wesnoth/src/picture.cpp

/*
   Copyright (C) 2003 - 2018 by David White <dave@whitevine.net>
   Part of the Battle for Wesnoth Project https://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

/**
 * @file
 * Routines for images: load, scale, re-color, etc.
 */

#define GETTEXT_DOMAIN "wesnoth-lib"

#include "picture.hpp"

#include "config.hpp"
#include "display.hpp"
#include "filesystem.hpp"
#include "game_config.hpp"
#include "gettext.hpp"
#include "image_modifications.hpp"
#include "log.hpp"
#include "preferences/general.hpp"
#include "serialization/base64.hpp"
#include "serialization/string_utils.hpp"
#include "sdl/rect.hpp"
#include "sdl/render_utils.hpp"
#include "sdl/texture.hpp"
#include "utils/general.hpp"

#include <SDL_image.h>

#include "utils/functional.hpp"

#include <boost/algorithm/string.hpp>
#include <boost/functional/hash_fwd.hpp>

#include <set>

static lg::log_domain log_display("display");
#define ERR_DP LOG_STREAM(err, log_display)
#define LOG_DP LOG_STREAM(info, log_display)

static lg::log_domain log_config("config");
#define ERR_CFG LOG_STREAM(err, log_config)

using game_config::tile_size;

template<typename T>
struct cache_item
{
	cache_item()
		: item()
		, loaded(false)
	{
	}

	cache_item(const T& item)
		: item(item)
		, loaded(true)
	{
	}

	T item;
	bool loaded;
};

namespace std
{
template<>
struct hash<image::locator::value>
{
	std::size_t operator()(const image::locator::value& val) const
	{
		std::size_t hash = std::hash<unsigned>{}(val.type_);

		if(val.type_ == image::locator::FILE || val.type_ == image::locator::SUB_FILE) {
			boost::hash_combine(hash, val.filename_);
		}

		if(val.type_ == image::locator::SUB_FILE) {
			boost::hash_combine(hash, val.loc_.x);
			boost::hash_combine(hash, val.loc_.y);
			boost::hash_combine(hash, val.center_x_);
			boost::hash_combine(hash, val.center_y_);
			boost::hash_combine(hash, val.modifications_);
		}

		return hash;
	}
};
}

namespace image
{
template<typename T>
class cache_type
{
public:
	cache_type()
		: content_()
	{
	}

	cache_item<T>& get_element(int index)
	{
		if(static_cast<unsigned>(index) >= content_.size())
			content_.resize(index + 1);
		return content_[index];
	}

	void flush()
	{
		content_.clear();
	}

private:
	std::vector<cache_item<T>> content_;
};

template<typename T>
bool locator::in_cache(cache_type<T>& cache) const
{
	return index_ < 0 ? false : cache.get_element(index_).loaded;
}

template<typename T>
const T& locator::locate_in_cache(cache_type<T>& cache) const
{
	static T dummy;
	return index_ < 0 ? dummy : cache.get_element(index_).item;
}

template<typename T>
T& locator::access_in_cache(cache_type<T>& cache) const
{
	static T dummy;
	return index_ < 0 ? dummy : cache.get_element(index_).item;
}

template<typename T>
void locator::add_to_cache(cache_type<T>& cache, const T& data) const
{
	if(index_ >= 0) {
		cache.get_element(index_) = cache_item<T>(data);
	}
}
}

namespace
{
image::locator::locator_finder_t locator_finder;

/** Definition of all image maps */
image::image_cache
	images_,
	scaled_to_zoom_,
	hexed_images_,
	scaled_to_hex_images_,
	tod_colored_images_,
	brightened_images_;

/**
 * Texture caches.
 * Note that the latter two are temporary and should be removed once we have OGL and shader support.
 */
using texture_cache_map = std::map<image::SCALE_QUALITY, image::texture_cache>;

texture_cache_map
	textures_,
	textures_hexed_,
	texture_tod_colored_;

// cache storing if each image fit in a hex
image::bool_cache in_hex_info_;

// cache storing if this is an empty hex
image::bool_cache is_empty_hex_;

// caches storing the different lighted cases for each image
image::lit_cache lit_images_, lit_scaled_images_;

// caches storing each lightmap generated
image::lit_variants lightmaps_;

// const int cache_version_ = 0;

std::map<std::string, bool> image_existence_map;

// directories where we already cached file existence
std::set<std::string> precached_dirs;

std::map<surface, surface> reversed_images_;

int red_adjust = 0, green_adjust = 0, blue_adjust = 0;

unsigned int zoom = tile_size;
unsigned int cached_zoom = 0;

const std::string data_uri_prefix = "data:";
struct parsed_data_URI{
	explicit parsed_data_URI(utils::string_view data_URI);
	utils::string_view scheme;
	utils::string_view mime;
	utils::string_view base64;
	utils::string_view data;
	bool good;
};
parsed_data_URI::parsed_data_URI(utils::string_view data_URI)
{
	const std::size_t colon = data_URI.find(':');
	const utils::string_view after_scheme = data_URI.substr(colon + 1);

	const std::size_t comma = after_scheme.find(',');
	const utils::string_view type_info = after_scheme.substr(0, comma);

	const std::size_t semicolon = type_info.find(';');

	scheme = data_URI.substr(0, colon);
	base64 = type_info.substr(semicolon + 1);
	mime = type_info.substr(0, semicolon);
	data = after_scheme.substr(comma + 1);
	good = (scheme == "data" && base64 == "base64" && mime.length() > 0 && data.length() > 0);
}

