//
// Client.swift
//
// Copyright © 2017 Peter Zignego. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#if os(Linux)
import Dispatch
#endif
import Foundation
#if !COCOAPODS
@_exported import SKCore
#endif

open class Client {
    internal(set) public var authenticatedUser: User?
    internal(set) public var team: Team?
    internal(set) public var channels = [String: Channel]()
    internal(set) public var users = [String: User]()
    internal(set) public var userGroups = [String: UserGroup]()
    internal(set) public var bots = [String: Bot]()
    internal(set) public var files = [String: File]()
    internal(set) public var sentMessages = [String: Message]()

    public init(){}

    open func notificationForEvent(_ event: Event, type: EventType) {
        switch type {
        case .hello:
            // Connection event
            break
        case .ok:
            messageSent(event)
        case .message:
            if event.subtype != nil {
                messageDispatcher(event)
            } else {
                messageReceived(event)
            }
        case .userTyping:
            userTyping(event)
        case .channelMarked, .imMarked, .groupMarked:
            channelMarked(event)
        case .channelCreated, .imCreated:
            channelCreated(event)
        case .channelJoined, .groupJoined:
            channelJoined(event)
        case .channelLeft, .groupLeft:
            channelLeft(event)
        case .channelDeleted:
            channelDeleted(event)
        case .channelRenamed, .groupRename:
            channelRenamed(event)
        case .channelArchive, .groupArchive:
            channelArchived(event, archived: true)
        case .channelUnarchive, .groupUnarchive:
            channelArchived(event, archived: false)
        case .channelHistoryChanged, .imHistoryChanged, .groupHistoryChanged:
            channelHistoryChanged(event)
        case .dndUpdated:
            doNotDisturbUpdated(event)
        case .dndUpatedUser:
            doNotDisturbUserUpdated(event)
        case .imOpen, .groupOpen:
            open(event, open: true)
        case .imClose, .groupClose:
            open(event, open: false)
        case .fileCreated:
            processFile(event)
        case .fileShared:
            processFile(event)
        case .fileUnshared:
            processFile(event)
        case .filePublic:
            processFile(event)
        case .filePrivate:
            filePrivate(event)
        case .fileChanged:
            processFile(event)
        case .fileDeleted:
            deleteFile(event)
        case .fileCommentAdded:
            fileCommentAdded(event)
        case .fileCommentEdited:
            fileCommentEdited(event)
        case .fileCommentDeleted:
            fileCommentDeleted(event)
        case .pinAdded:
            pinAdded(event)
        case .pinRemoved:
            pinRemoved(event)
        case .pong:
            // Pong event
            break
        case .presenceChange:
            presenceChange(event)
        case .manualPresenceChange:
            manualPresenceChange(event)
        case .prefChange:
            changePreference(event)
        case .memberJoinedChannel:
            memberJoinedChannel(event)
        case .memberLeftChannel:
            memberLeftChannel(event)
        case .userChange:
            userChange(event)
        case .teamJoin:
            teamJoin(event)
        case .starAdded:
            itemStarred(event, star: true)
        case .starRemoved:
            itemStarred(event, star: false)
        case .reactionAdded:
            addedReaction(event)
        case .reactionRemoved:
            removedReaction(event)
        case .emojiChanged:
            emojiChanged(event)
        case .commandsChanged:
            // This functionality is only used by our web client.
            // The other APIs required to support slash command metadata are currently unstable.
            // Until they are released other clients should ignore this event.
            break
        case .teamPlanChange:
            teamPlanChange(event)
        case .teamPrefChange:
            teamPreferenceChange(event)
        case .teamRename:
            teamNameChange(event)
        case .teamDomainChange:
            teamDomainChange(event)
        case .emailDomainChange:
            emailDomainChange(event)
        case .teamProfileChange:
            teamProfileChange(event)
        case .teamProfileDelete:
            teamProfileDeleted(event)
        case .teamProfileReorder:
            teamProfileReordered(event)
        case .botAdded:
            bot(event)
        case .botChanged:
            bot(event)
        case .accountsChanged:
            // The accounts_changed event is used by our web client to maintain a list of logged-in accounts.
            // Other clients should ignore this event.
            break
        case .teamMigrationStarted:
            // Team migration event
            break
        case .reconnectURL:
            // The reconnect_url event is currently unsupported and experimental.
            break
        case .subteamCreated, .subteamUpdated:
            subteam(event)
        case .subteamSelfAdded:
            subteamAddedSelf(event)
        case .subteamSelfRemoved:
            subteamRemovedSelf(event)
        case .error:
            // Error event
            break
        case .goodbye:
            // Goodbye event
            break
        case .unknown:
            // Unsupported event
            break
        }
    }

