/** 
 * @file llfontregistry.cpp
 * @author Brad Payne
 * @brief Storage for fonts.
 *
 * $LicenseInfo:firstyear=2008&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"
#include "llgl.h"
#include "llfontfreetype.h"
#include "llfontgl.h"
#include "llfontregistry.h"
#include <boost/tokenizer.hpp>
#include "llcontrol.h"
#include "lldir.h"
#include "llwindow.h"
#include "llxmlnode.h"

extern LLControlGroup gSavedSettings;

using std::string;
using std::map;

bool font_desc_init_from_xml(LLXMLNodePtr node, LLFontDescriptor& desc);
bool init_from_xml(LLFontRegistry* registry, LLXMLNodePtr node);

const std::string MACOSX_FONT_PATH_LIBRARY = "/Library/Fonts/";
const std::string MACOSX_FONT_SUPPLEMENTAL = "Supplemental/";

LLFontDescriptor::char_functor_map_t LLFontDescriptor::mCharFunctors({
	{ "is_emoji", LLStringOps::isEmoji }
});

LLFontDescriptor::LLFontDescriptor():
	mStyle(0)
{
}

LLFontDescriptor::LLFontDescriptor(const std::string& name,
								   const std::string& size, 
								   const U8 style,
								   const font_file_info_vec_t& font_files):
	mName(name),
	mSize(size),
	mStyle(style),
	mFontFiles(font_files)
{
}

LLFontDescriptor::LLFontDescriptor(const std::string& name,
	const std::string& size,
	const U8 style,
	const font_file_info_vec_t& font_list,
	const font_file_info_vec_t& font_collection_files) :
	LLFontDescriptor(name, size, style, font_list)
{
	mFontCollectionFiles = font_collection_files;
}

LLFontDescriptor::LLFontDescriptor(const std::string& name,
								   const std::string& size, 
								   const U8 style):
	mName(name),
	mSize(size),
	mStyle(style)
{
}

bool LLFontDescriptor::operator<(const LLFontDescriptor& b) const
{
	if (mName < b.mName)
		return true;
	else if (mName > b.mName)
		return false;
	
	if (mStyle < b.mStyle)
		return true;
	else if (mStyle > b.mStyle)
		return false;

	if (mSize < b.mSize)
		return true;
	else 
		return false;
}

static const std::string s_template_string("TEMPLATE");

bool LLFontDescriptor::isTemplate() const
{
	return getSize() == s_template_string;
}

// Look for substring match and remove substring if matched.
bool removeSubString(std::string& str, const std::string& substr)
{
	size_t pos = str.find(substr);
	if (pos != string::npos)
	{
		str.erase(pos, substr.size());
		return true;
	}
	return false;
}

// Check for substring match without modifying the source string.
bool findSubString(std::string& str, const std::string& substr)
{
	size_t pos = str.find(substr);
	if (pos != string::npos)
	{
		return true;
	}
	return false;
}


// Normal form is
// - raw name
// - bold, italic style info reflected in both style and font name.
// - other style info removed.
// - size info moved to mSize, defaults to Medium
// For example,
// - "SansSerifHuge" would normalize to { "SansSerif", "Huge", 0 }
// - "SansSerifBold" would normalize to { "SansSerifBold", "Medium", BOLD }
LLFontDescriptor LLFontDescriptor::normalize() const
{
	std::string new_name(mName);
	std::string new_size(mSize);
	U8 new_style(mStyle);

	// Only care about style to extent it can be picked up by font.
	new_style &= (LLFontGL::BOLD | LLFontGL::ITALIC);

	// All these transformations are to support old-style font specifications.
	if (removeSubString(new_name,"Small"))
		new_size = "Small";
	if (removeSubString(new_name,"Big"))
		new_size = "Large";
	if (removeSubString(new_name,"Medium"))
		new_size = "Medium";
	if (removeSubString(new_name,"Large"))
		new_size = "Large";
	if (removeSubString(new_name,"Huge"))
		new_size = "Huge";

