#!/usr/bin/env node
'use strict';

var cluster = require('cluster');

if (!cluster.isMaster) {
  require('../lib/worker.js');
  return;
}

var crypto = require('crypto');
var PromiseA = require('bluebird');
var fs = PromiseA.promisifyAll(require('fs'));
var configStorage;
function mergeSettings(orig, changes) {
  Object.keys(changes).forEach(function (key) {
    // TODO: use an API that can properly handle updating arrays.
    if (!changes[key] || (typeof changes[key] !== 'object') || Array.isArray(changes[key])) {
      orig[key] = changes[key];
    }
    else if (!orig[key] || typeof orig[key] !== 'object') {
      orig[key] = changes[key];
    }
    else {
      mergeSettings(orig[key], changes[key]);
    }
  });
}

function fixRawConfig(config) {
  var updated = false;

  // First converge all of the `bind` properties for protocols that are on top
  // of TCP to `tcp.bind`.
  if (config.tcp && config.tcp.bind && !Array.isArray(config.tcp.bind)) {
    config.tcp.bind = [ config.tcp.bind ];
    updated = true;
  }
  if (config.http && config.http.bind) {
    config.tcp = config.tcp || { bind: [] };
    config.tcp.bind = (config.tcp.bind || []).concat(config.http.bind);
    delete config.http.bind;
    updated = true;
  }
  if (config.tls && config.tls.bind) {
    config.tcp = config.tcp || { bind: [] };
    config.tcp.bind = (config.tcp.bind || []).concat(config.tls.bind);
    delete config.tls.bind;
    updated = true;
  }

  // Then we rename dns to udp since the only thing we currently do with those
  // modules is proxy the packets without inspecting them at all.
  if (config.dns) {
    config.udp = config.dns;
    delete config.dns;
    updated = true;
  }
  // Convert all 'proxy' UDP modules to 'forward' modules that specify which
  // incoming ports are relevant. Primarily to make 'proxy' modules consistent
  // in needing relevant domain names.
  if (config.udp && !Array.isArray(config.udp.bind)) {
    config.udp.bind = [].concat(config.udp.bind || []);
    updated = true;
  }
  if (config.udp && config.udp.modules) {
    if (!config.udp.bind.length || !Array.isArray(config.udp.modules)) {
      delete config.udp.modules;
      updated = true;
    } else {
      config.udp.modules.forEach(function (mod) {
        if (mod.type === 'proxy') {
          mod.type = 'forward';
          mod.ports = config.udp.bind.slice();
          updated = true;
        }
      });
    }
  }

  // This we take the old way of defining ACME options and put them into a tls module.
  if (config.tls) {
    var oldPropMap = {
      email:              'email'
    , acme_directory_url: 'server'
    , challenge_type:     'challenge_type'
    , servernames:        'approved_domains'
    };
    if (Object.keys(oldPropMap).some(config.tls.hasOwnProperty, config.tls)) {
      updated = true;
      if (config.tls.acme) {
        console.warn('TLS config has `acme` field and old style definitions');
      } else {
        config.tls.acme = {};
        Object.keys(oldPropMap).forEach(function (oldKey) {
          if (config.tls[oldKey]) {
            config.tls.acme[oldPropMap[oldKey]] = config.tls[oldKey];
          }
        });
      }
    }
    if (config.tls.acme) {
      updated = true;
      config.tls.acme.domains = config.tls.acme.approved_domains;
      delete config.tls.acme.approved_domains;
      config.tls.modules = config.tls.modules || [];
      config.tls.modules.push(Object.assign({}, config.tls.acme, {type: 'acme'}));
      delete config.tls.acme;
    }
  }

  // Then we make sure all modules have an ID and type, and makes sure all domains
  // are in the right spot and also have an ID.
  function updateModules(list) {
    if (!Array.isArray(list)) {
      return;
    }
    list.forEach(function (mod) {
      if (!mod.id) {
        mod.id = crypto.randomBytes(4).toString('hex');
        updated = true;
      }
      if (mod.name) {
        mod.type = mod.type || mod.name;
        delete mod.name;
        updated = true;
      }
    });
  }
  function moveDomains(name) {
    if (!config[name].domains) {
      return;
    }
    updated = true;
    var domList = config[name].domains;
    delete config[name].domains;

