/*
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                              888888  8888  888888
                              88888    88    88888
                              888888  8888  888888
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                        88888888888888888888888888888888
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                           888888  8888888888  888888
                           888     8888  8888     888
                                   888    888

                                   OCTOBANANA

Licensed under the MIT License

Copyright (c) 2019 Brett Robinson <https://octobanana.com/>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

#include "ob/readline.hh"
#include "ob/string.hh"
#include "ob/text.hh"
#include "ob/term.hh"

#include <cstdio>
#include <cstddef>
#include <cstdint>
#include <cstdlib>

#include <deque>
#include <string>
#include <vector>
#include <fstream>
#include <iostream>
#include <chrono>
#include <thread>
#include <algorithm>
#include <filesystem>

namespace OB
{

namespace aec = OB::Term::ANSI_Escape_Codes;
namespace fs = std::filesystem;

void Readline::autocomplete(std::function<std::vector<std::string>()> const& val_)
{
  _autocomplete._update = val_;
}

void Readline::boundaries(std::string const& val_)
{
  _boundaries = val_;
}

std::string Readline::word_under_cursor(std::string const& delimiters_)
{
  auto const word = std::string(_input.str.prev_word(_input.off + _input.idx - 1, OB::Text::View(delimiters_)));

  return word.size() == 1 && word.find_first_of(_boundaries) != std::string::npos ? "" : word;
}

Readline& Readline::style(std::string const& style_)
{
  _style.input = style_;
  _autocomplete._style.normal = style_;

  return *this;
}

Readline& Readline::prompt(std::string const& str_, std::string const& style_)
{
  _prompt.str = str_;
  _style.prompt = style_;
  _autocomplete._style.prompt = style_;
  _prompt.fmt = aec::wrap(str_, style_);

  return *this;
}

std::string Readline::render() const
{
  std::ostringstream ss;

  // -------------------------------------------------------------
  switch (_mode)
  {
    case Mode::autocomplete_init:
    case Mode::autocomplete:
    {
      ss
      // << aec::cursor_hide
      << aec::cr
      << _autocomplete
      << aec::clear;

      break;
    }

    default:
    {
      ss
      // << aec::cursor_hide
      << aec::cr
      << _style.input
      << OB::String::repeat(_width, " ")
      << aec::cr
      << _prompt.lhs
      << _style.input
      << _input.fmt
      << aec::clear
      << _prompt.rhs
      << aec::cr
      << aec::cursor_right(_input.cur + 1);
      if (_input.cur + 2 == _width) {
        if (_prompt.rhs.size()) {
          ss
          << aec::reverse
          << _prompt.rhs;
        }
        else {
          ss
          << _style.input
          << aec::reverse
          << " ";
        }
      }
      else {
        ss
        << _style.input
        << aec::reverse;
        auto const c = _input.fmt.colstr(_input.fmt.byte_to_char(_input.cur), 1);
        if (c.size())
        {
          ss << c;
        }
        else
        {
          ss << " ";
        }
      }
      ss << aec::clear;
      // << aec::cursor_right(_input.cur + 1)
      // << aec::cursor_show;

      break;
    }
  }
  // -------------------------------------------------------------

  // ss
  // << aec::cursor_hide
  // << aec::cr
  // << _style.input
  // << OB::String::repeat(_width, " ")
  // << aec::cr
  // << _prompt.lhs
  // << _style.input
  // << _input.fmt
  // << aec::clear
  // << _prompt.rhs;

  // switch (_mode)
  // {
  //   case Mode::autocomplete_init:
  //   case Mode::autocomplete:
  //   {
  //     ss
  //     << aec::nl
  //     << _autocomplete
  //     << aec::cursor_up(1);

  //     break;
  //   }

  //   default:
  //   {
  //     if (_mode_prev == Mode::autocomplete_init || _mode_prev == Mode::autocomplete)
  //     {
  //       ss
  //       << aec::nl
  //       << aec::erase_line
  //       << aec::cursor_up(1);
  //     }

