import {Slice, Fragment, DOMParser, DOMSerializer} from "prosemirror-model"

export function serializeForClipboard(view, slice) {
  let context = [], {content, openStart, openEnd} = slice
  while (openStart > 1 && openEnd > 1 && content.childCount == 1 && content.firstChild.childCount == 1) {
    openStart--
    openEnd--
    let node = content.firstChild
    context.push(node.type.name, node.attrs != node.type.defaultAttrs ? node.attrs : null)
    content = node.content
  }

  let serializer = view.someProp("clipboardSerializer") || DOMSerializer.fromSchema(view.state.schema)
  let doc = detachedDoc(), wrap = doc.createElement("div")
  wrap.appendChild(serializer.serializeFragment(content, {document: doc}))

  let firstChild = wrap.firstChild, needsWrap
  while (firstChild && firstChild.nodeType == 1 && (needsWrap = wrapMap[firstChild.nodeName.toLowerCase()])) {
    for (let i = needsWrap.length - 1; i >= 0; i--) {
      let wrapper = doc.createElement(needsWrap[i])
      while (wrap.firstChild) wrapper.appendChild(wrap.firstChild)
      wrap.appendChild(wrapper)
    }
    firstChild = wrap.firstChild
  }

  if (firstChild && firstChild.nodeType == 1)
    firstChild.setAttribute("data-pm-slice", `${openStart} ${openEnd} ${JSON.stringify(context)}`)

  let text = view.someProp("clipboardTextSerializer", f => f(slice)) ||
      slice.content.textBetween(0, slice.content.size, "\n\n")

  return {dom: wrap, text}
}

// : (EditorView, string, string, ?bool, ResolvedPos) → ?Slice
// Read a slice of content from the clipboard (or drop data).
export function parseFromClipboard(view, text, html, plainText, $context) {
  let dom, inCode = $context.parent.type.spec.code, slice
  if (!html && !text) return null
  let asText = text && (plainText || inCode || !html)
  if (asText) {
    view.someProp("transformPastedText", f => { text = f(text, inCode || plainText) })
    if (inCode) return new Slice(Fragment.from(view.state.schema.text(text.replace(/\r\n?/g, "\n"))), 0, 0)
    let parsed = view.someProp("clipboardTextParser", f => f(text, $context, plainText))
    if (parsed) {
      slice = parsed
    } else {
      dom = document.createElement("div")
      text.trim().split(/(?:\r\n?|\n)+/).forEach(block => {
        dom.appendChild(document.createElement("p")).textContent = block
      })
    }
  } else {
    view.someProp("transformPastedHTML", f => { html = f(html) })
    dom = readHTML(html)
  }

  let contextNode = dom && dom.querySelector("[data-pm-slice]")
  let sliceData = contextNode && /^(\d+) (\d+) (.*)/.exec(contextNode.getAttribute("data-pm-slice"))
  if (!slice) {
    let parser = view.someProp("clipboardParser") || view.someProp("domParser") || DOMParser.fromSchema(view.state.schema)
    slice = parser.parseSlice(dom, {preserveWhitespace: !!(asText || sliceData), context: $context})
  }
  if (sliceData)
    slice = addContext(closeSlice(slice, +sliceData[1], +sliceData[2]), sliceData[3])
  else // HTML wasn't created by ProseMirror. Make sure top-level siblings are coherent
    slice = Slice.maxOpen(normalizeSiblings(slice.content, $context), false)

  view.someProp("transformPasted", f => { slice = f(slice) })
  return slice
}

// Takes a slice parsed with parseSlice, which means there hasn't been
// any content-expression checking done on the top nodes, tries to
// find a parent node in the current context that might fit the nodes,
// and if successful, rebuilds the slice so that it fits into that parent.
//
// This addresses the problem that Transform.replace expects a
// coherent slice, and will fail to place a set of siblings that don't
// fit anywhere in the schema.
function normalizeSiblings(fragment, $context) {
  if (fragment.childCount < 2) return fragment
  for (let d = $context.depth; d >= 0; d--) {
    let parent = $context.node(d)
    let match = parent.contentMatchAt($context.index(d))
    let lastWrap, result = []
    fragment.forEach(node => {
      if (!result) return
      let wrap = match.findWrapping(node.type), inLast
      if (!wrap) return result = null
      if (inLast = result.length && lastWrap.length && addToSibling(wrap, lastWrap, node, result[result.length - 1], 0)) {
        result[result.length - 1] = inLast
      } else {
        if (result.length) result[result.length - 1] = closeRight(result[result.length - 1], lastWrap.length)
        let wrapped = withWrappers(node, wrap)
        result.push(wrapped)
        match = match.matchType(wrapped.type, wrapped.attrs)
        lastWrap = wrap
      }
    })
    if (result) return Fragment.from(result)
  }
  return fragment
}

function withWrappers(node, wrap, from = 0) {
  for (let i = wrap.length - 1; i >= from; i--)
    node = wrap[i].create(null, Fragment.from(node))
  return node
}

