/*
 * 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 <stdbool.h>
#include <stdio.h>
#include "oslib/help.h"
#include "oslib/os.h"
#include "oslib/taskmanager.h"
#include "oslib/wimp.h"
#include "netsurf/desktop/tree.h"
#include "netsurf/riscos/global_history.h"
#include "netsurf/riscos/gui.h"
#include "netsurf/riscos/help.h"
#include "netsurf/riscos/menus.h"
#include "netsurf/riscos/theme.h"
#include "netsurf/riscos/wimp.h"
#include "netsurf/riscos/wimp_event.h"
#include "netsurf/utils/messages.h"
#include "netsurf/utils/log.h"
#include "netsurf/utils/utf8.h"
#include "netsurf/utils/utils.h"


/*	Recognised help keys
	====================
	Help keys should be registered using the wimp_event system to be
	recognised. The only special case help values are:

	HelpIconbar		 Iconbar (no icon suffix is used)
	HelpHotlist		 Hotlist window [*]
	HelpGHistory		 Global history window [*]
	HelpBrowser		 Browser window [*]

	HelpIconMenu		 Iconbar menu
	HelpBrowserMenu		 Browser window menu
	HelpHotlistMenu		 Hotlist window menu
	HelpGHistoryMenu	 Global history 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;
	os_error *error;
	const char *auto_text;

	/* only accept help requests */
	if ((!message) || (message->action != message_HELP_REQUEST))
		return;

	/* remember the time of the request so we can track them */
	xos_read_monotonic_time(&help_time);

	/* set up our state */
	message_token[0] = 0x00;
	message_data = (help_full_message_request *)message;
	window = message_data->w;
	icon = message_data->i;

	/* do the basic window checks */
	auto_text = ro_gui_wimp_event_get_help_prefix(window);
	if (auto_text)
	  	sprintf(message_token, "%s%i", auto_text, (int)icon);
	else if (window == wimp_ICON_BAR)
		sprintf(message_token, "HelpIconbar");
	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 ((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 ((g = ro_gui_window_lookup(window)) != NULL)
		sprintf(message_token, "HelpBrowser%i", (int)icon);

	/* if we've managed to find something so far then we broadcast it */
	if (message_token[0]) {
		if ((icon >= 0) &&
				(ro_gui_get_icon_shaded_state(window, icon)))
			strcat(message_token, "g");
		ro_gui_interactive_help_broadcast(message,
				(char *)message_token);
		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 */
	if (icon == wimp_ICON_WINDOW)
		return;

	/* get the current menu tree */
	error = xwimp_get_menu_state(wimp_GIVEN_WINDOW_AND_ICON,
				&menu_tree, window, icon);
	if (error) {
		LOG(("xwimp_get_menu_state: 0x%x: %s",
				error->errnum, error->errmess));
		warn_user("WimpError", error->errmess);
		return;
	}
	if (menu_tree.items[0] == -1)
		return;

	/* get the menu 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 if (current_menu == global_history_menu)
		sprintf(message_token, "HelpGHistoryMenu");
	else
		return;

	/* decode the menu */
	index = 0;
	test_menu = current_menu;
	while (menu_tree.items[index] != -1) {
		greyed |= test_menu->entries[menu_tree.items[index]].icon_flags
				& wimp_ICON_SHADED;
		test_menu = test_menu->entries[menu_tree.items[index]].sub_menu;
		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");
	ro_gui_interactive_help_broadcast(message, (char *)message_token);
}


/**
 * 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;
	char *local_token;
	os_error *error;
	utf8_convert_ret err;

	/* 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) {
		/* no default help for 'g' suffix */
		if (token[strlen(token) - 1] != 'g') {
			/* find the base 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;
			}
			translated_token = messages_get(token);
		}
	}

	/* copy our message string */
	if (translated_token != token) {
		/* convert to local encoding */
		err = utf8_to_local_encoding(translated_token, 0,
				&local_token);
		if (err != UTF8_CONVERT_OK) {
			/* badenc should never happen */
			assert(err != UTF8_CONVERT_BADENC);
			/* simply use UTF-8 string */
			strncpy(reply->reply, translated_token, 235);
		}
		else {
			strncpy(reply->reply, local_token, 235);
			free(local_token);
		}
		reply->reply[235] = '\0';
	}

	/* broadcast the help reply */
	reply->size = 256;
	reply->action = message_HELP_REPLY;
	reply->your_ref = reply->my_ref;
	error = xwimp_send_message(wimp_USER_MESSAGE, (wimp_message *)reply,
			reply->sender);
	if (error) {
		LOG(("xwimp_send_message: 0x%x: %s",
				error->errnum, error->errmess));
		warn_user("WimpError", error->errmess);
	}
}


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

	/* generic test: any help request within the last 100cs */
	xos_read_monotonic_time(&time);
	if ((help_time + 100) > time)
		return true;

	/* special cases: check known application names */
	do {
		error = xtaskmanager_enumerate_tasks(context, &task,
				sizeof(taskmanager_task), &context, 0);
		if (error) {
			LOG(("xtaskmanager_enumerate_tasks: 0x%x: %s",
					error->errnum, error->errmess));
			warn_user("MiscError", error->errmess);
		}

		/* we can't just use strcmp due to string termination issues */
		if (!strncmp(task.name, "Help", 4) &&
				(task.name[4] < 32))
			return true;
		else if (!strncmp(task.name, "Bubble Help", 11) &&
				(task.name[11] < 32))
			return true;
		else if (!strncmp(task.name, "Floating Help", 13) &&
				(task.name[13] < 32))
			return true;
	} while (context >= 0);
	return false;
}


/**
 * Launches interactive help.
 */
void ro_gui_interactive_help_start(void) {
	char *help_start;
	wimp_t task = 0;
	os_error *error;

	/* launch <Help$Start> */
	help_start = getenv("Help$Start");
	if ((help_start) && (help_start[0])) {
		error = xwimp_start_task("<Help$Start>", &task);
		if (error) {
			LOG(("xwimp_start_tast: 0x%x: %s",
					error->errnum, error->errmess));
			warn_user("WimpError", error->errmess);
			return;
		}
	}

	/* first attempt failed, launch !Help */
	if (!task) {
		error = xwimp_start_task("Resources:$.Apps.!Help", &task);
		if (error) {
			LOG(("xwimp_start_tast: 0x%x: %s",
					error->errnum, error->errmess));
			warn_user("WimpError", error->errmess);
			return;
		}
	}

	/* pretend we got a help request straight away */
	if (task) {
		error = xos_read_monotonic_time(&help_time);
		if (error) {
			LOG(("xwimp_read_monotonic_time: 0x%x: %s",
					error->errnum, error->errmess));
			warn_user("WimpError", error->errmess);
		}
	}
}