  //     break;
  //   }
  // }

  // ss
  // << aec::cr
  // << aec::cursor_right(_input.cur + 1)
  // << aec::cursor_show;

  return ss.str();
}

Readline& Readline::refresh()
{
  _prompt.lhs = ">";
  _prompt.rhs = " ";

  if (_input.str.cols() + 2 > _width)
  {
    std::size_t pos {_input.off + _input.idx - 1};
    std::size_t cols {0};

    for (; pos != OB::Text::String::npos && cols < _width - 2; --pos)
    {
      cols += _input.str.at(pos).cols;
    }

    if (pos == OB::Text::String::npos)
    {
      pos = 0;
    }

    std::size_t end {_input.off + _input.idx - pos};
    _input.fmt.str(_input.str.substr(pos, end));

    if (_input.fmt.cols() > _width - 2)
    {
      while (_input.fmt.cols() > _width - 2)
      {
        _input.fmt.erase(0, 1);
      }

      _input.cur = _input.fmt.cols();

      if (_input.cur == OB::Text::String::npos)
      {
        _input.cur = 0;
      }

      _prompt.lhs = "<";
    }
    else
    {
      _input.cur = _input.fmt.cols();

      if (_input.cur == OB::Text::String::npos)
      {
        _input.cur = 0;
      }

      while (_input.fmt.cols() <= _width - 2)
      {
        _input.fmt.append(std::string(_input.str.at(end++).str));
      }

      _input.fmt.erase(_input.fmt.size() - 1, 1);
    }

    if (_input.off + _input.idx < _input.str.size())
    {
      _prompt.rhs = ">";
    }
  }
  else
  {
    _input.fmt = _input.str;
    _input.cur = _input.fmt.cols(0, _input.idx);

    if (_input.cur == OB::Text::String::npos)
    {
      _input.cur = 0;
    }
  }

  return *this;
}

// Readline& Readline::refresh()
// {
//   _prompt.lhs = _prompt.fmt;
//   _prompt.rhs.clear();

//   if (_input.str.cols() + 2 > _width)
//   {
//     std::size_t pos {_input.off + _input.idx - 1};
//     std::size_t cols {0};

//     for (; pos != OB::Text::String::npos && cols < _width - 2; --pos)
//     {
//       cols += _input.str.at(pos).cols;
//     }

//     if (pos == OB::Text::String::npos)
//     {
//       pos = 0;
//     }

//     std::size_t end {_input.off + _input.idx - pos};
//     _input.fmt.str(_input.str.substr(pos, end));

//     if (_input.fmt.cols() > _width - 2)
//     {
//       while (_input.fmt.cols() > _width - 2)
//       {
//         _input.fmt.erase(0, 1);
//       }

//       _input.cur = _input.fmt.cols();

//       if (_input.cur == OB::Text::String::npos)
//       {
//         _input.cur = 0;
//       }

//       _prompt.lhs = aec::wrap("<", _style.prompt);
//     }
//     else
//     {
//       _input.cur = _input.fmt.cols();

//       if (_input.cur == OB::Text::String::npos)
//       {
//         _input.cur = 0;
//       }

//       while (_input.fmt.cols() <= _width - 2)
//       {
//         _input.fmt.append(std::string(_input.str.at(end++).str));
//       }

//       _input.fmt.erase(_input.fmt.size() - 1, 1);
//     }

//     if (_input.off + _input.idx < _input.str.size())
//     {
//       _prompt.rhs = aec::wrap(
//         OB::String::repeat(_width - _input.fmt.cols() - 2, " ") + ">",
//         _style.prompt);
//     }
//   }
//   else
//   {
//     _input.fmt = _input.str;
//     _input.cur = _input.fmt.cols(0, _input.idx);

//     if (_input.cur == OB::Text::String::npos)
//     {
//       _input.cur = 0;
//     }
//   }

//   return *this;
// }

Readline& Readline::size(std::size_t const width_, std::size_t const height_)
{
  _width = width_;
  _height = height_;

  _autocomplete.width(width_);

  return *this;
}

Readline& Readline::clear()
{
  mode(Mode::normal);
  _input = {};

  return *this;
}

std::string Readline::get()
{
  return _res;
}

Readline& Readline::normal()
{
  mode(Mode::normal);
  _input.off = _input.offp;
  _input.idx = _input.idxp;
  _input.str = _input.buf;
  hist_reset();
  refresh();

  return *this;
}

bool Readline::operator()(OB::Text::Char32 input)
{
  bool loop {true};

  switch (input.ch())
  {
    case OB::Term::Key::escape:
    {
      if (_mode != Mode::normal)
      {
        normal();

        break;
      }

      loop = false;
      _input.save_file = false;
      _input.clear_input = true;

