import options
import streams
import strutils
import tables

import css/cssparser
import css/selectorparser
import css/stylednode
import html/dom
import html/tags

func attrSelectorMatches(elem: Element, sel: Selector): bool =
  case sel.rel
  of ' ': return elem.attrb(sel.attr)
  of '=': return elem.attr(sel.attr) == sel.value
  of '~': return sel.value in elem.attr(sel.attr).split(Whitespace)
  of '|':
    let val = elem.attr(sel.attr)
    return val == sel.value or sel.value.startsWith(val & '-')
  of '^': return elem.attr(sel.attr).startsWith(sel.value)
  of '$': return elem.attr(sel.attr).endsWith(sel.value)
  of '*': return elem.attr(sel.attr).contains(sel.value)
  else: return false

func selectorsMatch*[T: Element|StyledNode](elem: T, cxsel: ComplexSelector, felem: T = nil): bool

func selectorsMatch*[T: Element|StyledNode](elem: T, slist: SelectorList, felem: T = nil): bool =
  for cxsel in slist:
    if elem.selectorsMatch(cxsel, felem):
      return true
  return false

func pseudoSelectorMatches[T: Element|StyledNode](elem: T, sel: Selector, felem: T): bool =
  let selem = elem
  when elem is StyledNode:
    let elem = Element(elem.node)
  case sel.pseudo.t
  of PSEUDO_FIRST_CHILD: return elem.parentNode.firstElementChild == elem
  of PSEUDO_LAST_CHILD: return elem.parentNode.lastElementChild == elem
  of PSEUDO_ONLY_CHILD: return elem.parentNode.firstElementChild == elem and elem.parentNode.lastElementChild == elem
  of PSEUDO_HOVER:
    when selem is StyledNode: felem.addDependency(selem, DEPEND_HOVER)
    return elem.hover
  of PSEUDO_ROOT: return elem == elem.document.html
  of PSEUDO_NTH_CHILD:
    if sel.pseudo.ofsels.len != 0 and not selem.selectorsMatch(sel.pseudo.ofsels, felem):
      return false
    let A = sel.pseudo.anb.A # step
    let B = sel.pseudo.anb.B # start
    var i = 1
    let parent = when selem is StyledNode: selem.parent
    else: selem.parentNode
    if parent == nil: return false
    for child in parent.elementList:
      when selem is StyledNode:
        if not child.isDomElement: continue
      if child == selem:
        if A == 0:
          return i == B
        if A < 0:
          return (i - B) <= 0 and (i - B) mod A == 0
        return (i - B) >= 0 and (i - B) mod A == 0
      if sel.pseudo.ofsels.len == 0 or child.selectorsMatch(sel.pseudo.ofsels, felem):
        inc i
    return false
  of PSEUDO_NTH_LAST_CHILD:
    if sel.pseudo.ofsels.len == 0 and not selem.selectorsMatch(sel.pseudo.ofsels, felem):
      return false
    let A = sel.pseudo.anb.A # step
    let B = sel.pseudo.anb.B # start
    var i = 1
    let parent = when selem is StyledNode: selem.parent
    else: selem.parentNode
    if parent == nil: return false
    for child in parent.elementList_rev:
      when selem is StyledNode:
        if not child.isDomElement: continue
      if child == selem:
        if A == 0:
          return i == B
        if A < 0:
          return (i - B) <= 0 and (i - B) mod A == 0
        return (i - B) >= 0 and (i - B) mod A == 0
      if sel.pseudo.ofsels.len != 0 or child.selectorsMatch(sel.pseudo.ofsels, felem):
        inc i
    return false
  of PSEUDO_CHECKED:
    when selem is StyledNode: felem.addDependency(selem, DEPEND_CHECKED)
    if elem.tagType == TAG_INPUT:
      return HTMLInputElement(elem).checked
    elif elem.tagType == TAG_OPTION:
      return HTMLOptionElement(elem).selected
    return false
  of PSEUDO_FOCUS:
    when selem is StyledNode: felem.addDependency(selem, DEPEND_FOCUS)
    return elem.document.focus == elem
  of PSEUDO_NOT:
    return not selem.selectorsMatch(sel.pseudo.fsels, felem)
  of PSEUDO_IS, PSEUDO_WHERE:
    return selem.selectorsMatch(sel.pseudo.fsels, felem)
  of PSEUDO_LANG:
    return sel.pseudo.s == "en" #TODO languages?
  of PSEUDO_LINK:
    return elem.tagType in {TAG_A, TAG_AREA} and elem.attrb("href")
  of PSEUDO_VISITED:
    return false

func selectorMatches[T: Element|StyledNode](elem: T, sel: Selector, felem: T = nil): bool =
  let selem = elem
  when elem is StyledNode:
    let elem = Element(selem.node)
  case sel.t
  of TYPE_SELECTOR:
    return elem.tagType == sel.tag
  of CLASS_SELECTOR:
    return sel.class in elem.classList
  of ID_SELECTOR:
    return sel.id == elem.id
  of ATTR_SELECTOR:
    return elem.attrSelectorMatches(sel)
  of PSEUDO_SELECTOR:
    return pseudoSelectorMatches(selem, sel, felem)
  of PSELEM_SELECTOR:
    return true
  of UNIVERSAL_SELECTOR:
    return true

func selectorsMatch[T: Element|StyledNode](elem: T, sels: CompoundSelector, felem: T): bool =
  for sel in sels:
    if not<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; fo