/*
 * Copyright 2014 Vincent Sanders <vince@netsurf-browser.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * \file
 * Interface to form handling functions internal to render.
 */

#ifndef _NETSURF_RENDER_FORM_INTERNAL_H_
#define _NETSURF_RENDER_FORM_INTERNAL_H_

#include <stdbool.h>

#include "netsurf/form.h"

struct box;
struct form_control;
struct form_option;
struct form_select_menu;
struct form;
struct html_content;
struct dom_string;
struct content;
struct nsurl;
struct fetch_multipart_data;
struct redraw_context;
struct browser_window;

enum browser_mouse_state;

/** Type of a struct form_control. */
typedef enum {
	GADGET_HIDDEN,
	GADGET_TEXTBOX,
	GADGET_RADIO,
	GADGET_CHECKBOX,
	GADGET_SELECT,
	GADGET_TEXTAREA,
	GADGET_IMAGE,
	GADGET_PASSWORD,
	GADGET_SUBMIT,
	GADGET_RESET,
	GADGET_FILE,
	GADGET_BUTTON
} form_control_type;

/** Data for textarea */
struct form_textarea_data {
	struct form_control *gadget;
};

struct image_input_coords {
	int x;
	int y;
};

/** Form control. */
struct form_control {
	void *node;			/**< Corresponding DOM node */
	struct html_content *html;	/**< HTML content containing control */

	form_control_type type;		/**< Type of control */

	struct form *form;		/**< Containing form */

	char *name;			/**< Control name */
	char *value;			/**< Current value of control */
	char *initial_value;		/**< Initial value of control */
	bool disabled;			/**< Whether control is disabled */

	struct box *box;		/**< Box for control */

	unsigned int length;		/**< Number of characters in control */
	unsigned int maxlength;		/**< Maximum characters permitted */

	bool selected;			/**< Whether control is selected */

	union {
		struct {
			int mx, my;
		} image;
		struct {
			int num_items;
			struct form_option *items, *last_item;
			bool multiple;
			int num_selected;
			/** Currently selected item, if num_selected == 1. */
			struct form_option *current;
			struct form_select_menu *menu;
		} select;
		struct {
			struct textarea *ta;
			struct dom_string *initial;
			struct form_textarea_data data;
		} text;			/**< input type=text or textarea */
	} data;

	struct form_control *prev;      /**< Previous control in this form */
	struct form_control *next;	/**< Next control in this form. */
};

/** Form submit method. */
typedef enum {
	method_GET,		/**< GET, always url encoded. */
	method_POST_URLENC,	/**< POST, url encoded. */
	method_POST_MULTIPART	/**< POST, multipart/form-data. */
} form_method;

/** HTML form. */
struct form {
	void *node;			/**< Corresponding DOM node */

	char *action;			/**< Absolute URL to submit to. */
	char *target;			/**< Target to submit to. */
	form_method method;		/**< Method and enctype. */
	char *accept_charsets;		/**< Charset to submit form in */
	char *document_charset;		/**< Charset of document containing form */
	struct form_control *controls;	/**< Linked list of controls. */
	struct form_control *last_control;	/**< Last control in list. */

	struct form *prev;		/**< Previous form in doc. */
};

/**
 * Called by the select menu when it wants an area to be redrawn. The
 * coordinates are menu origin relative.
 *
 * \param client_data	data which was passed to form_open_select_menu
 * \param x		X coordinate of redraw rectangle
 * \param y		Y coordinate of redraw rectangle
 * \param width		width of redraw rectangle
 * \param height	height of redraw rectangle
 */
typedef void(*select_menu_redraw_callback)(void *client_data,
		int x, int y, int width, int height);