      break;
    }

    case OB::Term::ctrl_key('r'):
    case OB::Term::Key::tab:
    {
      if (_mode != Mode::autocomplete_init && _mode != Mode::autocomplete)
      {
        ac_init();
      }
      else
      {
        mode(Mode::autocomplete);
        ac_next();
      }

      break;
    }

    case OB::Term::ctrl_key('c'):
    {
      // exit the command prompt
      mode(Mode::normal);
      loop = false;
      _input.save_file = false;
      _input.save_local = false;
      _input.clear_input = true;

      break;
    }

    // TODO impl copy/paste like shell
    case OB::Term::ctrl_key('u'):
    {
      mode(Mode::normal);
      _input.clipboard = _input.str;
      edit_clear();
      refresh();
      hist_reset();

      break;
    }

    case OB::Term::ctrl_key('y'):
    {
      mode(Mode::normal);
      edit_insert(_input.clipboard);
      refresh();
      hist_reset();

      break;
    }

    case OB::Term::Key::newline:
    {
      switch (_mode)
      {
        case Mode::autocomplete_init:
        case Mode::autocomplete:
        {
          mode(Mode::normal);

          break;
        }

        default:
        {
          // submit the input string
          loop = false;

          break;
        }
      }

      break;
    }

    case OB::Term::Key::up:
    case OB::Term::ctrl_key('p'):
    {
      switch (_mode)
      {
        case Mode::normal:
        {
          mode(Mode::history_init);
          hist_next();

          break;
        }

        case Mode::history_init:
        {
          mode(Mode::history);
          hist_next();

          break;
        }

        case Mode::history:
        {
          hist_next();

          break;
        }

        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_prev_section();

          break;
        }

        case Mode::autocomplete:
        {
          ac_prev_section();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::down:
    case OB::Term::ctrl_key('n'):
    {
      switch (_mode)
      {
        case Mode::normal:
        {
          mode(Mode::history_init);
          hist_prev();

          break;
        }

        case Mode::history_init:
        {
          mode(Mode::history);
          hist_prev();

          break;
        }

        case Mode::history:
        {
          hist_prev();

          break;
        }

        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_next_section();

          break;
        }

        case Mode::autocomplete:
        {
          ac_next_section();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::right:
    case OB::Term::ctrl_key('f'):
    {
      switch (_mode)
      {
        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_next();

          break;
        }

        case Mode::autocomplete:
        {
          ac_next();

          break;
        }

        default:
        {
          curs_right();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::left:
    case OB::Term::ctrl_key('b'):
    {
      switch (_mode)
      {
        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_prev();

          break;
        }

        case Mode::autocomplete:
        {
          ac_prev();

          break;
        }

        default:
        {
          curs_left();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::end:
    case OB::Term::ctrl_key('e'):
    {
      switch (_mode)
      {
        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_end();

          break;
        }

        case Mode::autocomplete:
        {
          ac_end();

          break;
        }

        default:
        {
          curs_end();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::home:
    case OB::Term::ctrl_key('a'):
    {
      switch (_mode)
      {
        case Mode::autocomplete_init:
        {
          mode(Mode::autocomplete);
          ac_begin();

          break;
        }

        case Mode::autocomplete:
        {
          ac_begin();

          break;
        }

        default:
        {
          curs_begin();

          break;
        }
      }

      break;
    }

    case OB::Term::Key::delete_:
    case OB::Term::ctrl_key('d'):
    {
      mode(Mode::normal);
      edit_delete();
      refresh();
      hist_reset();

      break;
    }

    case OB::Term::Key::backspace:
    case OB::Term::ctrl_key('h'):
    {
      mode(Mode::normal);
      edit_backspace_autopair();
      refresh();
      hist_reset();

      break;
    }

    default:
    {
      mode(Mode::normal);
      if (input.ch() < 0xF0000 &&
        (input.ch() == OB::Term::Key::space ||
        OB::Text::is_graph(static_cast<std::int32_t>(input.ch()))))
      {
        edit_insert_autopair(input);
        refresh();
        hist_reset();
      }

      break;
    }
  }

  if (loop)
  {
    return false;
  }

  _res = normalize(_input.str);

  if (! _res.empty())
  {
    if (_input.save_local)
    {
      hist_push(_res);
    }

    if (_input.save_file && _input.str.str().front() != ' ')
    {
      hist_save(_res);
    }
  }

  hist_reset();

