<script>
  import Vue from 'vue'
  import MdAppSideDrawer from './MdAppSideDrawer'
  import MdAppInternalDrawer from './MdAppInternalDrawer'
  import MdDrawerRightPrevious from '../MdDrawer/MdDrawerRightPrevious';

  const componentTypes = [
    'md-app-toolbar',
    'md-app-drawer',
    'md-app-content'
  ]

  function isValidChild (componentOptions) {
    return componentOptions && componentTypes.includes(componentOptions.tag)
  }

  function isRightDrawer (propsData) {
    if (!propsData) return false
    return propsData.mdRight === '' || !!propsData.mdRight
  }

  function shouldRenderSlot (data, componentOptions) {
    return (data && componentTypes.includes(data.slot)) || isValidChild(componentOptions)
  }

  function generateAttrKeys (attrs) {
    return JSON.stringify({
      'persistent': attrs && attrs['md-persistent'],
      'permanent': attrs && attrs['md-permanent']
    })
  }

  /* eslint-disable complexity */
  function buildSlots (children, context, functionalContext, options, createElement) {
    let slots = []

    let hasDrawer = false

    if (children) {
      children.forEach(child => {
        const data = child.data
        const componentOptions = child.componentOptions

        if (shouldRenderSlot(data, componentOptions)) {
          const slotName = data.slot || componentOptions.tag
          child.data.slot = slotName

          if (slotName === 'md-app-drawer') {
            const isRight = isRightDrawer(componentOptions.propsData)

            if (hasDrawer) {
              Vue.util.warn(`There shouldn't be more than one drawer in a MdApp at one time.`)
              return
            }

            hasDrawer = true
            child.data.slot += `-${isRight ? 'right' : 'left'}`
            child.key = generateAttrKeys(data.attrs)

            if (isRight) {
              const drawerRightPrevious = createElement(MdDrawerRightPrevious, { props: {...child.data.attrs}})
              drawerRightPrevious.data.slot = 'md-app-drawer-right-previous'
              slots.push(drawerRightPrevious)
            }
          }

          child.data.provide = options.Ctor.options.provide
          child.context = context
          child.functionalContext = functionalContext

          slots.push(child)
        }
      })
    }

    return slots
  }
  /* eslint-enable complexity */

  function getDrawers (children) {
    const drawerVnodes = children.filter(child => {
      const tag = child.data.slot || child.componentOptions.tag
      return tag === 'md-app-drawer'
    })
    return drawerVnodes.length ? drawerVnodes : []
  }

  function hasInternalDrawer (attrs) {
    const mdPermanent = attrs && attrs['md-permanent']

    return mdPermanent && (mdPermanent === 'clipped' || mdPermanent === 'card')
  }

  export default {
    name: 'MdApp',
    functional: true,
    render (createElement, { children, props, data }) {
      let appComponent = MdAppSideDrawer
      const { context, functionalContext, componentOptions } = createElement(appComponent)
      const slots = buildSlots(children, context, functionalContext, componentOptions, createElement)
      const drawers = getDrawers(slots)

      drawers.forEach(drawer => {
        if (drawer && hasInternalDrawer(drawer.data.attrs)) {
          appComponent = MdAppInternalDrawer
        }
      })

      const staticClass = {}
      if (data.staticClass) {
        data.staticClass.split(/\s+/).forEach(name => {
          if (name.length === 0) return
          staticClass[name] = true
        })
      }

      return createElement(appComponent, {
        attrs: props,
        class: {...staticClass, ...data.class},
        style: {...data.staticStyle, ...data.style},
      }, slots)
    }
  }
</script>

<style lang="scss">
  @import "~components/MdAnimation/variables";
  @import "~components/MdLayout/mixins";

  .md-app {
    display: flex;
    overflow: hidden;
    position: relative;

    &.md-fixed {
      .md-app-scroller {
        overflow: auto;
      }
    }

    &.md-reveal,
    &.md-fixed-last,
    &.md-overlap,
    &.md-flexible {
      transform: translate3d(0, 0, 0);

      .md-app-toolbar {
        position: absolute;
        top: 0;
      }
    }

    &.md-flexible,
    &.md-overlap {
      .md-app-toolbar {
        min-height: 0;
      }
    }

    &.md-flexible {
      .md-toolbar-row {
        &:first-child {
          z-index: 2;
        }

        &:last-child {
          position: fixed;
          bottom: 0;
          z-index: 1;
        }
      }

      .md-display-1 {
        position: fixed;
      }
    }

    &.md-overlap {
      .md-app-toolbar {
        z-index: 1;
      }

      .md-app-content {
        margin: -64px 24px 24px;
        position: relative;
        z-index: 2;

        @include md-layout-small {
          margin: -64px 16px 16px;
        }

        @include md-layout-xsmall {
          margin: -64px 8px 8px;
        }
      }
    }
  }

  .md-app-drawer {
    &.md-permanent-card + .md-app-scroller .md-content {
      @include md-layout-small-and-up {
        padding-left: 0;
        padding-right: 0;
        border-left: none;
        border-right: none;
      }
    }
  }

  .md-app-content {
    padding: 16px;

    @include md-layout-small-and-up {
      border-left: 1px solid transparent;
      border-right: 1px solid transparent;
    }

    > p {
      &:first-child {
        margin-top: 0;
      }

      &:last-child {
        margin-bottom: 0;
      }
    }
  }

  .md-app-container {
    flex: 1;
    display: flex;
    overflow: auto;
    transform: translate3D(0, 0, 0);
    transition: padding-left .4s $md-transition-default-timing,
                padding-right .4s $md-transition-default-timing;
    will-change: padding-left, padding-right;
  }

  .md-app-scroller {
    flex: 1;
  }
</style>