/**
 * Create a struct form.
 *
 * \param node         DOM node associated with form
 * \param action       URL to submit form to, or NULL for default
 * \param target       Target frame of form, or NULL for default
 * \param method       method and enctype
 * \param charset      acceptable encodings for form submission, or NULL
 * \param doc_charset  encoding of containing document, or NULL
 * \return A new form or NULL on memory exhaustion
 */
struct form *form_new(void *node, const char *action, const char *target,
		form_method method, const char *charset,
		const char *doc_charset);

/**
 * Free a form and any controls it owns.
 *
 * \note There may exist controls attached to box tree nodes which are not
 * associated with any form. These will leak at present. Ideally, they will
 * be cleaned up when the box tree is destroyed. As that currently happens
 * via talloc, this won't happen. These controls are distinguishable, as their
 * form field will be NULL.
 *
 * \param form The form to free
 */
void form_free(struct form *form);

/**
 * Create a struct form_control.
 *
 * \param  node  Associated DOM node
 * \param  type  control type
 * \return  a new structure, or NULL on memory exhaustion
 */
struct form_control *form_new_control(void *node, form_control_type type);

void form_add_control(struct form *form, struct form_control *control);
void form_free_control(struct form_control *control);
bool form_add_option(struct form_control *control, char *value, char *text,
		     bool selected, void *node);
bool form_successful_controls(struct form *form,
		struct form_control *submit_button,
		struct fetch_multipart_data **successful_controls);

/**
 * Identify 'successful' controls via the DOM.
 *
 * All text strings in the successful controls list will be in the charset most
 * appropriate for submission. Therefore, no utf8_to_* processing should be
 * performed upon them.
 *
 * \todo The chosen charset needs to be made available such that it can be
 * included in the submission request (e.g. in the fetch's Content-Type header)
 *
 * See HTML 4.01 section 17.13.2.
 *
 * \param[in] form  form to search for successful controls
 * \param[in] submit_button  control used to submit the form, if any
 * \param[out] successful_controls  updated to point to linked list of
 *                        fetch_multipart_data, 0 if no controls
 * \return  true on success, false on memory exhaustion
 */
bool form_successful_controls_dom(struct form *form,
		struct form_control *submit_button,
		struct fetch_multipart_data **successful_controls);


/**
 * Open a select menu for a select form control, creating it if necessary.
 *
 * \param client_data  data passed to the redraw callback
 * \param control  The select form control for which the menu is being opened
 * \param redraw_callback  The callback to redraw the select menu.
 * \param c  The content the select menu is opening for.
 * \return false on memory exhaustion, true otherwise
 */
bool form_open_select_menu(void *client_data,
		struct form_control *control,
		select_menu_redraw_callback redraw_callback,
  		struct content *c);


void form_select_menu_callback(void *client_data,
		int x, int y, int width, int height);


/**
 * Destroy a select menu and free allocated memory.
 *
 * \param control  the select form control owning the select menu being
 *                  destroyed.
 */
void form_free_select_menu(struct form_control *control);


/**
 * Redraw an opened select menu.
 *
 * \param control  the select menu being redrawn
 * \param x        the X coordinate to draw the menu at
 * \param y        the Y coordinate to draw the menu at
 * \param scale    current redraw scale
 * \param clip     clipping rectangle
 * \param ctx      current redraw context
 * \return         true on success, false otherwise
 */
bool form_redraw_select_menu(struct form_control *control, int x, int y,
		float scale, const struct rect *clip,
		const struct redraw_context *ctx);

bool form_clip_inside_select_menu(struct form_control *control, float scale,
		const struct rect *clip);
const char *form_select_mouse_action(struct form_control *control,
		enum browser_mouse_state mouse, int x, int y);
void form_select_mouse_drag_end(struct form_control *control,
		enum browser_mouse_state mouse, int x, int y);
void form_select_get_dimensions(struct form_control *control,
		int *width, int *height);
void form_submit(struct nsurl *page_url, struct browser_window *target,
		struct form *form, struct form_control *submit_button);
void form_radio_set(struct form_control *radio);

void form_gadget_update_value(struct form_control *control, char *value);

#endif
