struct Section {
    var isCollaped: Bool
    let category: Category
}


class SourcesViewController: UIViewController {


    // MARK: - Variables and Constants


    fileprivate let defaults = UserDefaults.standard
    let realm = try! Realm()


    lazy var categories: Results<Category> = {
        self.realm.objects(Category.self)
    }()

    fileprivate var sections: [Section] = []


    // Views
    fileprivate lazy var titleView: UILabel = {

        let label = UILabel()

        label.text = "Sources"
        label.font = UIFont.boldSystemFont(ofSize: 48)
        label.layer.zPosition = 10

        return label
    }()

    fileprivate var waterView: YXWaveView?
    fileprivate let searchBar = SearchBar()
    fileprivate let addButton = UIButton(type: .custom)
    fileprivate var tableView: UITableView?
    fileprivate var createSourceLauncher: CreateSourceLauncher?


    fileprivate var prefersDarkMode: Bool {
        return UserDefaults.standard.bool(forKey: Keys.prefersDarkMode)
    }


    fileprivate var color: UIColor {
        return UIColor.getColor()
    }


    override var preferredStatusBarStyle: UIStatusBarStyle {
        return UserDefaults.standard.bool(forKey: Keys.prefersDarkMode) ? .lightContent : .default
    }




    // MARK: - Lifecycle Functions


    override func viewDidLoad() {

        super.viewDidLoad()
        self.navigationController?.isNavigationBarHidden = true

        loadCategories()
        createTableView()

    }


    override func viewSafeAreaInsetsDidChange() {
        setupWaveView()
        setupTableView()
        setupTitle()
        setupAddButton()
    }


    override func viewWillAppear(_ animated: Bool) {
        waterView?.start()
    }


    override func viewDidAppear(_ animated: Bool) {
        setColor()
        setStyle()
    }

    /*
        Removed setup functions for readability
    */


    // MARK: - Model


    private func loadCategories() {
        categories = realm.objects(Category.self)
        fillSections()
    }


    private func fillSections() {
        sections = []
        for category in categories {
            sections.append(Section(isCollaped: false, category: category))
        }
    }


    private func deleteSource(indexPath: IndexPath) {

        let confirmationController = UIAlertController(title: "Confirm", message: "", preferredStyle: .alert)

        let cancel = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
        let delete = UIAlertAction(title: "Delete", style: .destructive) { (action) in

            let source = self.categories[indexPath.section].items[indexPath.row]
            do {
                try self.realm.write {
                    self.realm.delete(source)
                }
            } catch {
                print("Error deleting category, \(error)")
            }

        }

        confirmationController.addAction(cancel)
        confirmationController.addAction(delete)

        self.present(confirmationController, animated: true) {
            self.tableView?.reloadData()
        }
    }


    private func createCategory() {

        guard categories.count == 0 else {
            return
        }

        do {
            try realm.write() {

                let defaultCategories = ["Coffee", "Supplements", "Tea"]

                for category in defaultCategories {
                    let newCategory = Category()
                    newCategory.name = category

                    realm.add(newCategory)
                }

            }
        } catch {
            print("Error creating Category, \(error)")
        }

        fillSections()
        tableView?.reloadData()
    }


    private func createSource() {

        let selectedCategory = categories[1]

        do {
            try realm.write() {

                let newSource = Source()
                newSource.name = "Starbucks Coffee"
                newSource.caffeineContent = 180

                selectedCategory.items.append(newSource)

            }
        } catch {
            print("Error creating source, \(error)")
        }

        fillSections()
        tableView?.reloadData()

    }




    // MARK: - Styling


    fileprivate func setStyle() {

        let styleColor = UIColor.getStyleColor()
        let maskingColor = UIColor.getMaskingColor()

        waterView?.realWaveColor = styleColor
        waterView?.maskWaveColor = maskingColor

        view.backgroundColor = styleColor
        tableView?.backgroundColor = styleColor

        titleView.textColor = UIColor.getTextColor()
        addButton.tintColor = UIColor.getTextColor()

        setNeedsStatusBarAppearanceUpdate()
    }


    fileprivate func setColor() {
        waterView?.backgroundColor = UIColor.getColor()
    }




