/*
 * Copyright © 2001 Red Hat, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of Red Hat not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  Red Hat makes no representations about the
 * suitability of this software for any purpose.  It is provided "as is"
 * without express or implied warranty.
 *
 * RED HAT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL RED HAT
 * BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Author:  Owen Taylor, Red Hat, Inc.
 */
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <X11/Xlib.h>
#include <X11/Xmd.h> /* For CARD16 */

#include "xsettings-client.h"
#include "server.h"
#include "panel.h"
#include "launcher.h"

struct _XSettingsClient {
	Display *display;
	int screen;
	XSettingsNotifyFunc notify;
	XSettingsWatchFunc watch;
	void *cb_data;

	Window manager_window;
	XSettingsList *settings;
};

void xsettings_notify_cb(const char *name, XSettingsAction action, XSettingsSetting *setting, void *data)
{
	if ((action == XSETTINGS_ACTION_NEW || action == XSETTINGS_ACTION_CHANGED) && name != NULL && setting != NULL) {
		if (strcmp(name, "Net/IconThemeName") == 0 && setting->type == XSETTINGS_TYPE_STRING) {
			fprintf(stderr, "xsettings: %s = %s\n", name, setting->data.v_string);
			if (icon_theme_name_xsettings) {
				if (strcmp(icon_theme_name_xsettings, setting->data.v_string) == 0)
					return;
				free(icon_theme_name_xsettings);
			}
			icon_theme_name_xsettings = strdup(setting->data.v_string);
			default_icon_theme_changed();
		} else if (strcmp(name, "Gtk/FontName") == 0 && setting->type == XSETTINGS_TYPE_STRING) {
			fprintf(stderr, "xsettings: %s = %s\n", name, setting->data.v_string);
			if (default_font) {
				if (strcmp(default_font, setting->data.v_string) == 0)
					return;
				free(default_font);
			}
			default_font = strdup(setting->data.v_string);
			default_font_changed();
		}
	}
}

static void notify_changes(XSettingsClient *client, XSettingsList *old_list)
{
	XSettingsList *old_iter = old_list;
	XSettingsList *new_iter = client->settings;

	if (!client->notify)
		return;

	while (old_iter || new_iter) {
		int cmp;

		if (old_iter && new_iter)
			cmp = strcmp(old_iter->setting->name, new_iter->setting->name);
		else if (old_iter)
			cmp = -1;
		else
			cmp = 1;

		if (cmp < 0) {
			client->notify(old_iter->setting->name, XSETTINGS_ACTION_DELETED, NULL, client->cb_data);
		} else if (cmp == 0) {
			if (!xsettings_setting_equal(old_iter->setting, new_iter->setting))
				client->notify(old_iter->setting->name, XSETTINGS_ACTION_CHANGED, new_iter->setting, client->cb_data);
		} else {
			client->notify(new_iter->setting->name, XSETTINGS_ACTION_NEW, new_iter->setting, client->cb_data);
		}

		if (old_iter)
			old_iter = old_iter->next;
		if (new_iter)
			new_iter = new_iter->next;
	}
}

static int ignore_errors(Display *display, XErrorEvent *event)
{
	return True;
}

static char local_byte_order = '\0';

#define BYTES_LEFT(buffer) ((buffer)->data + (buffer)->len - (buffer)->pos)

static XSettingsResult fetch_card16(XSettingsBuffer *buffer, CARD16 *result)
{
	CARD16 x;

	if (BYTES_LEFT(buffer) < 2)
		return XSETTINGS_ACCESS;

	x = *(CARD16 *)buffer->pos;
	buffer->pos += 2;

	if (buffer->byte_order == local_byte_order)
		*result = x;
	else
		*result = (x << 8) | (x >> 8);

	return XSETTINGS_SUCCESS;
}

static XSettingsResult fetch_ushort(XSettingsBuffer *buffer, unsigned short *result)
{
	CARD16 x;
	XSettingsResult r;

	r = fetch_card16(buffer, &x);
	if (r == XSETTINGS_SUCCESS)
		*result = x;

	return r;
}

static XSettingsResult fetch_card32(XSettingsBuffer *buffer, CARD32 *result)
{
	CARD32 x;

	if (BYTES_LEFT(buffer) < 4)
		return XSETTINGS_ACCESS;

	x = *(CARD32 *)buffer->pos;
	buffer->pos += 4;

	if (buffer->byte_order == local_byte_order)
		*result = x;
	else
		*result = (x << 24) | ((x & 0xff00) << 8) | ((x & 0xff0000) >> 8) | (x >> 24);

	return XSETTINGS_SUCCESS;
}

static XSettingsResult fetch_card8(XSettingsBuffer *buffer, CARD8 *result)
{
	if (BYTES_LEFT(buffer) < 1)
		return XSETTINGS_ACCESS;

