/*
 * Copyright (c) 2012 Petr Koupy
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup gui
 * @{
 */
/**
 * @file
 */

#include <stdbool.h>
#include <errno.h>
#include <stdio.h>

#include <as.h>
#include <malloc.h>
#include <str.h>

#include <fibril.h>
#include <task.h>
#include <adt/prodcons.h>
#include <adt/list.h>

#include <async.h>
#include <loc.h>

#include <io/pixel.h>
#include <source.h>
#include <font.h>
#include <drawctx.h>
#include <surface.h>

#include "connection.h"
#include "widget.h"
#include "window.h"

static sysarg_t border_thickness = 5;
static sysarg_t header_height = 20;
static sysarg_t header_min_width = 40;
static sysarg_t close_width = 20;

static pixel_t border_color = PIXEL(255, 0, 0, 0);
static pixel_t header_bg_focus_color = PIXEL(255, 88, 106, 196);
static pixel_t header_fg_focus_color = PIXEL(255, 255, 255, 255);
static pixel_t header_bg_unfocus_color = PIXEL(255, 12, 57, 92);
static pixel_t header_fg_unfocus_color = PIXEL(255, 255, 255, 255);

static void paint_internal(widget_t *w)
{
	surface_t *surface = window_claim(w->window);
	if (!surface) {
		window_yield(w->window);
	}

	source_t source;
	font_t font;
	drawctx_t drawctx;

	source_init(&source);
	font_init(&font, FONT_DECODER_EMBEDDED, NULL, 16);
	drawctx_init(&drawctx, surface);
	drawctx_set_source(&drawctx, &source);
	drawctx_set_font(&drawctx, &font);

	source_set_color(&source, border_color);
	drawctx_transfer(&drawctx, w->hpos, w->vpos, border_thickness, w->height);
	drawctx_transfer(&drawctx, w->hpos + w->width - border_thickness,
	    w->vpos, border_thickness, w->height);
	drawctx_transfer(&drawctx, w->hpos, w->vpos, w->width, border_thickness);
	drawctx_transfer(&drawctx, w->hpos,
	    w->vpos + w->height - border_thickness, w->width, border_thickness);

	source_set_color(&source, 
	    w->window->is_focused ? header_bg_focus_color : header_bg_unfocus_color);
	drawctx_transfer(&drawctx,
	    w->hpos + border_thickness, w->vpos + border_thickness,
		w->width - 2 * border_thickness, header_height);

	sysarg_t cpt_width;
	sysarg_t cpt_height;
	font_get_box(&font, w->window->caption, &cpt_width, &cpt_height);
	sysarg_t cls_width;
	sysarg_t cls_height;
	char cls_pict[] = "x";
	font_get_box(&font, cls_pict, &cls_width, &cls_height);
	source_set_color(&source, 
	    w->window->is_focused ? header_fg_focus_color : header_fg_unfocus_color);
	sysarg_t cls_x = ((close_width - cls_width) / 2) + w->hpos + w->width -
	    border_thickness - close_width;
	sysarg_t cls_y = ((header_height - cls_height) / 2) + w->vpos + border_thickness;
	drawctx_print(&drawctx, cls_pict, cls_x, cls_y);

	bool draw_title = (w->width >= 2 * border_thickness + close_width + cpt_width);
	if (draw_title) {
		sysarg_t cpt_x = ((w->width - cpt_width) / 2) + w->hpos;
		sysarg_t cpt_y = ((header_height - cpt_height) / 2) + w->vpos + border_thickness;
		if (w->window->caption) {
			drawctx_print(&drawctx, w->window->caption, cpt_x, cpt_y);
		}
	}

	font_release(&font);
	window_yield(w->window);
}

static void root_destroy(widget_t *widget)
{
	widget_deinit(widget);
}

static void root_reconfigure(widget_t *widget)
{
	if (widget->window->is_decorated) {
		list_foreach(widget->children, link, widget_t, child) {
			child->rearrange(child, 
			    widget->hpos + border_thickness,
			    widget->vpos + border_thickness + header_height,
			    widget->width - 2 * border_thickness,
			    widget->height - 2 * border_thickness - header_height);
		}
	} else {
		list_foreach(widget->children, link, widget_t, child) {
			child->rearrange(child, widget->hpos, widget->vpos,
			    widget->width, widget->height);
		}
	}
}

