/*************************************************************************/
/*  editor_resource_preview.cpp                                          */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#include "editor_resource_preview.h"
#include "editor_settings.h"
#include "os/file_access.h"
#include "io/resource_loader.h"
#include "io/resource_saver.h"
#include "globals.h"
#include "editor_scale.h"
#include "message_queue.h"

bool EditorResourcePreviewGenerator::handles(const String& p_type) const {

	if (get_script_instance() && get_script_instance()->has_method("handles")) {
		return get_script_instance()->call("handles",p_type);
	}
	ERR_EXPLAIN("EditorResourcePreviewGenerator::handles needs to be overriden");
	ERR_FAIL_V(false);
}
Ref<Texture> EditorResourcePreviewGenerator::generate(const RES& p_from){

	if (get_script_instance() && get_script_instance()->has_method("generate")) {
		return get_script_instance()->call("generate",p_from);
	}
	ERR_EXPLAIN("EditorResourcePreviewGenerator::generate needs to be overriden");
	ERR_FAIL_V(Ref<Texture>());

}


Ref<Texture> EditorResourcePreviewGenerator::generate_from_path(const String& p_path) {

	if (get_script_instance() && get_script_instance()->has_method("generate_from_path")) {
		return get_script_instance()->call("generate_from_path",p_path);
	}

	RES res = ResourceLoader::load(p_path);
	if (!res.is_valid())
		return res;
	return generate(res);
}


void EditorResourcePreviewGenerator::_bind_methods() {

	ClassDB::add_virtual_method(get_class_static(),MethodInfo(Variant::BOOL,"handles",PropertyInfo(Variant::STRING,"type")));
	ClassDB::add_virtual_method(get_class_static(),MethodInfo(Variant::OBJECT,"generate:Texture",PropertyInfo(Variant::OBJECT,"from",PROPERTY_HINT_RESOURCE_TYPE,"Resource")));
	ClassDB::add_virtual_method(get_class_static(),MethodInfo(Variant::OBJECT,"generate_from_path:Texture",PropertyInfo(Variant::STRING,"path",PROPERTY_HINT_FILE)));

}

EditorResourcePreviewGenerator::EditorResourcePreviewGenerator() {


}


EditorResourcePreview* EditorResourcePreview::singleton=NULL;


void EditorResourcePreview::_thread_func(void *ud) {

	EditorResourcePreview *erp=(EditorResourcePreview*)ud;
	erp->_thread();

}


void EditorResourcePreview::_preview_ready(const String& p_str,const Ref<Texture>& p_texture,ObjectID id,const StringName& p_func,const Variant& p_ud) {

	//print_line("preview is ready");
	preview_mutex->lock();

	String path = p_str;
	uint32_t hash=0;
	uint64_t modified_time=0;

	if (p_str.begins_with("ID:")) {
		hash=p_str.get_slicec(':',2).to_int();
		path="ID:"+p_str.get_slicec(':',1);
	} else {
		modified_time = FileAccess::get_modified_time(path);
	}

	Item item;
	item.order=order++;
	item.preview=p_texture;
	item.last_hash=hash;
	item.modified_time=modified_time;

	cache[path]=item;

	preview_mutex->unlock();

	MessageQueue::get_singleton()->push_call(id,p_func,path,p_texture,p_ud);

}

Ref<Texture> EditorResourcePreview::_generate_preview(const QueueItem& p_item,const String& cache_base) {

	String type;

	if (p_item.resource.is_valid())
		type=p_item.resource->get_class();
	else
		type=ResourceLoader::get_resource_type(p_item.path);
	//print_line("resource type is: "+type);

	if (type=="")
		return Ref<Texture>(); //could not guess type

	Ref<Texture> generated;

	for(int i=0;i<preview_generators.size();i++) {

		if (!preview_generators[i]->handles(type))
			continue;
		if (p_item.resource.is_valid()) {
			generated = preview_generators[i]->generate(p_item.resource);
		} else {
			generated = preview_generators[i]->generate_from_path(p_item.path);
		}