} // end anon namespace

namespace image
{
mini_terrain_cache_map mini_terrain_cache;
mini_terrain_cache_map mini_fogged_terrain_cache;
mini_terrain_cache_map mini_highlighted_terrain_cache;

static int last_index_ = 0;

void flush_cache()
{
	{
		images_.flush();
		hexed_images_.flush();
		tod_colored_images_.flush();
		scaled_to_zoom_.flush();
		scaled_to_hex_images_.flush();
		brightened_images_.flush();
		lit_images_.flush();
		lit_scaled_images_.flush();
		in_hex_info_.flush();
		is_empty_hex_.flush();
		mini_terrain_cache.clear();
		mini_fogged_terrain_cache.clear();
		mini_highlighted_terrain_cache.clear();
		reversed_images_.clear();
		image_existence_map.clear();
		precached_dirs.clear();
	}
	/* We can't reset last_index_, since some locators are still alive
	   when using :refresh. That would cause them to point to the wrong
	   images. Not resetting the variable causes a memory leak, though. */
	// last_index_ = 0;
}

void locator::init_index()
{
	auto i = locator_finder.find(val_);

	if(i == locator_finder.end()) {
		index_ = last_index_++;
		locator_finder.emplace(val_, index_);
	} else {
		index_ = i->second;
	}
}

void locator::parse_arguments()
{
	std::string& fn = val_.filename_;
	if(fn.empty()) {
		return;
	}

	if(boost::algorithm::starts_with(fn, data_uri_prefix)) {
		parsed_data_URI parsed{fn};

		if(!parsed.good) {
			utils::string_view view{ fn };
			utils::string_view stripped = view.substr(0, view.find(","));
			ERR_DP << "Invalid data URI: " << stripped << std::endl;
		}

		val_.is_data_uri_ = true;
	}

	std::size_t markup_field = fn.find('~');

	if(markup_field != std::string::npos) {
		val_.type_ = SUB_FILE;
		val_.modifications_ = fn.substr(markup_field, fn.size() - markup_field);
		fn = fn.substr(0, markup_field);
	}
}

locator::locator()
	: index_(-1)
	, val_()
{
}

locator::locator(const locator& a, const std::string& mods)
	: index_(-1)
	, val_(a.val_)
{
	if(!mods.empty()) {
		val_.modifications_ += mods;
		val_.type_ = SUB_FILE;
		init_index();
	} else {
		index_ = a.index_;
	}
}

locator::locator(const char* filename)
	: index_(-1)
	, val_(filename)
{
	parse_arguments();
	init_index();
}

locator::locator(const std::string& filename)
	: index_(-1)
	, val_(filename)
{
	parse_arguments();
	init_index();
}

locator::locator(const std::string& filename, const std::string& modifications)
	: index_(-1)
	, val_(filename, modifications)
{
	init_index();
}

locator::locator(const std::string& filename,
		const map_location& loc,
		int center_x,
		int center_y,
		const std::string& modifications)
	: index_(-1)
	, val_(filename, loc, center_x, center_y, modifications)
{
	init_index();
}

locator& locator::operator=(const locator& a)
{
	index_ = a.index_;
	val_ = a.val_;

	return *this;
}

locator::value::value(const locator::value& a)
	: type_(a.type_)
	, is_data_uri_(a.is_data_uri_)
	, filename_(a.filename_)
	, loc_(a.loc_)
	, modifications_(a.modifications_)
	, center_x_(a.center_x_)
	, center_y_(a.center_y_)
{
}

locator::value::value()
	: type_(NONE)
	, is_data_uri_(false)
	, filename_()
	, loc_()
	, modifications_()
	, center_x_(0)
	, center_y_(0)
{
}

locator::value::value(const char* filename)
	: type_(FILE)
	, is_data_uri_(false)
	, filename_(filename)
	, loc_()
	, modifications_()
	, center_x_(0)
	, center_y_(0)
{
}

locator::value::value(const std::string& filename)
	: type_(FILE)
	, is_data_uri_(false)
	, filename_(filename)
	, loc_()
	, modifications_()
	, center_x_(0)
	, center_y_(0)
{
}

locator::value::value(const std::string& filename, const std::string& modifications)
	: type_(SUB_FILE)
	, is_data_uri_(false)
	, filename_(filename)
	, loc_()
	, modifications_(modifications)
	, center_x_(0)
	, center_y_(0)
{
}

locator::value::value(const std::string& filename,
		const map_location& loc,
		int center_x,
		int center_y,
		const std::string& modifications)
	: type_(SUB_FILE)
	, is_data_uri_(false)
	, filename_(filename)
	, loc_(loc)
	, modifications_(modifications)
	, center_x_(center_x)
	, center_y_(center_y)
{
}

bool locator::value::operator==(const value& a) const
{
	if(a.type_ != type_) {
		return false;
	} else if(type_ == FILE) {
		return filename_ == a.filename_;
	} else if(type_ == SUB_FILE) {
		return filename_ == a.filename_ && loc_ == a.loc_ && modifications_ == a.modifications_
			   && center_x_ == a.center_x_ && center_y_ == a.center_y_;
	}

