#include "quam/archive.h"

#include "quam/pack.h"
#include "quam/wad2.h"

#include <QIcon>

namespace Arc {
	Option<ArcType> getArchiveType(std::istream &st) noexcept {
		try {
			auto pos = st.tellg();
			auto magic = readBytes<4>(st);
			st.seekg(pos);
			if(magic == std::array{'P', 'A', 'C', 'K'}) {return ArcType::Pack;}
			if(magic == std::array{'W', 'A', 'D', '2'}) {return ArcType::Wad2;}
		} catch(...) {
		}
		return None;
	}

	Node::Node(std::string _name) :
		name(_name),
		parent(nullptr)
	{
	}

	Node::~Node() {
	}

	Dir *Node::getRoot() {
		if(!parent) {
			return getDir();
		} else {
			Dir *rover = parent;
			while(rover->parent) {
				rover = rover->parent;
			}
			return rover;
		}
	}

	Node *Node::findPath(std::string path) {
		if(path.empty()) {
			return nullptr;
		}

		Dir *rover;

		// get the initial dir, which will either be:
		// - the root if the path starts with /
		// - the node itself
		// - the node's current Dir (when it's not a Dir)
		if(path.front() == '/') {
			path.erase(path.begin());
			rover = getRoot();
		} else {
			rover = getDir();
			if(!rover) {
				rover = parent;
			}
		}

		if(path.empty()) {
			// no file, so just the directory itself
			return rover;
		} else if(auto slash = path.find('/'); slash != std::string::npos) {
			std::string prev;
			prev = path.substr(0, slash);
			path = path.substr(slash + 1);

			if(prev == "..") {
				// parent dir on ".."
				rover = rover->parent ? rover->parent : rover;
			} else if(prev != ".") {
				if(auto node = rover->findNode(prev)) {
					// we want a subdirectory since this path continues
					rover = node->getDir();
				} else {
					// took a wrong turn
					rover = nullptr;
				}
			}

			// recurse
			return rover ? rover->findPath(path) : nullptr;
		} else {
			// must be a node inside a directory
			return rover->findNode(path);
		}
	}

	std::string Node::getPath(bool fromChild) const {
		if(parent) {
			return parent->getPath(true) + '/' + name;
		} else if(fromChild) {
			return std::string{};
		} else {
			return "/";
		}
	}

	Dir::Dir(std::string _name) :
		Node(_name),
		m_data()
	{
	}

	Dir::~Dir() {
	}

	UniquePtr<Node> const &Dir::emplaceBack(Node *node) {
		node->parent = this;
		return m_data.emplace_back(node);
	}

	Dir Dir::readArchive(std::istream &st, ArcType type) {
		switch(type) {
			case ArcType::Pack: return readPack(st);
			case ArcType::Wad2: return readWad2(st);
		}
		Q_UNREACHABLE();
	}

	Node *Dir::findNode(std::string const &name) {
		auto it = std::find_if(m_data.begin(), m_data.end(),
			[&name](auto const &node) {
				return node->name == name;
			});
		return it != m_data.end() ? &**it : nullptr;
	}

	File::File(std::string _name, QByteArray &&_data) :
		Node(_name),
		m_data(std::move(_data))
	{
	}

	File::~File() {
	}

	ArcInfo::ArcInfo(ArcType arcType) noexcept :
		type{arcType}
	{
		switch(type) {
			case ArcType::Pack:
				pathMaxChars  = 56;
				validatorType = PackValidator::staticMetaObject;
				break;
			case ArcType::Wad2:
				pathMaxChars  = 16;
				validatorType = Wad2Validator::staticMetaObject;
				break;
		}
	}

	Arc::Arc(std::istream &st, QObject *parent) :
		QObject{parent},
		info{ArcInfo(orThrow(getArchiveType(st),
		             FileFormatError("not an archive")))},
		root{Dir::readArchive(st, info.type)},
		validator{qobject_cast<QValidator *>(info.validatorType
		                                         .newInstance(Q_ARG(QObject *,
		                                                            this)))}
	{
	}