	*result = *(CARD8 *)buffer->pos;
	buffer->pos += 1;

	return XSETTINGS_SUCCESS;
}

#define XSETTINGS_PAD(n, m) ((n + m - 1) & (~(m - 1)))

static XSettingsList *parse_settings(unsigned char *data, size_t len)
{
	XSettingsBuffer buffer;
	XSettingsResult result = XSETTINGS_SUCCESS;
	XSettingsList *settings = NULL;
	CARD32 serial;
	CARD32 n_entries;
	CARD32 i;
	XSettingsSetting *setting = NULL;

	local_byte_order = xsettings_byte_order();

	buffer.byte_order = local_byte_order;
	buffer.pos = buffer.data = data;
	buffer.len = len;

	result = fetch_card8(&buffer, (CARD8 *)&buffer.byte_order);
	if (buffer.byte_order != MSBFirst && buffer.byte_order != LSBFirst) {
		fprintf(stderr, "Invalid byte order %x in XSETTINGS property\n", buffer.byte_order);
		result = XSETTINGS_FAILED;
		goto out;
	}

	buffer.pos += 3;

	result = fetch_card32(&buffer, &serial);
	if (result != XSETTINGS_SUCCESS)
		goto out;

	result = fetch_card32(&buffer, &n_entries);
	if (result != XSETTINGS_SUCCESS)
		goto out;

	for (i = 0; i < n_entries; i++) {
		CARD8 type;
		CARD16 name_len;
		CARD32 v_int;
		size_t pad_len;

		result = fetch_card8(&buffer, &type);
		if (result != XSETTINGS_SUCCESS)
			goto out;

		buffer.pos += 1;

		result = fetch_card16(&buffer, &name_len);
		if (result != XSETTINGS_SUCCESS)
			goto out;

		pad_len = XSETTINGS_PAD(name_len, 4);
		if (BYTES_LEFT(&buffer) < pad_len) {
			result = XSETTINGS_ACCESS;
			goto out;
		}

		setting = calloc(1, sizeof *setting);
		if (!setting) {
			result = XSETTINGS_NO_MEM;
			goto out;
		}
		setting->type = XSETTINGS_TYPE_INT; /* No allocated memory */

		setting->name = calloc(name_len + 1, 1);
		if (!setting->name) {
			result = XSETTINGS_NO_MEM;
			goto out;
		}

		memcpy(setting->name, buffer.pos, name_len);
		setting->name[name_len] = '\0';
		buffer.pos += pad_len;

		result = fetch_card32(&buffer, &v_int);
		if (result != XSETTINGS_SUCCESS)
			goto out;
		setting->last_change_serial = v_int;

		switch (type) {
		case XSETTINGS_TYPE_INT:
			result = fetch_card32(&buffer, &v_int);
			if (result != XSETTINGS_SUCCESS)
				goto out;
			setting->data.v_int = (INT32)v_int;
			break;
		case XSETTINGS_TYPE_STRING:
			result = fetch_card32(&buffer, &v_int);
			if (result != XSETTINGS_SUCCESS)
				goto out;

			pad_len = XSETTINGS_PAD(v_int, 4);
			if (v_int + 1 == 0 || /* Guard against wrap-around */
				BYTES_LEFT(&buffer) < pad_len) {
				result = XSETTINGS_ACCESS;
				goto out;
			}

			setting->data.v_string = calloc(v_int + 1, 1);
			if (!setting->data.v_string) {
				result = XSETTINGS_NO_MEM;
				goto out;
			}

			memcpy(setting->data.v_string, buffer.pos, v_int);
			setting->data.v_string[v_int] = '\0';
			buffer.pos += pad_len;
			break;
		case XSETTINGS_TYPE_COLOR:
			result = fetch_ushort(&buffer, &setting->data.v_color.red);
			if (result != XSETTINGS_SUCCESS)
				goto out;
			result = fetch_ushort(&buffer, &setting->data.v_color.green);
			if (result != XSETTINGS_SUCCESS)
				goto out;
			result = fetch_ushort(&buffer, &setting->data.v_color.blue);
			if (result != XSETTINGS_SUCCESS)
				goto out;
			result = fetch_ushort(&buffer, &setting->data.v_color.alpha);
			if (result != XSETTINGS_SUCCESS)
				goto out;
			break;
		default:
			/* Quietly ignore unknown types */
			break;
		}

		setting->type = type;

		result = xsettings_list_insert(&settings, setting);
		if (result != XSETTINGS_SUCCESS)
			goto out;

		setting = NULL;
	}

out:

