#ifndef EL__CONFIG_OPTIONS_H
#define EL__CONFIG_OPTIONS_H

#include "main/object.h"
#include "util/color.h"
#include "util/lists.h"
#include "util/memory.h"
#include "util/string.h"

/* TODO: We should provide some generic mechanism for options caching. */

/* Fix namespace clash on Cygwin. */
#define option option_elinks


/** Flags used in the option.flags bitmask */
enum option_flags {
	/** The option is hidden - it serves for internal purposes, never is
	 * read, never is written, never is displayed, never is crawled through
	 * etc. */
	OPT_HIDDEN = 1,

	/** For ::OPT_TREE, automatically create missing hiearchy piece just under
	 * this category when adding an option. The 'template' for the added
	 * hiearchy piece (category) is stored as "_template_" category. */
	OPT_AUTOCREATE = 2,

	/** The option has been modified in some way and must be saved
	 * to elinks.conf.  ELinks uses this flag only while it is
	 * saving the options.  When the "config.saving_style" option
	 * has value 3, saving works like this:
	 * -# First, ELinks sets ::OPT_MUST_SAVE in the options that have
	 *    ::OPT_TOUCHED or ::OPT_DELETED, and clears it in the rest.
	 * -# ELinks then parses the old configuration file and any
	 *    files named in "include" commands.
	 *    - While parsing the old configuration file itself, ELinks
	 *      copies the commands and comments from it to the new
	 *      configuration file (actually just a string variable
	 *      in this phase).  However, if the old configuration file
	 *      contains a "set" or "unset" command for this option,
	 *      then instead of copying the command as is, ELinks
	 *      rewrites it to match the current value of the option
	 *      and clears ::OPT_MUST_SAVE.
	 *    - While parsing included files, ELinks does not copy the
	 *      commands anywhere.  (It never automatically modifies
	 *      included configuration files.)  However, it still looks
	 *      for "set" and "unset" commands for this option.  If it
	 *      finds any, it compares the value of the option to the
	 *      value given in the command.  ELinks clears ::OPT_MUST_SAVE
	 *      if the values match, or sets it if they differ.
	 * -# After ELinks has rewritten the configuration file and
	 *    parsed the included files, it appends the options that
	 *    still have the ::OPT_MUST_SAVE flag.
	 *
	 * Other saving styles are variants of this:
	 * - 0: ELinks does not append any options to the
	 *   configuration file.  So ::OPT_MUST_SAVE has no effect.
	 * - 1: ELinks initially sets ::OPT_MUST_SAVE in all options,
	 *   regardless of ::OPT_TOUCHED and ::OPT_DELETED.
	 * - 2: ELinks initially sets ::OPT_MUST_SAVE in all options,
	 *   and does not read any configuration files.  */
	OPT_MUST_SAVE = 4,

	/** This is used to mark options modified after the last save. That's
	 * being useful if you want to save only the options whose value
	 * changed. */
	OPT_TOUCHED = 8,

	/** If set on the tree argument to add_opt (not necessarily the direct
	 * parent) or on the option itself, it will create the listbox (options
	 * manager) item for the option. */
	OPT_LISTBOX = 16,

	/** This is used to mark that the option @b and the option name is
	 * allocated and should be freed when the option is released. */
	OPT_ALLOC = 32,

	/** For ::OPT_TREE, automatically sort the content of the tree
	 * alphabetically (but all subtrees in front of ordinary options) when
	 * adding new options. Note that this applies only to the one level
	 * below - it will not apply to the sub-trees in this tree. Also, this
	 * can be quite expensive for busy-adding big trees, so think twice
	 * before doing it - in fact, it is supposed to be used only where you
	 * add stuff from more modules, not all at once; typically the
	 * config_options root tree. Especially NOT RECOMMENDED to be used on
	 * the template trees. */
	OPT_SORT = 64,

	/** This is used to mark option as deleted */
	OPT_DELETED = 128,

	/** Specifies that values of boolean aliases should be inverted. */
	OPT_ALIAS_NEGATE = 256
};

enum option_type {
	OPT_BOOL = 0,
	OPT_INT,
	OPT_LONG,
	OPT_STRING,

	OPT_CODEPAGE,
	OPT_LANGUAGE,
	OPT_COLOR,

	OPT_COMMAND,

	OPT_ALIAS,

	OPT_TREE,
};

struct listbox_item; /* bfu/listbox.h */
struct option; /* defined later in this file */
struct session; /* session/session.h */