static void root_rearrange(widget_t *widget, sysarg_t hpos, sysarg_t vpos,
    sysarg_t width, sysarg_t height)
{
	widget_modify(widget, hpos, vpos, width, height);
	if (widget->window->is_decorated) {
		paint_internal(widget);
		list_foreach(widget->children, link, widget_t, child) {
			child->rearrange(child, 
			    hpos + border_thickness,
			    vpos + border_thickness + header_height,
			    width - 2 * border_thickness,
			    height - 2 * border_thickness - header_height);
		}
	} else {
		list_foreach(widget->children, link, widget_t, child) {
			child->rearrange(child, hpos, vpos, width, height);
		}
	}
}

static void root_repaint(widget_t *widget)
{
	if (widget->window->is_decorated) {
		paint_internal(widget);
	}
	list_foreach(widget->children, link, widget_t, child) {
		child->repaint(child);
	}
	if (widget->window->is_decorated) {
		window_damage(widget->window);
	}
}

static void root_handle_keyboard_event(widget_t *widget, kbd_event_t event)
{
	if (!list_empty(&widget->children)) {
		widget_t *child = (widget_t *) list_first(&widget->children);
		child->handle_keyboard_event(child, event);
	}
}

static void root_handle_position_event(widget_t *widget, pos_event_t event)
{
	if (widget->window->is_decorated) {
		sysarg_t width = widget->width;
		sysarg_t height = widget->height;

		bool btn_left = (event.btn_num == 1) && (event.type == POS_PRESS);
		bool btn_right = (event.btn_num == 2) && (event.type == POS_PRESS);
		bool allowed_button = btn_left || btn_right;

		bool left = (event.hpos < border_thickness);
		bool right = (event.hpos >= width - border_thickness);
		bool top = (event.vpos < border_thickness);
		bool bottom = (event.vpos >= height - border_thickness);
		bool header = (event.hpos >= border_thickness) &&
		    (event.hpos < width - border_thickness) &&
		    (event.vpos >= border_thickness) &&
		    (event.vpos < border_thickness + header_height);
		bool close = header && (event.hpos >= width - border_thickness - close_width);

		if (top && left && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_X;
			flags |= GF_MOVE_Y;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (bottom && left && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_X;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (bottom && right && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (top && right && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_Y;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (top && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_Y;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (left && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_X;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (bottom && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= btn_left ? GF_RESIZE_Y : GF_SCALE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (right && allowed_button) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= btn_left ? GF_RESIZE_X : GF_SCALE_X;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else if (close && btn_left) {
			win_close_request(widget->window->osess);
		} else if (header && btn_left) {
			window_grab_flags_t flags = GF_EMPTY;
			flags |= GF_MOVE_X;
			flags |= GF_MOVE_Y;
			win_grab(widget->window->osess, event.pos_id, flags);
		} else {
			list_foreach(widget->children, link, widget_t, child) {
				child->handle_position_event(child, event);
			}
		}
	} else {
		list_foreach(widget->children, link, widget_t, child) {
			child->handle_position_event(child, event);
		}
	}
}

static void deliver_keyboard_event(window_t *win, kbd_event_t event)
{
	if (win->focus) {
		win->focus->handle_keyboard_event(win->focus, event);
	} else {
		win->root.handle_keyboard_event(&win->root, event);
	}
}

static void deliver_position_event(window_t *win, pos_event_t event)
{
	if (win->grab) {
		win->grab->handle_position_event(win->grab, event);
	} else {
		win->root.handle_position_event(&win->root, event);
	}
}

static void handle_signal_event(window_t *win, sig_event_t event)
{
	widget_t *widget = (widget_t *) event.object;
	slot_t slot = (slot_t) event.slot;
	void *data = (void *) event.argument;

	slot(widget, data);

	free(data);
}

static void handle_resize(window_t *win, sysarg_t width, sysarg_t height)
{
	int rc;
	surface_t *old_surface;
	surface_t *new_surface;

	if (width < 2 * border_thickness + header_min_width) {
		win_damage(win->osess, 0, 0, 0, 0);
		return;
	}

	if (height < 2 * border_thickness + header_height) {
		win_damage(win->osess, 0, 0, 0, 0);
		return;
	}

	/* Allocate resources for new surface. */
	new_surface = surface_create(width, height, NULL, SURFACE_FLAG_SHARED);
	if (!new_surface) {
		return;
	}

	/* Switch new and old surface. */
	fibril_mutex_lock(&win->guard);
	old_surface = win->surface;
	win->surface = new_surface;
	fibril_mutex_unlock(&win->guard);

