const { Emitter } = require('atom');

module.exports = class StatusBarItem {
  constructor() {
    this.element = document.createElement('a');
    this.element.className = 'line-ending-tile inline-block';
    this.emitter = new Emitter();
    this.setLineEndings(new Set());
  }

  setLineEndings(lineEndings) {
    this.lineEndings = lineEndings;
    this.element.textContent = lineEndingName(lineEndings);
    this.emitter.emit('did-change');
  }

  onDidChange(callback) {
    return this.emitter.on('did-change', callback);
  }

  hasLineEnding(lineEnding) {
    return this.lineEndings.has(lineEnding);
  }

  description() {
    return lineEndingDescription(this.lineEndings);
  }

  onClick(callback) {
    this.element.addEventListener('click', callback);
  }
};

function lineEndingName(lineEndings) {
  if (lineEndings.size > 1) {
    return 'Mixed';
  } else if (lineEndings.has('\n')) {
    return 'LF';
  } else if (lineEndings.has('\r\n')) {
    return 'CRLF';
  } else {
    return '';
  }
}

function lineEndingDescription(lineEndings) {
  switch (lineEndingName(lineEndings)) {
    case 'Mixed':
      return 'mixed';
    case 'LF':
      return 'LF (Unix)';
    case 'CRLF':
      return 'CRLF (Windows)';
    default:
      return 'unknown';
  }
}