/** Called when an ::OPT_COMMAND option is found in the command line.
 *
 * @param option
 * The option that was named in the command line, either directly
 * or via an ::OPT_ALIAS.  Its option.type is ::OPT_COMMAND,
 * and its option_value.command points to this function.
 *
 * @param[in,out] argv
 * The next arguments to be parsed from the command line.
 * This function can consume some of those arguments by
 * incremenenting *@a argv and decrementing *@a argc.
 *
 * @param[in,out] argc
 * Number of arguments remaining in the command line.
 *
 * @return NULL if successful, or a localized error string that the
 * caller will not free.  */
typedef unsigned char *option_command_fn_T(struct option *option,
					   unsigned char ***argv, int *argc);

union option_value {
	/** The ::OPT_TREE list_head is allocated.
	 *
	 * XXX: Keep first to make ::options_root initialization possible. */
	LIST_OF(struct option) *tree;

	/** Used by ::OPT_BOOL, ::OPT_INT, ::OPT_CODEPAGE and ::OPT_LANGUAGE */
	int number;

	/** Used by ::OPT_LONG */
	long big_number;

	/** The ::OPT_COLOR value */
	color_T color;

	/** The ::OPT_COMMAND value */
	option_command_fn_T *command;

	/** The ::OPT_STRING string is allocated and has length ::MAX_STR_LEN.
	 * The ::OPT_ALIAS string is NOT allocated, has variable length
	 * (option.max) and should remain untouched! It contains the full path to
	 * the "real" / aliased option. */
	unsigned char *string;
};


/** To be called when the option (or sub-option if it's a tree) is
 * changed.
 *
 * @param session
 * is the session via which the user changed the options, or NULL if
 * not known.  Because the options are currently not session-specific,
 * it is best to ignore this parameter.  In a future version of
 * ELinks, this parameter might mean the session to which the changed
 * options apply.
 *
 * @param current
 * is the option whose change hook is being called.  It is never NULL.
 *
 * @param changed
 * is the option that was changed, or NULL if multiple descendants of
 * @a current may have been changed.
 *
 * @return If it returns zero, we will continue descending the options
 * tree checking for change handlers.  */
typedef int (*change_hook_T)(struct session *session, struct option *current,
			     struct option *changed);

struct option {
	OBJECT_HEAD(struct option);

	unsigned char *name;
	enum option_flags flags;
	enum option_type type;
	long min, max;
	union option_value value;
	unsigned char *desc;
	unsigned char *capt;

	struct option *root;

	/** To be called when the option (or sub-option if it's a tree) is
	 * changed. If it returns zero, we will continue descending the options
	 * tree checking for change handlers. */
	change_hook_T change_hook;

	struct listbox_item *box_item;
};

/** An initializer for struct option.  This is quite rare:
 * most places should instead initialize struct option_init,
 * with ::INIT_OPT_INT or a similar macro.
 * @relates option */
#define INIT_OPTION(name, flags, type, min, max, value, desc, capt) \
	{ NULL_LIST_HEAD, INIT_OBJECT("option"), name, flags, type, min, max, { (LIST_OF(struct option) *) (value) }, desc, capt }

extern struct option *config_options;
extern struct option *cmdline_options;


extern void init_options(void);
extern void done_options(void);


struct change_hook_info {
	unsigned char *name;
	change_hook_T change_hook;
};

extern void register_change_hooks(const struct change_hook_info *change_hooks);


extern LIST_OF(struct option) *init_options_tree(void);
extern void prepare_mustsave_flags(LIST_OF(struct option) *, int set_all);
extern void untouch_options(LIST_OF(struct option) *);

extern void smart_config_string(struct string *, int, int,
				LIST_OF(struct option) *, unsigned char *, int,
				void (*)(struct string *, struct option *,
					 unsigned char *, int, int, int, int));

enum copy_option_flags {
	/* Do not create a listbox option for the new option. */
	CO_NO_LISTBOX_ITEM = (1 << 0),