	return false;
}

bool locator::value::operator<(const value& a) const
{
	if(type_ != a.type_) {
		return type_ < a.type_;
	} else if(type_ == FILE) {
		return filename_ < a.filename_;
	} else if(type_ == SUB_FILE) {
		if(filename_ != a.filename_)
			return filename_ < a.filename_;
		if(loc_ != a.loc_)
			return loc_ < a.loc_;
		if(center_x_ != a.center_x_)
			return center_x_ < a.center_x_;
		if(center_y_ != a.center_y_)
			return center_y_ < a.center_y_;
		return (modifications_ < a.modifications_);
	}

	return false;
}

// Check if localized file is up-to-date according to l10n track index.
// Make sure only that the image is not explicitly recorded as fuzzy,
// in order to be able to use non-tracked images (e.g. from UMC).
static std::set<std::string> fuzzy_localized_files;
static bool localized_file_uptodate(const std::string& loc_file)
{
	if(fuzzy_localized_files.empty()) {
		// First call, parse track index to collect fuzzy files by path.
		std::string fsep = "\xC2\xA6"; // UTF-8 for "broken bar"
		std::string trackpath = filesystem::get_binary_file_location("", "l10n-track");

		// l10n-track file not present. Assume image is up-to-date.
		if(trackpath.empty()) {
			return true;
		}

		std::string contents = filesystem::read_file(trackpath);

		for(const std::string& line : utils::split(contents, '\n')) {
			std::size_t p1 = line.find(fsep);
			if(p1 == std::string::npos) {
				continue;
			}

			std::string state = line.substr(0, p1);
			boost::trim(state);
			if(state == "fuzzy") {
				std::size_t p2 = line.find(fsep, p1 + fsep.length());
				if(p2 == std::string::npos) {
					continue;
				}

				std::string relpath = line.substr(p1 + fsep.length(), p2 - p1 - fsep.length());
				fuzzy_localized_files.insert(game_config::path + '/' + relpath);
			}
		}

		fuzzy_localized_files.insert(""); // make sure not empty any more
	}

	return fuzzy_localized_files.count(loc_file) == 0;
}

// Return path to localized counterpart of the given file, if any, or empty string.
// Localized counterpart may also be requested to have a suffix to base name.
static std::string get_localized_path(const std::string& file, const std::string& suff = "")
{
	std::string dir = filesystem::directory_name(file);
	std::string base = filesystem::base_name(file);

	const std::size_t pos_ext = base.rfind(".");

	std::string loc_base;
	if(pos_ext != std::string::npos) {
		loc_base = base.substr(0, pos_ext) + suff + base.substr(pos_ext);
	} else {
		loc_base = base + suff;
	}

	// TRANSLATORS: This is the language code which will be used
	// to store and fetch localized non-textual resources, such as images,
	// when they exist. Normally it is just the code of the PO file itself,
	// e.g. "de" of de.po for German. But it can also be a comma-separated
	// list of language codes by priority, when the localized resource
	// found for first of those languages will be used. This is useful when
	// two languages share sufficient commonality, that they can use each
	// other's resources rather than duplicating them. For example,
	// Swedish (sv) and Danish (da) are such, so Swedish translator could
	// translate this message as "sv,da", while Danish as "da,sv".
	std::vector<std::string> langs = utils::split(_("language code for localized resources^en_US"));

	// In case even the original image is split into base and overlay,
	// add en_US with lowest priority, since the message above will
	// not have it when translated.
	langs.push_back("en_US");
	for(const std::string& lang : langs) {
		std::string loc_file = dir + "/" + "l10n" + "/" + lang + "/" + loc_base;
		if(filesystem::file_exists(loc_file) && localized_file_uptodate(loc_file)) {
			return loc_file;
		}
	}

	return "";
}

// Ensure PNG images with an indexed palette are converted to 32-bit RGBA.
static void standardize_surface_format(surface& surf)
{
	if(!surf.null() && !is_neutral(surf)) {
		surf = make_neutral_surface(surf);
		assert(is_neutral(surf));
	}
}

// Load overlay image and compose it with the original surface.
static void add_localized_overlay(const std::string& ovr_file, surface& orig_surf)
{
	filesystem::rwops_ptr rwops = filesystem::make_read_RWops(ovr_file);
	surface ovr_surf = IMG_Load_RW(rwops.release(), true); // SDL takes ownership of rwops
	if(ovr_surf.null()) {
		return;
	}

	standardize_surface_format(ovr_surf);

	SDL_Rect area {0, 0, ovr_surf->w, ovr_surf->h};

	sdl_blit(ovr_surf, 0, orig_surf, &area);
}

static surface load_image_file(const image::locator& loc)
{
	surface res;

	std::string location = filesystem::get_binary_file_location("images", loc.get_filename());

	{
		if(!location.empty()) {
			// Check if there is a localized image.
			const std::string loc_location = get_localized_path(location);
			if(!loc_location.empty()) {
				location = loc_location;
			}

			filesystem::rwops_ptr rwops = filesystem::make_read_RWops(location);
			res = IMG_Load_RW(rwops.release(), true); // SDL takes ownership of rwops

			standardize_surface_format(res);