		break;
	}

	if (!p_item.resource.is_valid()) {
		// cache the preview in case it's a resource on disk
		if (generated.is_valid()) {
			//print_line("was generated");
			int thumbnail_size = EditorSettings::get_singleton()->get("filesystem/file_dialog/thumbnail_size");
			thumbnail_size*=EDSCALE;
			//wow it generated a preview... save cache
			ResourceSaver::save(cache_base+".png",generated);
			FileAccess *f=FileAccess::open(cache_base+".txt",FileAccess::WRITE);
			f->store_line(itos(thumbnail_size));
			f->store_line(itos(FileAccess::get_modified_time(p_item.path)));
			f->store_line(FileAccess::get_md5(p_item.path));
			memdelete(f);
		} else {
			//print_line("was not generated");

		}
	}

	return generated;
}

void EditorResourcePreview::_thread() {

	//print_line("begin thread");
	while(!exit) {

		//print_line("wait for semaphore");
		preview_sem->wait();
		preview_mutex->lock();

		//print_line("blue team go");

		if (queue.size()) {



			QueueItem item = queue.front()->get();
			queue.pop_front();

			if (cache.has(item.path)) {
				//already has it because someone loaded it, just let it know it's ready
				if (item.resource.is_valid()) {
					item.path+=":"+itos(cache[item.path].last_hash); //keep last hash (see description of what this is in condition below)
				}

				_preview_ready(item.path,cache[item.path].preview,item.id,item.function,item.userdata);

				preview_mutex->unlock();
			} else {
				preview_mutex->unlock();


				Ref<Texture> texture;

				//print_line("pop from queue "+item.path);

				int thumbnail_size = EditorSettings::get_singleton()->get("filesystem/file_dialog/thumbnail_size");
				thumbnail_size*=EDSCALE;


				if (item.resource.is_valid()){

					texture=_generate_preview(item,String());
					//adding hash to the end of path (should be ID:<objid>:<hash>) because of 5 argument limit to call_deferred
					_preview_ready(item.path+":"+itos(item.resource->hash_edited_version()),texture,item.id,item.function,item.userdata);

				} else {


					String temp_path=EditorSettings::get_singleton()->get_settings_path().plus_file("tmp");
					String cache_base = GlobalConfig::get_singleton()->globalize_path(item.path).md5_text();
					cache_base = temp_path.plus_file("resthumb-"+cache_base);

					//does not have it, try to load a cached thumbnail

					String file = cache_base+".txt";
					//print_line("cachetxt at "+file);
					FileAccess *f=FileAccess::open(file,FileAccess::READ);
					if (!f) {

						//print_line("generate because not cached");

						//generate
						texture=_generate_preview(item,cache_base);
					} else {

						uint64_t modtime = FileAccess::get_modified_time(item.path);
						int tsize = f->get_line().to_int64();
						uint64_t last_modtime = f->get_line().to_int64();

						bool cache_valid = true;

						if (tsize!=thumbnail_size) {
							cache_valid=false;
							memdelete(f);
						} else if (last_modtime!=modtime) {

							String last_md5 = f->get_line();
							String md5 = FileAccess::get_md5(item.path);
							memdelete(f);

							if (last_md5!=md5) {

								cache_valid=false;
							} else {
								//update modified time

								f=FileAccess::open(file,FileAccess::WRITE);
								f->store_line(itos(modtime));
								f->store_line(md5);
								memdelete(f);
							}
						} else {
							memdelete(f);
						}

						cache_valid=false;

						if (cache_valid) {

							texture = ResourceLoader::load(cache_base+".png","ImageTexture",true);
							if (!texture.is_valid()) {
								//well fuck
								cache_valid=false;
							}
						}

						if (!cache_valid) {

							texture=_generate_preview(item,cache_base);
						}

					}

					//print_line("notify of preview ready");
					_preview_ready(item.path,texture,item.id,item.function,item.userdata);

				}
			}


		} else {
			preview_mutex->unlock();
		}

	}
}



void EditorResourcePreview::queue_edited_resource_preview(const Ref<Resource>& p_res, Object* p_receiver, const StringName& p_receiver_func, const Variant& p_userdata) {

	ERR_FAIL_NULL(p_receiver);
	ERR_FAIL_COND(!p_res.is_valid());

	preview_mutex->lock();