	// HACK - Monospace is the only one we don't remove, so
	// name "Monospace" doesn't get taken down to ""
	// For other fonts, there's no ambiguity between font name and size specifier.
	if (new_size != s_template_string && new_size.empty() && findSubString(new_name,"Monospace"))
		new_size = "Monospace";
	if (new_size.empty())
		new_size = "Medium";

	if (removeSubString(new_name,"Bold"))
		new_style |= LLFontGL::BOLD;

	if (removeSubString(new_name,"Italic"))
		new_style |= LLFontGL::ITALIC;

	return LLFontDescriptor(new_name,new_size,new_style, getFontFiles(), getFontCollectionFiles());
}

void LLFontDescriptor::addFontFile(const std::string& file_name, const std::string& char_functor)
{
	char_functor_map_t::const_iterator it = mCharFunctors.find(char_functor);
	mFontFiles.push_back(LLFontFileInfo(file_name, (mCharFunctors.end() != it) ? it->second : nullptr));
}

void LLFontDescriptor::addFontCollectionFile(const std::string& file_name, const std::string& char_functor)
{
	char_functor_map_t::const_iterator it = mCharFunctors.find(char_functor);
	mFontCollectionFiles.push_back(LLFontFileInfo(file_name, (mCharFunctors.end() != it) ? it->second : nullptr));
}

LLFontRegistry::LLFontRegistry(bool create_gl_textures)
:	mCreateGLTextures(create_gl_textures)
{
	// This is potentially a slow directory traversal, so we want to
	// cache the result.
	mUltimateFallbackList = LLWindow::getDynamicFallbackFontList();
}

LLFontRegistry::~LLFontRegistry()
{
	clear();
}

bool LLFontRegistry::parseFontInfo(const std::string& xml_filename)
{
	bool success = false;  // Succeed if we find and read at least one XUI file
	const string_vec_t xml_paths = gDirUtilp->findSkinnedFilenames(LLDir::XUI, xml_filename);
	if (xml_paths.empty())
	{
		// We didn't even find one single XUI file
		return false;
	}

	for (string_vec_t::const_iterator path_it = xml_paths.begin();
		 path_it != xml_paths.end();
		 ++path_it)
	{
		LLXMLNodePtr root;
		bool parsed_file = LLXMLNode::parseFile(*path_it, root, NULL);

		if (!parsed_file)
			continue;

		if ( root.isNull() || ! root->hasName( "fonts" ) )
		{
			LL_WARNS() << "Bad font info file: " << *path_it << LL_ENDL;
			continue;
		}

		std::string root_name;
		root->getAttributeString("name",root_name);
		if (root->hasName("fonts"))
		{
			// Expect a collection of children consisting of "font" or "font_size" entries
			bool init_succ = init_from_xml(this, root);
			success = success || init_succ;
		}
	}

	//if (success)
	//	dump();

	return success;
}

std::string currentOsName()
{
#if LL_WINDOWS
	return "Windows";
#elif LL_DARWIN
	return "Mac";
#elif LL_SDL || LL_MESA_HEADLESS
	return "Linux";
#else
	return "";
#endif
}

bool font_desc_init_from_xml(LLXMLNodePtr node, LLFontDescriptor& desc)
{
	if (node->hasName("font"))
	{
		std::string attr_name;
		if (node->getAttributeString("name",attr_name))
		{
			desc.setName(attr_name);
		}

		std::string attr_style;
		if (node->getAttributeString("font_style",attr_style))
		{
			desc.setStyle(LLFontGL::getStyleFromString(attr_style));
		}

		desc.setSize(s_template_string);
	}

	LLXMLNodePtr child;	
	for (child = node->getFirstChild(); child.notNull(); child = child->getNextSibling())
	{
		std::string child_name;
		child->getAttributeString("name",child_name);
		if (child->hasName("file"))
		{
			std::string font_file_name = child->getTextContents();
			std::string char_functor;

			if (child->hasAttribute("functor"))
			{
				child->getAttributeString("functor", char_functor);
			}

			if (child->hasAttribute("load_collection"))
			{
				BOOL col = FALSE;
				child->getAttributeBOOL("load_collection", col);
				if (col)
				{
					desc.addFontCollectionFile(font_file_name, char_functor);
				}
			}

			desc.addFontFile(font_file_name, char_functor);
		}
		else if (child->hasName("os"))
		{
			if (child_name == currentOsName())
			{
				font_desc_init_from_xml(child, desc);
			}
		}
	}
	return true;
}

bool init_from_xml(LLFontRegistry* registry, LLXMLNodePtr node)
{
	LLXMLNodePtr child;
	
	for (child = node->getFirstChild(); child.notNull(); child = child->getNextSibling())
	{
		std::string child_name;
		child->getAttributeString("name",child_name);
		if (child->hasName("font"))
		{
			LLFontDescriptor desc;
			bool font_succ = font_desc_init_from_xml(child, desc);
			LLFontDescriptor norm_desc = desc.normalize();
			if (font_succ)
			{
				// if this is the first time we've seen this font name,
				// create a new template map entry for it.
				const LLFontDescriptor *match_desc = registry->getMatchingFontDesc(desc);
				if (match_desc == NULL)
				{
					// Create a new entry (with no corresponding font).
					registry->mFontMap[norm_desc] = NULL;
				}
				// otherwise, find the existing entry and combine data. 
				else
				{
					// Prepend files from desc.
					// A little roundabout because the map key is const,
					// so we have to fetch it, make a new map key, and
					// replace the old entry.
					font_file_info_vec_t font_files = match_desc->getFontFiles();
					font_files.insert(font_files.begin(),
									  desc.getFontFiles().begin(),
									  desc.getFontFiles().end());