	/* Do not copy children. */
	CO_SHALLOW         = (1 << 1),
};

extern struct option *copy_option(struct option *, int);

struct option *get_option_shadow(struct option *, struct option *,
                                 struct option *);

extern void delete_option(struct option *);
void mark_option_as_deleted(struct option *);

/** Some minimal option cache */
struct option_resolver {
	int id;
	unsigned char *name;
};

/** Update the visibility of the box item of each option
 * in config_options to honour the value of config.show_template. */
void update_options_visibility(void);

/** Toggle the value of the given option numeric, respecting option->min
 * and option->max.
 * @relates option */
void toggle_option(struct session *ses, struct option *option);

/** Call the change-hooks for the given option and recur on its parent.
 * @relates option */
void call_change_hooks(struct session *ses, struct option *current,
                       struct option *option);

/** Do proper bookkeeping after an option has changed - call this every time
 * you change an option value.
 * @relates option */
void option_changed(struct session *ses, struct option *option);

extern int commit_option_values(struct option_resolver *resolvers,
				struct option *root,
				union option_value *values, int size);
extern void checkout_option_values(struct option_resolver *resolvers,
				   struct option *root,
				   union option_value *values, int size);

/* Shitload of various incredible macro combinations and other unusable garbage
 * follows. Have fun. */

/* Basically, for main hiearchy addressed from root (almost always) you want to
 * use get_opt_type() and add_opt_type(). For command line options, you want to
 * use get_opt_type_tree(cmdline_options, "option", NULL). */

extern struct option *get_opt_rec(struct option *, const unsigned char *);
extern struct option *get_opt_rec_real(struct option *, const unsigned char *);
struct option *indirect_option(struct option *);
#ifdef CONFIG_DEBUG
extern union option_value *get_opt_(unsigned char *, int, enum option_type, struct option *, unsigned char *, struct session *);
#define get_opt(tree, name, ses, type) get_opt_(__FILE__, __LINE__, type, tree, name, ses)
#else
extern union option_value *get_opt_(struct option *, unsigned char *, struct session *);
#define get_opt(tree, name, ses, type) get_opt_(tree, name, ses)
#endif

#define get_opt_bool_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_BOOL)->number
#define get_opt_int_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_INT)->number
#define get_opt_long_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_LONG)->big_number
#define get_opt_str_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_STRING)->string
#define get_opt_codepage_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_CODEPAGE)->number
#define get_opt_color_tree(tree, name, ses)	get_opt(tree, name, ses, OPT_COLOR)->color
#define get_opt_tree_tree(tree_, name, ses)	get_opt(tree_, name, ses, OPT_TREE)->tree

#define get_opt_bool(name, ses) get_opt_bool_tree(config_options, name, ses)
#define get_opt_int(name, ses) get_opt_int_tree(config_options, name, ses)
#define get_opt_long(name, ses) get_opt_long_tree(config_options, name, ses)
#define get_opt_str(name, ses) get_opt_str_tree(config_options, name, ses)
#define get_opt_codepage(name, ses) get_opt_codepage_tree(config_options, name, ses)
#define get_opt_color(name, ses) get_opt_color_tree(config_options, name, ses)
#define get_opt_tree(name, ses) get_opt_tree_tree(config_options, name, ses)

#define get_cmd_opt_bool(name) get_opt_bool_tree(cmdline_options, name, NULL)
#define get_cmd_opt_int(name) get_opt_int_tree(cmdline_options, name, NULL)
#define get_cmd_opt_long(name) get_opt_long_tree(cmdline_options, name, NULL)
#define get_cmd_opt_str(name) get_opt_str_tree(cmdline_options, name, NULL)
#define get_cmd_opt_codepage(name) get_opt_codepage_tree(cmdline_options, name, NULL)
#define get_cmd_opt_color(name) get_opt_color_tree(cmdline_options, name, NULL)
#define get_cmd_opt_tree(name) get_opt_tree_tree(cmdline_options, name, NULL)

extern struct option *add_opt(struct option *, unsigned char *, unsigned char *,
			      unsigned char *, enum option_flags, enum option_type,
			      long, long, longptr_T, unsigned char *);