// Used to group adjacent nodes wrapped in similar parents by
// normalizeSiblings into the same parent node
function addToSibling(wrap, lastWrap, node, sibling, depth) {
  if (depth < wrap.length && depth < lastWrap.length && wrap[depth] == lastWrap[depth]) {
    let inner = addToSibling(wrap, lastWrap, node, sibling.lastChild, depth + 1)
    if (inner) return sibling.copy(sibling.content.replaceChild(sibling.childCount - 1, inner))
    let match = sibling.contentMatchAt(sibling.childCount)
    if (match.matchType(depth == wrap.length - 1 ? node.type : wrap[depth + 1]))
      return sibling.copy(sibling.content.append(Fragment.from(withWrappers(node, wrap, depth + 1))))
  }
}

function closeRight(node, depth) {
  if (depth == 0) return node
  let fragment = node.content.replaceChild(node.childCount - 1, closeRight(node.lastChild, depth - 1))
  let fill = node.contentMatchAt(node.childCount).fillBefore(Fragment.empty, true)
  return node.copy(fragment.append(fill))
}

function closeRange(fragment, side, from, to, depth, openEnd) {
  let node = side < 0 ? fragment.firstChild : fragment.lastChild, inner = node.content
  if (depth < to - 1) inner = closeRange(inner, side, from, to, depth + 1, openEnd)
  if (depth >= from)
    inner = side < 0 ? node.contentMatchAt(0).fillBefore(inner, fragment.childCount > 1 || openEnd <= depth).append(inner)
      : inner.append(node.contentMatchAt(node.childCount).fillBefore(Fragment.empty, true))
  return fragment.replaceChild(side < 0 ? 0 : fragment.childCount - 1, node.copy(inner))
}

function closeSlice(slice, openStart, openEnd) {
  if (openStart < slice.openStart)
    slice = new Slice(closeRange(slice.content, -1, openStart, slice.openStart, 0, slice.openEnd), openStart, slice.openEnd)
  if (openEnd < slice.openEnd)
    slice = new Slice(closeRange(slice.content, 1, openEnd, slice.openEnd, 0, 0), slice.openStart, openEnd)
  return slice
}

// Trick from jQuery -- some elements must be wrapped in other
// elements for innerHTML to work. I.e. if you do `div.innerHTML =
// "<td>..</td>"` the table cells are ignored.
const wrapMap = {
  thead: ["table"],
  tbody: ["table"],
  tfoot: ["table"],
  caption: ["table"],
  colgroup: ["table"],
  col: ["table", "colgroup"],
  tr: ["table", "tbody"],
  td: ["table", "tbody", "tr"],
  th: ["table", "tbody", "tr"]
}

let _detachedDoc = null
function detachedDoc() {
  return _detachedDoc || (_detachedDoc = document.implementation.createHTMLDocument("title"))
}

function readHTML(html) {
  let metas = /^(\s*<meta [^>]*>)*/.exec(html)
  if (metas) html = html.slice(metas[0].length)
  let elt = detachedDoc().createElement("div")
  let firstTag = /<([a-z][^>\s]+)/i.exec(html), wrap
  if (wrap = firstTag && wrapMap[firstTag[1].toLowerCase()])
    html = wrap.map(n => "<" + n + ">").join("") + html + wrap.map(n => "</" + n + ">").reverse().join("")
  elt.innerHTML = html
  if (wrap) for (let i = 0; i < wrap.length; i++) elt = elt.querySelector(wrap[i]) || elt
  return elt
}

function addContext(slice, context) {
  if (!slice.size) return slice
  let schema = slice.content.firstChild.type.schema, array
  try { array = JSON.parse(context) }
  catch(e) { return slice }
  let {content, openStart, openEnd} = slice
  for (let i = array.length - 2; i >= 0; i -= 2) {
    let type = schema.nodes[array[i]]
    if (!type || type.hasRequiredAttrs()) break
    content = Fragment.from(type.create(array[i + 1], content))
    openStart++; openEnd++
  }
  return new Slice(content, openStart, openEnd)
}