module.exports = function (eruda) {
  // eruda の util を使う（必要ならここで require にフォールバックできます）
  const { evalCss } = eruda.util
  const each = eruda.util.each
  const $ = eruda.util.$
  const toArr = eruda.util.toArr

  class Dom extends eruda.Tool {
    constructor() {
      super()
      this.name = 'dom'
      this.displayName = 'ドム'

      this._style = evalCss(require('./style.scss'))
      this._isInit = false
      this._htmlTagTpl = require('./htmlTag.hbs')
      this._textNodeTpl = require('./textNode.hbs')
      this._selectedEl = document.documentElement
      this._htmlCommentTpl = require('./htmlComment.hbs')
      this._elementChangeHandler = (el) => {
        if (this._selectedEl === el) return
        this.select(el)
      }
    }

    init($el, container) {
      super.init($el)
      this._container = container
      this._eruda = eruda // 明示的に eruda を保持
      $el.html(require('./template.hbs')())
      this._$domTree = $el.find('.eruda-dom-tree')

      this._bindEvent()
    }

    show() {
      super.show()

      if (!this._isInit) this._initTree()
    }

    hide() {
      super.hide()
    }

    select(el) {
      const els = []
      els.push(el)
      while (el.parentElement) {
        els.unshift(el.parentElement)
        el = el.parentElement
      }
      while (els.length > 0) {
        el = els.shift()
        const erudaDom = el.erudaDom
        if (erudaDom) {
          if (erudaDom.close && erudaDom.open) {
            erudaDom.close()
            erudaDom.open()
          }
        } else {
          break
        }
        if (els.length === 0 && el.erudaDom) {
          el.erudaDom.select()
        }
      }
    }

    destroy() {
      super.destroy()
      evalCss.remove(this._style)
      const elements = this._eruda.get('elements')
      if (elements && elements.off) {
        elements.off('change', this._elementChangeHandler)
      }
    }

    _bindEvent() {
      const elements = this._eruda.get('elements')
      if (elements && elements.on) {
        elements.on('change', this._elementChangeHandler)
      }

      this._$el.on('click', '.eruda-inspect', () => {
        this._setElement(this._selectedEl)
        // container.showTool -> eruda.showTool に変更（確実に eruda のメソッドを使う）
        if (elements) this._eruda.showTool('elements')
      })
    }

    _setElement(el) {
      const elements = this._eruda.get('elements')
      if (!elements || typeof elements.set !== 'function') return
      elements.set(el)
    }

    _initTree() {
      this._isInit = true

      this._renderChildren(null, this._$domTree)
      this.select(document.body)
    }

    _renderChildren(node, $container) {
      let children
      if (!node) {
        children = [document.documentElement]
      } else {
        children = toArr(node.childNodes)
      }

      const container = $container.get(0)

      if (node) {
        children.push({
          nodeType: 'END_TAG',
          node
        })
      }
      each(children, (child) => this._renderChild(child, container))
    }

    _renderChild(child, container) {
      const $tag = createEl('li')
      let isEndTag = false

      $tag.addClass('eruda-tree-item')

      // ノードタイプ判定はグローバル Node 定数を使う
      if (child.nodeType === Node.ELEMENT_NODE) {
        const childCount = child.childNodes.length
        const expandable = childCount > 0
        const data = {
          ...getHtmlTagData(child),
          hasTail: expandable
        }
        const hasOneTextNode =
          childCount === 1 && child.childNodes[0].nodeType === Node.TEXT_NODE
        if (hasOneTextNode) {
          data.text = child.childNodes[0].nodeValue
        }
        $tag.html(this._htmlTagTpl(data))
        if (expandable && !hasOneTextNode) {
          $tag.addClass('eruda-expandable')
        }
      } else if (child.nodeType === Node.TEXT_NODE) {
        const value = child.nodeValue
        if (value.trim() === '') return

        $tag.html(
          this._textNodeTpl({
            value
          })
        )
      } else if (child.nodeType === Node.COMMENT_NODE) {
        const value = child.nodeValue
        if (value.trim() === '') return

        $tag.html(
          this._htmlCommentTpl({
            value
          })
        )
      } else if (child.nodeType === 'END_TAG') {
        isEndTag = true
        child = child.node
        $tag.html(
          `<span class="eruda-html-tag" style="margin-left: -12px;">&lt;<span class="eruda-tag-name">/${child.tagName.toLowerCase()}</span>&gt;</span><span class="eruda-selection"></span>`
        )
      } else {
        return
      }

      const $children = createEl('ul')
      $children.addClass('eruda-children')

      container.appendChild($tag.get(0))
      container.appendChild($children.get(0))

      if (child.nodeType !== Node.ELEMENT_NODE) return

      let erudaDom = {}

      if ($tag.hasClass('eruda-expandable')) {
        const open = () => {
          $tag.html(
            this._htmlTagTpl({
              ...getHtmlTagData(child),
              hasTail: false
            })
          )
          $tag.addClass('eruda-expanded')
          this._renderChildren(child, $children)
        }
        const close = () => {
          $children.html('')
          $tag.html(
            this._htmlTagTpl({
              ...getHtmlTagData(child),
              hasTail: true
            })
          )
          $tag.rmClass && $tag.rmClass('eruda-expanded')
          // rmClass が無ければ代替で removeClass を試す
          if ($tag.removeClass && !$tag.rmClass) $tag.removeClass('eruda-expanded')
        }
        const toggle = () => {
          if ($tag.hasClass('eruda-expanded')) {
            close()
          } else {
            open()
          }
        }
        $tag.on('click', '.eruda-toggle-btn', (e) => {
          e.stopPropagation()
          toggle()
        })
        erudaDom = {
          open,
          close
        }
      }

      const select = () => {
        // rmClass が無ければ代替実装
        const $sel = this._$el.find('.eruda-selected')
        if ($sel && $sel.rmClass) $sel.rmClass('eruda-selected')
        else if ($sel && $sel.removeClass) $sel.removeClass('eruda-selected')

        $tag.addClass('eruda-selected')
        this._selectedEl = child
        this._setElement(child)
      }
      $tag.on('click', select)
      erudaDom.select = select
      if (!isEndTag) child.erudaDom = erudaDom
    }
  }

  function getHtmlTagData(el) {
    const ret = {}

    ret.tagName = el.tagName.toLowerCase()
    const attributes = []
    each(el.attributes, (attribute) => {
      const { name, value } = attribute
      attributes.push({
        name,
        value,
        underline: isUrlAttribute(el, name)
      })
    })
    ret.attributes = attributes

    return ret
  }

  function isUrlAttribute(el, name) {
    const tagName = el.tagName
    // 正しいタグ名 (例: IMG) をチェック
    if (
      tagName === 'SCRIPT' ||
      tagName === 'IMG' ||
      tagName === 'VIDEO' ||
      tagName === 'AUDIO'
    ) {
      if (name === 'src') return true
    }

    if (tagName === 'LINK') {
      if (name === 'href') return true
    }

    return false
  }

  function createEl(name) {
    // eruda.util.$ が使える想定
    return $(document.createElement(name))
  }

  return new Dom()
}