/*
 * This source file is part of RmlUi, the HTML/CSS Interface Middleware
 *
 * For the latest information, see http://github.com/mikke89/RmlUi
 *
 * Copyright (c) 2008-2010 CodePoint Ltd, Shift Technology Ltd
 * Copyright (c) 2019 The RmlUi Team, and contributors
 *
 * 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 "precompiled.h"
#include "../../Include/RmlUi/Core/StyleSheet.h"
#include <algorithm>
#include "ElementDefinition.h"
#include "StyleSheetFactory.h"
#include "StyleSheetNode.h"
#include "StyleSheetParser.h"
#include "../../Include/RmlUi/Core/Element.h"
#include "../../Include/RmlUi/Core/PropertyDefinition.h"
#include "../../Include/RmlUi/Core/StyleSheetSpecification.h"

namespace Rml {
namespace Core {

template <class T>
static inline void hash_combine(std::size_t& seed, const T& v)
{
	std::hash<T> hasher;
	seed ^= hasher(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}

// Sorts style nodes based on specificity.
static bool StyleSheetNodeSort(const StyleSheetNode* lhs, const StyleSheetNode* rhs)
{
	return lhs->GetSpecificity() < rhs->GetSpecificity();
}

StyleSheet::StyleSheet()
{
	root = new StyleSheetNode("", StyleSheetNode::ROOT);
	specificity_offset = 0;
}

StyleSheet::~StyleSheet()
{
	delete root;

	for (ElementDefinitionCache::iterator cache_iterator = node_cache.begin(); cache_iterator != node_cache.end(); ++cache_iterator)
		(*cache_iterator).second->RemoveReference();
}

bool StyleSheet::LoadStyleSheet(Stream* stream)
{
	StyleSheetParser parser;
	specificity_offset = parser.Parse(root, stream, *this, keyframes, decorator_map, spritesheet_list);
	return specificity_offset >= 0;
}

/// Combines this style sheet with another one, producing a new sheet
StyleSheet* StyleSheet::CombineStyleSheet(const StyleSheet* other_sheet) const
{
	RMLUI_ASSERT(other_sheet);

	StyleSheet* new_sheet = new StyleSheet();
	if (!new_sheet->root->MergeHierarchy(root) ||
		!new_sheet->root->MergeHierarchy(other_sheet->root, specificity_offset))
	{
		delete new_sheet;
		return NULL;
	}

	// Any matching @keyframe names are overridden as per CSS rules
	new_sheet->keyframes.reserve(keyframes.size() + other_sheet->keyframes.size());
	new_sheet->keyframes = keyframes;
	for (auto& other_keyframes : other_sheet->keyframes)
	{
		new_sheet->keyframes[other_keyframes.first] = other_keyframes.second;
	}

	// Copy over the decorators, and replace any matching decorator names from other_sheet
	new_sheet->decorator_map.reserve(decorator_map.size() + other_sheet->decorator_map.size());
	new_sheet->decorator_map = decorator_map;
	for (auto& other_decorator: other_sheet->decorator_map)
	{
		new_sheet->decorator_map[other_decorator.first] = other_decorator.second;
	}

	new_sheet->spritesheet_list.Reserve(
		spritesheet_list.NumSpriteSheets() + other_sheet->spritesheet_list.NumSpriteSheets(),
		spritesheet_list.NumSprites() + other_sheet->spritesheet_list.NumSprites()
	);
	new_sheet->spritesheet_list = other_sheet->spritesheet_list;
	new_sheet->spritesheet_list.Merge(spritesheet_list);

	new_sheet->specificity_offset = specificity_offset + other_sheet->specificity_offset;
	return new_sheet;
}

// Builds the node index for a combined style sheet.
void StyleSheet::BuildNodeIndexAndOptimizeProperties()
{
	if (complete_node_index.empty())
	{
		styled_node_index.clear();
		complete_node_index.clear();

		root->BuildIndexAndOptimizeProperties(styled_node_index, complete_node_index, *this);
		root->SetStructurallyVolatileRecursive(false);
	}
}

// Returns the Keyframes of the given name, or null if it does not exist.
Keyframes * StyleSheet::GetKeyframes(const String & name)
{
	auto it = keyframes.find(name);
	if (it != keyframes.end())
		return &(it->second);
	return nullptr;
}

std::shared_ptr<Decorator> StyleSheet::GetDecorator(const String& name) const
{
	auto it = decorator_map.find(name);
	if (it == decorator_map.end())
		return nullptr;
	return it->second.decorator;
}

const Sprite* StyleSheet::GetSprite(const String& name) const
{
	return spritesheet_list.GetSprite(name);
}

DecoratorList StyleSheet::InstanceDecoratorsFromString(const String& decorator_string_value, const String& source_file, int source_line_number) const
{
	// Decorators are declared as
	//   decorator: <decorator-value>[, <decorator-value> ...];
	// Where <decorator-value> is either a @decorator name:
	//   decorator: invader-theme-background, ...;
	// or is an anonymous decorator with inline properties
	//   decorator: tiled-box( <shorthand properties> ), ...;
	