    // MARK: - Present other views


    @objc private func showCreateSourceLauncher() {

        createSourceLauncher = CreateSourceLauncher()

        createSourceLauncher!.sourceDelegate = self
        createSourceLauncher!.setup()
        createSourceLauncher!.setStyle()
        createSourceLauncher!.showCollectionView(height: 100 + view.safeAreaInsets.bottom)

    }

    public func deallocateLauncher(type: LauncherType) {
        createSourceLauncher = nil
    }


    // Show View Controller for creating a new source
    public func showCreateSourceController() {

        createSource()
        return

        let addSourceVC = AddSourceViewController()

        if #available(iOS 13.0, *) {
            addSourceVC.modalPresentationStyle = .popover
        }

        self.present(addSourceVC, animated: true, completion: nil)
    }


    // Show View Controller for creating a new category
    public func showCreateCategoryController() {

        createCategory()
        return

        let addCategoryController = AddCategoryViewController()

        if #available(iOS 13.0, *) {
            addCategoryController.modalPresentationStyle = .popover
        }

        self.present(addCategoryController, animated: true, completion: nil)
    }


    public func showSourceViewController() {
        let sourceVC = SourceViewController()
        self.navigationController?.pushViewController(sourceVC, animated: true)
    }

}




// MARK: - Search Bar Methods


extension SourcesViewController: UISearchBarDelegate {


    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        // Filter results

        // Update table view
    }


    func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {

    }


    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        searchBar.endEditing(true)
        searchBar.resignFirstResponder()
    }


}




// MARK: - Table View Methods


extension SourcesViewController: UITableViewDelegate, UITableViewDataSource, SwipeTableViewCellDelegate {


    func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath, for orientation: SwipeActionsOrientation) -> [SwipeAction]? {

        guard orientation == .right else { return nil }

        let deleteAction = SwipeAction(style: .destructive, title: nil) { action, indexPath in
            self.deleteSource(indexPath: indexPath)
        }

        let deleteImage = UIImage(named: Assets.trashIcon)?.withRenderingMode(.alwaysTemplate)
        deleteAction.image = deleteImage?.withTintColor(UIColor.getTextColor())
        return [deleteAction]
    }


    func numberOfSections(in tableView: UITableView) -> Int {
        return categories.count
    }


    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        if sections[section].isCollaped {
            return 0
        }

        return categories[section].items.count
    }


    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {

        let headerFrame = CGRect(x: 0, y: 0, width: view.bounds.width, height: 40)

        let headerSection = sections[section]

        let headerButton = SectionTableViewHeader(frame: headerFrame, title: headerSection.category.name, isCollapsed: headerSection.isCollaped)
        headerButton.addTarget(self, action: #selector(handleExpandHeader), for: .touchUpInside)
        headerButton.setStyle()
        headerButton.tag = section

        return headerButton
    }



    @objc func handleExpandHeader(sender: SectionTableViewHeader) {

        let isCollapsed = sections[sender.tag].isCollaped
        sections[sender.tag].isCollaped = !isCollapsed

        var indexPaths: [IndexPath] = []
        for (index, _) in categories[sender.tag].items.enumerated() {
            indexPaths.append(IndexPath(row: index, section: sender.tag))
        }

        print(indexPaths.count)

        if isCollapsed {
            tableView?.insertRows(at: indexPaths, with: .fade)
        } else {
            tableView?.deleteRows(at: indexPaths, with: .fade)
        }

        var rotationAngle: CGFloat = CGFloat.pi / 2
        if !isCollapsed {
            rotationAngle = -rotationAngle
        }

        sender.rotateImage(angle: rotationAngle)

    }



    func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
        return 40
    }


    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: CellIdentifiers.sourceCellId, for: indexPath) as! CustomizableTableViewCell

        cell.delegate = self

        let category = sections[indexPath.section].category
        let item = category.items[indexPath.row]

        cell.titleText = item.name
        cell.primaryIconName = item.imageString

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return 48
    }


    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        tableView.deselectRow(at: indexPath, animated: true)



    }

}