//
//  TimelineTableViewController.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 10/1/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import AlamofireImage
import CoreData
import MastodonKit
import UIKit

class TimelineTableViewController: UITableViewController {
    let fetchLimit = 50
    
    var loading: Bool = false {
        didSet {
            DispatchQueue.main.async {
                if self.loading {
                    UIApplication.shared.isNetworkActivityIndicatorVisible = true
                    self.refreshControl?.beginRefreshing()
                } else {
                    UIApplication.shared.isNetworkActivityIndicatorVisible = false
                    self.refreshControl?.endRefreshing()
                }
            }
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let composeButtonItem = UIBarButtonItem(image: UIImage(named: "Compose"), style: .plain, target: self, action: #selector(compose))
        navigationItem.rightBarButtonItem = composeButtonItem
        navigationItem.title = "Home"
        
        refreshControl?.addTarget(self, action: #selector(self.fetchTimelineWithDefaultRange), for: .valueChanged)
        fetchTimelineWithDefaultRange()
    }
    
    @objc func compose() {
        let alertController = UIAlertController(title: "Compose", message: "Toot", preferredStyle: .alert)
        alertController.addAction(UIAlertAction(title: "OK", style: .default, handler: nil))
        present(alertController, animated: true)
    }
    
    func createDefaultTimelines(account: AccountMO) {
        let context = CoreDataManager.shared.getContext()
        let timelineNames = [
            "Home",
            "Local",
            "Federated",
        ]
        
        timelineNames.forEach { timelineName in
            let timeline = TimelineMO(context: context)
            timeline.name = timelineName
            timeline.account = account
        }
        
        CoreDataManager.shared.saveContext()
    }
    
    func fetchStatuses(request: Request<[Status]>, forTimeline timeline: TimelineMO) {
        if let client = AuthenticationManager.shared.getMKClientForSelectedSession() {
            print("Running request \(request)")
            client.run(request) { result in
                switch result {
                case .success(let remoteStatuses, _):
                    DispatchQueue.main.async {
                        let context = CoreDataManager.shared.getContext()
                        let statuses = remoteStatuses.compactMap { status in
                            return MastodonDataManager.upsertStatus(status)
                        }
                        
                        for (index, status) in statuses.enumerated() {
                            if index == 0 {
                                let boundary = TimelineBoundaryMO(context: context)
                                boundary.statusID = status.id!
                                boundary.start = true
                                boundary.createdAt = Date()
                                timeline.mutableSetValue(forKey: "boundaries").add(boundary)
                            } else if index == statuses.count {
                                let boundary = TimelineBoundaryMO(context: context)
                                boundary.statusID = status.id!
                                boundary.start = false
                                boundary.createdAt = Date()
                                timeline.mutableSetValue(forKey: "boundaries").add(boundary)
                            } else {
                                let predicate = NSPredicate(format: "statusID != %@", status.id!)
                                timeline.mutableSetValue(forKey: "boundaries").filter(using: predicate)
                            }
                        }
                        
                        timeline.addToStatuses(NSSet(array: statuses))
                        CoreDataManager.shared.saveContext()
                        
                        self.loading = false
                        self.tableView.reloadData()
                    }
                case .failure(let error):
                    print("\(error)")
                }
            }
        }
    }
    
    @objc func fetchTimelineWithDefaultRange() {
        fetchTimeline(withRange: .limit(fetchLimit))
    }
    
    func fetchTimeline(withRange requestRange: RequestRange) {
        guard let session = AuthenticationManager.shared.selectedSession, let account = session.account else {
            return
        }
        
        if session.selectedTimeline == nil {
            if let timelines = account.timelines, timelines.count == 0 {
                createDefaultTimelines(account: account)
            }
            
            let request = NSFetchRequest<TimelineMO>(entityName: "Timeline")
            request.predicate = NSPredicate(format: "name == %@", "Home")
            
            do {
                let results = try CoreDataManager.shared.getContext().fetch(request)
                session.selectedTimeline = results.first
                CoreDataManager.shared.saveContext()
            } catch {
                print("\(error)")
            }
        }
        
        loading = true
        
        if let selectedTimeline = session.selectedTimeline {
            var request: Request<[Status]>
            
            switch selectedTimeline.name {
            case "Home":
                request = Timelines.home(range: requestRange)
            case "Local":
                request = Timelines.public(local: true, range: requestRange)
            case "Federated":
                request = Timelines.public(local: false, range: requestRange)
            case let tag:
                request = Timelines.tag(tag!, range: requestRange)
            }
            
            fetchStatuses(request: request, forTimeline: selectedTimeline)
        }
    }
    
    func getTimelineRequest() -> NSFetchRequest<TimelineMO>? {
        guard let session = AuthenticationManager.shared.selectedSession, let selectedTimeline = session.selectedTimeline else {
            return nil
        }
        
        let request = NSFetchRequest<TimelineMO>(entityName: "Timeline")
        request.predicate = NSPredicate(format: "name == %@", selectedTimeline.name!)
        
