//
//  SelectLocationViewController.swift
//  MullvadVPN
//
//  Created by pronebird on 02/05/2019.
//  Copyright © 2019 Mullvad VPN AB. All rights reserved.
//

import MullvadLogging
import MullvadREST
import MullvadTypes
import UIKit

final class SelectLocationViewController: UIViewController {
    private let searchBar = UISearchBar()
    private let tableView = UITableView()
    private let topContentView = UIStackView()
    private let filterView = RelayFilterView()
    private var dataSource: LocationDataSource?
    private var cachedRelays: CachedRelays?
    private var filter = RelayFilter()
    var relayLocation: RelayLocation?

    override var preferredStatusBarStyle: UIStatusBarStyle {
        .lightContent
    }

    var filterViewShouldBeHidden: Bool {
        return (filter.ownership == .any) && (filter.providers == .any)
    }

    var navigateToFilter: (() -> Void)?
    var didSelectRelay: ((RelayLocation) -> Void)?
    var didUpdateFilter: ((RelayFilter) -> Void)?
    var didFinish: (() -> Void)?

    // MARK: - View lifecycle

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = .secondaryColor

        navigationItem.title = NSLocalizedString(
            "NAVIGATION_TITLE",
            tableName: "SelectLocation",
            value: "Select location",
            comment: ""
        )

        navigationItem.leftBarButtonItem = UIBarButtonItem(
            title: NSLocalizedString(
                "NAVIGATION_TITLE",
                tableName: "SelectLocation",
                value: "Filter",
                comment: ""
            ),
            primaryAction: UIAction(handler: { [weak self] _ in
                self?.navigateToFilter?()
            })
        )

        navigationItem.rightBarButtonItem = UIBarButtonItem(
            systemItem: .done,
            primaryAction: UIAction(handler: { [weak self] _ in
                self?.didFinish?()
            })
        )

        setUpDataSource()
        setUpTableView()
        setUpTopContent()

        view.addConstrainedSubviews([topContentView, tableView]) {
            topContentView.pinEdgesToSuperviewMargins(.all().excluding(.bottom))

            tableView.pinEdgesToSuperview(.all().excluding(.top))
            tableView.topAnchor.constraint(equalTo: topContentView.bottomAnchor)
        }
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        tableView.flashScrollIndicators()
    }

    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        coordinator.animate(alongsideTransition: nil) { _ in
            guard let indexPath = self.dataSource?.indexPathForSelectedRelay() else { return }

            self.tableView.scrollToRow(at: indexPath, at: .middle, animated: false)
        }
    }

    // MARK: - Public

    func setCachedRelays(_ cachedRelays: CachedRelays, filter: RelayFilter) {
        self.cachedRelays = cachedRelays
        self.filter = filter

        if filterViewShouldBeHidden {
            filterView.isHidden = true
        } else {
            filterView.isHidden = false
            filterView.setFilter(filter)
        }

        dataSource?.setRelays(cachedRelays.relays, filter: filter)
    }

    // MARK: - Private

    private func setUpDataSource() {
        dataSource = LocationDataSource(tableView: tableView)
        dataSource?.didSelectRelayLocation = { [weak self] location in
            self?.didSelectRelay?(location)
        }

        dataSource?.selectedRelayLocation = relayLocation

        if let cachedRelays {
            dataSource?.setRelays(cachedRelays.relays, filter: filter)
        }
    }

    private func setUpTableView() {
        tableView.backgroundColor = view.backgroundColor
        tableView.separatorColor = .secondaryColor
        tableView.separatorInset = .zero
        tableView.estimatedRowHeight = 53
        tableView.indicatorStyle = .white
        tableView.keyboardDismissMode = .onDrag
    }

    private func setUpTopContent() {
        topContentView.axis = .vertical
        topContentView.addArrangedSubview(filterView)
        topContentView.addArrangedSubview(searchBar)

        filterView.isHidden = filterViewShouldBeHidden

        filterView.didUpdateFilter = { [weak self] in
            guard let self else { return }

            filter = $0
            didUpdateFilter?($0)

            if let cachedRelays {
                setCachedRelays(cachedRelays, filter: filter)
            }
        }

        setUpSearchBar()
    }

    private func setUpSearchBar() {
        searchBar.delegate = self
        searchBar.searchBarStyle = .minimal
        searchBar.layer.cornerRadius = 8
        searchBar.clipsToBounds = true
        searchBar.placeholder = NSLocalizedString(
            "SEARCHBAR_PLACEHOLDER",
            tableName: "SelectLocation",
            value: "Search for...",
            comment: ""
        )

        UITextField.SearchTextFieldAppearance.inactive.apply(to: searchBar)
    }
}

extension SelectLocationViewController: UISearchBarDelegate {
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        dataSource?.filterRelays(by: searchText)
    }

    func searchBarTextDidBeginEditing(_ searchBar: UISearchBar) {
        UITextField.SearchTextFieldAppearance.active.apply(to: searchBar)
    }

    func searchBarTextDidEndEditing(_ searchBar: UISearchBar) {
        UITextField.SearchTextFieldAppearance.inactive.apply(to: searchBar)
    }
}