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

import CoreData
import Foundation

class UpsertResult<T: NSManagedObject> {
    var object: T
    var new: Bool = false
    
    init(object: T, new: Bool) {
        self.object = object
        self.new = new
    }
}

@objc public class AccountField: NSObject, NSCoding {
    let name: String
    let value: String
    
    init(name: String, value: String) {
        self.name = name
        self.value = value
    }
    
    public func encode(with aCoder: NSCoder) {
        aCoder.encode(name, forKey: "name")
        aCoder.encode(value, forKey: "value")
    }
    
    convenience required public init?(coder aDecoder: NSCoder) {
        guard
            let name = aDecoder.decodeObject(forKey: "name") as? String,
            let value = aDecoder.decodeObject(forKey: "value") as? String
        else {
            return nil
        }
        
        self.init(name: name, value: value)
    }
}

@objc public class Mention: NSObject, NSCoding {
    let id: String
    let url: URL
    let username: String
    let acct: String
    
    init(id: String, url: URL, username: String, acct: String) {
        self.id = id
        self.url = url
        self.username = username
        self.acct = acct
    }
    
    public func encode(with aCoder: NSCoder) {
        aCoder.encode(id, forKey: "id")
        aCoder.encode(url, forKey: "url")
        aCoder.encode(username, forKey: "username")
        aCoder.encode(acct, forKey: "acct")
    }
    
    convenience required public init?(coder aDecoder: NSCoder) {
        guard
            let id = aDecoder.decodeObject(forKey: "id") as? String,
            let url = aDecoder.decodeObject(forKey: "url") as? URL,
            let username = aDecoder.decodeObject(forKey: "username") as? String,
            let acct = aDecoder.decodeObject(forKey: "acct") as? String
        else {
            return nil
        }
        
        self.init(id: id, url: url, username: username, acct: acct)
    }
}

@objc public class Emoji: NSObject, NSCoding {
    let shortcode: String
    let staticURL: URL
    let url: URL
    let visibleInPicker: Bool
    
    init(shortcode: String, staticURL: URL, url: URL, visibleInPicker: Bool) {
        self.shortcode = shortcode
        self.staticURL = staticURL
        self.url = url
        self.visibleInPicker = visibleInPicker
    }
    
    public func encode(with aCoder: NSCoder) {
        aCoder.encode(shortcode, forKey: "shortcode")
        aCoder.encode(staticURL, forKey: "staticURL")
        aCoder.encode(url, forKey: "url")
        aCoder.encode(visibleInPicker, forKey: "visibleInPicker")
    }
    
    convenience required public init?(coder aDecoder: NSCoder) {
        guard
            let shortcode = aDecoder.decodeObject(forKey: "shortcode") as? String,
            let staticURL = aDecoder.decodeObject(forKey: "staticURL") as? URL,
            let url = aDecoder.decodeObject(forKey: "url") as? URL
        else {
            return nil
        }
        
        self.init(shortcode: shortcode, staticURL: staticURL, url: url, visibleInPicker: aDecoder.decodeBool(forKey: "acct"))
    }
}

@objc public class PaginationMarker: NSObject, NSCoding {
    let context: String
    let item: PaginationItem
    
    init(context: String, item: PaginationItem) {
        self.context = context
        self.item = item
    }
    
    public func encode(with aCoder: NSCoder) {
        aCoder.encode(context, forKey: "context")
        aCoder.encode(item, forKey: "item")
    }
    
    convenience required public init?(coder aDecoder: NSCoder) {
        guard
            let context = aDecoder.decodeObject(forKey: "context") as? String,
            let item = aDecoder.decodeObject(forKey: "item") as? PaginationItem
        else {
            return nil
        }
        
        self.init(context: context, item: item)
    }
}

public class MastodonDataManager {
    static var dateFormatter: DateFormatter {
        let dateFormatter = DateFormatter()
        
        dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SZ"
        dateFormatter.timeZone = TimeZone(abbreviation: "UTC")
        dateFormatter.locale = Locale(identifier: "en_US_POSIX")
        
        return dateFormatter
    }
    
    static func setAccount(_ account: AccountMO, withData data: JSONObject) -> AccountMO {
        let dateFormatter = self.dateFormatter
        
