//
//  AccountTableView.swift
//  elpha-ios
//
//  Created by Dwayne Harris on 10/9/18.
//  Copyright © 2018 Elpha. All rights reserved.
//

import CoreData
import Kingfisher
import UIKit
import SafariServices

class FieldTableViewController: NSObject, UITableViewDelegate, UITableViewDataSource {
    var fields: [AccountField]?
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return fields?.count ?? 0
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "FieldTableViewCell", for: indexPath) as? FieldTableViewCell else {
            fatalError("Unable to find reusable cell")
        }
        
        if let fields = fields {
            let field = fields[indexPath.row]
            
            cell.nameLabel.text = field.name
            
            do {
                let htmlString = """
                                 <style>
                                 html * {
                                     font-family: -apple-system !important;
                                     font-size: 12px !important;
                                     font-weight: bold;
                                     color: \(UIColor(named: "Text")!.hexString()) !important;
                                     text-align: right !important;
                                 }
                                 </style>
                                 \(field.value)
                                 """
                
                if let data = htmlString.data(using: String.Encoding.utf16) {
                    cell.valueTextView.attributedText = try NSAttributedString(
                        data: data,
                        options: [.documentType: NSAttributedString.DocumentType.html],
                        documentAttributes: nil
                    )
                }
            } catch {
                print("\(error)")
            }
        }
        
        return cell
    }
}

class AccountTableViewController: AbstractStatusTableViewController {
    @IBOutlet var headerView: UIView!
    @IBOutlet var headerImageView: UIImageView!
    @IBOutlet var avatarImageView: UIImageView!
    @IBOutlet var displayNameLabel: UILabel!
    @IBOutlet var usernameLabel: UILabel!
    @IBOutlet var statusesLabel: UILabel!
    @IBOutlet var followingLabel: UILabel!
    @IBOutlet var followersLabel: UILabel!
    @IBOutlet var statusTypeSegmentedControl: UISegmentedControl!
    @IBOutlet var contentTextView: UITextViewFixed!
    @IBOutlet var fieldTableView: UITableView!

    var account: AccountMO?
    var fieldTableViewController: FieldTableViewController?
    
    override var currentPaginationContext: String {
        get {
            guard let account = self.account else {
                return ""
            }
            
            return "account:\(account.acct!):\(statusTypeSegmentedControl.selectedSegmentIndex)"
        }
    }
    
    @IBAction func statusTypeChanged(_ sender: UISegmentedControl) {
        initializeFetchedResultsController()
        tableView.reloadData()
        
        fetch()
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        refreshControl?.addTarget(self, action: #selector(self.fetch), for: .valueChanged)
        fieldTableViewController = FieldTableViewController()
        
        avatarImageView.setRoundedCorners()
        avatarImageView.setShadow()
        
        if self.account == nil {
            if let session = AuthenticationManager.session {
                self.account = session.account
            }
        }
        
        if let account = account {
            updateHeader(withAccount: account)
            // sizeHeaderToFit()
            
            initializeFetchedResultsController()
        }
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        if let account = self.account {
            MastodonAPI.account(id: account.id!) { data, error in
                guard let data = data, error == nil else {
                    return
                }
                
                self.account = MastodonDataManager.upsertAccount(data)
                
                if let account = self.account {
                    DispatchQueue.main.async {
                        self.updateHeader(withAccount: account)
                        self.fetch()
                    }
                }
            }
        }
    }
    
    private func sizeHeaderToFit() {
        headerView.translatesAutoresizingMaskIntoConstraints = false
        
        let headerWidth = headerView.bounds.size.width
        let headerWidthConstraints = NSLayoutConstraint.constraints(withVisualFormat: "[headerView(width)]", options: NSLayoutConstraint.FormatOptions(rawValue: UInt(0)), metrics: ["width": headerWidth], views: ["headerView": headerView])
        