    // MARK: - Client setup
    open func initialSetup(JSON: [String: Any]) {
        team = Team(team: JSON["team"] as? [String: Any])
        authenticatedUser = User(user: JSON["self"] as? [String: Any])
        authenticatedUser?.doNotDisturbStatus = DoNotDisturbStatus(status: JSON["dnd"] as? [String: Any])
        enumerateObjects(JSON["users"] as? Array) { (user) in self.addUser(user) }
        enumerateObjects(JSON["channels"] as? Array) { (channel) in self.addChannel(channel) }
        enumerateObjects(JSON["groups"] as? Array) { (group) in self.addChannel(group) }
        enumerateObjects(JSON["mpims"] as? Array) { (mpim) in self.addChannel(mpim) }
        enumerateObjects(JSON["ims"] as? Array) { (ims) in self.addChannel(ims) }
        enumerateObjects(JSON["bots"] as? Array) { (bots) in self.addBot(bots) }
        enumerateSubteams(JSON["subteams"] as? [String: Any])
    }

    private func messageDispatcher(_ event: Event) {
        guard let value = event.subtype, let subtype = MessageSubtype(rawValue:value) else {
            return
        }
        switch subtype {
        case .messageChanged:
            messageChanged(event)
        case .messageDeleted:
            messageDeleted(event)
        default:
            messageReceived(event)
        }
    }
}

// MARK: - Messages
extension Client {
    func messageSent(_ event: Event) {
        guard
            let reply = event.replyTo,
            let message = sentMessages[NSNumber(value: reply).stringValue],
            let channel = message.channel,
            let ts = message.ts
        else {
            return
        }
        message.ts = event.ts
        message.text = event.text
        channels[channel]?.messages[ts] = message
    }

    func messageReceived(_ event: Event) {
        guard
            let channel = event.channel,
            let message = event.message,
            let id = channel.id,
            let ts = message.ts
        else {
            return
        }
        channels[id]?.messages[ts] = message
    }

    func messageChanged(_ event: Event) {
        guard
            let id = event.channel?.id,
            let nested = event.nestedMessage,
            let ts = nested.ts
        else {
            return
        }
        channels[id]?.messages[ts] = nested
    }

    func messageDeleted(_ event: Event) {
        guard
            let id = event.channel?.id,
            let key = event.message?.deletedTs
        else {
            return
        }
        _ = channels[id]?.messages.removeValue(forKey: key)
    }
}

// MARK: - Channels
extension Client {
    func userTyping(_ event: Event) {
        guard
            let channel = event.channel,
            let channelID = channel.id,
            let user = event.user,
            let userID = user.id,
            channels.index(forKey: channelID) != nil,
            !channels[channelID]!.usersTyping.contains(userID)
        else {
            return
        }
        channels[channelID]?.usersTyping.append(userID)

        let timeout = DispatchTime.now() + Double(Int64(5.0 * Double(UInt64.nanosecondsPerSecond))) / Double(UInt64.nanosecondsPerSecond)
        DispatchQueue.main.asyncAfter(deadline: timeout, execute: {
            if let index = self.channels[channelID]?.usersTyping.index(of: userID) {
                self.channels[channelID]?.usersTyping.remove(at: index)
            }
        })
    }

