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

import Cocoa
import NIO
import Combine

class DatabaseCollectionListViewController: NSViewController {
    
    @IBOutlet weak var outlineView: NSOutlineView!
    
    let mongoController: MongoController
    
    let selectedCollection = PassthroughSubject<DatabaseCollection, Never>()
    
    private var databaseCollections: [DatabaseCollections] = []
    
    init(mongoController: MongoController) {
        self.mongoController = mongoController
        
        super.init(nibName: "DatabaseCollectionListViewController", bundle: .main)
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        mongoController.client.listDatabaseNames().flatMap { (databaseNames) -> EventLoopFuture<[DatabaseCollections]> in
            let futures = databaseNames.map { (name: String) -> EventLoopFuture<DatabaseCollections> in
                let db = self.mongoController.client.db(name)
                return db.listCollectionNames().map { (collectionNames: [String]) -> DatabaseCollections in
                    let sortedNames = collectionNames.sorted()
                    return DatabaseCollections(database: name, collections: sortedNames)
                }
            }
            return EventLoopFuture.whenAllSucceed(futures, on: futures.first!.eventLoop)
        }.whenComplete { [weak self] (res) in
            guard let self = self else { return }
            
            switch res {
            case let .success(databaseCollections):
                let sortedCollections = databaseCollections.sorted(by: { $0.database < $1.database })
                self.databaseCollections = sortedCollections
                DispatchQueue.main.async {
                    self.outlineView.reloadData()
                }
            case let .failure(error):
                fatalError("error getting database names: \(error)")
            }
        }
        
        outlineView.dataSource = self
        outlineView.delegate = self
    }
    
    @IBAction func outlineCellDoubleClicked(_ sender: Any) {
        let item = outlineView.item(atRow: outlineView.clickedRow)!
        
        if item is DatabaseCollections {
            if outlineView.isItemExpanded(item) {
                outlineView.collapseItem(item)
            } else {
                outlineView.expandItem(item)
            }
        } else if let collection = item as? DatabaseCollection {
            selectedCollection.send(collection)
        }
    }
}

extension DatabaseCollectionListViewController: NSOutlineViewDataSource {
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        if item == nil {
            return databaseCollections.count
        } else if let database = item as? DatabaseCollections {
            return database.collections.count
        } else {
            return 0
        }
    }
    
    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        return item is DatabaseCollections
    }
    
    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        if item == nil {
            return databaseCollections[index]
        } else if let databaseCollections = item as? DatabaseCollections {
            let collection = databaseCollections.collections[index]
            return DatabaseCollection(database: databaseCollections.database, name: collection)
        } else {
            fatalError()
        }
    }
}

extension DatabaseCollectionListViewController: NSOutlineViewDelegate {
    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        if let database = item as? DatabaseCollections {
            let cell = outlineView.makeView(withIdentifier: .databaseNameCell, owner: nil) as! NSTableCellView
            cell.textField!.stringValue = database.database
            cell.textField!.isEditable = false
            return cell
        } else if let collection = item as? DatabaseCollection {
            let cell = outlineView.makeView(withIdentifier: .collectionNameCell, owner: nil) as! NSTableCellView
            cell.textField!.stringValue = collection.name
            cell.textField!.isEditable = false
            return cell
        } else {
            fatalError()
        }
    }
}

extension NSUserInterfaceItemIdentifier {
    static let databaseNameCell = NSUserInterfaceItemIdentifier(rawValue: "DatabaseNameCell")
    static let collectionNameCell = NSUserInterfaceItemIdentifier(rawValue: "CollectionNameCell")
}