPAND_FUZZY_MATCH is set.
    EXPAND_NO_FUZZY_DIRECTORIES = 1 << 10,
    // Do expansions specifically to support cd (CDPATH, etc).
    EXPAND_SPECIAL_CD = 1 << 11
};
typedef int expand_flags_t;

class completion_t;

enum
{
    // Character representing a home directory.
    HOME_DIRECTORY = EXPAND_RESERVED_BASE,
    // Character representing process expansion.
    PROCESS_EXPAND,
    // Character representing variable expansion.
    VARIABLE_EXPAND,
    // Character representing variable expansion into a single element.
    VARIABLE_EXPAND_SINGLE,
    // Character representing the start of a bracket expansion.
    BRACKET_BEGIN,
    // Character representing the end of a bracket expansion.
    BRACKET_END,
    // Character representing separation between two bracket elements.
    BRACKET_SEP,
    // Separate subtokens in a token with this character.
    INTERNAL_SEPARATOR,
    // Character representing an empty variable expansion. Only used
    // transitively while expanding variables.
    VARIABLE_EXPAND_EMPTY,
    // This is a special psuedo-char that is not used other than to mark the
    // end of the the special characters so we can sanity check the enum range.
    EXPAND_SENTINAL
};

/** These are the possible return values for expand_string. Note how zero value is the only error. */
enum expand_error_t
{
    /** Error */
    EXPAND_ERROR,
    /** Ok */
    EXPAND_OK,
    /** Ok, a wildcard in the string matched no files */
    EXPAND_WILDCARD_NO_MATCH,
    /* Ok, a wildcard in the string matched a file */
    EXPAND_WILDCARD_MATCH
};

/** Character for separating two array elements. We use 30, i.e. the ascii record separator since that seems logical. */
#define ARRAY_SEP ((wchar_t)(0x1e))

/** String containing the character for separating two array elements */
#define ARRAY_SEP_STR L"\x1e"

/**
   Error issued on array out of bounds
*/
#define ARRAY_BOUNDS_ERR _(L"Array index out of bounds")

/**
   Perform various forms of expansion on in, such as tilde expansion
   (\~USER becomes the users home directory), variable expansion
   (\$VAR_NAME becomes the value of the environment variable VAR_NAME),
   cmdsubst expansion and wildcard expansion. The results are inserted
   into the list out.

   If the parameter does not need expansion, it is copied into the list
   out.

   \param input The parameter to expand
   \param output The list to which the result will be appended.
   \param flag Specifies if any expansion pass should be skipped. Legal values are any combination of EXPAND_SKIP_CMDSUBST EXPAND_SKIP_VARIABLES and EXPAND_SKIP_WILDCARDS
   \param errors Resulting errors, or NULL to ignore
   \return One of EXPAND_OK, EXPAND_ERROR, EXPAND_WILDCARD_MATCH and EXPAND_WILDCARD_NO_MATCH. EXPAND_WILDCARD_NO_MATCH and EXPAND_WILDCARD_MATCH are normal exit conditions used only on strings containing wildcards to tell if the wildcard produced any matches.
*/
__warn_unused expand_error_t expand_string(const wcstring &input, std::vector<completion_t> *output, expand_flags_t flags, parse_error_list_t *errors);


/**
   expand_one is identical to expand_string, except it will fail if in
   expands to more than one string. This is used for expanding command
   names.

   \param inout_str The parameter to expand in-place
   \param flag Specifies if any expansion pass should be skipped. Legal values are any combination of EXPAND_SKIP_CMDSUBST EXPAND_SKIP_VARIABLES and EXPAND_SKIP_WILDCARDS
   \param errors Resulting errors, or NULL to ignore
   \return Whether expansion succeded
*/
bool expand_one(wcstring &inout_str, expand_flags_t flags, parse_error_list_t *errors = NULL);

/**
   Convert the variable value to a human readable form, i.e. escape things, handle arrays, etc. Suitable for pretty-printing. The result must be free'd!

   \param in the value to escape
*/
wcstring expand_escape_variable(const wcstring &in);

/**
   Perform tilde expansion and nothing else on the specified string, which is modified in place.

   \param input the string to tilde expand
*/
void expand_tilde(wcstring &input);

/** Perform the opposite of tilde expansion on the string, which is modified in place */
wcstring replace_home_directory_with_tilde(const wcstring &str);

/**
   Testing function for getting all process names.
*/
std::vector<wcstring> expand_get_all_process_names(void);

/** Abbreviation support. Expand src as an abbreviation, returning true if one was found, false if not. If result is not-null, returns the abbreviation by reference. */
#define USER_ABBREVIATIONS_VARIABLE_NAME L"fish_user_abbreviations"
bool expand_abbreviation(const wcstring &src, wcstring *output);

/* Terrible hacks */
bool fish_xdm_login_hack_hack_hack_hack(std::vector<std::string> *cmds, int argc, const char * const *argv);


#endif