					font_file_info_vec_t font_collection_files = match_desc->getFontCollectionFiles();
					font_collection_files.insert(font_collection_files.begin(),
						desc.getFontCollectionFiles().begin(),
						desc.getFontCollectionFiles().end());

					LLFontDescriptor new_desc = *match_desc;
					new_desc.setFontFiles(font_files);
					new_desc.setFontCollectionFiles(font_collection_files);
					registry->mFontMap.erase(*match_desc);
					registry->mFontMap[new_desc] = NULL;
				}
			}
		}
		else if (child->hasName("font_size"))
		{
			std::string size_name;
			F32 size_value;
			if (child->getAttributeString("name",size_name) &&
				child->getAttributeF32("size",size_value))
			{
				registry->mFontSizes[size_name] = size_value;
			}

		}
	}
	return true;
}

bool LLFontRegistry::nameToSize(const std::string& size_name, F32& size)
{
	font_size_map_t::iterator it = mFontSizes.find(size_name);
	if (it != mFontSizes.end())
	{
		size = it->second;
		return true;
	}
	return false;
}


LLFontGL *LLFontRegistry::createFont(const LLFontDescriptor& desc)
{
	// Name should hold a font name recognized as a setting; the value
	// of the setting should be a list of font files.
	// Size should be a recognized string value
	// Style should be a set of flags including any implied by the font name.

	// First decipher the requested size.
	LLFontDescriptor norm_desc = desc.normalize();
	F32 point_size;
	bool found_size = nameToSize(norm_desc.getSize(),point_size);
	if (!found_size)
	{
		LL_WARNS() << "createFont unrecognized size " << norm_desc.getSize() << LL_ENDL;
		return NULL;
	}
	LL_INFOS() << "createFont " << norm_desc.getName() << " size " << norm_desc.getSize() << " style " << ((S32) norm_desc.getStyle()) << LL_ENDL;
	F32 fallback_scale = 1.0;

	// Find corresponding font template (based on same descriptor with no size specified)
	LLFontDescriptor template_desc(norm_desc);
	template_desc.setSize(s_template_string);
	const LLFontDescriptor *match_desc = getClosestFontTemplate(template_desc);
	if (!match_desc)
	{
		LL_WARNS() << "createFont failed, no template found for "
				<< norm_desc.getName() << " style [" << ((S32)norm_desc.getStyle()) << "]" << LL_ENDL;
		return NULL;
	}

	// See whether this best-match font has already been instantiated in the requested size.
	LLFontDescriptor nearest_exact_desc = *match_desc;
	nearest_exact_desc.setSize(norm_desc.getSize());
	font_reg_map_t::iterator it = mFontMap.find(nearest_exact_desc);
	// If we fail to find a font in the fonts directory, it->second might be NULL.
	// We shouldn't construcnt a font with a NULL mFontFreetype.
	// This may not be the best solution, but it at least prevents a crash.
	if (it != mFontMap.end() && it->second != NULL)
	{
		LL_INFOS() << "-- matching font exists: " << nearest_exact_desc.getName() << " size " << nearest_exact_desc.getSize() << " style " << ((S32) nearest_exact_desc.getStyle()) << LL_ENDL;
		
		// copying underlying Freetype font, and storing in LLFontGL with requested font descriptor
		LLFontGL *font = new LLFontGL;
		font->mFontDescriptor = desc;
		font->mFontFreetype = it->second->mFontFreetype;
		mFontMap[desc] = font;

		return font;
	}

	// Build list of font names to look for.
	// Files specified for this font come first, followed by those from the default descriptor.
	font_file_info_vec_t font_files = match_desc->getFontFiles();
	font_file_info_vec_t font_collection_files = match_desc->getFontCollectionFiles();
	LLFontDescriptor default_desc("default",s_template_string,0);
	const LLFontDescriptor *match_default_desc = getMatchingFontDesc(default_desc);
	if (match_default_desc)
	{
		font_files.insert(font_files.end(),
						  match_default_desc->getFontFiles().begin(),
						  match_default_desc->getFontFiles().end());
		font_collection_files.insert(font_collection_files.end(),
			match_default_desc->getFontCollectionFiles().begin(),
			match_default_desc->getFontCollectionFiles().end());
	}