/** Check whether the character @a c may be used in the name of an
 * option.  This does not allow the '.' used in multi-part names like
 * "config.comments".  If you want to allow that too, check for it
 * separately.
 *
 * If you modify this, please update the error message in
 * check_option_name().  */
#define is_option_name_char(c) (isasciialnum(c) || (c) == '_' \
				|| (c) == '-' || (c) == '+' || (c) == '*')

/* Hack which permit to disable option descriptions, to reduce elinks binary size.
 * It may of some use for people wanting a very small static non-i18n elinks binary,
 * at time of writing gain is over 25Kbytes. --Zas */
#ifndef CONFIG_SMALL
#define DESC(x) (x)
#else
#define DESC(x) ((unsigned char *) "")
#endif


/*! @relates option */
#define add_opt_bool_tree(tree, path, capt, name, flags, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_BOOL, 0, 1, (longptr_T) def, DESC(desc))

/*! @relates option */
#define add_opt_int_tree(tree, path, capt, name, flags, min, max, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_INT, min, max, (longptr_T) def, DESC(desc))

/*! @relates option */
#define add_opt_long_tree(tree, path, capt, name, flags, min, max, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_LONG, min, max, (longptr_T) def, DESC(desc))

/*! @relates option */
#define add_opt_str_tree(tree, path, capt, name, flags, def, desc) \
do { \
	unsigned char *ptr = mem_alloc(MAX_STR_LEN); \
	safe_strncpy(ptr, def, MAX_STR_LEN); \
	add_opt(tree, path, capt, name, flags, OPT_STRING, 0, MAX_STR_LEN, (longptr_T) ptr, DESC(desc)); \
} while (0)

/*! @relates option */
#define add_opt_codepage_tree(tree, path, capt, name, flags, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_CODEPAGE, 0, 0, (longptr_T) get_cp_index(def), DESC(desc))

/*! @relates option */
#define add_opt_lang_tree(tree, path, capt, name, flags, desc) \
	add_opt(tree, path, capt, name, flags, OPT_LANGUAGE, 0, 0, (longptr_T) 0, DESC(desc))

/*! @relates option */
#define add_opt_color_tree(tree, path, capt, name, flags, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_COLOR, 0, 0, (longptr_T) def, DESC(desc))

/*! @relates option */
#define add_opt_command_tree(tree, path, capt, name, flags, cmd, desc) \
	add_opt(tree, path, capt, name, flags, OPT_COMMAND, 0, 0, (longptr_T) cmd, DESC(desc));

/*! @relates option */
#define add_opt_alias_tree(tree, path, capt, name, flags, def, desc) \
	add_opt(tree, path, capt, name, flags, OPT_ALIAS, 0, strlen(def), (longptr_T) def, DESC(desc))

/*! @relates option */
#define add_opt_tree_tree(tree, path, capt, name, flags, desc) \
	add_opt(tree, path, capt, name, flags, OPT_TREE, 0, 0, (longptr_T) init_options_tree(), DESC(desc));


/* Builtin options */

/** How to initialize and register struct option.  register_options()
 * moves the values from this to struct option.  This initialization
 * must be deferred to run time because C89 provides no portable way
 * to initialize the correct member of union option_value at compile
 * time.  */
struct option_init {
	/** The name of the option tree where the option should be
	 * registered.  option.root is computed from this.  */
	unsigned char *path;

	/** The name of the option.  This goes to option.name.  */
	unsigned char *name;

	/** The caption shown in the option manager.  This goes to
	 * option.capt.  */
	unsigned char *capt;

	/** The long description shown when the user edits the option,
	 * or NULL if not available.  This goes to option.desc.  */
	unsigned char *desc;

	/** Flags for the option.  These go to option.flags.  */
	enum option_flags flags;

	/** Type of the option.  This goes to option.type.  */
	enum option_type type;

	/** Minimum value of the option.  This goes to option.min.  */
	long min;

	/** Maximum value of the option.  This goes to option.max.
	 * For some option types, @c max is the maximum length or
	 * fixed length instead.  */
	long max;

