//
//  NCFiles.swift
//  Nextcloud
//
//  Created by Marino Faggiana on 26/09/2020.
//  Copyright © 2020 Marino Faggiana. All rights reserved.
//
//  Author Marino Faggiana <marino.faggiana@nextcloud.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, see <http://www.gnu.org/licenses/>.
//

import UIKit
import NextcloudKit
import RealmSwift

class NCFiles: NCCollectionViewCommon {
    internal var isRoot: Bool = true
    internal var fileNameBlink: String?
    internal var fileNameOpen: String?
    internal var matadatasHash: String = ""

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)

        titleCurrentFolder = NCBrandOptions.shared.brand
        layoutKey = NCGlobal.shared.layoutViewFiles
        enableSearchBar = true
        headerRichWorkspaceDisable = false
        headerMenuTransferView = true
        emptyTitle = "_files_no_files_"
        emptyDescription = "_no_file_pull_down_"
    }

    // MARK: - View Life Cycle

    override func viewDidLoad() {
        super.viewDidLoad()

        if isRoot {
            NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: NCGlobal.shared.notificationCenterChangeUser), object: nil, queue: nil) { notification in

                if let userInfo = notification.userInfo, let account = userInfo["account"] as? String {
                    if let controller = userInfo["controller"] as? NCMainTabBarController,
                       controller == self.controller {
                        controller.account = account
                    } else {
                        return
                    }
                }

                self.navigationController?.popToRootViewController(animated: false)
                self.serverUrl = self.utilityFileSystem.getHomeServer(session: self.session)
                self.isSearchingMode = false
                self.isEditMode = false
                self.fileSelect.removeAll()
                self.layoutForView = self.database.getLayoutForView(account: self.session.account, key: self.layoutKey, serverUrl: self.serverUrl)

                if self.isLayoutList {
                    self.collectionView?.collectionViewLayout = self.listLayout
                } else if self.isLayoutGrid {
                    self.collectionView?.collectionViewLayout = self.gridLayout
                } else if self.isLayoutPhoto {
                    self.collectionView?.collectionViewLayout = self.mediaLayout
                }

                self.titleCurrentFolder = self.getNavigationTitle()
                self.setNavigationLeftItems()

                self.dataSource.removeAll()
                self.reloadDataSource()
                self.getServerData()
            }
        }
    }

    override func viewWillAppear(_ animated: Bool) {
        if isRoot {
            serverUrl = utilityFileSystem.getHomeServer(session: session)
            titleCurrentFolder = getNavigationTitle()
        }
        super.viewWillAppear(animated)

        reloadDataSource()
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        if !self.dataSource.isEmpty() {
            self.blinkCell(fileName: self.fileNameBlink)
            self.openFile(fileName: self.fileNameOpen)
            self.fileNameBlink = nil
            self.fileNameOpen = nil
        }

        if !isSearchingMode {
            getServerData()
        }
    }

    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)

        fileNameBlink = nil
        fileNameOpen = nil
    }

    // MARK: - DataSource

    override func reloadDataSource() {
        guard !isSearchingMode else {
            return super.reloadDataSource()
        }

        var predicate = self.defaultPredicate
        let predicateDirectory = NSPredicate(format: "account == %@ AND serverUrl == %@", session.account, self.serverUrl)
        let dataSourceMetadatas = self.dataSource.getMetadatas()

        if NCKeychain().getPersonalFilesOnly(account: session.account) {
            predicate = NSPredicate(format: "account == %@ AND serverUrl == %@ AND (ownerId == %@ || ownerId == '') AND mountType == '' AND NOT (status IN %@)", session.account, self.serverUrl, session.userId, global.metadataStatusHideInView)
        }

        self.metadataFolder = database.getMetadataFolder(session: session, serverUrl: self.serverUrl)
        self.richWorkspaceText = database.getTableDirectory(predicate: predicateDirectory)?.richWorkspace

        let metadatas = self.database.getResultsMetadatasPredicate(predicate, layoutForView: layoutForView)

        self.dataSource = NCCollectionViewDataSource(metadatas: metadatas, layoutForView: layoutForView)