  if (_input.clear_input)
  {
    _res.clear();
  }

  return true;
}

void Readline::curs_begin()
{
  // move cursor to start of line

  if (_input.idx || _input.off)
  {
    _input.idx = 0;
    _input.off = 0;

    refresh();
  }
}

void Readline::curs_end()
{
  // move cursor to end of line

  if (_input.str.empty())
  {
    return;
  }

  if (_input.off + _input.idx < _input.str.size())
  {
    if (_input.str.cols() + 2 > _width)
    {
      _input.off = _input.str.size() - _width + 2;
      _input.idx = _width - 2;
    }
    else
    {
      _input.idx = _input.str.size();
    }

    refresh();
  }
}

void Readline::curs_left()
{
  // move cursor left

  if (_input.off || _input.idx)
  {
    if (_input.off)
    {
      --_input.off;
    }
    else
    {
      --_input.idx;
    }

    refresh();
  }
}

void Readline::curs_right()
{
  // move cursor right

  if (_input.off + _input.idx < _input.str.size())
  {
    if (_input.idx + 2 < _width)
    {
      ++_input.idx;
    }
    else
    {
      ++_input.off;
    }

    refresh();
  }
}

void Readline::edit_insert(std::string const& str)
{
  // insert or append char to input buffer

  auto size {_input.str.size()};
  _input.str.insert(_input.off + _input.idx, str);

  if (size != _input.str.size())
  {
    size = _input.str.size() - size;

    if (_input.idx + size + 1 < _width)
    {
      _input.idx += size;
    }
    else
    {
      _input.off += _input.idx + size - _width + 1;
      _input.idx = _width - 1;
    }
  }
}

void Readline::edit_clear()
{
  // clear line

  _input.idx = 0;
  _input.off = 0;
  _input.str.clear();
}

bool Readline::edit_delete()
{
  // erase char under cursor

  if (_input.str.empty())
  {
    _input.str.clear();

    return false;
  }

  if (_input.off + _input.idx < _input.str.size())
  {
    if (_input.idx + 2 < _width)
    {
      _input.str.erase(_input.off + _input.idx, 1);
    }
    else
    {
      _input.str.erase(_input.idx, 1);
    }

    return true;
  }
  else if (_input.off || _input.idx)
  {
    if (_input.off)
    {
      _input.str.erase(_input.off + _input.idx - 1, 1);
      --_input.off;
    }
    else
    {
      --_input.idx;
      _input.str.erase(_input.idx, 1);
    }

    return true;
  }

  return false;
}

bool Readline::edit_backspace()
{
  // erase char behind cursor

  if (_input.str.empty())
  {
    _input.str.clear();

    return false;
  }

  _input.str.erase(_input.off + _input.idx - 1, 1);

  if (_input.off || _input.idx)
  {
    if (_input.off)
    {
      --_input.off;
    }
    else if (_input.idx)
    {
      --_input.idx;
    }

    return true;
  }

  return false;
}

void Readline::hist_next()
{
  // cycle backwards in history

  if (_history().empty() && _history.search().empty())
  {
    return;
  }

  bool bounds {_history.search().empty() ?
    (_history.idx < _history().size() - 1) :
    (_history.idx < _history.search().size() - 1)};

  if (bounds || _history.idx == History::npos)
  {
    if (_history.idx == History::npos)
    {
      _input.buf = _input.str;

      if (! _input.buf.empty())
      {
        hist_search(_input.buf);
      }
    }

    ++_history.idx;

    if (_history.search().empty())
    {
      // normal search
      _input.str = _history().at(_history.idx);
    }
    else
    {
      // fuzzy search
      _input.str = _history().at(_history.search().at(_history.idx).idx);
    }

    if (_input.str.size() + 1 >= _width)
    {
      _input.off = _input.str.size() - _width + 2;
      _input.idx = _width - 2;
    }
    else
    {
      _input.off = 0;
      _input.idx = _input.str.size();
    }

    refresh();
  }
}

void Readline::hist_prev()
{
  // cycle forwards in history

  if (_history.idx != History::npos)
  {
    --_history.idx;

    if (_history.idx == History::npos)
    {
      _input.str = _input.buf;
    }
    else if (_history.search().empty())
    {
      // normal search
      _input.str = _history().at(_history.idx);
    }
    else
    {
      // fuzzy search
      _input.str = _history().at(_history.search().at(_history.idx).idx);
    }

    if (_input.str.size() + 1 >= _width)
    {
      _input.off = _input.str.size() - _width + 2;
      _input.idx = _width - 2;
    }
    else
    {
      _input.off = 0;
      _input.idx = _input.str.size();
    }

    refresh();
  }
}

void Readline::hist_reset()
{
  _history.search.clear();
  _history.idx = History::npos;
}

void Readline::hist_search(std::string const& str)
{
  _history.search.clear();