	// Add ultimate fallback list - generated dynamically on linux,
	// null elsewhere.
	std::transform(getUltimateFallbackList().begin(), getUltimateFallbackList().end(), std::back_inserter(font_files),
	               [](const std::string& file_name) { return LLFontFileInfo(file_name); });

	// Load fonts based on names.
	if (font_files.empty())
	{
		LL_WARNS() << "createFont failed, no file names specified" << LL_ENDL;
		return NULL;
	}

	LLFontGL *result = NULL;

	// The first font will get pulled will be the "head" font, set to non-fallback.
	// Rest will consitute the fallback list.
	BOOL is_first_found = TRUE;
	
	string_vec_t font_search_paths;
	font_search_paths.push_back(LLFontGL::getFontPathLocal());
	font_search_paths.push_back(LLFontGL::getFontPathSystem());
#if LL_DARWIN
	font_search_paths.push_back(MACOSX_FONT_PATH_LIBRARY);
#endif

	// The fontname string may contain multiple font file names separated by semicolons.
	// Break it apart and try loading each one, in order.
	for(font_file_info_vec_t::iterator font_file_it = font_files.begin();
		font_file_it != font_files.end();
		++font_file_it)
	{
		LLFontGL *fontp = NULL;
		font_paths.push_back(MACOSX_FONT_PATH_LIBRARY + MACOSX_FONT_SUPPLEMENTAL + *file_name_it);
		font_paths.push_back(sys_path +  MACOSX_FONT_SUPPLEMENTAL + *file_name_it);

		bool is_ft_collection = (std::find_if(font_collection_files.begin(), font_collection_files.end(),
		                                      [&font_file_it](const LLFontFileInfo& ffi) { return font_file_it->FileName == ffi.FileName; }) != font_collection_files.end());

		// *HACK: Fallback fonts don't render, so we can use that to suppress
		// creation of OpenGL textures for test apps. JC
		BOOL is_fallback = !is_first_found || !mCreateGLTextures;
		F32 extra_scale = (is_fallback)?fallback_scale:1.0;
		F32 point_size_scale = extra_scale * point_size;
		bool is_font_loaded = false;
		for(string_vec_t::iterator font_search_path_it = font_search_paths.begin();
			font_search_path_it != font_search_paths.end();
			++font_search_path_it)
		{
			const std::string font_path = *font_search_path_it + font_file_it->FileName;

			fontp = new LLFontGL;
			S32 num_faces = is_ft_collection ? fontp->getNumFaces(font_path) : 1;
			for (S32 i = 0; i < num_faces; i++)
			{
				if (fontp == NULL)
				{
					fontp = new LLFontGL;
				}
				if (fontp->loadFace(font_path, point_size_scale,
								 LLFontGL::sVertDPI, LLFontGL::sHorizDPI, is_fallback, i))
				{
					is_font_loaded = true;
					if (is_first_found)
					{
						result = fontp;
						is_first_found = false;
					}
					else
					{
						result->mFontFreetype->addFallbackFont(fontp->mFontFreetype, font_file_it->CharFunctor);

						delete fontp;
						fontp = NULL;
					}
				}
				else
				{
					delete fontp;
					fontp = NULL;
				}
			}
			if (is_font_loaded) break;
		}
		if(!is_font_loaded)
		{
			LL_INFOS_ONCE("LLFontRegistry") << "Couldn't load font " << font_file_it->FileName <<  LL_ENDL;
			delete fontp;
			fontp = NULL;
		}
	}

	if (result)
	{
		result->mFontDescriptor = desc;
	}
	else
	{
		LL_WARNS() << "createFont failed in some way" << LL_ENDL;
	}

	mFontMap[desc] = result;
	return result;
}

void LLFontRegistry::reset()
{
	for (font_reg_map_t::iterator it = mFontMap.begin();
		 it != mFontMap.end();
		 ++it)
	{
		// Reset the corresponding font but preserve the entry.
		if (it->second)
			it->second->reset();
	}
}

void LLFontRegistry::clear()
{
	for (font_reg_map_t::iterator it = mFontMap.begin();
		 it != mFontMap.end();
		 ++it)
	{
		LLFontGL *fontp = it->second;
		delete fontp;
	}
	mFontMap.clear();
}

void LLFontRegistry::destroyGL()
{
	for (font_reg_map_t::iterator it = mFontMap.begin();
		 it != mFontMap.end();
		 ++it)
	{
		// Reset the corresponding font but preserve the entry.
		if (it->second)
			it->second->destroyGL();
	}
}