        account.fetchedAt = Date()
        account.id = data["id"] as? String
        account.username = data["username"] as? String
        account.acct = data["acct"] as? String
        account.displayName = data["display_name"] as? String
        account.note = data["note"] as? String
        account.url = URL(string: data["url"] as! String)
        account.avatarURL = URL(string: data["avatar"] as! String)
        account.avatarStaticURL = URL(string: data["avatar_static"] as! String)
        account.headerURL = URL(string: data["header"] as! String)
        account.headerStaticURL = URL(string: data["header_static"] as! String)
        account.locked = data["locked"] as? Bool ?? false
        account.createdAt = dateFormatter.date(from: data["created_at"] as! String)
        account.followersCount = data["followers_count"] as! Int32
        account.followingCount = data["following_count"] as! Int32
        account.statusesCount = data["statuses_count"] as! Int32
        
        if let fields = data["fields"] as? [[String: Any]] {
            account.fields = fields.map { AccountField(name: $0["name"] as! String, value: $0["value"] as! String) }
        }
        
        return account
    }
    
    static func upsertAccount(_ data: JSONObject) -> AccountMO? {
        let request = NSFetchRequest<AccountMO>(entityName: "Account")
        request.predicate = NSPredicate(format: "id == %@", data["id"] as! String)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            if let account = results.first {
                return setAccount(account, withData: data)
            } else {
                return setAccount(AccountMO(context: CoreDataManager.shared.context), withData: data)
            }
        } catch {
            print("\(error)")
            return nil
        }
    }
    
    static func setAttachment(_ attachment: AttachmentMO, withData data: JSONObject) -> AttachmentMO {
        attachment.id = data["id"] as? String
        attachment.type = data["type"] as? String
        attachment.url = URL(string: data["url"] as! String)
        attachment.previewURL = URL(string: data["preview_url"] as! String)
        
        if let remoteURL = data["remote_url"] as? String {
            attachment.remoteURL = URL(string: remoteURL)
        }
        
        if let textURL = data["text_url"] as? String {
            attachment.textURL = URL(string: textURL)
        }
        
        attachment.fetchedAt = Date()
        
        return attachment
    }
    
    static func upsertAttachment(_ data: JSONObject) -> AttachmentMO? {
        let request = NSFetchRequest<AttachmentMO>(entityName: "Attachment")
        request.predicate = NSPredicate(format: "id == %@", data["id"] as! String)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            if let attachment = results.first {
                return setAttachment(attachment, withData: data)
            } else {
                return setAttachment(AttachmentMO(context: CoreDataManager.shared.context), withData: data)
            }
        } catch {
            print("\(error)")
            return nil
        }
    }
    
    static func setTag(_ tag: TagMO, withData data: JSONObject) -> TagMO {
        tag.name = data["name"] as? String
        tag.url = URL(string: data["url"] as! String)
        
        return tag
    }
    
    static func upsertTag(_ data: JSONObject) -> TagMO? {
        let request = NSFetchRequest<TagMO>(entityName: "Tag")
        request.predicate = NSPredicate(format: "name == %@", data["name"] as! String)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            if let tag = results.first {
                return setTag(tag, withData: data)
            } else {
                return setTag(TagMO(context: CoreDataManager.shared.context), withData: data)
            }
        } catch {
            print("\(error)")
            return nil
        }
    }
    
    static func setApp(_ app: AppMO, withData data: JSONObject) -> AppMO {
        app.name = data["name"] as? String
        
        if let website = data["website"] as? String {
            app.website = URL(string: website)
        }
        
        return app
    }
    
    static func upsertApp(_ data: JSONObject) -> AppMO? {
        let request = NSFetchRequest<AppMO>(entityName: "App")
        request.predicate = NSPredicate(format: "name == %@", data["name"] as! String)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            if let app = results.first {
                return setApp(app, withData: data)
            } else {
                return setApp(AppMO(context: CoreDataManager.shared.context), withData: data)
            }
        } catch {
            print("\(error)")
            return nil
        }
    }
    
    static func setStatus(_ status: StatusMO, withData data: JSONObject) -> StatusMO {
        let dateFormatter = self.dateFormatter
        