	if (result != XSETTINGS_SUCCESS) {
		switch (result) {
		case XSETTINGS_NO_MEM:
			fprintf(stderr, "Out of memory reading XSETTINGS property\n");
			break;
		case XSETTINGS_ACCESS:
			fprintf(stderr, "Invalid XSETTINGS property (read off end)\n");
			break;
		case XSETTINGS_DUPLICATE_ENTRY:
			fprintf(stderr, "Duplicate XSETTINGS entry for '%s'\n", setting->name);
		case XSETTINGS_FAILED:
		case XSETTINGS_SUCCESS:
		case XSETTINGS_NO_ENTRY:
			break;
		}

		if (setting)
			xsettings_setting_free(setting);

		xsettings_list_free(settings);
		settings = NULL;
	}

	return settings;
}

static void read_settings(XSettingsClient *client)
{
	Atom type;
	int format;
	unsigned long n_items;
	unsigned long bytes_after;
	unsigned char *data;

	int (*old_handler)(Display *, XErrorEvent *);

	XSettingsList *old_list = client->settings;
	client->settings = NULL;

	old_handler = XSetErrorHandler(ignore_errors);
	int result = XGetWindowProperty(client->display,
								client->manager_window,
								server.atom._XSETTINGS_SETTINGS,
								0,
								LONG_MAX,
								False,
								server.atom._XSETTINGS_SETTINGS,
								&type,
								&format,
								&n_items,
								&bytes_after,
								&data);
	XSetErrorHandler(old_handler);

	if (result == Success && type == server.atom._XSETTINGS_SETTINGS) {
		if (format != 8) {
			fprintf(stderr, "Invalid format for XSETTINGS property %d", format);
		} else
			client->settings = parse_settings(data, n_items);
		XFree(data);
	}

	notify_changes(client, old_list);
	xsettings_list_free(old_list);
}

static void check_manager_window(XSettingsClient *client)
{
	if (client->manager_window && client->watch)
		client->watch(client->manager_window, False, 0, client->cb_data);

	XGrabServer(client->display);

	client->manager_window = XGetSelectionOwner(server.display, server.atom._XSETTINGS_SCREEN);
	if (client->manager_window)
		XSelectInput(server.display, client->manager_window, PropertyChangeMask | StructureNotifyMask);

	XUngrabServer(client->display);
	XFlush(client->display);

	if (client->manager_window && client->watch)
		client->watch(client->manager_window, True, PropertyChangeMask | StructureNotifyMask, client->cb_data);

	read_settings(client);
}

XSettingsClient *xsettings_client_new(Display *display,
									  int screen,
									  XSettingsNotifyFunc notify,
									  XSettingsWatchFunc watch,
									  void *cb_data)
{
	XSettingsClient *client = calloc(1, sizeof *client);
	if (!client)
		return NULL;

	client->display = display;
	client->screen = screen;
	client->notify = notify;
	client->watch = watch;
	client->cb_data = cb_data;

	client->manager_window = None;
	client->settings = NULL;

	if (client->watch)
		client->watch(RootWindow(display, screen), True, StructureNotifyMask, client->cb_data);

	check_manager_window(client);

	if (client->manager_window == None) {
		printf("No XSETTINGS manager, tint2 uses config option 'launcher_icon_theme'.\n");
		free(client);
		return NULL;
	} else {
		return client;
	}
}

void xsettings_client_destroy(XSettingsClient *client)
{
	if (!client)
		return;
	if (client->watch)
		client->watch(RootWindow(client->display, client->screen), False, 0, client->cb_data);
	if (client->manager_window && client->watch)
		client->watch(client->manager_window, False, 0, client->cb_data);

	xsettings_list_free(client->settings);
	free(client);
}

XSettingsResult xsettings_client_get_setting(XSettingsClient *client, const char *name, XSettingsSetting **setting)
{
	XSettingsSetting *search = xsettings_list_lookup(client->settings, name);
	if (search) {
		*setting = xsettings_setting_copy(search);
		return *setting ? XSETTINGS_SUCCESS : XSETTINGS_NO_MEM;
	} else
		return XSETTINGS_NO_ENTRY;
}

Bool xsettings_client_process_event(XSettingsClient *client, XEvent *xev)
{
	/* The checks here will not unlikely cause us to reread
	* the properties from the manager window a number of
	* times when the manager changes from A->B. But manager changes
	* are going to be pretty rare.
	*/
	if (xev->xany.window == RootWindow(server.display, server.screen)) {
		if (xev->xany.type == ClientMessage && xev->xclient.message_type == server.atom.MANAGER) {
			check_manager_window(client);
			return True;
		}
	} else if (xev->xany.window == client->manager_window) {
		if (xev->xany.type == DestroyNotify) {
			check_manager_window(client);
			return True;
		} else if (xev->xany.type == PropertyNotify) {
			read_settings(client);
			return True;
		}
	}

	return False;
}