/* Copyright 2013 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <QDir>
#include <QDirIterator>
#include <QCryptographicHash>
#include <QJsonParseError>
#include <QJsonDocument>
#include <QJsonObject>

#include "AssetsUtils.h"
#include "MultiMC.h"

namespace AssetsUtils
{
void migrateOldAssets()
{
	QDir assets_dir("assets");
	if (!assets_dir.exists())
		return;
	assets_dir.setFilter(QDir::AllEntries | QDir::NoDotAndDotDot);
	int base_length = assets_dir.path().length();

	QList<QString> blacklist = {"indexes", "objects", "virtual"};

	if (!assets_dir.exists("objects"))
		assets_dir.mkdir("objects");
	QDir objects_dir("assets/objects");

	QDirIterator iterator(assets_dir, QDirIterator::Subdirectories);
	int successes = 0;
	int failures = 0;
	while (iterator.hasNext())
	{
		QString currentDir = iterator.next();
		currentDir = currentDir.remove(0, base_length + 1);

		bool ignore = false;
		for (QString blacklisted : blacklist)
		{
			if (currentDir.startsWith(blacklisted))
				ignore = true;
		}

		if (!iterator.fileInfo().isDir() && !ignore)
		{
			QString filename = iterator.filePath();

			QFile input(filename);
			input.open(QIODevice::ReadOnly | QIODevice::WriteOnly);
			QString sha1sum =
				QCryptographicHash::hash(input.readAll(), QCryptographicHash::Sha1)
					.toHex()
					.constData();

			QString object_name = filename.remove(0, base_length + 1);
			QLOG_DEBUG() << "Processing" << object_name << ":" << sha1sum << input.size();

			QString object_tlk = sha1sum.left(2);
			QString object_tlk_dir = objects_dir.path() + "/" + object_tlk;

			QDir tlk_dir(object_tlk_dir);
			if (!tlk_dir.exists())
				objects_dir.mkdir(object_tlk);

			QString new_filename = tlk_dir.path() + "/" + sha1sum;
			QFile new_object(new_filename);
			if (!new_object.exists())
			{
				bool rename_success = input.rename(new_filename);
				QLOG_DEBUG() << " Doesn't exist, copying to" << new_filename << ":"
							 << QString::number(rename_success);
				if (rename_success)
					successes++;
				else
					failures++;
			}
			else
			{
				input.remove();
				QLOG_DEBUG() << " Already exists, deleting original and not copying.";
			}
		}
	}

	if (successes + failures == 0)
	{
		QLOG_DEBUG() << "No legacy assets needed importing.";
	}
	else
	{
		QLOG_DEBUG() << "Finished copying legacy assets:" << successes << "successes and"
					 << failures << "failures.";

		QDirIterator cleanup_iterator(assets_dir);

		while (cleanup_iterator.hasNext())
		{
			QString currentDir = cleanup_iterator.next();
			currentDir = currentDir.remove(0, base_length + 1);

			bool ignore = false;
			for (QString blacklisted : blacklist)
			{
				if (currentDir.startsWith(blacklisted))
					ignore = true;
			}

			if (cleanup_iterator.fileInfo().isDir() && !ignore)
			{
				QString path = cleanup_iterator.filePath();
				QDir folder(path);

				QLOG_DEBUG() << "Cleaning up legacy assets folder:" << path;

				folder.removeRecursively();
			}
		}
	}
}

/*
 * Returns true on success, with index populated
 * index is undefined otherwise
 */
bool loadAssetsIndexJson(QString path, AssetsIndex *index)
{
	/*
	{
	  "objects": {
		"icons/icon_16x16.png": {
		  "hash": "bdf48ef6b5d0d23bbb02e17d04865216179f510a",
		  "size": 3665
		},
		...
		}
	  }
	}
	*/

	QFile file(path);

	// Try to open the file and fail if we can't.
	// TODO: We should probably report this error to the user.
	if (!file.open(QIODevice::ReadOnly))
	{
		QLOG_ERROR() << "Failed to read assets index file" << path;
		return false;
	}

	// Read the file and close it.
	QByteArray jsonData = file.readAll();
	file.close();

	QJsonParseError parseError;
	QJsonDocument jsonDoc = QJsonDocument::fromJson(jsonData, &parseError);

	// Fail if the JSON is invalid.
	if (parseError.error != QJsonParseError::NoError)
	{
		QLOG_ERROR() << "Failed to parse assets index file:" << parseError.errorString()
					 << "at offset " << QString::number(parseError.offset);
		return false;
	}

	// Make sure the root is an object.
	if (!jsonDoc.isObject())
	{
		QLOG_ERROR() << "Invalid assets index JSON: Root should be an array.";
		return false;
	}

	QJsonObject root = jsonDoc.object();

	QJsonValue isVirtual = root.value("virtual");
	if (!isVirtual.isUndefined())
	{
		index->isVirtual = isVirtual.toBool(false);
	}

	QJsonValue objects = root.value("objects");
	QVariantMap map = objects.toVariant().toMap();

	for (QVariantMap::const_iterator iter = map.begin(); iter != map.end(); ++iter)
	{
		// QLOG_DEBUG() << iter.key();

		QVariant variant = iter.value();
		QVariantMap nested_objects = variant.toMap();

		AssetObject object;

		for (QVariantMap::const_iterator nested_iter = nested_objects.begin();
			 nested_iter != nested_objects.end(); ++nested_iter)
		{
			// QLOG_DEBUG() << nested_iter.key() << nested_iter.value().toString();
			QString key = nested_iter.key();
			QVariant value = nested_iter.value();

			if (key == "hash")
			{
				object.hash = value.toString();
			}
			else if (key == "size")
			{
				object.size = value.toDouble();
			}
		}

		index->objects.insert(iter.key(), object);
	}

	return true;
}
}