// (C) Copyright 2015 Martin Dougiamas
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import { Injectable, Injector } from '@angular/core';
import { CoreFileProvider } from '@providers/file';
import { CoreFileSessionProvider } from '@providers/file-session';
import { CoreFilepoolProvider } from '@providers/filepool';
import { CoreSitesProvider } from '@providers/sites';
import { CoreWSProvider } from '@providers/ws';
import { CoreUtilsProvider } from '@providers/utils/utils';
import { CoreFileUploaderProvider } from '@core/fileuploader/providers/fileuploader';
import { AddonModAssignProvider } from '../../../providers/assign';
import { AddonModAssignOfflineProvider } from '../../../providers/assign-offline';
import { AddonModAssignHelperProvider } from '../../../providers/helper';
import { AddonModAssignSubmissionHandler } from '../../../providers/submission-delegate';
import { AddonModAssignSubmissionFileComponent } from '../component/file';

/**
 * Handler for file submission plugin.
 */
@Injectable()
export class AddonModAssignSubmissionFileHandler implements AddonModAssignSubmissionHandler {
    static FOLDER_NAME = 'submission_file';

    name = 'AddonModAssignSubmissionFileHandler';
    type = 'file';

    constructor(private sitesProvider: CoreSitesProvider, private wsProvider: CoreWSProvider,
        private assignProvider: AddonModAssignProvider, private assignOfflineProvider: AddonModAssignOfflineProvider,
        private assignHelper: AddonModAssignHelperProvider, private fileSessionProvider: CoreFileSessionProvider,
        private fileUploaderProvider: CoreFileUploaderProvider, private filepoolProvider: CoreFilepoolProvider,
        private fileProvider: CoreFileProvider, private utils: CoreUtilsProvider) { }

    /**
     * Whether the plugin can be edited in offline for existing submissions. In general, this should return false if the
     * plugin uses Moodle filters. The reason is that the app only prefetches filtered data, and the user should edit
     * unfiltered data.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @return {boolean|Promise<boolean>} Boolean or promise resolved with boolean: whether it can be edited in offline.
     */
    canEditOffline(assign: any, submission: any, plugin: any): boolean | Promise<boolean> {
        // This plugin doesn't use Moodle filters, it can be edited in offline.
        return true;
    }

    /**
     * Should clear temporary data for a cancelled submission.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} inputData Data entered by the user for the submission.
     */
    clearTmpData(assign: any, submission: any, plugin: any, inputData: any): void {
        const files = this.fileSessionProvider.getFiles(AddonModAssignProvider.COMPONENT, assign.id);

        // Clear the files in session for this assign.
        this.fileSessionProvider.clearFiles(AddonModAssignProvider.COMPONENT, assign.id);

        // Now delete the local files from the tmp folder.
        this.fileUploaderProvider.clearTmpFiles(files);
    }

    /**
     * This function will be called when the user wants to create a new submission based on the previous one.
     * It should add to pluginData the data to send to server based in the data in plugin (previous attempt).
     *
     * @param {any} assign The assignment.
     * @param {any} plugin The plugin object.
     * @param {any} pluginData Object where to store the data to send.
     * @param {number} [userId] User ID. If not defined, site's current user.
     * @param {string} [siteId] Site ID. If not defined, current site.
     * @return {void|Promise<any>} If the function is async, it should return a Promise resolved when done.
     */
    copySubmissionData(assign: any, plugin: any, pluginData: any, userId?: number, siteId?: string): void | Promise<any> {
        // We need to re-upload all the existing files.
        const files = this.assignProvider.getSubmissionPluginAttachments(plugin);

        return this.assignHelper.uploadFiles(assign.id, files).then((itemId) => {
            pluginData.files_filemanager = itemId;
        });
    }

    /**
     * Return the Component to use to display the plugin data, either in read or in edit mode.
     * It's recommended to return the class of the component, but you can also return an instance of the component.
     *
     * @param {Injector} injector Injector.
     * @param {any} plugin The plugin object.
     * @param {boolean} [edit] Whether the user is editing.
     * @return {any|Promise<any>} The component (or promise resolved with component) to use, undefined if not found.
     */
    getComponent(injector: Injector, plugin: any, edit?: boolean): any | Promise<any> {
        return AddonModAssignSubmissionFileComponent;
    }

