// Copyright 2016-2018, Pulumi Corporation.
//
// 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.

/**
 * configEnvKey is the environment variable key that the language plugin uses to set configuration values.
 */
const configEnvKey = "PULUMI_CONFIG";

const config: {[key: string]: string} = {};

/**
 * allConfig returns a copy of the full config map.
 */
export function allConfig(): {[key: string]: string} {
    ensureConfig();
    return Object.assign({}, config);
}

/**
 * setConfig sets a configuration variable.
 */
export function setConfig(k: string, v: string): void {
    ensureConfig();
    config[cleanKey(k)] = v;
}

/**
 * getConfig returns a configuration variable's value or undefined if it is unset.
 */
export function getConfig(k: string): string | undefined {
    ensureConfig();
    return config[k];
}

/**
 * loaded is set to true if and when we've attempted to load config from the environment.
 */
let loaded: boolean = false;

/**
 * ensureConfig populates the runtime.config object based on configuration set in the environment.
 */
export function ensureConfig() {
    if (!loaded) {
        const envConfig = process.env.PULUMI_CONFIG;
        if (envConfig) {
            const envObject: {[key: string]: string} = JSON.parse(envConfig);
            for (const k of Object.keys(envObject)) {
                config[cleanKey(k)] = envObject[k];
            }
        }
        loaded = true;
    }
}

/**
 * cleanKey takes a configuration key, and if it is of the form "<string>:config:<string>" removes the ":config:"
 * portion. Previously, our keys always had the string ":config:" in them, and we'd like to remove it. However, the
 * language host needs to continue to set it so we can be compatable with older versions of our packages. Once we
 * stop supporting older packages, we can change the language host to not add this :config: thing and remove this
 * function.
 */
function cleanKey(key: string): string {
    const idx = key.indexOf(":");

    if (idx > 0 && key.startsWith("config:", idx + 1)) {
        return key.substring(0, idx) + ":" + key.substring(idx + 1 + "config:".length);
    }

    return key;
}