/*
 *  Copyright (C) 2021-2022 Savoir-faire Linux Inc.
 *
 *  Author: Kateryna Kostiuk <kateryna.kostiuk@savoirfairelinux.com>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.
 */

import Foundation
import UIKit
import MobileCoreServices
import Photos
import os

class AdapterService {
    enum InteractionAttributes: String {
        case interactionId = "id"
        case type = "type"
        case invited = "invited"
        case fileId = "fileId"
        case displayName = "displayName"
        case body = "body"
        case author = "author"
        case timestamp = "timestamp"
        case parent = "linearizedParent"
        case action = "action"
        case duration = "duration"
    }

    enum InteractionType: String {
        case message = "text/plain"
        case fileTransfer = "application/data-transfer+json"
    }

    enum EventType: Int {
        case message
        case fileTransferDone
        case fileTransferInProgress
        case syncCompleted
        case call
        case invitation
    }

    enum PeerConnectionRequestType {
        case call(peerId: String, isVideo: Bool)
        case gitMessage
        case unknown
    }

    enum DataTransferEventCode: Int {
        case invalid
        case created
        case unsupported
        case waitPeeracceptance
        case waitHostAcceptance
        case ongoing
        case finished
        case closedByHost
        case closedByPeer
        case invalidPathname
        case unjoinablePeer

        func isCompleted() -> Bool {
            switch self {
            case .finished, .closedByHost, .closedByPeer, .unjoinablePeer, .invalidPathname:
                return true
            default:
                return false
            }
        }
    }

    private let maxSizeForAutoaccept = 20 * 1024 * 1024

    private let adapter: Adapter
    var eventHandler: ((EventType, EventData) -> Void)?
    var loadingFiles = [String: EventData]()

    init(withAdapter adapter: Adapter) {
        self.adapter = adapter
        Adapter.delegate = self
    }

    func startAccountsWithListener(accountId: String, listener: @escaping (EventType, EventData) -> Void) {
        self.eventHandler = listener
        start(accountId: accountId)
    }

    func decrypt(keyPath: String, messagesPath: String, value: [String: Any]) -> PeerConnectionRequestType {
        let result = adapter.decrypt(keyPath, treated: messagesPath, value: value)
        guard let peerId = result?.keys.first,
              let type = result?.values.first else {
            return .unknown}
        switch type {
        case "videoCall":
            return PeerConnectionRequestType.call(peerId: peerId, isVideo: true)
        case "audioCall":
            return PeerConnectionRequestType.call(peerId: peerId, isVideo: false)
        case "text/plain", "application/im-gitmessage-id":
            return PeerConnectionRequestType.gitMessage
        default:
            return .unknown
        }
    }

    func start(accountId: String) {
        self.adapter.start(accountId)
    }

    func stop() {
        self.adapter.stop()
    }

    func getNameFor(address: String, accountId: String) -> String {
        return adapter.getNameFor(address, accountId: accountId)
    }

    func getNameServerFor(accountId: String) -> String {
        return adapter.nameServer(forAccountId: accountId)
    }

    private func fileAlreadyDownloaded(fileName: String, accountId: String, conversationId: String) -> Bool {
        guard let url = getFileUrlFor(fileName: fileName, accountId: accountId, conversationId: conversationId) else {
            return false
        }
        return FileManager.default.fileExists(atPath: url.path)
    }

    private func getFileUrlFor(fileName: String, accountId: String, conversationId: String) -> URL? {
        guard let documentsURL = Constants.documentsPath else {
            return nil
        }
        let pathUrl = documentsURL.appendingPathComponent(accountId)
            .appendingPathComponent("conversation_data")
            .appendingPathComponent(conversationId)
            .appendingPathComponent(fileName)
        return pathUrl
    }
}

extension AdapterService: AdapterDelegate {

    func didReceiveMessage(_ message: [String: String],
                           from senderAccount: String,
                           messageId: String,
                           to receiverAccountId: String) {
        guard let content = message["text/plain"],
              let handler = self.eventHandler else { return }
        handler(.message, EventData(accountId: receiverAccountId, jamiId: senderAccount, conversationId: "", content: content, groupTitle: ""))
    }

    func dataTransferEvent(withFileId transferId: String, withEventCode eventCode: Int, accountId: String, conversationId: String, interactionId: String) {
        guard let handler = self.eventHandler,
              let data = loadingFiles[transferId],
              let code = DataTransferEventCode(rawValue: eventCode),
              code.isCompleted() else { return }
        handler(.fileTransferDone, data)
        loadingFiles.removeValue(forKey: transferId)
    }

    func conversationSyncCompleted(accountId: String) {
        guard let handler = self.eventHandler else {
            return
        }
        handler(.syncCompleted, EventData(accountId: accountId))
    }

    func receivedCallConnectionRequest(accountId: String, peerId: String, hasVideo: Bool) {
        guard let handler = self.eventHandler else {
            return
        }
        handler(.call, EventData(accountId: accountId, jamiId: peerId, content: "\(hasVideo)"))
    }

    func receivedContactRequest(accountId: String, peerId: String) {
        /// TODO add invitation notification
    }

    func receivedConversationRequest(accountId: String, conversationId: String, metadata: [String: String]) {
        guard let handler = self.eventHandler else {
            return
        }
        let contentMessage = L10n.GeneratedMessage.invitationReceived
        var groupTitle = ""
        var peerId = ""
        if let title = metadata["title"], !title.isEmpty {
            groupTitle = title
        }
        if let from = metadata["from"] {
            peerId = from
        }
        if !peerId.isEmpty || !groupTitle.isEmpty {
            handler(.invitation, EventData(accountId: accountId, jamiId: peerId, conversationId: conversationId, content: contentMessage, groupTitle: groupTitle))
        }
    }

    func newInteraction(conversationId: String, accountId: String, message: [String: String]) {
        guard let handler = self.eventHandler else {
            return
        }
        guard let type = message[InteractionAttributes.type.rawValue],
              let interactionType = InteractionType(rawValue: type) else {
            return
        }
        let from = message[InteractionAttributes.author.rawValue] ?? ""
        let content = message[InteractionAttributes.body.rawValue] ?? ""
        switch interactionType {
        case .message:
            handler(.message, EventData(accountId: accountId, jamiId: from, conversationId: conversationId, content: content, groupTitle: ""))
        case.fileTransfer:
            guard let fileId = message[InteractionAttributes.fileId.rawValue],
                  let url = self.getFileUrlFor(fileName: fileId, accountId: accountId, conversationId: conversationId) else {
                return
            }
            let data = EventData(accountId: accountId, jamiId: from, conversationId: conversationId, content: url.path, groupTitle: "")
            // check if the file has already been downloaded. If no, download the file if filesize is less than a downloading limit
            if fileAlreadyDownloaded(fileName: fileId, accountId: accountId, conversationId: conversationId) {
                handler(.fileTransferDone, data)
            } else {
                guard let interactionId = message[InteractionAttributes.interactionId.rawValue],
                      let size = message["totalSize"],
                      (Int(size) ?? (maxSizeForAutoaccept + 1)) <= maxSizeForAutoaccept else { return }
                let path = ""
                self.adapter.downloadFile(withFileId: fileId, accountId: accountId, conversationId: conversationId, interactionId: interactionId, withFilePath: path)
                self.loadingFiles[fileId] = data
                handler(.fileTransferInProgress, data)
            }
        }
    }
}