EngagementCrawler.swift

//
//  EngagementCrawler.swift
//  Instagrowth
//
//  Created by Zachary Shakked on 10/8/15.
//  Copyright © 2015 Zachary Shakked. All rights reserved.
//

import UIKit

class EngagementCrawler: NSObject {
    
    //MARK:- Instance Vars
    
    let analyticCrawler : AnalyticCrawler
    var likes : [Like]?
    var comments : [Comment]?
    var followers : Set<User> = []
    var engagedFollowers : Set<User> = []
    var ghostFollowers : Set<User> = []
    var userInteractions : [UserInteraction] = []
    var didCrunch : Bool = false
    
    //MARK:- Init
    
    init(analyticCrawler: AnalyticCrawler) {
        self.analyticCrawler = analyticCrawler
        super.init()
    }
    
    //MARK:- Sorts
    
    func leastLikes() -> Set<User> {
        let likers : Set<User> = Set(userInteractions.filter({$0.likes.count > 0}).map({ $0.user }))
        
        return followers.subtract(likers)
    }
    
    func leastComments() -> Set<User> {
        let commenters : Set<User> = Set(userInteractions.filter({$0.comments.count > 0}).map({ $0.user }))

        return followers.subtract(commenters)
    }
    
    func noLikesOrComments() -> Set<User> {
        return followers.subtract(engagedFollowers)
    }
    
    //MARK:- Config
    
    func crunch(completion: (Bool) -> (Void)) {
        
        let userInteractionFetcher = UserInteractionFetcher(postSummaries: analyticCrawler.postSummaries, accessToken: analyticCrawler.account.accessToken)
        let group = dispatch_group_create()
        
        dispatch_group_enter(group)
        userInteractionFetcher.fetchLikes { (succeeded, likes) -> (Void) in
            self.likes = succeeded ? likes : []
            dispatch_group_leave(group)
        }
        
        dispatch_group_enter(group)
        userInteractionFetcher.fetchComments { (succeeded, comments) -> (Void) in
            self.comments = succeeded ? comments : []
            dispatch_group_leave(group)
        }
        
        dispatch_group_enter(group)
        InstagramQuerier.sharedQuerier.fetchFollowers(analyticCrawler.account.params) { (succeeded, followers: [User]) -> (Void) in
            self.followers = succeeded ? Set<User>(followers) : []
            dispatch_group_leave(group)
        }
        
        dispatch_group_notify(group, dispatch_get_main_queue()) {
            guard let likes = self.likes, comments = self.comments else {
                return
            }
            
            self.configureUserInteractions(likes, comments: comments)
            self.configureEngagedUsers()
            self.configureGhostFollowers()
            self.didCrunch = true
            completion(true)
        }
    }
    
    
    private func configureUserInteractions(likes: [Like], comments: [Comment]) {
        var userInteractions : [String : UserInteraction] = Dictionary<String, UserInteraction>()
        guard let likes = self.likes, comments = self.comments else {
            return
        }
        
        for like in likes {
            if let userInteraction = userInteractions[like.user.username] {
                userInteraction.addLike(like)
            } else {
                let userInteraction = UserInteraction(user: like.user)
                userInteraction.addLike(like)
                userInteractions[like.user.username] = userInteraction
            }
        }
        for comment in comments {
            if let from = comment.from {
                if let userInteraction = userInteractions[from.username] {
                    userInteraction.addComment(comment)
                } else {
                    let userInteraction = UserInteraction(user: from)
                    userInteraction.addComment(comment)
                    userInteractions[from.username] = userInteraction
                }
                
            }
        }
        
        self.userInteractions = Array(userInteractions.values)
    }
    
    private func configureEngagedUsers() {
        guard let comments = comments, likes = likes else {
            return
        }
        for comment in comments {
            if let user = comment.from {
                engagedFollowers.insert(user)
            }
        }
        
        for like in likes {
            engagedFollowers.insert(like.user)
        }
    }
    
    private func configureGhostFollowers() {
        let engagedFollowers = self.engagedFollowers
        let allFollowers = self.followers
        let ghostFollowers = allFollowers.subtract(engagedFollowers)
        self.ghostFollowers = ghostFollowers
    }
}