        headerView.addConstraints(headerWidthConstraints)
        headerView.setNeedsLayout()
        headerView.layoutIfNeeded()
        
        let headerSize = headerView.systemLayoutSizeFitting(UIView.layoutFittingCompressedSize)
        let height = headerSize.height
        var frame = headerView.frame
        
        frame.size.height = height
        headerView.frame = frame
        
        headerView.removeConstraints(headerWidthConstraints)
        headerView.translatesAutoresizingMaskIntoConstraints = true
    }
    
    private func updateHeader(withAccount account: AccountMO) {
        navigationItem.title = account.displayName
        
        if let headerURL = account.headerURL {
            headerImageView.kf.setImage(with: headerURL)
        }
        
        if let avatarURL = account.avatarURL {
            let options: KingfisherOptionsInfo = SettingsManager.automaticallyPlayGIFs ? [] : [.onlyLoadFirstFrame]
            avatarImageView.kf.setImage(with: avatarURL, options: options)
        }
        
        displayNameLabel.text = account.displayName
        usernameLabel.text = "@\(account.acct!)"
        
        if let note = account.note {
            contentTextView.attributedText = note.htmlAttributed(size: 15, centered: true)
        }
        
        statusesLabel.text = NumberFormatter.localizedString(from: NSNumber(value: account.statusesCount), number: .decimal)
        followingLabel.text = NumberFormatter.localizedString(from: NSNumber(value: account.followingCount), number: .decimal)
        followersLabel.text = NumberFormatter.localizedString(from: NSNumber(value: account.followersCount), number: .decimal)
        
        if let fields = account.fields, fields.count > 0 {
            fieldTableViewController!.fields = fields
            
            fieldTableView.dataSource = fieldTableViewController
            fieldTableView.delegate = fieldTableViewController
            
            fieldTableView.isHidden = false
        } else {
            fieldTableView.isHidden = true
        }
    }
    
    override func loadMoreTapped(_ sender: Any, status: StatusMO, direction: PaginationDirection) {
        func removeMarker(at: Int) {
            status.markers?.remove(at: at)
            CoreDataManager.shared.saveContext()
        }
        
        if let markers = status.markers {
            for (index, marker) in markers.enumerated() {
                if marker.context == self.currentPaginationContext && marker.item.direction == direction {
                    fetchStatuses(withPagination: marker.item) { error in
                        if error == nil {
                            removeMarker(at: index)
                        } else {
                            AlertManager.shared.show(message: error!.localizedDescription, category: .error)
                        }
                    }
                }
            }
        }
    }
    
    @objc func fetch() {
        fetchStatuses { error in
            if error != nil {
                AlertManager.shared.show(message: error!.localizedDescription, category: .error)
            }
        }
    }
    
    func fetchStatuses(withPagination pagination: PaginationItem? = nil, completion: @escaping (Error?) -> Void) {
        if let account = account {
            func requestCompletion(data: JSONObjectArray?, pagination: [PaginationItem]?, error: Error?) {
                guard let data = data, error == nil else {
                    self.loading = false
                    completion(error)
                    return
                }
                
                for (index, status) in data.enumerated() {
                    if let upsertResult = MastodonDataManager.upsertStatus(status) {
                        let status = upsertResult.object
                        
                        if let pagination = pagination {
                            var markers: [PaginationMarker] = status.markers ?? []
                            
                            if index == 0 {
                                pagination.forEach { item in
                                    if item.direction == .prev {
                                        markers.append(PaginationMarker(context: self.currentPaginationContext, item: item))
                                    }
                                }
                            }
                            
                            if index == data.count - 1 {
                                pagination.forEach { item in
                                    if item.direction == .next {
                                        markers.append(PaginationMarker(context: self.currentPaginationContext, item: item))
                                    }
                                }
                            }
                            
                            status.markers = markers
                        }
                    }
                }
                
