WWDC/ConfCore/SessionProgress.swift

//
//  SessionProgress.swift
//  WWDC
//
//  Created by Guilherme Rambo on 11/05/17.
//  Copyright © 2017 Guilherme Rambo. All rights reserved.
//

import Cocoa
import RealmSwift

/// Defines the user action of adding a session as favorite
public class SessionProgress: Object {
    
    /// Unique identifier
    public dynamic var identifier = UUID().uuidString
    
    /// When the progress was created
    public dynamic var createdAt = Date()
    
    /// When the progress was last update
    public dynamic var updatedAt = Date()
    
    /// The current position in the video (in seconds)
    public dynamic var currentPosition: Double = 0
    
    /// The current position in the video, relative to the duration (from 0 to 1)
    public dynamic var relativePosition: Double = 0
    
    /// The session this progress is associated with
    public let session = LinkingObjects(fromType: Session.self, property: "progresses")
    
    public override class func primaryKey() -> String? {
        return "identifier"
    }
    
}

extension Session {
    
    public func setCurrentPosition(_ position: Double, _ duration: Double) {
        guard let realm = self.realm else { return }
        
        guard !duration.isNaN, !duration.isZero, !duration.isInfinite else { return }
        guard !position.isNaN, !position.isZero, !position.isInfinite else { return }
        
        do {
            let mustCommit: Bool
            
            if !realm.isInWriteTransaction {
                realm.beginWrite()
                mustCommit = true
            } else {
                mustCommit = false
            }
            
            var progress: SessionProgress
            
            if let p = progresses.first {
                progress = p
            } else {
                progress = SessionProgress()
                progresses.append(progress)
            }
            
            progress.currentPosition = position
            progress.relativePosition = position / duration
            progress.updatedAt = Date()
            
            if mustCommit { try realm.commitWrite() }
        } catch {
            NSLog("Error updating session progress: \(error)")
        }
    }
    
    public func resetProgress() {
        guard let realm = self.realm else { return }
        do {
            let mustCommit: Bool
            
            if !realm.isInWriteTransaction {
                realm.beginWrite()
                mustCommit = true
            } else {
                mustCommit = false
            }
            
            progresses.removeAll()
            
            if mustCommit { try realm.commitWrite() }
        } catch {
            NSLog("Error updating session progress: \(error)")
        }
    }
    
    public func currentPosition() -> Double {
        return progresses.first?.currentPosition ?? 0
    }
    
}