/*
 * Copyright 2018 Brigham Young University
 *
 * 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 * as AWS from 'aws-sdk';
import * as fs from 'fs';
import { AccountConfig } from 'handel-extension-api';
import * as yaml from 'js-yaml';
import * as path from 'path';
import * as winston from 'winston';
import * as util from '../common/util';
import * as defaultAccountConfig from './default-account-config';

function throwValidateError(field: string) {
    throw new Error(`'${field}' field missing in the account config file`);
}

// TODO - We should turn this into a json schema validation
function validateAccountConfig(configToValidate: any) {
    const requiredFields = [
        'account_id',
        'region',
        'vpc',
        'public_subnets',
        'private_subnets',
        'data_subnets'
    ];

    for (const requiredField of requiredFields) {
        if (!configToValidate[requiredField]) {
            throwValidateError(requiredField);
        }
    }
}

function getAbsoluteConfigFilePath(filePath: string): string {
    let absolutePath: string = '';
    if (fs.existsSync(filePath)) {
        absolutePath = path.resolve(filePath);
    }
    if (!absolutePath) {
        winston.error(`Invalid file path for config file: ${filePath}`);
        process.exit(1);
    }
    return absolutePath;
}

function configureAwsSdk(region: string): void {
    process.env.AWS_REGION = region;
    AWS.config.update({
        maxRetries: 10,
        retryDelayOptions: {
            base: 300
        }
    });
}

/**
 * Given an account config file path or base64 encoded string, loads the account config
 */
export default async function(accountConfigParam: string): Promise<AccountConfig> {
    let accountConfig;
    if (accountConfigParam.startsWith('default')) {
        const region = accountConfigParam.substring(accountConfigParam.indexOf('-') + 1);
        configureAwsSdk(region); // Set up AWS to use our chosen region
        accountConfig = await defaultAccountConfig.getDefaultAccountConfig(region);
    }
    else if (fs.existsSync(accountConfigParam)) {
        const absoluteConfigFilePath = getAbsoluteConfigFilePath(accountConfigParam);
        accountConfig = util.readYamlFileSync(absoluteConfigFilePath);
        configureAwsSdk(accountConfig.region); // Set up AWS to use our chosen region
        validateAccountConfig(accountConfig);
    }
    else {
        accountConfig = yaml.safeLoad(new Buffer(accountConfigParam, 'base64').toString()) as AccountConfig;
        configureAwsSdk(accountConfig.region); // Set up AWS to use our chosen region
        validateAccountConfig(accountConfig);
    }
    return accountConfig;
}