    /**
     * Delete any stored data for the plugin and submission.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} offlineData Offline data stored.
     * @param {string} [siteId] Site ID. If not defined, current site.
     * @return {void|Promise<any>} If the function is async, it should return a Promise resolved when done.
     */
    deleteOfflineData(assign: any, submission: any, plugin: any, offlineData: any, siteId?: string): void | Promise<any> {
        return this.assignHelper.deleteStoredSubmissionFiles(assign.id, AddonModAssignSubmissionFileHandler.FOLDER_NAME,
                submission.userid, siteId).catch(() => {
            // Ignore errors, maybe the folder doesn't exist.
        });
    }

    /**
     * Get files used by this plugin.
     * The files returned by this function will be prefetched when the user prefetches the assign.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {string} [siteId] Site ID. If not defined, current site.
     * @return {any[]|Promise<any[]>} The files (or promise resolved with the files).
     */
    getPluginFiles(assign: any, submission: any, plugin: any, siteId?: string): any[] | Promise<any[]> {
        return this.assignProvider.getSubmissionPluginAttachments(plugin);
    }

    /**
     * Get the size of data (in bytes) this plugin will send to copy a previous submission.
     *
     * @param {any} assign The assignment.
     * @param {any} plugin The plugin object.
     * @return {number|Promise<number>} The size (or promise resolved with size).
     */
    getSizeForCopy(assign: any, plugin: any): number | Promise<number> {
        const files = this.assignProvider.getSubmissionPluginAttachments(plugin),
            promises = [];
        let totalSize = 0;

        files.forEach((file) => {
            promises.push(this.wsProvider.getRemoteFileSize(file.fileurl).then((size) => {
                if (size == -1) {
                    // Couldn't determine the size, reject.
                    return Promise.reject(null);
                }

                totalSize += size;
            }));
        });

        return Promise.all(promises).then(() => {
            return totalSize;
        });
    }

    /**
     * Get the size of data (in bytes) this plugin will send to add or edit a submission.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} inputData Data entered by the user for the submission.
     * @return {number|Promise<number>} The size (or promise resolved with size).
     */
    getSizeForEdit(assign: any, submission: any, plugin: any, inputData: any): number | Promise<number> {
        const siteId = this.sitesProvider.getCurrentSiteId();

        // Check if there's any change.
        if (this.hasDataChanged(assign, submission, plugin, inputData)) {
            const files = this.fileSessionProvider.getFiles(AddonModAssignProvider.COMPONENT, assign.id),
                promises = [];
            let totalSize = 0;

            files.forEach((file) => {
                if (file.filename && !file.name) {
                    // It's a remote file. First check if we have the file downloaded since it's more reliable.
                    promises.push(this.filepoolProvider.getFilePathByUrl(siteId, file.fileurl).then((path) => {
                        return this.fileProvider.getFile(path).then((fileEntry) => {
                            return this.fileProvider.getFileObjectFromFileEntry(fileEntry);
                        }).then((file) => {
                            totalSize += file.size;
                        });
                    }).catch(() => {
                        // Error getting the file, maybe it's not downloaded. Get remote size.
                        return this.wsProvider.getRemoteFileSize(file.fileurl).then((size) => {
                            if (size == -1) {
                                // Couldn't determine the size, reject.
                                return Promise.reject(null);
                            }

                            totalSize += size;
                        });
                    }));
                } else if (file.name) {
                    // It's a local file, get its size.
                    promises.push(this.fileProvider.getFileObjectFromFileEntry(file).then((file) => {
                        totalSize += file.size;
                    }));
                }
            });

            return Promise.all(promises).then(() => {
                return totalSize;
            });
        } else {
            // Nothing has changed, we won't upload any file.
            return 0;
        }
    }

    /**
     * Check if the submission data has changed for this plugin.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} inputData Data entered by the user for the submission.
     * @return {boolean|Promise<boolean>} Boolean (or promise resolved with boolean): whether the data has changed.
     */
    hasDataChanged(assign: any, submission: any, plugin: any, inputData: any): boolean | Promise<boolean> {
        // Check if there's any offline data.
        return this.assignOfflineProvider.getSubmission(assign.id, submission.userid).catch(() => {
            // No offline data found.
        }).then((offlineData) => {
            if (offlineData && offlineData.plugindata && offlineData.plugindata.files_filemanager) {
                // Has offline data, return the number of files.
                return offlineData.plugindata.files_filemanager.offline + offlineData.plugindata.files_filemanager.online.length;
            }