	DecoratorList decorator_list;
	if (decorator_string_value.empty() || decorator_string_value == NONE)
		return decorator_list;

	// Make sure we don't split inside the parenthesis since they may appear in decorator shorthands.
	StringList decorator_string_list;
	StringUtilities::ExpandString(decorator_string_list, decorator_string_value, ',', '(', ')');

	decorator_list.reserve(decorator_string_list.size());

	// Get or instance each decorator in the comma-separated string list
	for (const String& decorator_string : decorator_string_list)
	{
		const size_t shorthand_open = decorator_string.find('(');
		const size_t shorthand_close = decorator_string.rfind(')');
		const bool invalid_parenthesis = (shorthand_open == String::npos || shorthand_close == String::npos || shorthand_open >= shorthand_close);

		if (invalid_parenthesis)
		{
			// We found no parenthesis, that means the value must be a name of a @decorator rule, look it up
			std::shared_ptr<Decorator> decorator = GetDecorator(decorator_string);
			if (decorator)
				decorator_list.emplace_back(std::move(decorator));
			else
				Log::Message(Log::LT_WARNING, "Decorator name '%s' could not be found in any @decorator rule, declared at %s:%d", decorator_string.c_str(), source_file.c_str(), source_line_number);
		}
		else
		{
			// Since we have parentheses it must be an anonymous decorator with inline properties
			const String type = StringUtilities::StripWhitespace(decorator_string.substr(0, shorthand_open));

			// Check for valid decorator type
			DecoratorInstancer* instancer = Factory::GetDecoratorInstancer(type);
			if (!instancer)
			{
				Log::Message(Log::LT_WARNING, "Decorator type '%s' not found, declared at %s:%d", type.c_str(), source_file.c_str(), source_line_number);
				continue;
			}

			const String shorthand = decorator_string.substr(shorthand_open + 1, shorthand_close - shorthand_open - 1);
			const PropertySpecification& specification = instancer->GetPropertySpecification();

			// Parse the shorthand properties given by the 'decorator' shorthand property
			PropertyDictionary properties;
			if (!specification.ParsePropertyDeclaration(properties, "decorator", shorthand, source_file, source_line_number))
			{
				Log::Message(Log::LT_WARNING, "Could not parse decorator value '%s' at %s:%d", decorator_string.c_str(), source_file.c_str(), source_line_number);
				continue;
			}

			// Set unspecified values to their defaults
			specification.SetPropertyDefaults(properties);

			std::shared_ptr<Decorator> decorator = instancer->InstanceDecorator(type, properties, DecoratorInstancerInterface(*this));

			if (decorator)
				decorator_list.emplace_back(std::move(decorator));
			else
			{
				Log::Message(Log::LT_WARNING, "Decorator '%s' could not be instanced, declared at %s:%d", decorator_string.c_str(), source_file.c_str(), source_line_number);
				continue;
			}
		}
	}

	return decorator_list;
}


// Returns the compiled element definition for a given element hierarchy.
ElementDefinition* StyleSheet::GetElementDefinition(const Element* element) const
{
	RMLUI_ASSERT_NONRECURSIVE;

	// See if there are any styles defined for this element.
	// Using static to avoid allocations. Make sure we don't call this function recursively.
	static std::vector< const StyleSheetNode* > applicable_nodes;
	applicable_nodes.clear();

	String tags[] = {element->GetTagName(), ""};
	for (int i = 0; i < 2; i++)
	{
		auto it_nodes = styled_node_index.find(tags[i]);
		if (it_nodes != styled_node_index.end())
		{
			const NodeList& nodes = it_nodes->second;

			// There are! Now see if we satisfy all of their parenting requirements. What this involves is traversing the style
			// nodes backwards, trying to match nodes in the element's hierarchy to nodes in the style hierarchy.
			for (StyleSheetNode* node : nodes)
			{
				if (node->IsApplicable(element))
				{
					// Get the node to add any of its non-tag children that we match into our list.
					node->GetApplicableDescendants(applicable_nodes, element);
				}
			}
		}
	}

	std::sort(applicable_nodes.begin(), applicable_nodes.end(), StyleSheetNodeSort);

	// If this element definition won't actually store any information, don't bother with it.
	if (applicable_nodes.empty())
		return NULL;

	// Check if this puppy has already been cached in the node index; it may be that it has already been created by an
	// element with a different address but an identical output definition.
	size_t seed = 0;
	for (const auto* node : applicable_nodes)
		hash_combine(seed, node);

	auto cache_iterator = node_cache.find(seed);
	if (cache_iterator != node_cache.end())
	{
		ElementDefinition* definition = (*cache_iterator).second;
		definition->AddReference();
		applicable_nodes.clear();
		return definition;
	}

	// Create the new definition and add it to our cache. One reference count is added, bringing the total to two; one
	// for the element that requested it, and one for the cache.
	ElementDefinition* new_definition = new ElementDefinition(applicable_nodes);

	// Add to the node cache.
	node_cache[seed] = new_definition;
	new_definition->AddReference();

	return new_definition;
}

// Destroys the style sheet.
void StyleSheet::OnReferenceDeactivate()
{
	delete this;
}

}
}