    func channelMarked(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id]?.lastRead = event.ts
    }

    func channelCreated(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id] = channel
    }

    func channelDeleted(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels.removeValue(forKey: id)
    }

    func channelJoined(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id] = event.channel
    }

    func channelLeft(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }

        if let userID = authenticatedUser?.id, let index = channels[id]?.members?.index(of: userID) {
            channels[id]?.members?.remove(at: index)
        }
    }

    func channelRenamed(_ event: Event) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id]?.name = channel.name
    }

    func channelArchived(_ event: Event, archived: Bool) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id]?.isArchived = archived
    }

    func channelHistoryChanged(_ event: Event) {

    }

    func memberJoinedChannel(_ event: Event) {
        guard
            let channel = event.channel?.id,
            let member = event.user?.id
        else {
            return
        }

        channels[channel]?.members?.append(member)
    }

    func memberLeftChannel(_ event: Event) {
        guard
            let channel = event.channel?.id,
            let member = event.user?.id
        else {
            return
        }

        if let index = channels[channel]?.members?.index(of: member) {
            channels[channel]?.members?.remove(at: index)
        }
    }
}

// MARK: - Do Not Disturb
extension Client {
    func doNotDisturbUpdated(_ event: Event) {
        guard let dndStatus = event.dndStatus else {
            return
        }
        authenticatedUser?.doNotDisturbStatus = dndStatus
    }

    func doNotDisturbUserUpdated(_ event: Event) {
        guard
            let dndStatus = event.dndStatus,
            let user = event.user,
            let id = user.id
        else {
            return
        }
        users[id]?.doNotDisturbStatus = dndStatus
    }
}

// MARK: - IM & Group Open/Close
extension Client {
    func open(_ event: Event, open: Bool) {
        guard
            let channel = event.channel,
            let id = channel.id
        else {
            return
        }
        channels[id]?.isOpen = open
    }
}

// MARK: - Files
extension Client {
    func processFile(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id
            else {
                continue
            }
            if let comment = file.initialComment, let commentID = comment.id {
                if files[id]?.comments[commentID] == nil {
                    files[id]?.comments[commentID] = comment
                }
            }
            files[id] = file
        }
    }

    func filePrivate(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id
            else {
                continue
            }
            files[id]?.isPublic = false
        }
    }

    func deleteFile(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id
            else {
                continue
            }
            if files[id] != nil {
                files.removeValue(forKey: id)
            }
        }
    }

    func fileCommentAdded(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id,
                let comment = event.comment,
                let commentID = comment.id
            else {
                continue
            }
            files[id]?.comments[commentID] = comment
        }
    }

    func fileCommentEdited(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id,
                let comment = event.comment,
                let commentID = comment.id
            else {
                continue
            }
            files[id]?.comments[commentID]?.comment = comment.comment
        }
    }

    func fileCommentDeleted(_ event: Event) {
        for file in event.files {
            guard
                let id = file.id,
                let comment = event.comment,
                let commentID = comment.id
            else {
                continue
            }
            _ = files[id]?.comments.removeValue(forKey: commentID)
        }
    }
}

// MARK: - Pins
extension Client {
    func pinAdded(_ event: Event) {
        guard
            let id = event.channelID,
            let item = event.item
        else {
            return
        }
        channels[id]?.pinnedItems.append(item)
    }

    func pinRemoved(_ event: Event) {
        guard
            let id = event.channelID,
            let item = event.item
        else {
            return
        }
        if let pins = channels[id]?.pinnedItems.filter({$0 != item}) {
            channels[id]?.pinnedItems = pins
        }
    }
}