			// If there was no standalone localized image, check if there is an overlay.
			if(!res.null() && loc_location.empty()) {
				const std::string ovr_location = get_localized_path(location, "--overlay");
				if(!ovr_location.empty()) {
					add_localized_overlay(ovr_location, res);
				}
			}
		}
	}

	if(res.null() && !loc.get_filename().empty()) {
		ERR_DP << "could not open image '" << loc.get_filename() << "'" << std::endl;
		if(game_config::debug && loc.get_filename() != game_config::images::missing)
			return get_image(game_config::images::missing, UNSCALED);
	}

	return res;
}

static surface load_image_sub_file(const image::locator& loc)
{
	surface surf = get_image(loc.get_filename(), UNSCALED);
	if(surf == nullptr) {
		return nullptr;
	}

	modification_queue mods = modification::decode(loc.get_modifications());

	while(!mods.empty()) {
		modification* mod = mods.top();

		try {
			surf = (*mod)(surf);
		} catch(const image::modification::imod_exception& e) {
			std::ostringstream ss;
			ss << "\n";

			for(const std::string& mod2 : utils::parenthetical_split(loc.get_modifications(), '~')) {
				ss << "\t" << mod2 << "\n";
			}

			ERR_CFG << "Failed to apply a modification to an image:\n"
					<< "Image: " << loc.get_filename() << "\n"
					<< "Modifications: " << ss.str() << "\n"
					<< "Error: " << e.message << "\n";
		}

		// NOTE: do this *after* applying the mod or you'll get crashes!
		mods.pop();
	}

	if(loc.get_loc().valid()) {
		SDL_Rect srcrect = sdl::create_rect(
			((tile_size * 3) / 4)                           *  loc.get_loc().x,
			  tile_size * loc.get_loc().y + (tile_size / 2) * (loc.get_loc().x % 2),
			  tile_size,
			  tile_size
		);

		if(loc.get_center_x() >= 0 && loc.get_center_y() >= 0) {
			srcrect.x += surf->w / 2 - loc.get_center_x();
			srcrect.y += surf->h / 2 - loc.get_center_y();
		}

		// cut and hex mask, but also check and cache if empty result
		surface cut(cut_surface(surf, srcrect));
		bool is_empty = false;
		surf = mask_surface(cut, get_hexmask(), &is_empty);

		// discard empty images to free memory
		if(is_empty) {
			// Safe because those images are only used by terrain rendering
			// and it filters them out.
			// A safer and more general way would be to keep only one copy of it
			surf = nullptr;
		}

		loc.add_to_cache(is_empty_hex_, is_empty);
	}

	return surf;
}

static surface load_image_data_uri(const image::locator& loc)
{
	surface surf;

	parsed_data_URI parsed{loc.get_filename()};

	if(!parsed.good) {
		utils::string_view fn = loc.get_filename();
		utils::string_view stripped = fn.substr(0, fn.find(","));
		ERR_DP << "Invalid data URI: " << stripped << std::endl;
	} else if(parsed.mime.substr(0, 5) != "image") {
		ERR_DP << "Data URI not of image MIME type: " << parsed.mime << std::endl;
	} else {
		const std::vector<uint8_t> image_data = base64::decode(parsed.data);
		filesystem::rwops_ptr rwops{SDL_RWFromConstMem(image_data.data(), image_data.size()), &SDL_FreeRW};

		if(image_data.empty()) {
			ERR_DP << "Invalid encoding in data URI" << std::endl;
		} else if(parsed.mime == "image/png") {
			surf = IMG_LoadTyped_RW(rwops.release(), true, "PNG");
		} else if(parsed.mime == "image/jpeg") {
			surf = IMG_LoadTyped_RW(rwops.release(), true, "JPG");
		} else {
			ERR_DP << "Invalid image MIME type: " << parsed.mime << std::endl;
		}
	}

	return surf;
}

// small utility function to store an int from (-256,254) to an signed char
static signed char col_to_uchar(int i)
{
	return static_cast<signed char>(std::min<int>(127, std::max<int>(-128, i / 2)));
}

light_string get_light_string(int op, int r, int g, int b)
{
	light_string ls;
	ls.reserve(4);
	ls.push_back(op);
	ls.push_back(col_to_uchar(r));
	ls.push_back(col_to_uchar(g));
	ls.push_back(col_to_uchar(b));

	return ls;
}

static surface apply_light(surface surf, const light_string& ls)
{
	// atomic lightmap operation are handled directly (important to end recursion)
	if(ls.size() == 4) {
		// if no lightmap (first char = -1) then we need the initial value
		//(before the halving done for lightmap)
		int m = ls[0] == -1 ? 2 : 1;
		return adjust_surface_color(surf, ls[1] * m, ls[2] * m, ls[3] * m);
	}