LLFontGL *LLFontRegistry::getFont(const LLFontDescriptor& desc)
{
	font_reg_map_t::iterator it = mFontMap.find(desc);
	if (it != mFontMap.end())
		return it->second;
	else
	{
		LLFontGL *fontp = createFont(desc);
		if (!fontp)
		{
			LL_WARNS() << "getFont failed, name " << desc.getName()
					<<" style=[" << ((S32) desc.getStyle()) << "]"
					<< " size=[" << desc.getSize() << "]" << LL_ENDL;
		}
		return fontp;
	}
}

const LLFontDescriptor *LLFontRegistry::getMatchingFontDesc(const LLFontDescriptor& desc)
{
	LLFontDescriptor norm_desc = desc.normalize();

	font_reg_map_t::iterator it = mFontMap.find(norm_desc);
	if (it != mFontMap.end())
		return &(it->first);
	else
		return NULL;
}

static U32 bitCount(U8 c)
{
	U32 count = 0;
	if (c & 1) 
		count++;
	if (c & 2)
		count++;
	if (c & 4)
		count++;
	if (c & 8)
		count++;
	if (c & 16)
		count++;
	if (c & 32)
		count++;
	if (c & 64)
		count++;
	if (c & 128)
		count++;
	return count;
}

// Find nearest match for the requested descriptor.
const LLFontDescriptor *LLFontRegistry::getClosestFontTemplate(const LLFontDescriptor& desc)
{
	const LLFontDescriptor *exact_match_desc = getMatchingFontDesc(desc);
	if (exact_match_desc)
	{
		return exact_match_desc;
	}

	LLFontDescriptor norm_desc = desc.normalize();

	const LLFontDescriptor *best_match_desc = NULL;
	for (font_reg_map_t::iterator it = mFontMap.begin();
		 it != mFontMap.end();
		 ++it)
	{
		const LLFontDescriptor* curr_desc = &(it->first);

		// Ignore if not a template.
		if (!curr_desc->isTemplate())
			continue;

		// Ignore if font name is wrong.
		if (curr_desc->getName() != norm_desc.getName())
			continue;

		// Reject font if it matches any bits we don't want
		if (curr_desc->getStyle() & ~norm_desc.getStyle())
		{
			continue;
		}

		// Take if it's the first plausible candidate we've found.
		if (!best_match_desc)
		{
			best_match_desc = curr_desc;
			continue;
		}

		// Take if it matches more bits than anything before.
		U8 best_style_match_bits =
			norm_desc.getStyle() & best_match_desc->getStyle();
		U8 curr_style_match_bits =
			norm_desc.getStyle() & curr_desc->getStyle();
		if (bitCount(curr_style_match_bits) > bitCount(best_style_match_bits))
		{
			best_match_desc = curr_desc;
			continue;
		}

		// Tie-breaker: take if it matches bold.
		if (curr_style_match_bits & LLFontGL::BOLD)  // Bold is requested and this descriptor matches it.
		{
			best_match_desc = curr_desc;
			continue;
		}
	}

	// Nothing matched.
	return best_match_desc;
}

void LLFontRegistry::dump()
{
	LL_INFOS() << "LLFontRegistry dump: " << LL_ENDL;
	for (font_size_map_t::iterator size_it = mFontSizes.begin();
		 size_it != mFontSizes.end();
		 ++size_it)
	{
		LL_INFOS() << "Size: " << size_it->first << " => " << size_it->second << LL_ENDL;
	}
	for (font_reg_map_t::iterator font_it = mFontMap.begin();
		 font_it != mFontMap.end();
		 ++font_it)
	{
		const LLFontDescriptor& desc = font_it->first;
		LL_INFOS() << "Font: name=" << desc.getName()
				<< " style=[" << ((S32)desc.getStyle()) << "]"
				<< " size=[" << desc.getSize() << "]"
				<< " fileNames="
				<< LL_ENDL;
		for (font_file_info_vec_t::const_iterator file_it=desc.getFontFiles().begin();
			 file_it != desc.getFontFiles().end();
			 ++file_it)
		{
			LL_INFOS() << "  file: " << file_it->FileName << LL_ENDL;
		}
	}
}

void LLFontRegistry::dumpTextures()
{
	for (const auto& fontEntry : mFontMap)
	{
		if (fontEntry.second)
		{
			fontEntry.second->dumpTextures();
		}
	}
}

const string_vec_t& LLFontRegistry::getUltimateFallbackList() const 
{ 
	return mUltimateFallbackList;
}