/*
 * This file is part of NetSurf, http://netsurf.sourceforge.net/
 * Licensed under the GNU General Public License,
 *		  http://www.opensource.org/licenses/gpl-license
 * Copyright 2004, 2005 Richard Wilson <info@tinct.net>
 */

/** \file
 * Interactive help (implementation).
 */

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include "oslib/help.h"
#include "oslib/os.h"
#include "oslib/taskmanager.h"
#include "oslib/wimp.h"
#include "netsurf/riscos/global_history.h"
#include "netsurf/riscos/gui.h"
#include "netsurf/riscos/help.h"
#include "netsurf/riscos/theme.h"
#include "netsurf/riscos/wimp.h"
#include "netsurf/utils/messages.h"
#include "netsurf/utils/log.h"


/*	Recognised help keys
	====================

	HelpIconbar		 Iconbar (no icon suffix is used)

	HelpAppInfo		 Application info window
	HelpBrowser		 Browser window [*]
	HelpHistory		 History window [*]
	HelpObjInfo		 Object info window
	HelpPageInfo		 Page info window
	HelpSaveAs		 Save as window
	HelpScaleView		 Scale view window
	HelpStatus		 Status window
	HelpToolbar		 Toolbar window
	HelpHotlist		 Hotlist window [*]
	HelpHotToolbar		 Hotlist window toolbar
	HelpHotEntry		 Hotlist entry window
	HelpHotFolder		 Hotlist entry window
	HelpGHistory		 Global history window [*]
	HelpGHistoryToolbar	 Global history window toolbar

	HelpIconMenu		 Iconbar menu
	HelpBrowserMenu 	 Browser window menu
	HelpHotlistMenu 	 Hotlist window menu

	The prefixes are followed by either the icon number (eg 'HelpToolbar7'), or a series
	of numbers representing the menu structure (eg 'HelpBrowserMenu3-1-2').
	If '<key><identifier>' is not available, then simply '<key>' is then used. For example
	if 'HelpToolbar7' is not available then 'HelpToolbar' is then tried.

	If an item is greyed out then a suffix of 'g' is added (eg 'HelpToolbar7g'). For this to
	work, windows must have bit 4 of the window flag byte set and the user must be running
	RISC OS 5.03 or greater.

	For items marked with an asterisk [*] a call must be made to determine the required
	help text as the window does not contain any icons. An example of this is the hotlist
	window where ro_gui_hotlist_help() is called.
*/

static void ro_gui_interactive_help_broadcast(wimp_message *message, char *token);
static os_t help_time = 0;

/**
 * Attempts to process an interactive help message request
 *
 * \param  message the request message
 */
void ro_gui_interactive_help_request(wimp_message *message) {
	char message_token[32];
	char menu_buffer[4];
	wimp_selection menu_tree;
	help_full_message_request *message_data;
	wimp_w window;
	wimp_i icon;
	struct gui_window *g;
	unsigned int index;
	bool greyed = false;
	wimp_menu *test_menu;

	/*	Ensure we have a help request
	*/
	if ((!message) || (message->action != message_HELP_REQUEST)) return;

	/*	Remember the time of the request
	*/
	xos_read_monotonic_time(&help_time);

	/*	Initialise the basic token to a null byte
	*/
	message_token[0] = 0x00;

	/*	Get the message data
	*/
	message_data = (help_full_message_request *)message;
	window = message_data->w;
	icon = message_data->i;

	/*	Do the basic window checks
	*/
	if (window == (wimp_w)-2) {
		sprintf(message_token, "HelpIconbar");
	} else if (window == dialog_info) {
		sprintf(message_token, "HelpAppInfo%i", (int)icon);
	} else if (window == history_window) {
		sprintf(message_token, "HelpHistory%i", (int)icon);
	} else if (window == dialog_objinfo) {
		sprintf(message_token, "HelpObjInfo%i", (int)icon);
	} else if (window == dialog_pageinfo) {
		sprintf(message_token, "HelpPageInfo%i", (int)icon);
	} else if (window == dialog_saveas) {
		sprintf(message_token, "HelpSaveAs%i", (int)icon);
	} else if (window == dialog_zoom) {
		sprintf(message_token, "HelpScaleView%i", (int)icon);
	} else if (window == dialog_folder) {
		sprintf(message_token, "HelpHotFolder%i", (int)icon);
	} else if (window == dialog_entry) {
		sprintf(message_token, "HelpHotEntry%i", (int)icon);
	} else if ((hotlist_tree) && (window == (wimp_w)hotlist_tree->handle)) {
		sprintf(message_token, "HelpHotlist%i",
				ro_gui_hotlist_help(message_data->pos.x,
						message_data->pos.y));
	} else if ((hotlist_tree) && (hotlist_tree->toolbar) &&
			(window == hotlist_tree->toolbar->toolbar_handle)) {
		sprintf(message_token, "HelpHotToolbar%i", (int)icon);
	} else if ((global_history_tree) && (window == (wimp_w)global_history_tree->handle)) {
		sprintf(message_token, "HelpGHistory%i",
				ro_gui_global_history_help(message_data->pos.x,
						message_data->pos.y));
	} else if ((global_history_tree) && (global_history_tree->toolbar) &&
			(window == global_history_tree->toolbar->toolbar_handle)) {
		sprintf(message_token, "HelpGHistoryToolbar%i", (int)icon);
	} else if ((g = ro_gui_window_lookup(window)) != NULL) {
		sprintf(message_token, "HelpBrowser%i", (int)icon);
	} else if ((g = ro_gui_toolbar_lookup(window)) != NULL) {
		sprintf(message_token, "HelpToolbar%i", (int)icon);
	} else if ((g = ro_gui_status_lookup(window)) != NULL) {
		sprintf(message_token, "HelpStatus%i", (int)icon);
	}