    if (!Array.isArray(domList)) {
      return;
    }
    if (!Array.isArray(config.domains)) {
      config.domains = [];
    }
    domList.forEach(function (dom) {
      updateModules(dom.modules);

      var strDoms = dom.names.slice().sort().join(',');
      var added = config.domains.some(function (existing) {
        if (strDoms !== existing.names.slice().sort().join(',')) {
          return;
        }
        existing.modules = existing.modules || {};
        existing.modules[name] = (existing.modules[name] || []).concat(dom.modules);
        return true;
      });
      if (added) {
        return;
      }

      var newDom = {
        id:    crypto.randomBytes(4).toString('hex')
      , names: dom.names
      , modules: {}
      };
      newDom.modules[name] = dom.modules;
      config.domains.push(newDom);
    });
  }

  [ 'udp', 'tcp', 'http', 'tls' ].forEach(function (key) {
    if (!config[key]) {
      return;
    }
    updateModules(config[key].modules);
    moveDomains(key);
  });

  return updated;
}
async function createStorage(filename, filetype) {
  var recase = require('recase').create({});
  var snakeCopy = recase.snakeCopy.bind(recase);
  var camelCopy = recase.camelCopy.bind(recase);

  var parse, dump;
  if (filetype === 'json') {
    parse = JSON.parse;
    dump  = function (arg) { return JSON.stringify(arg, null, '  '); };
  } else {
    var yaml = require('js-yaml');
    parse = function (text) { return yaml.safeLoad(text) || {}; };
    dump  = yaml.safeDump;
  }

  async function read() {
    var text;
    try {
      text = await fs.readFileAsync(filename);
    } catch (err) {
      if (err.code === 'ENOENT') {
        return {};
      }
      throw err;
    }

    var rawConfig = parse(text);
    if (fixRawConfig(rawConfig)) {
      await fs.writeFileAsync(filename, dump(rawConfig));
      text = await fs.readFileAsync(filename);
      rawConfig = parse(text);
    }

    return rawConfig;
  }

  var result = {
    read: function () {
      return read().then(camelCopy);
    }
  , save: function (changes) {
      if (!changes || typeof changes !== 'object' || Array.isArray(changes)) {
        return PromiseA.reject(new Error('invalid config'));
      }
      changes = snakeCopy(changes);
      return read()
        .then(snakeCopy)
        .then(function (current) {
          mergeSettings(current, changes);
          // TODO: validate/lint the config before we actually write it.
          return dump(current);
        })
        .then(function (newText) {
          return fs.writeFileAsync(filename, newText);
        })
        .then(function () {
          return result.read();
        })
        ;
    }
  };
  return result;
}
async function checkConfigLocation(cwd, configFile) {
  cwd = cwd || process.cwd();
  var path = require('path');
  var filename, text;

  if (configFile) {
    filename = path.resolve(cwd, configFile);
    try {
      text = await fs.readFileAsync(filename);
    } catch (err) {
      if (err.code !== 'ENOENT') {
        throw err;
      }
      if (path.extname(filename) === '.json') {
        return { name: filename, type: 'json' };
      } else {
        return { name: filename, type: 'yaml' };
      }
    }
  } else {
    // Note that `path.resolve` can handle both relative and absolute paths.
    var defLocations = [
      path.resolve(cwd, 'goldilocks.yml')
    , path.resolve(cwd, 'goldilocks.json')
    , path.resolve(cwd, 'etc/goldilocks/goldilocks.yml')
    , '/etc/goldilocks/goldilocks.yml'
    ];

    var ind;
    for (ind = 0; ind < defLocations.length; ind += 1) {
      try {
        text = await fs.readFileAsync(defLocations[ind]);
        filename = defLocations[ind];
        break;
      } catch (err) {
        if (err.code !== 'ENOENT') {
          throw err;
        }
      }
    }

    if (!filename) {
      filename = defLocations[0];
      text = '';
    }
  }

  try {
    JSON.parse(text);
    return { name: filename, type: 'json' };
  } catch (err) {}

  try {
    require('js-yaml').safeLoad(text);
    return { name: filename, type: 'yaml' };
  } catch (err) {}

  throw new Error('Could not load "' + filename + '" as JSON nor YAML');
}
async function createConfigStorage(args) {
  var result = await checkConfigLocation(args.cwd, args.config);
  console.log('config file', result.name, 'is of type', result.type);
  configStorage = await createStorage(result.name, result.type);
  return configStorage.read();
}

var tcpProm;
function fillConfig(config, args) {
  config.debug = config.debug || args.debug;

  config.socks5 = config.socks5 || { enabled: false };

