var _ = require('./index')
var config = require('../config')

/**
 * Query an element selector if it's not an element already.
 *
 * @param {String|Element} el
 * @return {Element}
 */

exports.query = function (el) {
  if (typeof el === 'string') {
    var selector = el
    el = document.querySelector(el)
    if (!el) {
      process.env.NODE_ENV !== 'production' && _.warn(
        'Cannot find element: ' + selector
      )
    }
  }
  return el
}

/**
 * Check if a node is in the document.
 * Note: document.documentElement.contains should work here
 * but always returns false for comment nodes in phantomjs,
 * making unit tests difficult. This is fixed byy doing the
 * contains() check on the node's parentNode instead of
 * the node itself.
 *
 * @param {Node} node
 * @return {Boolean}
 */

exports.inDoc = function (node) {
  var doc = document.documentElement
  var parent = node && node.parentNode
  return doc === node ||
    doc === parent ||
    !!(parent && parent.nodeType === 1 && (doc.contains(parent)))
}

/**
 * Extract an attribute from a node.
 *
 * @param {Node} node
 * @param {String} attr
 */

exports.attr = function (node, attr) {
  attr = config.prefix + attr
  var val = node.getAttribute(attr)
  if (val !== null) {
    node.removeAttribute(attr)
  }
  return val
}

/**
 * Insert el before target
 *
 * @param {Element} el
 * @param {Element} target
 */

exports.before = function (el, target) {
  target.parentNode.insertBefore(el, target)
}

/**
 * Insert el after target
 *
 * @param {Element} el
 * @param {Element} target
 */

exports.after = function (el, target) {
  if (target.nextSibling) {
    exports.before(el, target.nextSibling)
  } else {
    target.parentNode.appendChild(el)
  }
}

/**
 * Remove el from DOM
 *
 * @param {Element} el
 */

exports.remove = function (el) {
  el.parentNode.removeChild(el)
}

/**
 * Prepend el to target
 *
 * @param {Element} el
 * @param {Element} target
 */

exports.prepend = function (el, target) {
  if (target.firstChild) {
    exports.before(el, target.firstChild)
  } else {
    target.appendChild(el)
  }
}

/**
 * Replace target with el
 *
 * @param {Element} target
 * @param {Element} el
 */

exports.replace = function (target, el) {
  var parent = target.parentNode
  if (parent) {
    parent.replaceChild(el, target)
  }
}

/**
 * Add event listener shorthand.
 *
 * @param {Element} el
 * @param {String} event
 * @param {Function} cb
 */

exports.on = function (el, event, cb) {
  el.addEventListener(event, cb)
}

/**
 * Remove event listener shorthand.
 *
 * @param {Element} el
 * @param {String} event
 * @param {Function} cb
 */

exports.off = function (el, event, cb) {
  el.removeEventListener(event, cb)
}

/**
 * Add class with compatibility for IE & SVG
 *
 * @param {Element} el
 * @param {Strong} cls
 */

exports.addClass = function (el, cls) {
  if (el.classList) {
    el.classList.add(cls)
  } else {
    var cur = ' ' + (el.getAttribute('class') || '') + ' '
    if (cur.indexOf(' ' + cls + ' ') < 0) {
      el.setAttribute('class', (cur + cls).trim())
    }
  }
}

/**
 * Remove class with compatibility for IE & SVG
 *
 * @param {Element} el
 * @param {Strong} cls
 */

exports.removeClass = function (el, cls) {
  if (el.classList) {
    el.classList.remove(cls)
  } else {
    var cur = ' ' + (el.getAttribute('class') || '') + ' '
    var tar = ' ' + cls + ' '
    while (cur.indexOf(tar) >= 0) {
      cur = cur.replace(tar, ' ')
    }
    el.setAttribute('class', cur.trim())
  }
}

/**
 * Extract raw content inside an element into a temporary
 * container div
 *
 * @param {Element} el
 * @param {Boolean} asFragment
 * @return {Element}
 */

exports.extractContent = function (el, asFragment) {
  var child
  var rawContent
  /* istanbul ignore if */
  if (
    exports.isTemplate(el) &&
    el.content instanceof DocumentFragment
  ) {
    el = el.content
  }
  if (el.hasChildNodes()) {
    trim(el, el.firstChild)
    trim(el, el.lastChild)
    rawContent = asFragment
      ? document.createDocumentFragment()
      : document.createElement('div')
    /* eslint-disable no-cond-assign */
    while (child = el.firstChild) {
    /* eslint-enable no-cond-assign */
      rawContent.appendChild(child)
    }
  }
  return rawContent
}

function trim (content, node) {
  if (node && node.nodeType === 3 && !node.data.trim()) {
    content.removeChild(node)
  }
}

/**
 * Check if an element is a template tag.
 * Note if the template appears inside an SVG its tagName
 * will be in lowercase.
 *
 * @param {Element} el
 */

exports.isTemplate = function (el) {
  return el.tagName &&
    el.tagName.toLowerCase() === 'template'
}

/**
 * Create an "anchor" for performing dom insertion/removals.
 * This is used in a number of scenarios:
 * - fragment instance
 * - v-html
 * - v-if
 * - component
 * - repeat
 *
 * @param {String} content
 * @param {Boolean} persist - IE trashes empty textNodes on
 *                            cloneNode(true), so in certain
 *                            cases the anchor needs to be
 *                            non-empty to be persisted in
 *                            templates.
 * @return {Comment|Text}
 */

exports.createAnchor = function (content, persist) {
  return config.debug
    ? document.createComment(content)
    : document.createTextNode(persist ? ' ' : '')
}