	/* Let all widgets in the tree alter their position and size. Widgets might
	 * also paint themselves onto the new surface. */
	win->root.rearrange(&win->root, 0, 0, width, height);

	fibril_mutex_lock(&win->guard);
	surface_reset_damaged_region(win->surface);
	fibril_mutex_unlock(&win->guard);

	/* Inform compositor about new surface. */
	rc = win_resize(win->osess,
		width, height, surface_direct_access(new_surface));

	if (rc != EOK) {
		/* Rollback to old surface. Reverse all changes. */

		sysarg_t old_width = 0;
		sysarg_t old_height = 0;
		if (old_surface) {
			surface_get_resolution(old_surface, &old_width, &old_height);
		}

		fibril_mutex_lock(&win->guard);
		new_surface = win->surface;
		win->surface = old_surface;
		fibril_mutex_unlock(&win->guard);

		win->root.rearrange(&win->root, 0, 0, old_width, old_height);
		
		if (win->surface) {
			fibril_mutex_lock(&win->guard);
			surface_reset_damaged_region(win->surface);
			fibril_mutex_unlock(&win->guard);
		}

		surface_destroy(new_surface);
		return;
	}

	/* Finally deallocate old surface. */
	if (old_surface) {
		surface_destroy(old_surface);
	}
}

static void handle_refresh(window_t *win)
{
	win->root.repaint(&win->root);
}

static void handle_damage(window_t *win)
{
	sysarg_t x, y, width, height;
	fibril_mutex_lock(&win->guard);
	surface_get_damaged_region(win->surface, &x, &y, &width, &height);
	surface_reset_damaged_region(win->surface);
	fibril_mutex_unlock(&win->guard);

	if (width > 0 && height > 0) {
		/* Notify compositor. */
		win_damage(win->osess, x, y, width, height);
	}
}

static void destroy_children(widget_t *widget)
{
	/* Recursively destroy widget tree in bottom-top order. */
	while (!list_empty(&widget->children)) {
		widget_t *child =
		    list_get_instance(list_first(&widget->children), widget_t, link);
		destroy_children(child);
		child->destroy(child);
	}
}

static void handle_close(window_t *win)
{
	destroy_children(&win->root);
	win->root.destroy(&win->root);
	win->grab = NULL;
	win->focus = NULL;

	win_close(win->osess);
	async_hangup(win->isess);
	async_hangup(win->osess);

	while (!list_empty(&win->events.list)) {
		window_event_t *event = (window_event_t *) list_first(&win->events.list);
		list_remove(&event->link);
		free(event);
	}

	if (win->surface) {
		surface_destroy(win->surface);
	}

	free(win->caption);

	free(win);
}

/* Window event loop. Runs in own dedicated fibril. */
static int event_loop(void *arg)
{
	bool is_main = false;
	bool terminate = false;
	window_t *win = (window_t *) arg;

	while (true) {
		window_event_t *event = (window_event_t *) prodcons_consume(&win->events);

		switch (event->type) {
		case ET_KEYBOARD_EVENT:
			deliver_keyboard_event(win, event->data.kbd);
			break;
		case ET_POSITION_EVENT:
			if (!win->is_focused) {
				win->is_focused = true;
				handle_refresh(win);
			}
			deliver_position_event(win, event->data.pos);
			break;
		case ET_SIGNAL_EVENT:
			handle_signal_event(win, event->data.sig);
			break;
		case ET_WINDOW_RESIZE:
			handle_resize(win, event->data.rsz.width, event->data.rsz.height);
			break;
		case ET_WINDOW_FOCUS:
			if (!win->is_focused) {
				win->is_focused = true;
				handle_refresh(win);
			}
			break;
		case ET_WINDOW_UNFOCUS:
			if (win->is_focused) {
				win->is_focused = false;
				handle_refresh(win);
			}
			break;
		case ET_WINDOW_REFRESH:
			handle_refresh(win);
			break;
		case ET_WINDOW_DAMAGE:
			handle_damage(win);
			break;
		case ET_WINDOW_CLOSE:
			is_main = win->is_main;
			handle_close(win);
			terminate = true;
			break;
		default:
			break;
		}

		free(event);
		if (terminate) {
			break;
		}
	}

	if (is_main) {
		exit(0); /* Terminate whole task. */
	}
	return 0;
}

/* Input fetcher from compositor. Runs in own dedicated fibril. */
static int fetch_input(void *arg)
{
	int rc;
	bool terminate = false;
	window_t *win = (window_t *) arg;