  // Use Object.assign to copy any real config values over the default values so we can
  // easily make sure all the fields we need exist .
  var mdnsDefaults = { disabled: false, port: 5353, broadcast: '224.0.0.251', ttl: 300 };
  config.mdns = Object.assign(mdnsDefaults, config.mdns);

  if (!Array.isArray(config.domains)) {
    config.domains = [];
  }

  function fillComponent(name, fillBind) {
    if (!config[name]) {
      config[name] = {};
    }
    if (!Array.isArray(config[name].modules)) {
      config[name].modules = [];
    }

    if (fillBind && !Array.isArray(config[name].bind)) {
      config[name].bind = [];
    }
  }
  fillComponent('udp',   true);
  fillComponent('tcp',   true);
  fillComponent('http',  false);
  fillComponent('tls',   false);
  fillComponent('ddns',  false);

  config.device = { hostname: require('os').hostname() };

  if (Array.isArray(config.tcp.bind) && config.tcp.bind.length) {
    return PromiseA.resolve(config);
  }

  // We need to make sure we only check once, because even though our workers can
  // all bind on the same port witout issue we cannot. This will lead to failure
  // to determine which ports will work once the first worker starts.
  if (!tcpProm) {
    tcpProm = new PromiseA(function (resolve, reject) {
      require('../lib/check-ports').checkTcpPorts(function (failed, bound) {
        var result = Object.keys(bound).map(Number);
        if (result.length > 0) {
          resolve(result);
        } else {
          reject(failed);
        }
      });
    });
  }

  return tcpProm.then(
    function (bound) {
      config.tcp.bind = bound;
      return config;
    }, function (failed) {
      Object.keys(failed).forEach(function (key) {
        console.log('[error bind]', key, failed[key].code);
      });
      return PromiseA.reject(new Error("could not bind to the default ports"));
    });
}

function run(args) {
  var workers = {};
  var cachedConfig;

  function updateConfig(config) {
    fillConfig(config, args).then(function (config) {
      cachedConfig = config;
      console.log('changed config', config);
      Object.keys(workers).forEach(function (key) {
        workers[key].send(cachedConfig);
      });
    });
  }

  process.on('SIGHUP', function () {
    configStorage.read().then(updateConfig).catch(function (err) {
      console.error('error updating config after SIGHUP', err);
    });
  });

  cluster.on('message', function (worker, message) {
    if (message.type !== 'com.daplie.goldilocks/config') {
      return;
    }
    configStorage.save(message.changes).then(updateConfig).catch(function (err) {
      console.error('error changing config', err);
    });
  });

  cluster.on('online', function (worker) {
    console.log('[worker]', worker.id, 'online');
    workers[worker.id] = worker;
    // Worker is listening
    worker.send(cachedConfig);
  });

  cluster.on('exit', function (worker) {
    delete workers[worker.id];
    cluster.fork();
  });

  createConfigStorage(args)
    .then(function (config) {
      return fillConfig(config, args);
    })
    .then(function (config) {
      console.log('config.tcp.bind', config.tcp.bind);
      cachedConfig = config;
      // TODO spin up multiple workers
      // TODO use greenlock-cluster
      cluster.fork();
    }).catch(function (err) {
      console.error(err);
      process.exit(1);
    })
    ;
}

function readEnv(args) {
  // TODO
  try {
    if (process.env.GOLDILOCKS_HOME) {
      process.chdir(process.env.GOLDILOCKS_HOME);
    }
  } catch (err) {}

  var env = {
    cwd: process.env.GOLDILOCKS_HOME || process.cwd()
  , debug: process.env.GOLDILOCKS_DEBUG && true
  };

  run(Object.assign({}, env, args));
}

var program = require('commander');

program
  .version(require('../package.json').version)
  .option('-c --config <file>', 'Path to config file (Goldilocks.json or Goldilocks.yml) example: --config /etc/goldilocks/Goldilocks.json')
  .option('--debug', "Enable debug output")
  .parse(process.argv);

readEnv(program);