//
//  MainSplitViewController.swift
//  MongoView
//
//  Created by Shadowfacts on 8/11/20.
//  Copyright © 2020 Shadowfacts. All rights reserved.
//

import Cocoa
import Combine

class MainSplitViewController: NSSplitViewController {
    
    let mongoController: MongoController
    let initialCollection: DatabaseCollection?
    
    private var detailViewController = DetailViewController()
    private var currentQueryViewController: QueryViewController? {
        detailViewController.children.first as? QueryViewController
    }
    
    private var collectionSubscriber: Cancellable?
    private var titleObservation: NSKeyValueObservation?
    
    init(mongoController: MongoController, initialCollection: DatabaseCollection?) {
        self.mongoController = mongoController
        self.initialCollection = initialCollection
        
        super.init(nibName: nil, bundle: nil)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let listVC = DatabaseCollectionListViewController(mongoController: mongoController)
        let sourceListItem = NSSplitViewItem(sidebarWithViewController: listVC)
        let detailItem = NSSplitViewItem(viewController: detailViewController)
        detailItem.maximumThickness = NSSplitViewItem.unspecifiedDimension

        addSplitViewItem(sourceListItem)
        addSplitViewItem(detailItem)
        
        NSLayoutConstraint.activate([
            sourceListItem.viewController.view.widthAnchor.constraint(greaterThanOrEqualToConstant: 200),
            sourceListItem.viewController.view.widthAnchor.constraint(lessThanOrEqualToConstant: 500),
            detailItem.viewController.view.widthAnchor.constraint(greaterThanOrEqualToConstant: 200),
        ])
        
        collectionSubscriber = listVC.selectedCollection.sink(receiveValue: self.selectCollection)
        
        if let initialCollection = initialCollection {
            selectCollection(initialCollection)
        }
    }
    
    private func selectCollection(_ collection: DatabaseCollection) {
        if currentQueryViewController?.hasFilterChanged ?? false {
            (NSApp.delegate as! AppDelegate).newWindow(mongoController: mongoController, collection: collection)
        } else {
            let queryVC = QueryViewController(mongoController: mongoController, collection: collection)
            setDetailChild(queryVC)
        }
    }
    
    private func setDetailChild(_ vc: NSViewController) {
        if let child = detailViewController.children.first {
            child.removeFromParent()
            child.view.removeFromSuperview()
        }
        
        vc.view.translatesAutoresizingMaskIntoConstraints = false
        
        detailViewController.addChild(vc)
        detailViewController.view.addSubview(vc.view)
        
        NSLayoutConstraint.activate([
            detailViewController.view.leadingAnchor.constraint(equalTo: vc.view.leadingAnchor),
            detailViewController.view.trailingAnchor.constraint(equalTo: vc.view.trailingAnchor),
            detailViewController.view.topAnchor.constraint(equalTo: vc.view.topAnchor),
            detailViewController.view.bottomAnchor.constraint(equalTo: vc.view.bottomAnchor),
        ])
        
        titleObservation = vc.observe(\.title, options: .initial, changeHandler: { [unowned self] (_, _) in
            self.title = vc.title
        })
    }
    
    @IBAction func refresh(_ sender: Any) {
        currentQueryViewController?.refresh()
    }

}

extension MainSplitViewController: NSMenuItemValidation {
    func validateMenuItem(_ menuItem: NSMenuItem) -> Bool {
        if menuItem.action == #selector(refresh(_:)) {
            return currentQueryViewController != nil
        }
        return true
    }
}