	while (true) {
		window_event_t *event = (window_event_t *) malloc(sizeof(window_event_t));
		
		if (event) {
			rc = win_get_event(win->isess, event);
			if (rc == EOK) {
				terminate = (event->type == ET_WINDOW_CLOSE);
				link_initialize(&event->link);
				prodcons_produce(&win->events, &event->link);
			} else {
				free(event);
				terminate = true;
			}
		} else {
			terminate = true;
		}

		if (terminate) {
			break;
		}
	}

	return 0;
}

window_t *window_open(char *winreg, bool is_main, bool is_decorated, 
    const char *caption, sysarg_t x_offset, sysarg_t y_offset)
{
	int rc;

	window_t *win = (window_t *) malloc(sizeof(window_t));
	if (!win) {
		return NULL;
	}

	win->is_main = is_main;
	win->is_decorated = is_decorated;
	win->is_focused = true;
	prodcons_initialize(&win->events);
	fibril_mutex_initialize(&win->guard);
	widget_init(&win->root, NULL);
	win->root.window = win;
	win->root.destroy = root_destroy;
	win->root.reconfigure = root_reconfigure;
	win->root.rearrange = root_rearrange;
	win->root.repaint = root_repaint;
	win->root.handle_keyboard_event = root_handle_keyboard_event;
	win->root.handle_position_event = root_handle_position_event;
	win->grab = NULL;
	win->focus = NULL;
	win->surface = NULL;

	service_id_t reg_dsid;
	async_sess_t *reg_sess;

	rc = loc_service_get_id(winreg, &reg_dsid, 0);
	if (rc != EOK) {
		free(win);
		return NULL;
	}

	reg_sess = loc_service_connect(EXCHANGE_SERIALIZE, reg_dsid, 0);
	if (reg_sess == NULL) {
		free(win);
		return NULL;
	}

	service_id_t in_dsid;
	service_id_t out_dsid;
	
	rc = win_register(reg_sess, &in_dsid, &out_dsid, x_offset, y_offset);
	async_hangup(reg_sess);
	if (rc != EOK) {
		free(win);
		return NULL;
	}

	win->osess = loc_service_connect(EXCHANGE_SERIALIZE, out_dsid, 0);
	if (win->osess == NULL) {
		free(win);
		return NULL;
	}

	win->isess = loc_service_connect(EXCHANGE_SERIALIZE, in_dsid, 0);
	if (win->isess == NULL) {
		async_hangup(win->osess);
		free(win);
		return NULL;
	}

	if (caption == NULL) {
		win->caption = NULL;
	} else {
		win->caption = str_dup(caption);
	}

	return win;
}

void window_resize(window_t *win, sysarg_t width, sysarg_t height)
{
	window_event_t *event = (window_event_t *) malloc(sizeof(window_event_t));
	if (event) {
		link_initialize(&event->link);
		event->type = ET_WINDOW_RESIZE;
		event->data.rsz.width = width;
		event->data.rsz.height = height;
		prodcons_produce(&win->events, &event->link);
	}
}

void window_refresh(window_t *win)
{
	window_event_t *event = (window_event_t *) malloc(sizeof(window_event_t));
	if (event) {
		link_initialize(&event->link);
		event->type = ET_WINDOW_REFRESH;
		prodcons_produce(&win->events, &event->link);
	}
}

void window_damage(window_t *win)
{
	window_event_t *event = (window_event_t *) malloc(sizeof(window_event_t));
	if (event) {
		link_initialize(&event->link);
		event->type = ET_WINDOW_DAMAGE;
		prodcons_produce(&win->events, &event->link);
	}
}

widget_t *window_root(window_t *win)
{
	return &win->root;
}

void window_exec(window_t *win)
{
	fid_t ev_fid = fibril_create(event_loop, win);
	fid_t fi_fid = fibril_create(fetch_input, win);
	if (!ev_fid || !fi_fid) {
		return;
	}
	fibril_add_ready(ev_fid);
	fibril_add_ready(fi_fid);
}

surface_t *window_claim(window_t *win)
{
	fibril_mutex_lock(&win->guard);
	return win->surface;
}

void window_yield(window_t *win)
{
	fibril_mutex_unlock(&win->guard);
}

void window_close(window_t *win)
{
	/* Request compositor to init closing cascade. */
	win_close_request(win->osess);
}

/** @}
 */