var Q = require('q');
var path = require('path');
var minimatch = require('minimatch');

module.exports = {
  processToPromise: processToPromise,
  streamToPromise: streamToPromise,
  insertSrcFolder: insertSrcFolder,
  filterByFile: filterByFile
};


function processToPromise(process) {
  var defer = Q.defer();
  process.on('close', function(code) {
    if (code) {
      defer.reject(code);
    } else {
      defer.resolve();
    }
  });
  return defer.promise;
}

function streamToPromise(stream) {
  var defer = Q.defer();
  stream.on('end', defer.resolve);
  stream.on('error', defer.reject);
  return defer.promise;
}

function filterByFile(pathMapping, folder) {
  var folderParts = folder.split(path.sep);
  var match;
  var lastPattern;
  for (var pattern in pathMapping) {
    if (minimatch(folder, pattern)) {
      if (!lastPattern || lastPattern.length < pattern.length) {
        match = pathMapping[pattern];
        lastPattern = pattern;
      }
    }
  }
  if (match !== undefined) {
    return match;
  } else {
    throw new Error('No entry for folder '+folder+' found in '+JSON.stringify(pathMapping));
  }
}

function insertSrcFolder(plugins, srcFolderInsertion) {
  return plugins.rename(function(file) {
    var folder = file.dirname;
    var srcDir = filterByFile(srcFolderInsertion, path.join(folder, file.basename));
    if (srcDir) {
      var folderParts = file.dirname.split(path.sep);
      folder = [folderParts[0], srcDir].concat(folderParts.slice(1)).join(path.sep);
    }
    file.dirname = folder;
  });
}