	Arc::~Arc() {
	}

	Model::Model(QObject *parent) :
		QAbstractItemModel{parent},
		m_dir{nullptr}
	{
	}

	Model::~Model() {
	}

	QVariant Model::data(QModelIndex const &index, int role) const {
		if(!index.isValid()) {
			return QVariant{};
		}

		auto node = static_cast<Node *>(index.internalPointer());
		auto col  = Column(index.column());

		switch(role) {
			case Qt::DecorationRole:
				if(col == Column::Name) {
					auto icon = node->getDir() ? "folder" : "text-x-generic";
					return QVariant{QIcon::fromTheme(QString::fromUtf8(icon))};
				}
				break;
			case Qt::DisplayRole:
				switch(col) {
					case Column::Size:
						if(auto file = node->getFile()) {
							return QVariant{QString::number(file->size())};
						}
						break;
					case Column::Type:
						if(auto file = node->getFile()) {
							return QVariant{tr(enumToString(file->type))};
						} else {
							return QVariant{tr("Directory")};
						}
					case Column::Name:
						return QVariant{tr(node->name.data())};
				}
			case Qt::UserRole:
				return QVariant::fromValue(static_cast<void *>(node));
			default:
				break;
		}
		return QVariant{};
	}

	Qt::ItemFlags Model::flags(QModelIndex const &index) const {
		if(!index.isValid()) {
			return Qt::NoItemFlags;
		} else {
			return Qt::ItemIsSelectable  |
			       Qt::ItemIsDragEnabled |
			       Qt::ItemIsEnabled     |
			       Qt::ItemNeverHasChildren;
		}
	}

	QVariant Model::headerData(int section,
	                           Qt::Orientation ori,
	                           int role) const {
		if(ori == Qt::Horizontal && role == Qt::DisplayRole) {
			switch(Column(section)) {
				case Column::Size: return QVariant{tr("Size")};
				case Column::Type: return QVariant{tr("Type")};
				case Column::Name: return QVariant{tr("Name")};
			}
		}
		return QVariant{};
	}

	QModelIndex Model::index(int row,
	                         int col,
	                         QModelIndex const &parent) const {
		if(!m_dir || !hasIndex(row, col, parent) || row > m_dir->size()) {
			return QModelIndex{};
		} else {
			return createIndex(row, col, m_dir->at(row));
		}
	}

	QModelIndex Model::parent(QModelIndex const &) const {
		return QModelIndex{};
	}

	int Model::rowCount(QModelIndex const &) const {
		return m_dir ? m_dir->size() : 0;
	}

	int Model::columnCount(QModelIndex const &) const {
		return enumMax<Column>();
	}

	Dir *Model::dir() const {
		return m_dir;
	}

	Node *Model::findPath(std::string path) {
		return m_dir->findPath(path);
	}

	void Model::setDir(Dir *to) {
		auto from = m_dir;
		if(to != from) {
			emit layoutAboutToBeChanged();
			for(int row = 0, rows = rowCount(); row < rows; row++) {
				for(int col = 0, cols = columnCount(); col < cols; col++) {
					changePersistentIndex(index(row, col), QModelIndex{});
				}
			}
			m_dir = to;
			emit layoutChanged();
			emit dirChanged(from, to);
		}
	}

	void Model::setDirToIndex(QModelIndex const &ind) {
		auto node = static_cast<Node *>(ind.data(Qt::UserRole).value<void *>());
		if(auto dir = node->getDir()) {
			setDir(dir);
		}
	}

	bool Model::goUp() {
		if(m_dir && m_dir->parent) {
			setDir(m_dir->parent);
			return true;
		} else {
			return false;
		}
	}

	bool Model::goPath(std::string path) {
		Node *node;
		Dir  *dir;
		if(m_dir && (node = m_dir->findPath(path)) && (dir = node->getDir())) {
			setDir(dir);
			return true;
		} else {
			return false;
		}
	}
}

// EOF