	/*! @name Default value of the option
	 * The value of an option can be an integer, a data pointer,
	 * or a function pointer.  This structure has a separate
	 * member for each of those types, to avoid compile-time casts
	 * that could lose some bits of the value.  Although this
	 * scheme looks a bit bloaty, struct option_init remains
	 * smaller than struct option and so does not require any
	 * extra space in union option_info.  @{ */

	/** The default value of the option, if the #type is ::OPT_BOOL,
	 * ::OPT_INT, or ::OPT_LONG.  Zero otherwise.  This goes to
	 * option_value.number or option_value.big_number.  */
	long value_long;

	/** The default value of the option, if the #type is ::OPT_STRING,
	 * ::OPT_CODEPAGE, ::OPT_COLOR, or ::OPT_ALIAS.  NULL otherwise.
	 * This goes to option_value.string, or after some parsing to
	 * option_value.color or option_value.number.  */
	void *value_dataptr;

	/** The constant value of the option, if the #type is ::OPT_COMMAND.
	 * NULL otherwise.  This goes to option_value.command.  */
	option_command_fn_T *value_funcptr;

	/** @} */
};

/** Instructions for registering an option, and storage for the option
 * itself.  */
union option_info {
	/** How to initialize and register #option.  This must be the
	 * first member of the union, to let C89 compilers initialize
	 * it.  */
	struct option_init init;

	/** register_options() constructs the option here, based on
	 * the instructions in #init.  By doing so, it of course
	 * overwrites #init.  Thus, only @c option can be used
	 * afterwards.  */
	struct option option;
};

extern void register_options(union option_info info[], struct option *tree);
extern void unregister_options(union option_info info[], struct option *tree);

/*! @relates option_info */
#define NULL_OPTION_INFO \
	{{ NULL, NULL, NULL, NULL, 0, \
	   0, 0, 0,  0, NULL, NULL }}

/*! @relates option_info */
#define INIT_OPT_BOOL(path, capt, name, flags, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_BOOL, 0, 1,  def, NULL, NULL }}

/*! @relates option_info */
#define INIT_OPT_INT(path, capt, name, flags, min, max, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_INT, min, max,  def, NULL, NULL }}

/*! @relates option_info */
#define INIT_OPT_LONG(path, capt, name, flags, min, max, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_LONG, min, max,  def, NULL, NULL }}

/*! @relates option_info */
#define INIT_OPT_STRING(path, capt, name, flags, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_STRING, 0, MAX_STR_LEN,  0, def, NULL }}

/*! @relates option_info */
#define INIT_OPT_CODEPAGE(path, capt, name, flags, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_CODEPAGE, 0, 0,  0, def, NULL }}

/*! @relates option_info */
#define INIT_OPT_COLOR(path, capt, name, flags, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_COLOR, 0, 0,  0, def, NULL }}

/*! @relates option_info */
#define INIT_OPT_LANGUAGE(path, capt, name, flags, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_LANGUAGE, 0, 0,  0, NULL, NULL }}

/*! @relates option_info */
#define INIT_OPT_COMMAND(path, capt, name, flags, cmd, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_COMMAND, 0, 0,  0, NULL, cmd }}

/*! @relates option_info */
#define INIT_OPT_CMDALIAS(path, capt, name, flags, def, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_ALIAS, 0, sizeof(def) - 1,  0, def, NULL }}

/*! @relates option_info */
#define INIT_OPT_ALIAS(path, name, flags, def) \
	{{ path, name, NULL, NULL, flags, \
	   OPT_ALIAS, 0, sizeof(def) - 1,  0, def, NULL }}

/*! @relates option_info */
#define INIT_OPT_TREE(path, capt, name, flags, desc) \
	{{ path, name, capt, DESC(desc), flags, \
	   OPT_TREE, 0, 0,  0, NULL, NULL }}


/* TODO: We need to do *something* with this ;). */

enum referer {
	REFERER_NONE,
	REFERER_SAME_URL,
	REFERER_FAKE,
	REFERER_TRUE,
};

enum verbose_level {
	VERBOSE_QUIET,
	VERBOSE_WARNINGS,
	VERBOSE_ALL,

	VERBOSE_LEVELS,
};

#endif