	/*	If we've managed to find something so far then we broadcast it
	*/
	if (message_token[0] != 0x00) {
		/*	Check to see if we are greyed out
		*/
		if ((icon >= 0) && (ro_gui_get_icon_shaded_state(window, icon))) {
			strcat(message_token, "g");
		}

		/*	Broadcast out message
		*/
		ro_gui_interactive_help_broadcast(message, &message_token[0]);
		return;
	}

	/*	If we are not on an icon, we can't be in a menu (which stops separators
		giving help for their parent) so we abort. You don't even want to think
		about the awful hack I was considering before I realised this...
	*/
	if (icon == (wimp_i)-1) return;

	/*	As a last resort, check for menu help.
	*/
	if (xwimp_get_menu_state((wimp_menu_state_flags)1,
				&menu_tree,
				window, icon)) return;
	if (menu_tree.items[0] == -1) return;

	/*	Set the prefix
	*/
	if (current_menu == iconbar_menu) {
		sprintf(message_token, "HelpIconMenu");
	} else if (current_menu == browser_menu) {
		sprintf(message_token, "HelpBrowserMenu");
	} else if (current_menu == hotlist_menu) {
		sprintf(message_token, "HelpHotlistMenu");
	} else {
		return;
	}

	/*	Decode the menu
	*/
	index = 0;
	test_menu = current_menu;
	while (menu_tree.items[index] != -1) {
		/*	Check if we're greyed out
		*/
		greyed |= test_menu->entries[menu_tree.items[index]].icon_flags & wimp_ICON_SHADED;
		test_menu = test_menu->entries[menu_tree.items[index]].sub_menu;

		/*	Continue adding the entries
		*/
		if (index == 0) {
			sprintf(menu_buffer, "%i", menu_tree.items[index]);
		} else {
			sprintf(menu_buffer, "-%i", menu_tree.items[index]);
		}
		strcat(message_token, menu_buffer);
		index++;
	}
	if (greyed) strcat(message_token, "g");

	/*	Finally, broadcast the menu help
	*/
	ro_gui_interactive_help_broadcast(message, &message_token[0]);
}


/**
 * Broadcasts a help reply
 *
 * \param  message the original request message
 * \param  token the token to look up
 */
static void ro_gui_interactive_help_broadcast(wimp_message *message, char *token) {
	const char *translated_token;
	help_full_message_reply *reply;
	char *base_token;

	/*	Start off with an empty reply
	*/
	reply = (help_full_message_reply *)message;
	reply->reply[0] = '\0';

	/*	Check if the message exists
	*/
	translated_token = messages_get(token);
	if (translated_token == token) {
		/*	We must never provide default help for a 'g' suffix.
		*/
		if (token[strlen(token) - 1] != 'g') {
			/*	Find the key from the token.
			*/
			base_token = token;
			while (base_token[0] != 0x00) {
				if ((base_token[0] == '-') ||
						((base_token[0] >= '0') && (base_token[0] <= '9'))) {
					base_token[0] = 0x00;
				} else {
					++base_token;
				}
			}

			/*	Check if the base key exists and use an empty string if not
			*/
			translated_token = messages_get(token);
		}
	}


	/*	Copy our message string
	*/
	if (translated_token != token) {
		reply->reply[235] = 0;
		strncpy(reply->reply, translated_token, 235);
	}

	/*	Broadcast the help reply
	*/
	reply->size = 256;
	reply->action = message_HELP_REPLY;
	reply->your_ref = reply->my_ref;
	wimp_send_message(wimp_USER_MESSAGE, (wimp_message *)reply, reply->sender);
}


/**
 * Checks if interactive help is running
 *
 * \return non-zero if interactive help is available, or 0 if not available
 */
int ro_gui_interactive_help_available() {
	taskmanager_task task;
	int context = 0;
	char *end;
	os_t time;

	/*	Check if we've received a help request in the last 1.0s to test for generic
		interactive help applications
	*/
	xos_read_monotonic_time(&time);
	if ((help_time + 100) > time) return true;

	/*	Attempt to find the task 'Help'
	*/
	do {
		if (xtaskmanager_enumerate_tasks(context, &task, sizeof(taskmanager_task),
					&context, &end)) return 0;

		/*	We can't just use strcmp due to string termination issues.
		*/
		if (strncmp(task.name, "Help", 4) == 0) {
			if (task.name[4] < 32) return true;
		} else if (strncmp(task.name, "Floating Help", 13) == 0) {
			if (task.name[13] < 32) return true;
		}
	} while (context >= 0);

	/*	Return failure
	*/
	return 0;
}