	// check if the lightmap is already cached or need to be generated
	surface lightmap = nullptr;
	auto i = lightmaps_.find(ls);
	if(i != lightmaps_.end()) {
		lightmap = i->second;
	} else {
		// build all the paths for lightmap sources
		static const std::string p = "terrain/light/light";
		static const std::string lm_img[19] {
			p + ".png",
			p + "-concave-2-tr.png", p + "-concave-2-r.png", p + "-concave-2-br.png",
			p + "-concave-2-bl.png", p + "-concave-2-l.png", p + "-concave-2-tl.png",
			p + "-convex-br-bl.png", p + "-convex-bl-l.png", p + "-convex-l-tl.png",
			p + "-convex-tl-tr.png", p + "-convex-tr-r.png", p + "-convex-r-br.png",
			p + "-convex-l-bl.png",  p + "-convex-tl-l.png", p + "-convex-tr-tl.png",
			p + "-convex-r-tr.png",  p + "-convex-br-r.png", p + "-convex-bl-br.png"
		};

		// decompose into atomic lightmap operations (4 chars)
		for(std::size_t c = 0; c + 3 < ls.size(); c += 4) {
			light_string sls = ls.substr(c, 4);

			// get the corresponding image and apply the lightmap operation to it
			// This allows to also cache lightmap parts.
			// note that we avoid infinite recursion by using only atomic operation
			surface lts = image::get_lighted_image(lm_img[sls[0]], sls, HEXED);

			// first image will be the base where we blit the others
			if(lightmap == nullptr) {
				// copy the cached image to avoid modifying the cache
				lightmap = make_neutral_surface(lts);
			} else {
				sdl_blit(lts, nullptr, lightmap, nullptr);
			}
		}

		// cache the result
		lightmaps_[ls] = lightmap;
	}

	// apply the final lightmap
	return light_surface(surf, lightmap);
}

bool locator::file_exists() const
{
	return val_.is_data_uri_
		? parsed_data_URI{val_.filename_}.good
		: !filesystem::get_binary_file_location("images", val_.filename_).empty();
}

surface load_from_disk(const locator& loc)
{
	switch(loc.get_type()) {
	case locator::FILE:
		if(loc.is_data_uri()){
			return load_image_data_uri(loc);
		} else {
			return load_image_file(loc);
		}
	case locator::SUB_FILE:
		return load_image_sub_file(loc);
	default:
		return surface(nullptr);
	}
}

manager::manager()
{
}

manager::~manager()
{
	flush_cache();
}

void set_color_adjustment(int r, int g, int b)
{
	if(r != red_adjust || g != green_adjust || b != blue_adjust) {
		red_adjust = r;
		green_adjust = g;
		blue_adjust = b;
		tod_colored_images_.flush();
		brightened_images_.flush();
		lit_images_.flush();
		lit_scaled_images_.flush();
		reversed_images_.clear();
	}
}

void set_zoom(unsigned int amount)
{
	if(amount != zoom) {
		zoom = amount;
		tod_colored_images_.flush();
		brightened_images_.flush();
		reversed_images_.clear();

		// We keep these caches if:
		// we use default zoom (it doesn't need those)
		// or if they are already at the wanted zoom.
		if(zoom != tile_size && zoom != cached_zoom) {
			scaled_to_zoom_.flush();
			scaled_to_hex_images_.flush();
			lit_scaled_images_.flush();
			cached_zoom = zoom;
		}
	}
}

static surface get_hexed(const locator& i_locator)
{
	surface image(get_image(i_locator, UNSCALED));
	// hex cut tiles, also check and cache if empty result
	bool is_empty = false;
	surface res = mask_surface(image, get_hexmask(), &is_empty, i_locator.get_filename());
	i_locator.add_to_cache(is_empty_hex_, is_empty);
	return res;
}

static surface get_scaled_to_hex(const locator& i_locator)
{
	surface img = get_image(i_locator, HEXED);
	// return scale_surface(img, zoom, zoom);

	if(!img.null()) {
		return scale_surface_nn(img, zoom, zoom);
	}

	return surface(nullptr);

}

static surface get_tod_colored(const locator& i_locator)
{
	surface img = get_image(i_locator, SCALED_TO_HEX);
	return adjust_surface_color(img, red_adjust, green_adjust, blue_adjust);
}

static surface get_scaled_to_zoom(const locator& i_locator)
{
	assert(zoom != tile_size);
	assert(tile_size != 0);

	surface res(get_image(i_locator, UNSCALED));
	// For some reason haloes seems to have invalid images, protect against crashing
	if(!res.null()) {
		return scale_surface_nn(res, ((res->w * zoom) / tile_size), ((res->h * zoom) / tile_size));
	}

	return surface(nullptr);
}

static surface get_brightened(const locator& i_locator)
{
	surface image(get_image(i_locator, TOD_COLORED));
	return brighten_image(image, ftofxp(game_config::hex_brightening));
}