        return request
    }
    
    func getTimelineStatuses() -> [StatusMO]? {
        guard let request = getTimelineRequest() else {
            return []
        }
        
        do {
            let response = try CoreDataManager.shared.getContext().fetch(request)
            guard let timeline = response.first, let statuses = timeline.statuses else {
                return []
            }
            
            let sortDescriptor = NSSortDescriptor(key: "createdAt", ascending: false)
            return statuses.sortedArray(using: [sortDescriptor]) as? [StatusMO]
        } catch {
            print("\(error)")
            return []
        }
    }
    
    func getTimelineStatusesCount() -> Int {
        guard let statuses = getTimelineStatuses() else {
            return 0
        }
        
        return statuses.count
    }
    
    func getTimelineBoundaries() -> NSSet? {
        guard let session = AuthenticationManager.shared.selectedSession, let timeline = session.selectedTimeline else {
            return nil
        }
        
        return timeline.boundaries
    }
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return getTimelineStatusesCount()
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "TimelineTableViewCell", for: indexPath) as? TimelineTableViewCell else {
            fatalError("Unable to find reusable cell")
        }
        
        cell.topDividerView.isHidden = false
        cell.topLoadMoreView.isHidden = true
        cell.boostView.isHidden = true
        cell.replyView.isHidden = true
        cell.bottomLoadMoreView.isHidden = true
        cell.bottomDividerView.isHidden = false
        cell.attachmentImageView.isHidden = true
        
        if let statuses = getTimelineStatuses() {
            let status = statuses[indexPath.row]
            let boundaries = getTimelineBoundaries() ?? NSSet()
            
            let avatarFilter = AspectScaledToFillSizeWithRoundedCornersFilter(
                size: CGSize(width: 40.0, height: 40.0),
                radius: 20.0,
                divideRadiusByImageScale: true
            )
            
            if indexPath.row != 0 {
                if let boundary = boundaries.filtered(using: NSPredicate(format: "statusID = %@", status.id!)).first as? TimelineBoundaryMO {
                    if boundary.start {
                        if let previousBoundary = boundaries.filtered(using: NSPredicate(format: "statusID = %@", statuses[indexPath.row - 1])).first as? TimelineBoundaryMO {
                            if !previousBoundary.start {
                                cell.topDividerView.isHidden = true
                                cell.topLoadMoreView.isHidden = false
                            }
                        }
                    }
                }
            }
            
            if indexPath.row < statuses.count - 1 {
                if let boundary = boundaries.filtered(using: NSPredicate(format: "statusID = %@", status.id!)).first as? TimelineBoundaryMO {
                    if !boundary.start {
                        if let nextBoundary = boundaries.filtered(using: NSPredicate(format: "statusID = %@", statuses[indexPath.row + 1])).first as? TimelineBoundaryMO {
                            if nextBoundary.start {
                                cell.bottomDividerView.isHidden = true
                                cell.bottomLoadMoreView.isHidden = false
                            }
                        }
                    }
                }
            }
            
            if let reblog = status.reblog {
                cell.boostView.isHidden = false
                
                if let account = reblog.account {
                    cell.avatarImageView.af_setImage(withURL: account.avatarURL!, filter: avatarFilter)
                    cell.displayNameLabel.text = account.displayName
                    cell.usernameLabel.text = account.acct
                }
                
                if let account = status.account {
                    cell.boostAvatarImageView.af_setImage(withURL: account.avatarURL!, filter: avatarFilter)
                    cell.boostDisplayNameLabel.text = account.displayName
                    cell.boostUsernameLabel.text = account.acct
                }
            } else {
                if let account = status.account {
                    cell.avatarImageView.af_setImage(withURL: account.avatarURL!, filter: avatarFilter)
                    cell.displayNameLabel.text = account.displayName
                    cell.usernameLabel.text = account.acct
                }
            }
            
            if let replyAccountID = status.inReplyToAccountID {
                if let replyAccount = MastodonDataManager.getAccountByID(replyAccountID) {
                    cell.replyView.isHidden = false
                    cell.replyAvatarImageView.af_setImage(withURL: replyAccount.avatarURL!, filter: avatarFilter)
                    cell.replyDisplayNameLabel.text = replyAccount.displayName
                    cell.replyUsernameLabel.text = replyAccount.acct
                }
            }
            
            if let content = status.content {
                do {
                    let styledContent = "<style>html * { font-size: 15px; color: #170c49; font-family: -apple-system } html, body { margin: 0; padding: 0 }</style> \(content)"
                    let attributedText = try NSAttributedString(
                        data: styledContent.data(using: String.Encoding.unicode, allowLossyConversion: true)!,
                        options: [.documentType: NSAttributedString.DocumentType.html],
                        documentAttributes: nil
                    )
                    
                    cell.contentLabel.attributedText = attributedText
                } catch {
                    print("\(error)")
                }
            }
            
            if let attachments = status.attachments, let attachment = attachments.anyObject() as? AttachmentMO {
                cell.attachmentImageView.isHidden = false
                cell.attachmentImageView.af_setImage(withURL: attachment.url!)
            }
            
            cell.timestampLabel.text = status.createdAt!.timeAgo()
            cell.repliesLabel.text = "0"
            cell.boostsLabel.text = NumberFormatter.localizedString(from: NSNumber(value: status.reblogsCount), number: .decimal)
            cell.favoritesLabel.text = NumberFormatter.localizedString(from: NSNumber(value: status.favouritesCount), number: .decimal)
            
            if status.reblogged {
                cell.boostsImageView.image = UIImage(named: "Boost Bold")
            } else {
                cell.boostsImageView.image = UIImage(named: "Boost Regular")
            }
            
            if status.favourited {
                cell.favoritesImageView.image = UIImage(named: "Star Filled")
            } else {
                cell.favoritesImageView.image = UIImage(named: "Star Regular")
            }
            
            if indexPath.row == statuses.count - 1 && !loading {
                fetchTimeline(withRange: .max(id: status.id!, limit: fetchLimit))
            }
            
            return cell
        }
        
        return cell
    }
}