#include "World.h"

#include <algorithm>
#include <tuple>

#include "log.h"
#include "Game.h"
#include "Clock.h"
#include "assets.h"

namespace Swan {

static void chunkLine(int l, WorldPlane &plane, ChunkPos &abspos, const Vec2i &dir) {
	for (int i = 0; i < l; ++i) {
		plane.slowGetChunk(abspos).keepActive();
		abspos += dir;
	}
}

std::vector<ModWrapper> World::loadMods(std::vector<std::string> paths) {
	std::vector<ModWrapper> mods;
	mods.reserve(paths.size());

	for (auto &path: paths) {
		OS::Dynlib dl(path + "/mod");
		auto create = dl.get<Mod *(*)(World &)>("mod_create");
		if (create == NULL) {
			warn << path << ": No 'mod_create' function!";
			continue;
		}

		std::unique_ptr<Mod> mod(create(*this));
		mods.push_back(ModWrapper(std::move(mod), std::move(path), std::move(dl)));
	}

	return mods;
}

Cygnet::ResourceManager World::buildResources() {
	Cygnet::ResourceBuilder builder(game_->renderer_);

	auto fillTileImage = [&](unsigned char *data, int r, int g, int b, int a) {
		for (size_t i = 0; i < TILE_SIZE * TILE_SIZE; ++i) {
			data[i * 4 + 0] = r;
			data[i * 4 + 1] = g;
			data[i * 4 + 2] = b;
			data[i * 4 + 2] = a;
		}
	};

	struct ImageAsset fallbackImage = {
		.width = 32,
		.frameHeight = 32,
		.frameCount = 1,
		.data = std::make_unique<unsigned char[]>(TILE_SIZE * TILE_SIZE * 4),
	};
	fillTileImage(fallbackImage.data.get(),
			PLACEHOLDER_RED, PLACEHOLDER_GREEN, PLACEHOLDER_BLUE, 255);

	auto airImage = std::make_unique<unsigned char[]>(TILE_SIZE * TILE_SIZE * 4);
	fillTileImage(airImage.get(),
			PLACEHOLDER_RED, PLACEHOLDER_GREEN, PLACEHOLDER_BLUE, 255);

	// Let tile ID 0 be the invalid tile
	builder.addTile(INVALID_TILE_ID, fallbackImage.data.get());
	tilesMap_[INVALID_TILE_NAME] = INVALID_TILE_ID;
	tiles_.push_back(Tile(INVALID_TILE_ID, INVALID_TILE_NAME, {
		.name = "", .image = "", // Not used in this case
		.isSolid = false,
	}));
	items_.emplace(INVALID_TILE_NAME, Item(INVALID_TILE_ID, INVALID_TILE_NAME, {
		.name = "", .image = "", // Not used in this case
	}));

	// ...And tile ID 1 be the air tile
	builder.addTile(AIR_TILE_ID, std::move(airImage));
	tilesMap_[AIR_TILE_NAME] = AIR_TILE_ID;
	tiles_.push_back(Tile(AIR_TILE_ID, AIR_TILE_NAME, {
		.name = "", .image = "", // Not used in this case
		.isSolid = false,
	}));
	items_.emplace(AIR_TILE_NAME, Item(AIR_TILE_ID, AIR_TILE_NAME, {
		.name = "", .image = "", // Not used in this case
	}));

	// Assets are namespaced on the mod, so if something references, say,
	// "core::stone", we need to know which directory the "core" mod is in
	std::unordered_map<std::string, std::string> modPaths;
	for (auto &mod: mods_) {
		modPaths[mod.name()] = mod.path_;
	}

	auto loadTileImage = [&](std::string path) -> Result<ImageAsset> {
		// Don't force all tiles/items to have an associated image.
		// It could be that some tiles/items exist for a purpose which implies
		// it should never actually be visible.
		if (path == INVALID_TILE_NAME) {
			ImageAsset asset{
				.width = 32,
				.frameHeight = 32,
				.frameCount = 1,
				.data = std::make_unique<unsigned char[]>(TILE_SIZE * TILE_SIZE * 4),
			};
			memcpy(asset.data.get(), fallbackImage.data.get(), TILE_SIZE * TILE_SIZE * 4);
			return {Ok, std::move(asset)};
		}

		auto image = loadImageAsset(modPaths, path);
		if (!image) {
			warn << '\'' << path << "': " << image.err();
			return {Err, '\'' + path + "': " + image.err()};
		} else if (image->width != TILE_SIZE) {
			warn << '\'' << path << "': Width must be " << TILE_SIZE << " pixels";
			return {Err, '\'' + path + "': Width must be " + std::to_string(TILE_SIZE) + " pixels"};
		} else {
			return image;
		}
	};

	// Need to fill in every tile before we do items,
	// because all items will end up after all tiles in the tile atlas.
	// In the rendering system, there's no real difference between a tile
	// and an item.
	for (auto &mod: mods_) {
		for (auto &tileBuilder: mod.tiles()) {
			auto image = loadTileImage(tileBuilder.image);

			std::string tileName = mod.name() + "::" + tileBuilder.name;
			Tile::ID tileId = tiles_.size();

			if (image) {
				builder.addTile(tileId, std::move(image->data));
			} else {
				warn << image.err();
				builder.addTile(tileId, fallbackImage.data.get());
			}

			tilesMap_[tileName] = tileId;
			tiles_.push_back(Tile(tileId, tileName, tileBuilder));

			// All tiles should have an item.
			// Some items will be overwritten later my mod_->items,
			// but if not, this is their default item.
			items_.emplace(tileName, Item(tileId, tileName, {
				.name = "", .image = "", // Not used in this case
			}));
		}
	}