/// translate type to a simpler one when possible
static TYPE simplify_type(const image::locator& i_locator, TYPE type)
{
	switch(type) {
	case SCALED_TO_ZOOM:
		if(zoom == tile_size) {
			type = UNSCALED;
		}

		break;
	case BRIGHTENED:
		if(ftofxp(game_config::hex_brightening) == ftofxp(1.0)) {
			type = TOD_COLORED;
		}

		break;
	default:
		break;
	}

	if(type == TOD_COLORED) {
		if(red_adjust == 0 && green_adjust == 0 && blue_adjust == 0) {
			type = SCALED_TO_HEX;
		}
	}

	if(type == SCALED_TO_HEX) {
		if(zoom == tile_size) {
			type = HEXED;
		}
	}

	if(type == HEXED) {
		// check if the image is already hex-cut by the location system
		if(i_locator.get_loc().valid()) {
			type = UNSCALED;
		}
	}

	return type;
}

surface get_image(const image::locator& i_locator, TYPE type)
{
	surface res;

	if(i_locator.is_void()) {
		return res;
	}

	type = simplify_type(i_locator, type);

	image_cache* imap;
	// select associated cache
	switch(type) {
	case UNSCALED:
		imap = &images_;
		break;
	case TOD_COLORED:
		imap = &tod_colored_images_;
		break;
	case SCALED_TO_ZOOM:
		imap = &scaled_to_zoom_;
		break;
	case HEXED:
		imap = &hexed_images_;
		break;
	case SCALED_TO_HEX:
		imap = &scaled_to_hex_images_;
		break;
	case BRIGHTENED:
		imap = &brightened_images_;
		break;
	default:
		return res;
	}

	// return the image if already cached
	bool tmp = i_locator.in_cache(*imap);

	if(tmp) {
		surface result = i_locator.locate_in_cache(*imap);
		return result;
	}

	// not cached, generate it
	switch(type) {
	case UNSCALED:
		// If type is unscaled, directly load the image from the disk.
		res = load_from_disk(i_locator);
		break;
	case TOD_COLORED:
		res = get_tod_colored(i_locator);
		break;
	case SCALED_TO_ZOOM:
		res = get_scaled_to_zoom(i_locator);
		break;
	case HEXED:
		res = get_hexed(i_locator);
		break;
	case SCALED_TO_HEX:
		res = get_scaled_to_hex(i_locator);
		break;
	case BRIGHTENED:
		res = get_brightened(i_locator);
		break;
	default:
		return res;
	}

	i_locator.add_to_cache(*imap, res);

	return res;
}

surface get_lighted_image(const image::locator& i_locator, const light_string& ls, TYPE type)
{
	surface res;
	if(i_locator.is_void()) {
		return res;
	}

	if(type == SCALED_TO_HEX && zoom == tile_size) {
		type = HEXED;
	}

	// select associated cache
	lit_cache* imap = &lit_images_;
	if(type == SCALED_TO_HEX) {
		imap = &lit_scaled_images_;
	}

	// if no light variants yet, need to add an empty map
	if(!i_locator.in_cache(*imap)) {
		i_locator.add_to_cache(*imap, lit_variants());
	}

	// need access to add it if not found
	{ // enclose reference pointing to data stored in a changing vector
		const lit_variants& lvar = i_locator.locate_in_cache(*imap);
		auto lvi = lvar.find(ls);
		if(lvi != lvar.end()) {
			return lvi->second;
		}
	}

	// not cached yet, generate it
	switch(type) {
	case HEXED:
		res = get_image(i_locator, HEXED);
		res = apply_light(res, ls);
		break;
	case SCALED_TO_HEX:
		// we light before scaling to reuse the unscaled cache
		res = get_lighted_image(i_locator, ls, HEXED);
		res = scale_surface(res, zoom, zoom);
		break;
	default:
		break;
	}

	// record the lighted surface in the corresponding variants cache
	i_locator.access_in_cache(*imap)[ls] = res;

	return res;
}

surface get_hexmask()
{
	static const image::locator terrain_mask(game_config::images::terrain_mask);
	return get_image(terrain_mask, UNSCALED);
}

bool is_in_hex(const locator& i_locator)
{
	bool result;
	{
		if(i_locator.in_cache(in_hex_info_)) {
			result = i_locator.locate_in_cache(in_hex_info_);
		} else {
			const surface image(get_image(i_locator, UNSCALED));

			bool res = in_mask_surface(image, get_hexmask());

			i_locator.add_to_cache(in_hex_info_, res);

			// std::cout << "in_hex : " << i_locator.get_filename()
			//		<< " " << (res ? "yes" : "no") << "\n";

			result = res;
		}
	}

	return result;
}

bool is_empty_hex(const locator& i_locator)
{
	if(!i_locator.in_cache(is_empty_hex_)) {
		const surface surf = get_image(i_locator, HEXED);
		// emptiness of terrain image is checked during hex cut
		// so, maybe in cache now, let's recheck
		if(!i_locator.in_cache(is_empty_hex_)) {
			// should never reach here
			// but do it manually if it happens
			// assert(false);
			bool is_empty = false;
			mask_surface(surf, get_hexmask(), &is_empty);
			i_locator.add_to_cache(is_empty_hex_, is_empty);
		}
	}

	return i_locator.locate_in_cache(is_empty_hex_);
}

surface reverse_image(const surface& surf)
{
	if(surf == nullptr) {
		return surface(nullptr);
	}

	const auto itor = reversed_images_.find(surf);
	if(itor != reversed_images_.end()) {
		// sdl_add_ref(itor->second);
		return itor->second;
	}

	const surface rev(flip_surface(surf));
	if(rev == nullptr) {
		return surface(nullptr);
	}

	reversed_images_.emplace(surf, rev);
	// sdl_add_ref(rev);
	return rev;
}

bool exists(const image::locator& i_locator)
{
	typedef image::locator loc;
	loc::type type = i_locator.get_type();
	if(type != loc::FILE && type != loc::SUB_FILE) {
		return false;
	}