        status.id = data["id"] as? String
        status.uri = URL(string: data["uri"] as! String)
        status.account = MastodonDataManager.upsertAccount(data["account"] as! JSONObject)
        status.inReplyToID = data["in_reply_to_id"] as? String
        status.inReplyToAccountID = data["in_reply_to_account_id"] as? String
        status.content = data["content"] as? String
        status.createdAt = dateFormatter.date(from: data["created_at"] as! String)
        status.repliesCount = data["replies_count"] as! Int32
        status.reblogsCount = data["reblogs_count"] as! Int32
        status.favoritesCount = data["favourites_count"] as! Int32
        status.reblogged = data["reblogged"] as? Bool ?? false
        status.favorited = data["favourited"] as? Bool ?? false
        status.sensitive = data["sensitive"] as? Bool ?? false
        status.pinned = data["pinned"] as? Bool ?? false
        status.spoilerText = data["spoiler_text"] as? String
        status.visibility = data["visibility"] as? String
        status.attributedContent = status.content?.htmlAttributed(size: 15.0)
        
        status.fetchedAt = Date()
        
        if let url = data["url"] as? String {
            status.url = URL(string: url)
        }
        
        if let app = data["application"] as? JSONObject {
            status.app = MastodonDataManager.upsertApp(app)
        }
        
        if let attachments = data["media_attachments"] as? [JSONObject] {
            attachments.forEach { attachment in
                if let attachment = MastodonDataManager.upsertAttachment(attachment) {
                    status.addToAttachments(attachment)
                }
            }
        }
        
        if let mentions = data["mentions"] as? [JSONObject] {
            status.mentions = mentions.map { mention in
                return Mention(
                    id: mention["id"] as! String,
                    url: URL(string: mention["url"] as! String)!,
                    username: mention["username"] as! String,
                    acct: mention["acct"] as! String
                )
            }
        }
        
        if let tags = data["tags"] as? [JSONObject] {
            tags.forEach { tag in
                if let tag = MastodonDataManager.upsertTag(tag) {
                    status.addToTags(tag)
                }
            }
        }
        
        if let emojis = data["emojis"] as? [JSONObject] {
            status.emojis = emojis.map { emoji in
                return Emoji(
                    shortcode: emoji["shortcode"] as! String,
                    staticURL: URL(string: emoji["static_url"] as! String)!,
                    url: URL(string: emoji["url"] as! String)!,
                    visibleInPicker: emoji["visible_in_picker"] as? Bool ?? false
                )
            }
        }
        
        if let reblog = data["reblog"] as? JSONObject {
            let upsertResult = upsertStatus(reblog)
            status.reblog = upsertResult?.object
        }
        
        return status
    }
    
    static func upsertStatus(_ data: JSONObject) -> UpsertResult<StatusMO>? {
        let request = NSFetchRequest<StatusMO>(entityName: "Status")
        request.predicate = NSPredicate(format: "id == %@", data["id"] as! String)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            if let status = results.first {
                return UpsertResult(
                    object: setStatus(status, withData: data),
                    new: false
                )
            } else {
                let status = StatusMO(context: CoreDataManager.shared.context)
                status.hidden = !(data["spoiler_text"] as! String).isEmpty
                
                return UpsertResult(
                    object: setStatus(status, withData: data),
                    new: true
                )
            }
        } catch {
            print("\(error)")
            return nil
        }
    }
    
    static func saveClient(id: String, clientID: String, clientSecret: String, host: String) -> ClientMO {
        let client = ClientMO(context: CoreDataManager.shared.context)
        client.id = id
        client.clientID = clientID
        client.clientSecret = clientSecret
        client.host = host
        
        CoreDataManager.shared.saveContext()
        return client
    }
    
    static func account(id: String) -> AccountMO? {
        let request = NSFetchRequest<AccountMO>(entityName: "Account")
        request.predicate = NSPredicate(format: "id == %@", id)
        
        do {
            let results = try CoreDataManager.shared.context.fetch(request)
            guard let account = results.first else {
                return nil
            }
            
            return account
        } catch {
            print("\(error)")
            return nil
        }
    }
}