	// Put all items after all the tiles
	Tile::ID nextItemId = tiles_.size();

	// Load all items which aren't just tiles in disguise.
	for (auto &mod: mods_) {
		for (auto &itemBuilder: mod.items()) {
			auto image = loadTileImage(itemBuilder.image);

			std::string itemName = mod.name() + "::" + itemBuilder.name;
			Tile::ID itemId = nextItemId++;

			if (image) {
				builder.addTile(itemId, std::move(image->data));
			} else {
				warn << image.err();
				builder.addTile(itemId, fallbackImage.data.get());
			}

			items_.emplace(itemName, Item(itemId, itemName, itemBuilder));
		}
	}

	// Load sprites
	for (auto &mod: mods_) {
		for (auto spritePath: mod.sprites()) {
			std::string path = mod.name() + "::" + spritePath;
			auto image = loadImageAsset(modPaths, path);

			if (image) {
				builder.addSprite(
						path, image->data.get(), image->width,
						image->frameHeight * image->frameCount,
						image->frameHeight);
			} else {
				warn << '\'' << path << "': " << image.err();
				builder.addSprite(
						path, fallbackImage.data.get(), fallbackImage.width,
						fallbackImage.frameHeight * fallbackImage.frameCount,
						fallbackImage.frameHeight);
			}
		}
	}

	// Load world gens and entities
	for (auto &mod: mods_) {
		for (auto &worldGenFactory: mod.worldGens()) {
			std::string name = mod.name() + "::" + worldGenFactory.name;
			worldGenFactories_.emplace(name, worldGenFactory);
		}

		for (auto &entCollFactory: mod.entities()) {
			std::string name = mod.name() + "::" + entCollFactory.name;
			entCollFactories_.emplace(name, entCollFactory);
		}
	}

	return Cygnet::ResourceManager(std::move(builder));
}

World::World(Game *game, unsigned long randSeed, std::vector<std::string> modPaths):
		game_(game), random_(randSeed), mods_(loadMods(std::move(modPaths))),
		resources_(buildResources()) {}

void World::ChunkRenderer::tick(WorldPlane &plane, ChunkPos abspos) {
	ZoneScopedN("World::ChunkRenderer tick");
	int l = 0;

	RTClock clock;
	for (int i = 0; i < 4; ++i) {
		chunkLine(l, plane, abspos, Vec2i(0, -1));
		chunkLine(l, plane, abspos, Vec2i(1, 0));
		l += 1;
		chunkLine(l, plane, abspos, Vec2i(0, 1));
		chunkLine(l, plane, abspos, Vec2i(-1, 0));
		l += 1;
	}
}

void World::setWorldGen(std::string gen) {
	defaultWorldGen_ = std::move(gen);
}

void World::spawnPlayer() {
	player_ = &((dynamic_cast<BodyTrait *>(
		planes_[currentPlane_]->spawnPlayer().get()))->get(BodyTrait::Tag{}));
}

void World::setCurrentPlane(WorldPlane &plane) {
	currentPlane_ = plane.id_;
}

WorldPlane &World::addPlane(const std::string &gen) {
	WorldPlane::ID id = planes_.size();
	auto it = worldGenFactories_.find(gen);
	if (it == worldGenFactories_.end()) {
		panic << "Tried to add plane with non-existent world gen " << gen << "!";
		abort();
	}

	std::vector<std::unique_ptr<EntityCollection>> colls;
	colls.reserve(entCollFactories_.size());
	for (auto &fact: entCollFactories_) {
		colls.emplace_back(fact.second.create(fact.second.name));
	}

	WorldGen::Factory &factory = it->second;
	std::unique_ptr<WorldGen> g = factory.create(*this);
	planes_.push_back(std::make_unique<WorldPlane>(
			id, this, std::move(g), std::move(colls)));
	return *planes_[id];
}

Tile::ID World::getTileID(const std::string &name) {
	auto iter = tilesMap_.find(name);
	if (iter == tilesMap_.end()) {
		warn << "Tried to get non-existent item " << name << "!";
		return INVALID_TILE_ID;
	}

	return iter->second;
}

Tile &World::getTile(const std::string &name) {
	Tile::ID id = getTileID(name);
	return getTileByID(id);
}

Item &World::getItem(const std::string &name) {
	auto iter = items_.find(name);
	if (iter == items_.end()) {
		warn << "Tried to get non-existent item " << name << "!";
		return items_.at(INVALID_TILE_NAME);
	}

	return iter->second;
}

Cygnet::RenderSprite &World::getSprite(const std::string &name) {
	auto iter = resources_.sprites_.find(name);
	if (iter == resources_.sprites_.end()) {
		warn << "Tried to get non-existent sprite " << name << "!";
		return resources_.sprites_.at(INVALID_TILE_NAME);
	}

	return iter->second;
}

SDL_Color World::backgroundColor() {
	return planes_[currentPlane_]->backgroundColor();
}

void World::draw(Cygnet::Renderer &rnd) {
	ZoneScopedN("World draw");
	planes_[currentPlane_]->draw(rnd);
}

void World::update(float dt) {
	ZoneScopedN("World update");
	for (auto &plane: planes_)
		plane->update(dt);

	game_->cam_.pos = player_->pos + Vec2{0.5, 0.5};
}

void World::tick(float dt) {
	ZoneScopedN("World tick");
	for (auto &plane: planes_)
		plane->tick(dt);

	chunkRenderer_.tick(
		*planes_[currentPlane_],
		ChunkPos((int)player_->pos.x / CHUNK_WIDTH, (int)player_->pos.y / CHUNK_HEIGHT));
}

}