	// The insertion will fail if there is already an element in the cache
	// and this will point to the existing element.
	auto iter = image_existence_map.begin();
	bool success;

	std::tie(iter, success) = image_existence_map.emplace(i_locator.get_filename(), false);

	bool& cache = iter->second;
	if(success) {
		if(i_locator.is_data_uri()) {
			cache = parsed_data_URI{i_locator.get_filename()}.good;
		} else {
			cache = !filesystem::get_binary_file_location("images", i_locator.get_filename()).empty();
		}
	}

	return cache;
}

static void precache_file_existence_internal(const std::string& dir, const std::string& subdir)
{
	const std::string checked_dir = dir + "/" + subdir;
	if(precached_dirs.find(checked_dir) != precached_dirs.end()) {
		return;
	}

	precached_dirs.insert(checked_dir);

	if(!filesystem::is_directory(checked_dir)) {
		return;
	}

	std::vector<std::string> files_found;
	std::vector<std::string> dirs_found;
	filesystem::get_files_in_dir(checked_dir, &files_found, &dirs_found, filesystem::FILE_NAME_ONLY,
			filesystem::NO_FILTER, filesystem::DONT_REORDER);

	for(const auto& f : files_found) {
		image_existence_map[subdir + f] = true;
	}

	for(const auto& d : dirs_found) {
		precache_file_existence_internal(dir, subdir + d + "/");
	}
}

void precache_file_existence(const std::string& subdir)
{
	const std::vector<std::string>& paths = filesystem::get_binary_paths("images");

	for(const auto& p : paths) {
		precache_file_existence_internal(p, subdir);
	}
}

bool precached_file_exists(const std::string& file)
{
	const auto b = image_existence_map.find(file);
	if(b != image_existence_map.end()) {
		return b->second;
	}

	return false;
}

save_result save_image(const locator& i_locator, const std::string& filename)
{
	return save_image(get_image(i_locator), filename);
}

save_result save_image(const surface& surf, const std::string& filename)
{
	if(surf.null()) {
		return save_result::no_image;
	}

#ifdef SDL_IMAGE_VERSION_ATLEAST
#if SDL_IMAGE_VERSION_ATLEAST(2, 0, 2)
	if(filesystem::ends_with(filename, ".jpeg") || filesystem::ends_with(filename, ".jpg") || filesystem::ends_with(filename, ".jpe")) {
		LOG_DP << "Writing a JPG image to " << filename << std::endl;

		const int err = IMG_SaveJPG_RW(surf, filesystem::make_write_RWops(filename).release(), true, 75); // SDL takes ownership of the RWops
		return err == 0 ? save_result::success : save_result::save_failed;
	}
#endif
#endif

	if(filesystem::ends_with(filename, ".png")) {
		LOG_DP << "Writing a PNG image to " << filename << std::endl;

		const int err = IMG_SavePNG_RW(surf, filesystem::make_write_RWops(filename).release(), true); // SDL takes ownership of the RWops
		return err == 0 ? save_result::success : save_result::save_failed;
	}

	if(filesystem::ends_with(filename, ".bmp")) {
		LOG_DP << "Writing a BMP image to " << filename << std::endl;
		const int err = SDL_SaveBMP(surf, filename.c_str()) == 0;
		return err == 0 ? save_result::success : save_result::save_failed;
	}

	return save_result::unsupported_format;
}

/*
 * TEXTURE INTERFACE ======================================================================
 *
 * I'm keeping this seperate from the surface-based handling above since the two approaches
 * are so different. Might move this to a file of its own in the future.
 */

/** Sets the texture scale quality hint. Must be called *before* creating textures! */
static void set_scale_quality_pre_texture_creation(SCALE_QUALITY quality)
{
	static const std::string n_scale_str = "nearest";
	static const std::string l_scale_str = "linear";

	set_texture_scale_quality(quality == NEAREST ? n_scale_str : l_scale_str);
}

/** Loads a new texture directly from disk. */
static texture create_texture_from_file(const image::locator& loc)
{
	texture res;

	// We need the window renderer to load the texture.
	SDL_Renderer* renderer = CVideo::get_singleton().get_renderer();
	if(!renderer) {
		return res;
	}

	std::string location = filesystem::get_binary_file_location("images", loc.get_filename());

	if(!location.empty()) {
#if 0
		// Check if there is a localized image.
		const std::string loc_location = get_localized_path(location);
		if(!loc_location.empty()) {
			location = loc_location;
		}
#endif

		// TODO: if we need to use SDL_RWops we should use IMG_LoadTexture_RW here instead.
		{
			res.assign(IMG_LoadTexture(renderer, location.c_str()));
		}

		// TODO: decide what to do about this.
#if 0
		// If there was no standalone localized image, check if there is an overlay.
		if(!res.null() && loc_location.empty()) {
			const std::string ovr_location = get_localized_path(location, "--overlay");
			if(!ovr_location.empty()) {
				add_localized_overlay(ovr_location, res);
			}
		}
#endif
	}

	if(res.null() && !loc.get_filename().empty()) {
		ERR_DP << "Could not load texture for image '" << loc.get_filename() << "'" << std::endl;

