import co from 'co';

import { render } from './server/render';

/**

* Transforms strange AWS properties syntax, into a proper JSON string.

* @param {String} str String containing the JSON-like structure of parameters.

* @return {String} Returns a JSON string obtained from reading the parameters.

*/

function JSONize(str) {

return str

.replace(/([\$\w]+)\s*:/g, function(_, $1){ return '"'+$1+'":'; })

.replace(/:([\$\w]+)\s*/g, function(_, $1) { return ':"'+$1+'"'; })

.replace(/'([^']+)'/g, function(_, $1){ return '"'+$1+'"'; });

}

/**

* Transforms strange AWS properties syntax, into a proper JS Object.

* @param {String} str String containing the JSON-like structure of parameters.

* @return {Object} Returns a JS Object obtained from reading the parameters.

*/

function parse(str) {

return JSON.parse(JSONize(str.replace(/=/g, ':')));

}

/**

* Creates a full URL path from parameters obtained as input parameters to AWS Lambda function.

* @param {Object} pathParts Object containing the list of path parameters eg.

* {0: 'level1', 1: 'level2'}

* @param {Object} queryString Object containing query string parameters that were passed to Lambda function, eg.

* {param1: 'someValue', param2: 'otherValue'}

* @return {String} Returns a full path of the request as it came from AWS API Gateway, for the examples above result would be:

* '/level1/level2?param1=someValue&param2=otherValue'

*/

function createFullPath(pathParts, queryString) {

let path = '/';

path += Object.keys(pathParts).sort((a, b) => a - b).map(partKey => pathParts[partKey]).join('/');

const queryStringKeys = Object.keys(queryString);

if(queryStringKeys.length > 0) {

path += '?';

path += queryStringKeys.map(queryStringKey => `${queryStringKey}=${queryString[queryStringKey]}`).join('&');

}

return path;

}

/**

* Main Lambda function handler. It takes parameters passed from AWS API Gateway and returns generated HTML content,

* based on the path of the request, and query string parameters.

* @param {[type]} event Event object containing parameters passed from AWS API Gateway call.

* @param {[type]} context Object used to return result from the AWS Lambda function.

*/

export const mainHandler = co.wrap(function *(event, context) {

try {

console.log(event, context);

const path = event.path;

const querystring = event.querystring;

const fullPath = createFullPath(path, querystring);

const [urlPath, renderedContent] = yield render(fullPath);

context.succeed({urlPath, variableHTML: renderedContent});

} catch (error) {

console.error('ERROR: ', error, error.stack);

context.succeed({error});

}

});