                MastodonAPI.pinnedStatuses(accountID: account.id!, limit: fetchLimit) { data, error in
                    guard let data = data, error == nil else {
                        self.loading = false
                        completion(error)
                        return
                    }
                    
                    data.forEach { status in
                        _ = MastodonDataManager.upsertStatus(status.merging(["pinned": true]) { (_, new) in new })
                    }
                }
                
                CoreDataManager.shared.saveContext()
                
                self.loading = false
                completion(nil)
            }
            
            switch statusTypeSegmentedControl.selectedSegmentIndex {
            case 1:
                MastodonAPI.statuses(
                    accountID: account.id!,
                    onlyMedia: false,
                    excludeReplies: false,
                    limit: fetchLimit,
                    pagination: pagination,
                    completion: requestCompletion
                )
            case 2:
                MastodonAPI.statuses(
                    accountID: account.id!,
                    onlyMedia: true,
                    excludeReplies: true,
                    limit: fetchLimit,
                    pagination: pagination,
                    completion: requestCompletion
                )
            default:
                MastodonAPI.statuses(
                    accountID: account.id!,
                    onlyMedia: false,
                    excludeReplies: true,
                    limit: fetchLimit,
                    pagination: pagination,
                    completion: requestCompletion
                )
            }
        }
    }
}

extension AccountTableViewController: NSFetchedResultsControllerDelegate {
    func initializeFetchedResultsController() {
        if let account = self.account {
            let request = NSFetchRequest<StatusMO>(entityName: "Status")
            request.sortDescriptors = [
                NSSortDescriptor(key: "pinned", ascending: false),
                NSSortDescriptor(key: "createdAt", ascending: false),
            ]
            
            switch statusTypeSegmentedControl.selectedSegmentIndex {
            case 1:
                request.predicate = NSPredicate(format: "account == %@", account)
            case 2:
                request.predicate = NSPredicate(format: "account == %@ AND attachments.@count > 0", account)
            default:
                request.predicate = NSPredicate(format: "account == %@ AND inReplyToID == nil", account)
            }
            
            fetchedResultsController = NSFetchedResultsController(
                fetchRequest: request,
                managedObjectContext: CoreDataManager.shared.context,
                sectionNameKeyPath: nil,
                cacheName: nil
            )
            
            fetchedResultsController!.delegate = self
            
            do {
                try fetchedResultsController!.performFetch()
            } catch {
                print("\(error)")
            }
        }
    }
    
    func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        tableView.beginUpdates()
    }
    
    func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
        switch type {
        case NSFetchedResultsChangeType.insert:
            tableView.insertRows(at: [newIndexPath!], with: UITableView.RowAnimation.none)
        case NSFetchedResultsChangeType.delete:
            tableView.deleteRows(at: [indexPath!], with: UITableView.RowAnimation.none)
        case NSFetchedResultsChangeType.update:
            if let cell = tableView.cellForRow(at: indexPath!) as? AccountTableViewCell {
                updateCell(cell, withStatusAt: indexPath!)
            }
        case NSFetchedResultsChangeType.move:
            tableView.deleteRows(at: [indexPath!], with: UITableView.RowAnimation.fade)
            tableView.insertRows(at: [newIndexPath!], with: UITableView.RowAnimation.fade)
        }
    }
    
    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        tableView.endUpdates()
    }
    
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }
    
//    override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
//        if let cell = cell as? AccountTableViewCell {
//            CellHeightManager.set(status: cell.statusView.status, height: cell.frame.size.height)
//        }
//    }
    
//    override func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
//        return CellHeightManager.get(status: fetchedResultsController?.object(at: indexPath))
//    }
    
    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return fetchedResultsController?.fetchedObjects?.count ?? 0
    }
    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "AccountTableViewCell", for: indexPath) as? AccountTableViewCell else {
            fatalError("Unable to find reusable cell")
        }
        
        updateCell(cell, withStatusAt: indexPath)
        cell.statusView.delegate = self
        
        return cell
    }
}