        if metadatas.isEmpty {
            return super.reloadDataSource()
        }

        self.dataSource.caching(metadatas: metadatas, dataSourceMetadatas: dataSourceMetadatas) { updated in
            if updated || self.isNumberOfItemsInAllSectionsNull || self.numberOfItemsInAllSections != metadatas.count {
                super.reloadDataSource()
            }
        }
    }

    override func getServerData() {
        if UIApplication.shared.applicationState == .background {
            NextcloudKit.shared.nkCommonInstance.writeLog("[DEBUG] Files not reload datasource network with the application in background")
            return
        }
        guard !isSearchingMode else {
            return networkSearch()
        }

        func downloadMetadata(_ metadata: tableMetadata) -> Bool {
            let fileSize = utilityFileSystem.fileProviderStorageSize(metadata.ocId, fileNameView: metadata.fileNameView)
            guard fileSize > 0 else { return false }

            if let localFile = database.getResultsTableLocalFile(predicate: NSPredicate(format: "ocId == %@", metadata.ocId))?.first {
                if localFile.etag != metadata.etag {
                    return true
                }
            }
            return false
        }

        DispatchQueue.global().async {
            self.networkReadFolder { metadatas, isChanged, error in
                DispatchQueue.main.async {
                    self.refreshControl.endRefreshing()

                    if isChanged || self.isNumberOfItemsInAllSectionsNull {
                        self.reloadDataSource()
                    }
                }

                if error == .success {
                    let metadatas: [tableMetadata] = metadatas ?? self.dataSource.getMetadatas()
                    for metadata in metadatas where !metadata.directory && downloadMetadata(metadata) {
                        if NCNetworking.shared.downloadQueue.operations.filter({ ($0 as? NCOperationDownload)?.metadata.ocId == metadata.ocId }).isEmpty {
                            NCNetworking.shared.downloadQueue.addOperation(NCOperationDownload(metadata: metadata, selector: NCGlobal.shared.selectorDownloadFile))
                        }
                    }
                }
            }
        }
    }

    private func networkReadFolder(completion: @escaping (_ metadatas: [tableMetadata]?, _ isDataChanged: Bool, _ error: NKError) -> Void) {
        NCNetworking.shared.readFile(serverUrlFileName: serverUrl, account: session.account) { task in
            self.dataSourceTask = task
            if self.dataSource.isEmpty() {
                self.collectionView.reloadData()
            }
        } completion: { account, metadata, error in
            let isDirectoryE2EE = NCUtilityFileSystem().isDirectoryE2EE(session: self.session, serverUrl: self.serverUrl)
            guard error == .success, let metadata else {
                return completion(nil, false, error)
            }
            /// Check change eTag or E2EE  or DataSource empty
            self.database.updateDirectoryRichWorkspace(metadata.richWorkspace, account: account, serverUrl: self.serverUrl)
            let tableDirectory = self.database.getTableDirectory(ocId: metadata.ocId)
            guard tableDirectory?.etag != metadata.etag || metadata.e2eEncrypted || self.dataSource.isEmpty() else {
                return completion(nil, false, NKError())
            }
            /// Check Response DataC hanged
            var checkResponseDataChanged = true
            if tableDirectory?.etag.isEmpty ?? true || isDirectoryE2EE {
                checkResponseDataChanged = false
            }

            NCNetworking.shared.readFolder(serverUrl: self.serverUrl,
                                           account: metadata.account,
                                           checkResponseDataChanged: checkResponseDataChanged,
                                           queue: NextcloudKit.shared.nkCommonInstance.backgroundQueue) { task in
                self.dataSourceTask = task
                if self.dataSource.isEmpty() {
                    self.collectionView.reloadData()
                }
            } completion: { account, metadataFolder, metadatas, isDataChanged, error in
                /// Error
                guard error == .success else {
                    return completion(nil, false, error)
                }
                /// Updata folder
                if let metadataFolder {
                    self.metadataFolder = metadataFolder
                    self.richWorkspaceText = metadataFolder.richWorkspace
                }
                /// check Response Data Changed
                if !isDataChanged {
                    return completion(nil, false, error)
                }

                guard let metadataFolder,
                      isDirectoryE2EE,
                      NCKeychain().isEndToEndEnabled(account: account),
                      !NCNetworkingE2EE().isInUpload(account: account, serverUrl: self.serverUrl) else {
                    return completion(metadatas, true, error)
                }

