import std/streams
import std/strutils
import std/unicode

import bindings/quickjs
import display/winattrs
import js/javascript
import types/cell
import types/opt
import utils/strwidth
import utils/twtstr

import chakasu/charset
import chakasu/decoderstream
import chakasu/encoderstream

type
  LineEditState* = enum
    EDIT, FINISH, CANCEL

  LineHistory* = ref object
    lines: seq[string]

  LineEdit* = ref object
    news*: string
    prompt*: string
    promptw: int
    state*: LineEditState
    escNext*: bool
    cursorx: int # 0 ..< news.notwidth
    cursori: int # 0 ..< news.len
    shiftx: int # 0 ..< news.notwidth
    shifti: int # 0 ..< news.len
    padding: int # 0 or 1
    maxwidth: int
    disallowed: set[char]
    hide: bool
    hist: LineHistory
    histindex: int
    histtmp: string
    invalid*: bool

jsDestructor(LineEdit)

func newLineHistory*(): LineHistory =
  return LineHistory()

# Note: capped at edit.maxwidth.
func getDisplayWidth(edit: LineEdit): int =
  var dispw = 0
  var i = edit.shifti
  var r: Rune
  while i < edit.news.len and dispw < edit.maxwidth:
    fastRuneAt(edit.news, i, r)
    dispw += r.width()
  return dispw

proc shiftView(edit: LineEdit) =
  # Shift view so it contains the cursor.
  if edit.cursorx < edit.shiftx:
    edit.shiftx = edit.cursorx
    edit.shifti = edit.cursori
  # Shift view so it is completely filled.
  if edit.shiftx > 0:
    let dispw = edit.getDisplayWidth()
    if dispw < edit.maxwidth:
      let targetx = edit.shiftx - edit.maxwidth + dispw
      if targetx <= 0:
        edit.shiftx = 0
        edit.shifti = 0
      else:
        while edit.shiftx > targetx:
          let (r, len) = edit.news.lastRune(edit.shifti - 1)
          edit.shiftx -= r.width()
          edit.shifti -= len
  edit.padding = 0
  # Shift view so it contains the cursor. (act 2)
  if edit.shiftx < edit.cursorx - edit.maxwidth:
    while edit.shiftx < edit.cursorx - edit.maxwidth and
        edit.shifti < edit.news.len:
      var r: Rune
      fastRuneAt(edit.news, edit.shifti, r)
      edit.shiftx += r.width()
    if edit.shiftx > edit.cursorx - edit.maxwidth:
      # skipped over a cell because of a double-width char
      edit.padding = 1

proc generateOutput*(edit: LineEdit): FixedGrid =
  edit.shiftView()
  # Make the output grid +1 cell wide, so it covers the whole input area.
  result = newFixedGrid(edit.promptw + edit.maxwidth + 1)
  var x = 0
  for r in edit.prompt.runes:
    result[x].str &= $r
    x += r.width()
    if x >= result.width: break
  for i in 0 ..< edit.padding:
    if x < result.width:
      result[x].str = " "
      inc x
  var i = edit.shifti
  while i < edit.news.len:
    var r: Rune
    fastRuneAt(edit.news, i, r)
    if not edit.hide:
      let w = r.width()
      if x + w > result.width: break
      if r.isControlChar():
        result[x].str &= '^'
        inc x
        result[x].str &= char(r).getControlLetter()
        inc x
      else:
        result[x].str &= $r
        x += w
    else:
      if x + 1 > result.width: break
      result[x].str &= '*'
      inc x

proc getCursorX*(edit: LineEdit): int =
  return edit.promptw + edit.cursorx + edit.padding - edit.shiftx

proc insertCharseq(edit: LineEdit, s: string) =
  let s = if edit.escNext:
    s
  else:
    deleteChars(s, edit.disallowed)
  edit.escNext = false
  if s.len == 0:
    return
  let rem = edit.news.substr(edit.cursori)
  edit.news.setLen(edit.cursori)
  edit.news &= s
  edit.news &= rem
  edit.cursori += s.len
  edit.cursorx += s.notwidth()
  edit.invalid = true

proc cancel(edit: LineEdit) {.jsfunc.} =
  edit.state = CANCEL

proc submit(edit: LineEdit) {.jsfunc.} =
  if edit.hist.lines.len == 0 or edit.news != edit.hist.lines[^1]:
    edit.hist.lines.add(edit.news)
  edit.state = FINISH

proc backspace(edit: LineEdit) {.jsfunc.} =
  if edit.cursori > 0:
    let (r, len) = edit.news.lastRune(edit.cursori - 1)
    edit.news.delete(edit.cursori -<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; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 }