// MARK: - Stars
extension Client {
    func itemStarred(_ event: Event, star: Bool) {
        guard
            let item = event.item,
            let type = item.type
        else {
            return
        }
        switch type {
        case "message":
            starMessage(item, star: star)
        case "file":
            starFile(item, star: star)
        case "file_comment":
            starComment(item)
        default:
            break
        }
    }

    func starMessage(_ item: Item, star: Bool) {
        guard
            let message = item.message,
            let ts = message.ts,
            let channel = item.channel,
            channels[channel]?.messages[ts] != nil
        else {
            return
        }
        channels[channel]?.messages[ts]?.isStarred = star
    }

    func starFile(_ item: Item, star: Bool) {
        guard
            let file = item.file,
            let id = file.id
        else {
            return
        }
        files[id]?.isStarred = star
        if let stars = files[id]?.stars {
            if star == true {
                files[id]?.stars = stars + 1
            } else {
                if stars > 0 {
                    files[id]?.stars = stars - 1
                }
            }
        }
    }

    func starComment(_ item: Item) {
        guard
            let file = item.file,
            let id = file.id,
            let comment = item.comment,
            let commentID = comment.id
        else {
            return
        }
        files[id]?.comments[commentID] = comment
    }
}

// MARK: - Reactions
extension Client {
    func addedReaction(_ event: Event) {
        guard
            let item = event.item,
            let type = item.type,
            let reaction = event.reaction,
            let userID = event.user?.id
        else {
            return
        }
        switch type {
        case "message":
            guard
                let channel = item.channel,
                let ts = item.ts,
                let message = channels[channel]?.messages[ts]
            else {
                return
            }
            message.reactions.append(Reaction(name: reaction, user: userID))
        case "file":
            guard let id = item.file?.id else {
                return
            }
            files[id]?.reactions.append(Reaction(name: reaction, user: userID))
        case "file_comment":
            guard
                let id = item.file?.id,
                let commentID = item.fileCommentID
            else {
                return
            }
            files[id]?.comments[commentID]?.reactions.append(Reaction(name: reaction, user: userID))
        default:
            break
        }
    }

    func removedReaction(_ event: Event) {
        guard
            let item = event.item,
            let type = item.type,
            let key = event.reaction,
            let userID = event.user?.id
        else {
            return
        }
        switch type {
        case "message":
            guard
                let channel = item.channel,
                let ts = item.ts,
                let message = channels[channel]?.messages[ts]
            else {
                return
            }
            message.reactions = message.reactions.filter({$0.name != key && $0.user != userID})
        case "file":
            guard
                let itemFile = item.file,
                let id = itemFile.id
            else {
                return
            }
            files[id]?.reactions = files[id]!.reactions.filter({$0.name != key && $0.user != userID})
        case "file_comment":
            guard
                let id = item.file?.id,
                let commentID = item.fileCommentID
            else {
                return
            }
            files[id]?.comments[commentID]?.reactions = files[id]!.comments[commentID]!.reactions.filter({$0.name != key && $0.user != userID})
        default:
            break
        }
    }
}

// MARK: - Preferences
extension Client {
    func changePreference(_ event: Event) {
        guard let name = event.name else {
            return
        }
        authenticatedUser?.preferences?[name] = event.value
    }
}

// MARK: - User Change
extension Client {
    func userChange(_ event: Event) {
        guard
            let user = event.user,
            let id = user.id
        else {
            return
        }
        let preferences = users[id]?.preferences
        users[id] = user
        users[id]?.preferences = preferences
    }
}

// MARK: - User Presence
extension Client {
    func presenceChange(_ event: Event) {
        guard
            let user = event.user,
            let id = user.id
        else {
            return
        }
        users[id]?.presence = event.presence
    }
}