		// Also decide what to do here.
#if 0
		if(game_config::debug && loc.get_filename() != game_config::images::missing) {
			return get_texture(game_config::images::missing, UNSCALED);
		}
#endif
	}

	return res;
}

/**
 * Handle IPF manipulation. Since we don't have shaders yet, we need to use the surface
 * modification code for now. It appears each result is saved in the relevant cache,
 * so this should hopefully only result in a small slowdown when first processing the
 * results.
 */
static texture create_texture_from_sub_file(const image::locator& loc)
{
	surface surf = get_image(loc.get_filename(), UNSCALED);
	if(surf == nullptr) {
		return texture();
	}

	modification_queue mods = modification::decode(loc.get_modifications());

	while(!mods.empty()) {
		modification* mod = mods.top();

		try {
			surf = (*mod)(surf);
		} catch(const image::modification::imod_exception& e) {
			std::ostringstream ss;
			ss << "\n";

			for(const std::string& mod2 : utils::parenthetical_split(loc.get_modifications(), '~')) {
				ss << "\t" << mod2 << "\n";
			}

			ERR_CFG << "Failed to apply a modification to an image:\n"
					<< "Image: " << loc.get_filename() << "\n"
					<< "Modifications: " << ss.str() << "\n"
					<< "Error: " << e.message << "\n";
		}

		// NOTE: do this *after* applying the mod or you'll get crashes!
		mods.pop();
	}

#if 0
	if(loc.get_loc().valid()) {
		SDL_Rect srcrect = sdl::create_rect(
			((tile_size * 3) / 4)                           *  loc.get_loc().x,
			  tile_size * loc.get_loc().y + (tile_size / 2) * (loc.get_loc().x % 2),
			  tile_size,
			  tile_size
		);

		if(loc.get_center_x() >= 0 && loc.get_center_y() >= 0) {
			srcrect.x += surf->w / 2 - loc.get_center_x();
			srcrect.y += surf->h / 2 - loc.get_center_y();
		}

		// cut and hex mask, but also check and cache if empty result
		surface cut(cut_surface(surf, srcrect));
		bool is_empty = false;
		surf = mask_surface(cut, get_hexmask(), &is_empty);

		// discard empty images to free memory
		if(is_empty) {
			// Safe because those images are only used by terrain rendering
			// and it filters them out.
			// A safer and more general way would be to keep only one copy of it
			surf = nullptr;
		}

		loc.add_to_cache(is_empty_hex_, is_empty);
	}
#endif

	return texture(surf);
}

texture create_texture_from_disk(const locator& loc)
{
	switch(loc.get_type()) {
	case locator::FILE:
		if(loc.is_data_uri()){
			return texture(load_image_data_uri(loc));
		} else {
			return create_texture_from_file(loc);
		}
	case locator::SUB_FILE:
		return create_texture_from_sub_file(loc);
	default:
		return texture();
	}
}

/**
 * Small wrapper for creating a texture after applying a specific type of surface op.
 * Won't be necessary once we get shader support.
 */
static texture create_texture_post_surface_op(const image::locator& i_locator, TYPE type)
{
	surface surf = get_image(i_locator, type);
	if(!surf) {
		return texture();
	}

	return texture(surf);
}

texture get_texture(const image::locator& i_locator, TYPE type)
{
	return get_texture(i_locator, NEAREST, type);
}

/** Returns a texture for the corresponding image. */
texture get_texture(const image::locator& i_locator, SCALE_QUALITY quality, TYPE type)
{
	texture res;

	if(i_locator.is_void()) {
		return res;
	}

	// FIXME
	//type = simplify_type(i_locator, type);

	//
	// Select the appropriate cache. We don't need caches for every single image types,
	// since some types can be handled by render-time operations.
	//
	texture_cache* cache = nullptr;

	switch(type) {
	case HEXED:
		cache = &textures_hexed_[quality];
		break;
	case TOD_COLORED:
		cache = &texture_tod_colored_[quality];
		break;
	default:
		cache = &textures_[quality];
	}

	//
	// Now attempt to find a cached texture. If found, return it.
	//
	bool in_cache = i_locator.in_cache(*cache);

	if(in_cache) {
		res = i_locator.locate_in_cache(*cache);
		return res;
	}

	//
	// No texture was cached. In that case, create a new one. The explicit cases require special
	// handling with surfaces in order to generate the desired effect. This shouldn't be the case
	// once we get OGL and shader support.
	//
	set_scale_quality_pre_texture_creation(quality);

	switch(type) {
	case TOD_COLORED:
	case HEXED:
		res = create_texture_post_surface_op(i_locator, type);
		break;
	default:
		res = create_texture_from_disk(i_locator);
	}

	// If the texture is null at this point, return without any further action (like caching).
	if(!res) {
		return res;
	}

	//
	// Apply the appropriate render flags. (TODO)
	//
#if 0
	switch(type) {
	case SCALED_TO_ZOOM:

		break;
	case SCALED_TO_HEX:

		break;
	case BRIGHTENED:

		break;
	default:
		// Ignore other types.
		break;
	}
#endif

	//
	// And finally add the texture to the cache.
	//
	i_locator.add_to_cache(*cache, res);

	return res;
}

} // end namespace image