/*

    Copyright (C) 2016 Apple Inc. All Rights Reserved.

    See LICENSE.txt for this sample’s licensing information

    Abstract:

    This file contains the ContentFilterController class, which controls a view used to start and stop a content filter, and display current filtering rules.

*/

import UIKit

import NetworkExtension

import SimpleTunnelServices

/// A view controller object for a view that displays Content Filter configuration and rules.

class ContentFilterController: UITableViewController {

    // MARK: Properties

    /// A table view cell that contains the status of the filter.

    @IBOutlet weak var statusCell: SwitchCell!

    /// A table view cell that contains the 

    @IBOutlet weak var rulesServerCell: TextFieldCell!

    /// A variable to pass as the context to addObserver()

    var rulesContext = 0

    /// The current list of filtering rules

    var currentRules = [(String, String)]()

    // MARK: Initializers

    deinit {

        var context = self

        FilterUtilities.defaults?.removeObserver(self, forKeyPath: "rules", context:&context)

    }

    // MARK: UIViewController

    /// Handle the event where the view is loaded into memory.

    override func viewDidLoad() {

        FilterUtilities.defaults?.addObserver(self, forKeyPath: "rules", options: NSKeyValueObservingOptions.initial, context:&rulesContext)

        statusCell.valueChanged = {

            if self.statusCell.isOn && NEFilterManager.shared().providerConfiguration == nil {

                let newConfiguration = NEFilterProviderConfiguration()

                newConfiguration.username = "TestUser"

                newConfiguration.organization = "Acme Inc."

                newConfiguration.filterBrowsers = true

                newConfiguration.filterSockets = true

                newConfiguration.serverAddress = self.rulesServerCell.textField.text ?? "my.great.filter.server"

                NEFilterManager.shared().providerConfiguration = newConfiguration

            }

            NEFilterManager.shared().isEnabled = self.statusCell.isOn

            NEFilterManager.shared().saveToPreferences { error in

                if let saveError = error {

                    simpleTunnelLog("Failed to save the filter configuration: \(saveError)")

                    self.statusCell.isOn = false

                    return

                }

                self.rulesServerCell.textField.text = NEFilterManager.shared().providerConfiguration?.serverAddress

                FilterUtilities.defaults?.setValue(NEFilterManager.shared().providerConfiguration?.serverAddress, forKey: "serverAddress")

            }

        }

        rulesServerCell.valueChanged = {

            guard let serverIPAddress = self.rulesServerCell.textField.text , !serverIPAddress.isEmpty else { return }

            NEFilterManager.shared().providerConfiguration?.serverAddress = serverIPAddress

            NEFilterManager.shared().saveToPreferences { error in

                if let saveError = error {

                    simpleTunnelLog("Failed to save the filter configuration: \(saveError)")

                    return

                }

                FilterUtilities.defaults?.setValue(serverIPAddress, forKey: "serverAddress")

            }

        }

    }

    /// Handle the event where the view is loaded into memory.

    override func viewWillAppear(_ animated: Bool) {

        super.viewWillAppear(animated)

        NEFilterManager.shared().loadFromPreferences { error in

            if let loadError = error {

                simpleTunnelLog("Failed to load the filter configuration: \(loadError)")

                self.statusCell.isOn = false

                return

            }

            self.statusCell.isOn = NEFilterManager.shared().isEnabled

            self.rulesServerCell.textField.text = NEFilterManager.shared().providerConfiguration?.serverAddress

            self.reloadRules()

        }

    }

    // MARK: NSObject

    /// Handle changes to the rules

    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {

        if context == &rulesContext && keyPath == "rules" {

            reloadRules()

        } else {

            super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)

        }

    }

    // MARK: UITableViewDataSource

    /// Return the number of sections to display.

    override func numberOfSections(in tableView: UITableView) -> Int {

        return !currentRules.isEmpty ? 2 : 1

    }

    /// Return the number of rows in a section.

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

        switch section {

            case 0: return 2

            case 1: return currentRules.count

            default: return 0

        }

    }

    /// Return the cell for given index path.

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

        if (indexPath as NSIndexPath).section == 0 {

            return (indexPath as NSIndexPath).row == 0 ? statusCell : rulesServerCell

        }

        else if let cell = tableView.dequeueReusableCell(withIdentifier: "rule-cell") {

            let (hostString, actionString) = currentRules[(indexPath as NSIndexPath).row]

            cell.textLabel?.text = hostString

            cell.detailTextLabel?.text = actionString

            return cell

        }

        else {

            return UITableViewCell()

        }

    }

    /// Return the title for a section in the table.

    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {

        return section == 1 ? "Current Rules" : nil

    }

    // MARK: Interface

    /// Re-load the current filerting rules from the defaults.

    func reloadRules() {

        currentRules = [(String, String)]()

        guard let rules = FilterUtilities.defaults?.object(forKey: "rules") as? [String : [String : AnyObject]] else { return }

        for (hostname, ruleInfo) in rules {

            guard let ruleActionNum = ruleInfo["kRule"] as? Int,

                let ruleAction = FilterRuleAction(rawValue: ruleActionNum)

                else { continue }

            currentRules.append((hostname as String, ruleAction.description))

        }

        tableView.reloadData()

    }

    /// Download a new set of filtering rules from the server.

    @IBAction func fetchRulesButtonTouchUpInside(_ sender: UIButton) {

        FilterUtilities.fetchRulesFromServer(NEFilterManager.shared().providerConfiguration?.serverAddress)

        reloadRules()

    }

}