// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.
'use strict';

import * as path from 'path';

import { IWorkspaceService } from '../common/application/types';

import { IConfigurationService } from '../common/types';
import { IDataScienceFileSystem } from './types';

export async function calculateWorkingDirectory(
    configService: IConfigurationService,
    workspace: IWorkspaceService,
    fs: IDataScienceFileSystem
): Promise<string | undefined> {
    let workingDir: string | undefined;
    // For a local launch calculate the working directory that we should switch into
    const settings = configService.getSettings(undefined);
    const fileRoot = settings.datascience.notebookFileRoot;

    // If we don't have a workspace open the notebookFileRoot seems to often have a random location in it (we use ${workspaceRoot} as default)
    // so only do this setting if we actually have a valid workspace open
    if (fileRoot && workspace.hasWorkspaceFolders) {
        const workspaceFolderPath = workspace.workspaceFolders![0].uri.fsPath;
        if (path.isAbsolute(fileRoot)) {
            if (await fs.localDirectoryExists(fileRoot)) {
                // User setting is absolute and exists, use it
                workingDir = fileRoot;
            } else {
                // User setting is absolute and doesn't exist, use workspace
                workingDir = workspaceFolderPath;
            }
        } else if (!fileRoot.includes('${')) {
            // fileRoot is a relative path, combine it with the workspace folder
            const combinedPath = path.join(workspaceFolderPath, fileRoot);
            if (await fs.localDirectoryExists(combinedPath)) {
                // combined path exists, use it
                workingDir = combinedPath;
            } else {
                // Combined path doesn't exist, use workspace
                workingDir = workspaceFolderPath;
            }
        } else {
            // fileRoot is a variable that hasn't been expanded
            workingDir = fileRoot;
        }
    }
    return workingDir;
}