            // No offline data, return the number of online files.
            const pluginFiles = this.assignProvider.getSubmissionPluginAttachments(plugin);

            return pluginFiles && pluginFiles.length;
        }).then((numFiles) => {
            const currentFiles = this.fileSessionProvider.getFiles(AddonModAssignProvider.COMPONENT, assign.id);

            if (currentFiles.length != numFiles) {
                // Number of files has changed.
                return true;
            }

            // Search if there is any local file added.
            for (let i = 0; i < currentFiles.length; i++) {
                const file = currentFiles[i];
                if (!file.filename && typeof file.name != 'undefined' && !file.offline) {
                    // There's a local file added, list has changed.
                    return true;
                }
            }

            // No local files and list length is the same, this means the list hasn't changed.
            return false;
        });
    }

    /**
     * Whether or not the handler is enabled on a site level.
     *
     * @return {boolean|Promise<boolean>} True or promise resolved with true if enabled.
     */
    isEnabled(): boolean | Promise<boolean> {
        return true;
    }

    /**
     * Whether or not the handler is enabled for edit on a site level.
     *
     * @return {boolean|Promise<boolean>} Whether or not the handler is enabled for edit on a site level.
     */
    isEnabledForEdit(): boolean | Promise<boolean> {
        return true;
    }

    /**
     * Prepare and add to pluginData the data to send to the server based on the input data.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} inputData Data entered by the user for the submission.
     * @param {any} pluginData Object where to store the data to send.
     * @param {boolean} [offline] Whether the user is editing in offline.
     * @param {number} [userId] User ID. If not defined, site's current user.
     * @param {string} [siteId] Site ID. If not defined, current site.
     * @return {void|Promise<any>} If the function is async, it should return a Promise resolved when done.
     */
    prepareSubmissionData(assign: any, submission: any, plugin: any, inputData: any, pluginData: any, offline?: boolean,
            userId?: number, siteId?: string): void | Promise<any> {

        if (this.hasDataChanged(assign, submission, plugin, inputData)) {
            // Data has changed, we need to upload new files and re-upload all the existing files.
            const currentFiles = this.fileSessionProvider.getFiles(AddonModAssignProvider.COMPONENT, assign.id),
                error = this.utils.hasRepeatedFilenames(currentFiles);

            if (error) {
                return Promise.reject(error);
            }

            return this.assignHelper.uploadOrStoreFiles(assign.id, AddonModAssignSubmissionFileHandler.FOLDER_NAME,
                    currentFiles, offline, userId, siteId).then((result) => {
                pluginData.files_filemanager = result;
            });
        }
    }

    /**
     * Prepare and add to pluginData the data to send to the server based on the offline data stored.
     * This will be used when performing a synchronization.
     *
     * @param {any} assign The assignment.
     * @param {any} submission The submission.
     * @param {any} plugin The plugin object.
     * @param {any} offlineData Offline data stored.
     * @param {any} pluginData Object where to store the data to send.
     * @param {string} [siteId] Site ID. If not defined, current site.
     * @return {void|Promise<any>} If the function is async, it should return a Promise resolved when done.
     */
    prepareSyncData(assign: any, submission: any, plugin: any, offlineData: any, pluginData: any, siteId?: string)
            : void | Promise<any> {

        const filesData = offlineData && offlineData.plugindata && offlineData.plugindata.files_filemanager;
        if (filesData) {
            // Has some data to sync.
            let files = filesData.online || [],
                promise;

            if (filesData.offline) {
                // Has offline files, get them and add them to the list.
                promise = this.assignHelper.getStoredSubmissionFiles(assign.id, AddonModAssignSubmissionFileHandler.FOLDER_NAME,
                        submission.userid, siteId).then((result) => {
                    files = files.concat(result);
                }).catch(() => {
                    // Folder not found, no files to add.
                });
            } else {
                promise = Promise.resolve();
            }

            return promise.then(() => {
                return this.assignHelper.uploadFiles(assign.id, files, siteId).then((itemId) => {
                    pluginData.files_filemanager = itemId;
                });
            });
        }
    }
}