	String path_id = "ID:"+itos(p_res->get_instance_ID());


	if (cache.has(path_id) && cache[path_id].last_hash==p_res->hash_edited_version()) {

		cache[path_id].order=order++;
		p_receiver->call_deferred(p_receiver_func,path_id,cache[path_id].preview,p_userdata);
		preview_mutex->unlock();
		return;

	}

	cache.erase(path_id); //erase if exists, since it will be regen

	//print_line("send to thread "+p_path);
	QueueItem item;
	item.function=p_receiver_func;
	item.id=p_receiver->get_instance_ID();
	item.resource=p_res;
	item.path=path_id;
	item.userdata=p_userdata;

	queue.push_back(item);
	preview_mutex->unlock();
	preview_sem->post();
}

void EditorResourcePreview::queue_resource_preview(const String& p_path, Object* p_receiver, const StringName& p_receiver_func, const Variant& p_userdata) {

	ERR_FAIL_NULL(p_receiver);
	preview_mutex->lock();
	if (cache.has(p_path)) {
		cache[p_path].order=order++;
		p_receiver->call_deferred(p_receiver_func,p_path,cache[p_path].preview,p_userdata);
		preview_mutex->unlock();
		return;
	}

	//print_line("send to thread "+p_path);
	QueueItem item;
	item.function=p_receiver_func;
	item.id=p_receiver->get_instance_ID();
	item.path=p_path;
	item.userdata=p_userdata;

	queue.push_back(item);
	preview_mutex->unlock();
	preview_sem->post();

}

void EditorResourcePreview::add_preview_generator(const Ref<EditorResourcePreviewGenerator>& p_generator) {

	preview_generators.push_back(p_generator);
}

void EditorResourcePreview::remove_preview_generator(const Ref<EditorResourcePreviewGenerator>& p_generator) {

	preview_generators.erase(p_generator);
}

EditorResourcePreview* EditorResourcePreview::get_singleton() {

	return singleton;
}

void EditorResourcePreview::_bind_methods() {

	ClassDB::bind_method("_preview_ready",&EditorResourcePreview::_preview_ready);

	ClassDB::bind_method(_MD("queue_resource_preview","path","receiver","receiver_func","userdata:Variant"),&EditorResourcePreview::queue_resource_preview);
	ClassDB::bind_method(_MD("queue_edited_resource_preview","resource:Resource","receiver","receiver_func","userdata:Variant"),&EditorResourcePreview::queue_edited_resource_preview);
	ClassDB::bind_method(_MD("add_preview_generator","generator:EditorResourcePreviewGenerator"),&EditorResourcePreview::add_preview_generator);
	ClassDB::bind_method(_MD("remove_preview_generator","generator:EditorResourcePreviewGenerator"),&EditorResourcePreview::remove_preview_generator);
	ClassDB::bind_method(_MD("check_for_invalidation","path"),&EditorResourcePreview::check_for_invalidation);


	ADD_SIGNAL(MethodInfo("preview_invalidated",PropertyInfo(Variant::STRING,"path")));
}

void EditorResourcePreview::check_for_invalidation(const String& p_path) {

	preview_mutex->lock();

	bool call_invalidated=false;
	if (cache.has(p_path)) {

		uint64_t modified_time = FileAccess::get_modified_time(p_path);
		if (modified_time!=cache[p_path].modified_time) {
			cache.erase(p_path);
			call_invalidated=true;
		}
	}

	preview_mutex->unlock();

	if (call_invalidated) {//do outside mutex
		call_deferred("emit_signal","preview_invalidated",p_path);
	}



}

EditorResourcePreview::EditorResourcePreview() {
	singleton=this;
	preview_mutex = Mutex::create();
	preview_sem  = Semaphore::create();
	order=0;
	exit=false;

	thread = Thread::create(_thread_func,this);
}


EditorResourcePreview::~EditorResourcePreview()
{

	exit=true;
	preview_sem->post();
	Thread::wait_to_finish(thread);
	memdelete(thread);
	memdelete(preview_mutex);
	memdelete(preview_sem);


}