  OB::Text::String input {OB::Text::normalize_foldcase(
    std::regex_replace(OB::Text::trim(str), std::regex("\\s+"),
    " ", std::regex_constants::match_not_null))};

  if (input.empty())
  {
    return;
  }

  std::size_t idx {0};
  std::size_t count {0};
  std::size_t weight {0};
  std::string prev_hist {" "};
  std::string prev_input {" "};
  OB::Text::String hist;

  for (std::size_t i = 0; i < _history().size(); ++i)
  {
    hist.str(OB::Text::normalize_foldcase(_history().at(i)));

    if (hist.size() <= input.size())
    {
      continue;
    }

    idx = 0;
    count = 0;
    weight = 0;
    prev_hist = " ";
    prev_input = " ";

    for (std::size_t j = 0, seq = 0; j < hist.size(); ++j)
    {
      if (idx < input.size() &&
        hist.at(j).str == input.at(idx).str)
      {
        ++seq;
        count += 1;

        if (seq > 1)
        {
          count += 1;
        }

        if (prev_hist == " " && prev_input == " ")
        {
          count += 1;
        }

        prev_input = input.at(idx).str;
        ++idx;

        // short circuit to keep history order
        // comment out to search according to closest match
        if (idx == input.size())
        {
          break;
        }
      }
      else
      {
        seq = 0;
        weight += 2;

        if (prev_input == " ")
        {
          weight += 1;
        }
      }

      prev_hist = hist.at(j).str;
    }

    if (idx != input.size())
    {
      continue;
    }

    while (count && weight)
    {
      --count;
      --weight;
    }

    _history.search().emplace_back(weight, i);
  }

  std::sort(_history.search().begin(), _history.search().end(),
  [](auto const& lhs, auto const& rhs)
  {
    // default to history order if score is equal
    return lhs.score == rhs.score ? lhs.idx < rhs.idx : lhs.score < rhs.score;
  });
}

void Readline::hist_push(std::string const& str)
{
  if (_history().empty())
  {
    _history().emplace_front(str);
  }
  else if (_history().back() != str)
  {
    if (auto pos = std::find(_history().begin(), _history().end(), str);
      pos != _history().end())
    {
      _history().erase(pos);
    }

    _history().emplace_front(str);
  }
}

void Readline::hist_load(fs::path const& path)
{
  if (! path.empty())
  {
    std::ifstream ifile {path};

    if (ifile && ifile.is_open())
    {
      std::string line;

      while (std::getline(ifile, line))
      {
        hist_push(line);
      }
    }

    hist_open(path);
  }
}

void Readline::hist_save(std::string const& str)
{
  if (_history.file.is_open())
  {
    _history.file
    << str << "\n"
    << std::flush;
  }
}

void Readline::hist_open(fs::path const& path)
{
  _history.file.open(path, std::ios::app);

  if (! _history.file.is_open())
  {
    throw std::runtime_error("could not open file '" + path.string() + "'");
  }
}

void Readline::ac_init()
{
  mode(Mode::autocomplete_init);

  _input.offp = _input.off;
  _input.idxp = _input.idx;
  _input.buf = _input.str;

  _autocomplete.word(word_under_cursor(_boundaries));
  _autocomplete.generate().refresh();

  ac_sync();
}

void Readline::ac_sync()
{
  _input.str = _input.buf;
  auto const word = _autocomplete._match.at(_autocomplete._off + _autocomplete._idx);

  _input.str.replace(_input.offp + _input.idxp - _autocomplete.word().size(), _autocomplete.word().size(), word);

