#! /usr/bin/env node

/**
 * Gaia autoland task definitions and outputs content to /autolander.json.
 */
var decorate = require('../lib/decorate_task');
var yaml = require('js-yaml');
var fs = require('fs');
var fsPath = require('path');
var util = require('util');
var template = require('json-templater/object');

// Cache for task definitions...
var TASK_DEFINITIONS = {};
function loadTask(name, parameters) {
  if (!TASK_DEFINITIONS[name]) {
    var path = fsPath.resolve(__dirname + '/../tasks/' + name + '.yml');
    TASK_DEFINITIONS[name] = yaml.safeLoad(fs.readFileSync(path));
  }

  // decorate_task hook.
  parameters.externalHook = true;

  return decorate(TASK_DEFINITIONS[name], parameters);
}

function params() {
  return Array.prototype.slice.call(arguments).reduce(function(target, props) {
    for (var key in props) target[key] = props[key];
    return target;
  }, {});
}

// List of all the possible definitions...
var config = yaml.safeLoad(fs.readFileSync(__dirname + '/../autolander.yml'));

// Final task graph definition place holder...
var graph = {
  tasks: []
};

// Expand all tasks based on the `tasks.yml` file...
Object.keys(config.definitions).forEach(function(name) {
  var definition = config.definitions[name];

  // If we are not using chunks don't loop.
  if (!definition || !definition.chunks) {
    var task = loadTask(name, params(config.params, {
      // Useful for environment variables.
      process: process
    }));

    graph.tasks.push(task);
    return;
  }

  // Handle all chunking options...
  for (var chunk = 1; chunk <= definition.chunks; chunk++) {
    // In practice relying on chunks in the graph is probably a bad idea unless
    // doing it explicitly with some sort of specific logic but here for
    // consistency.
    var task = loadTask(name, params(config.params, {
      // Allow process to be used in variables useful for process.env.
      process: process,

      // Chunk parameters
      chunk: chunk,
      totalChunks: definition.chunks,

      // whether this is a private image
      privateImage: definition.privateImage,
    }));
    graph.tasks.push(task);
  }
});

graph.tasks = graph.tasks.map(function(task) {
  return template(task);
});

// Write the content to autolander.json
var jsonPath = fsPath.resolve(__dirname + '/../../../autolander.json');
fs.writeFileSync(jsonPath, JSON.stringify(graph, null, 2));