// MARK: - Team
extension Client {
    func teamJoin(_ event: Event) {
        guard
            let user = event.user,
            let id = user.id
        else {
            return
        }
        users[id] = user
    }

    func teamPlanChange(_ event: Event) {
        guard let plan = event.plan else {
            return
        }
        team?.plan = plan
    }

    func teamPreferenceChange(_ event: Event) {
        guard let name = event.name else {
            return
        }
        team?.prefs?[name] = event.value
    }

    func teamNameChange(_ event: Event) {
        guard let name = event.name else {
            return
        }
        team?.name = name
    }

    func teamDomainChange(_ event: Event) {
        guard let domain = event.domain else {
            return
        }
        team?.domain = domain
    }

    func emailDomainChange(_ event: Event) {
        guard let domain = event.emailDomain else {
            return
        }
        team?.emailDomain = domain
    }

    func emojiChanged(_ event: Event) {}
}

// MARK: - Bots
extension Client {
    func bot(_ event: Event) {
        guard
            let bot = event.bot,
            let id = bot.id
        else {
            return
        }
        bots[id] = bot
    }
}

// MARK: - Subteams
extension Client {
    func subteam(_ event: Event) {
        guard
            let subteam = event.subteam,
            let id = subteam.id
        else {
            return
        }
        userGroups[id] = subteam
    }

    func subteamAddedSelf(_ event: Event) {
        guard
            let subteamID = event.subteamID,
            authenticatedUser?.userGroups != nil
        else {
            return
        }
        authenticatedUser?.userGroups![subteamID] = subteamID
    }

    func subteamRemovedSelf(_ event: Event) {
        guard let subteamID = event.subteamID else {
            return
        }
        _ = authenticatedUser?.userGroups?.removeValue(forKey: subteamID)
    }
}

// MARK: - Team Profiles
extension Client {
    func teamProfileChange(_ event: Event) {
        guard let profile = event.profile else {
            return
        }
        for user in users {
            for key in profile.fields.keys {
                users[user.0]?.profile?.customProfile?.fields[key]?.updateProfileField(profile.fields[key])
            }
        }
    }

    func teamProfileDeleted(_ event: Event) {
        guard let profile = event.profile else {
            return
        }
        for user in users {
            if let id = profile.fields.first?.0 {
                users[user.0]?.profile?.customProfile?.fields[id] = nil
            }
        }
    }

    func teamProfileReordered(_ event: Event) {
        guard let profile = event.profile else {
            return
        }
        for user in users {
            for key in profile.fields.keys {
                users[user.0]?.profile?.customProfile?.fields[key]?.ordering = profile.fields[key]?.ordering
            }
        }
    }
}

// MARK: - Authenticated User
extension Client {
    func manualPresenceChange(_ event: Event) {
        guard let presence = event.presence else {
            return
        }
        authenticatedUser?.presence = presence
    }
}

// MARK: - Utilities
public extension Client {
    fileprivate func addUser(_ aUser: [String: Any]) {
        let user = User(user: aUser)
        if let id = user.id {
            users[id] = user
        }
    }

    fileprivate func addChannel(_ aChannel: [String: Any]) {
        let channel = Channel(channel: aChannel)
        if let id = channel.id {
            channels[id] = channel
        }
    }

    fileprivate func addBot(_ aBot: [String: Any]) {
        let bot = Bot(bot: aBot)
        if let id = bot.id {
            bots[id] = bot
        }
    }

    fileprivate func enumerateSubteams(_ subteams: [String: Any]?) {
        if let subteams = subteams {
            if let all = subteams["all"] as? [[String: Any]] {
                for item in all {
                    let u = UserGroup(userGroup: item)
                    if let id = u.id {
                        self.userGroups[id] = u
                    }
                }
            }
            if let auth = subteams["self"] as? [String] {
                for item in auth {
                    authenticatedUser?.userGroups = [String: String]()
                    authenticatedUser?.userGroups?[item] = item
                }
            }
        }
    }

    fileprivate func enumerateObjects(_ array: [Any]?, initalizer: ([String: Any]) -> Void) {
        if let array = array {
            for object in array {
                if let dictionary = object as? [String: Any] {
                    initalizer(dictionary)
                }
            }
        }
    }
}