                /// E2EE
                let lock = self.database.getE2ETokenLock(account: account, serverUrl: self.serverUrl)
                NCNetworkingE2EE().getMetadata(fileId: metadataFolder.ocId, e2eToken: lock?.e2eToken, account: account) { account, version, e2eMetadata, signature, _, error in

                    if error == .success, let e2eMetadata = e2eMetadata {
                        let error = NCEndToEndMetadata().decodeMetadata(e2eMetadata, signature: signature, serverUrl: self.serverUrl, session: self.session)

                        if error == .success {
                            if version == "v1", NCCapabilities.shared.getCapabilities(account: account).capabilityE2EEApiVersion == NCGlobal.shared.e2eeVersionV20 {
                                NextcloudKit.shared.nkCommonInstance.writeLog("[E2EE] Conversion v1 to v2")
                                NCActivityIndicator.shared.start()
                                Task {
                                    let serverUrl = metadataFolder.serverUrl + "/" + metadataFolder.fileName
                                    let error = await NCNetworkingE2EE().uploadMetadata(serverUrl: serverUrl, updateVersionV1V2: true, account: account)
                                    if error != .success {
                                        NCContentPresenter().showError(error: error)
                                    }
                                    NCActivityIndicator.shared.stop()
                                }
                            }
                        } else {
                            // Client Diagnostic
                            self.database.addDiagnostic(account: account, issue: NCGlobal.shared.diagnosticIssueE2eeErrors)
                            NCContentPresenter().showError(error: error)
                        }
                    } else if error.errorCode == NCGlobal.shared.errorResourceNotFound {
                        // no metadata found, send a new metadata
                        Task {
                            let serverUrl = metadataFolder.serverUrl + "/" + metadataFolder.fileName
                            let error = await NCNetworkingE2EE().uploadMetadata(serverUrl: serverUrl, account: account)
                            if error != .success {
                                NCContentPresenter().showError(error: error)
                            }
                        }
                    } else {
                        NCContentPresenter().showError(error: NKError(errorCode: NCGlobal.shared.errorE2EEKeyDecodeMetadata, errorDescription: "_e2e_error_"))
                    }
                    completion(metadatas, true, error)
                }
            }
        }
    }

    func blinkCell(fileName: String?) {
        if let fileName = fileName, let metadata = database.getMetadata(predicate: NSPredicate(format: "account == %@ AND serverUrl == %@ AND fileName == %@", session.account, self.serverUrl, fileName)) {
            let indexPath = self.dataSource.getIndexPathMetadata(ocId: metadata.ocId)
            if let indexPath = indexPath {
                DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                    UIView.animate(withDuration: 0.3) {
                        self.collectionView.scrollToItem(at: indexPath, at: .centeredVertically, animated: false)
                    } completion: { _ in
                        if let cell = self.collectionView.cellForItem(at: indexPath) {
                            cell.backgroundColor = .darkGray
                            UIView.animate(withDuration: 2) {
                                cell.backgroundColor = .clear
                            }
                        }
                    }
                }
            }
        }
    }

    func openFile(fileName: String?) {
        if let fileName = fileName, let metadata = database.getMetadata(predicate: NSPredicate(format: "account == %@ AND serverUrl == %@ AND fileName == %@", session.account, self.serverUrl, fileName)) {
            let indexPath = self.dataSource.getIndexPathMetadata(ocId: metadata.ocId)
            if let indexPath = indexPath {
                DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                    self.collectionView(self.collectionView, didSelectItemAt: indexPath)
                }
            }
        }
    }

    // MARK: - NCAccountSettingsModelDelegate

    override func accountSettingsDidDismiss(tableAccount: tableAccount?, controller: NCMainTabBarController?) {
        let currentAccount = session.account
        if database.getAllTableAccount().isEmpty {
            appDelegate.openLogin(selector: NCGlobal.shared.introLogin)
        } else if let account = tableAccount?.account, account != currentAccount {
            NCAccount().changeAccount(account, userProfile: nil, controller: controller) { }
        } else if isRoot {
            titleCurrentFolder = getNavigationTitle()
            navigationItem.title = titleCurrentFolder
        }
    }
}