  // place cursor at end of new word
  std::size_t const pos {_input.offp + _input.idxp - _autocomplete.word().size() + word.size()};
  if (pos + 1 >= _width)
  {
    _input.off = pos - _width + 2;
    _input.idx = _width - 2;
  }
  else
  {
    _input.idx = pos;
  }

  refresh();
}

void Readline::ac_begin()
{
  _autocomplete.begin().refresh();
  ac_sync();
}

void Readline::ac_end()
{
  _autocomplete.end().refresh();
  ac_sync();
}

void Readline::ac_prev()
{
  _autocomplete.prev().refresh();
  ac_sync();
}

void Readline::ac_next()
{
  _autocomplete.next().refresh();
  ac_sync();
}

void Readline::ac_prev_section()
{
  _autocomplete.prev_section().refresh();
  ac_sync();
}

void Readline::ac_next_section()
{
  _autocomplete.next_section().refresh();
  ac_sync();
}

void Readline::edit_insert_autopair(OB::Text::Char32 const& val)
{
  auto const i = _input.off + _input.idx;
  auto const lhs = val.ch();
  auto const rhs = i < _input.str.size() ? OB::Text::Char32(std::string(_input.str.at(i))).ch() : '\0';
  auto const prv = i > 0 ? OB::Text::Char32(std::string(_input.str.at(i - 1))).ch() : '\0';

  switch (lhs)
  {
    case '"':
    {
      if (rhs == '"')
      {
        if (prv == '\\')
        {
          edit_insert(val.str());
        }
        else
        {
          curs_right();
        }
      }
      else if (prv != '\\')
      {
        edit_insert(val.str());
        edit_insert("\"");
        curs_left();
      }
      else
      {
        edit_insert(val.str());
      }

      break;
    }

    case '(':
    {
      if (prv == '\\')
      {
        edit_insert(val.str());
      }
      else
      {
        edit_insert(val.str());
        edit_insert(")");
        curs_left();
      }

      break;
    }

    case ')':
    {
      if (rhs == ')')
      {
        if (prv == '\\')
        {
          edit_insert(val.str());
        }
        else
        {
          curs_right();
        }
      }
      else
      {
        edit_insert(val.str());
      }

      break;
    }

    case '[':
    {
      if (prv == '\\')
      {
        edit_insert(val.str());
      }
      else
      {
        edit_insert(val.str());
        edit_insert("]");
        curs_left();
      }

      break;
    }

    case ']':
    {
      if (rhs == ']')
      {
        if (prv == '\\')
        {
          edit_insert(val.str());
        }
        else
        {
          curs_right();
        }
      }
      else
      {
        edit_insert(val.str());
      }

      break;
    }

    case '{':
    {
      if (prv == '\\')
      {
        edit_insert(val.str());
      }
      else
      {
        edit_insert(val.str());
        edit_insert("}");
        curs_left();
      }

      break;
    }

    case '}':
    {
      if (rhs == '}')
      {
        if (prv == '\\')
        {
          edit_insert(val.str());
        }
        else
        {
          curs_right();
        }
      }
      else
      {
        edit_insert(val.str());
      }

      break;
    }

    default:
    {
      edit_insert(val.str());

      break;
    }
  }
}

void Readline::edit_backspace_autopair()
{
  auto const i = _input.off + _input.idx;

  if (i < 1 || i >= _input.str.size())
  {
    edit_backspace();

    return;
  }

  auto const lhs = OB::Text::Char32(std::string(_input.str.at(i - 1))).ch();
  auto const rhs = OB::Text::Char32(std::string(_input.str.at(i))).ch();
  auto const prv = i > 1 ? OB::Text::Char32(std::string(_input.str.at(i - 2))).ch() : '\0';

  switch (lhs)
  {
    case '"':
    {
      if (rhs == '"' && prv != '\\')
      {
        edit_delete();
      }

      break;
    }

    case '(':
    {
      if (rhs == ')' && prv != '\\')
      {
        edit_delete();
      }

      break;
    }

    case '[':
    {
      if (rhs == ']' && prv != '\\')
      {
        edit_delete();
      }

      break;
    }

    case '{':
    {
      if (rhs == '}' && prv != '\\')
      {
        edit_delete();
      }

      break;
    }

    default:
    {
      break;
    }
  }

  edit_backspace();
}

std::string Readline::normalize(std::string const& str) const
{
  // trim leading and trailing whitespace
  // collapse sequential whitespace
  // return std::regex_replace(OB::Text::trim(str), std::regex("\\s+"),
  //   " ", std::regex_constants::match_not_null);
  return str;
}

void Readline::mode(Readline::Mode const mode_)
{
  _mode_prev = _mode;
  _mode = mode_;
}

std::ostream& operator<<(std::ostream& os, Readline const& obj)
{
  os << obj.render();

  return os;
}

} // namespace OB