#include "substitutionstable.h"
#include "debug.h"
#include "languagecodes.h"

#include <QComboBox>
#include <QLineEdit>
#include <QPainter>
#include <QStringListModel>
#include <QStyledItemDelegate>

namespace
{
class SubstitutionDelegate : public QStyledItemDelegate
{
public:
  explicit SubstitutionDelegate(QObject *parent = nullptr)
    : QStyledItemDelegate(parent)
  {
  }

  void paint(QPainter *painter, const QStyleOptionViewItem &option,
             const QModelIndex &index) const override
  {
    painter->drawText(option.rect, Qt::AlignCenter, index.data().toString());
  }

  QWidget *createEditor(QWidget *parent,
                        const QStyleOptionViewItem & /*option*/,
                        const QModelIndex & /*index*/) const override
  {
    return new QLineEdit(parent);
  }

  void setEditorData(QWidget *editor, const QModelIndex &index) const override
  {
    auto casted = qobject_cast<QLineEdit *>(editor);
    SOFT_ASSERT(casted, return );
    auto text = index.data(Qt::EditRole).toString();

    text.replace('\\', "\\\\");
    text.replace('\n', "\\n");

    casted->setText(text);
  }

  void setModelData(QWidget *editor, QAbstractItemModel *model,
                    const QModelIndex &index) const override
  {
    auto casted = qobject_cast<QLineEdit *>(editor);
    SOFT_ASSERT(casted, return );
    auto text = casted->text();

    if (!text.isEmpty()) {
      const QMap<QString, QString> replacements{
          {"\\\\", "\\"},
          {"\\n", "\n"},
      };
      for (auto i = 0, end = text.size() - 1; i < end; ++i) {
        const auto pair = text.mid(i, 2);
        const auto replaced = replacements.value(pair);
        if (replaced.isEmpty())
          continue;

        text.replace(i, 2, replaced);
        --end;
      }
    }

    model->setData(index, text);
  }
};  // namespace

}  // namespace

SubstitutionsTable::SubstitutionsTable(QWidget *parent)
  : QTableWidget(parent)
  , substitutionLanguages_(new QStringListModel(this))
{
  setItemDelegate(new SubstitutionDelegate(this));
  setColumnCount(int(Column::Count));
  setHorizontalHeaderLabels({tr("Language"), tr("Source"), tr("Changed")});
  connect(this, &SubstitutionsTable::itemChanged,  //
          this, &SubstitutionsTable::handleItemChange);
}

void SubstitutionsTable::setSourceLanguageModel(QStringListModel *model)
{
  sourceLanguages_ = model;
  connect(model, &QStringListModel::modelReset,  //
          this, [this] {
            if (rowCount() > 0)  // must be at least 1 if inited
              setSubstitutions(substitutions());
          });
}

void SubstitutionsTable::setSubstitutions(const Substitutions &substitutions)
{
  setRowCount(0);

  updateModel(substitutions);

  for (const auto &i : substitutions) addRow(i.first, i.second);

  addRow();  // for editing
  resizeColumnsToContents();
}

void SubstitutionsTable::updateModel(const Substitutions &substitutions)
{
  auto strings = sourceLanguages_->stringList();

  if (!substitutions.empty()) {
    for (const auto &i : substitutions) {
      const auto name =
          LanguageCodes::name(LanguageCodes::idForTesseract(i.first));

      if (!strings.contains(name))
        strings.append(name);
    }
  }

  const auto any = LanguageCodes::name(LanguageCodes::anyLanguageId());
  if (!strings.contains(any))
    strings.append(any);

  std::sort(strings.begin(), strings.end());
  substitutionLanguages_->setStringList(strings);
}

Substitutions SubstitutionsTable::substitutions() const
{
  Substitutions result;
  for (auto row = 0, end = rowCount(); row < end; ++row) {
    const auto pair = at(row);
    if (pair.first.isEmpty() || pair.second.source.isEmpty())
      continue;
    result.emplace(pair.first, pair.second);
  }
  return result;
}

void SubstitutionsTable::addRow(const LanguageId &language,
                                const Substitution &substutution)
{
  QSignalBlocker blocker(this);
  auto row = rowCount();
  insertRow(row);

  auto combo = new QComboBox(this);
  combo->setModel(substitutionLanguages_);

  using E = Column;
  if (!language.isEmpty()) {
    combo->setCurrentText(LanguageCodes::name(language));
  } else if (rowCount() > 1) {
    const auto previousRow = rowCount() - 2;
    auto previousCombo =
        static_cast<QComboBox *>(cellWidget(previousRow, int(E::Language)));
    SOFT_ASSERT(previousCombo, return );
    combo->setCurrentText(previousCombo->currentText());
  }

  setCellWidget(row, int(E::Language), combo);
  setItem(row, int(E::Source), new QTableWidgetItem(substutution.source));
  setItem(row, int(E::Target), new QTableWidgetItem(substutution.target));
}

std::pair<LanguageId, Substitution> SubstitutionsTable::at(int row) const
{
  SOFT_ASSERT(row >= 0 && row < rowCount(), return {});

  using E = Column;
  auto combo = static_cast<QComboBox *>(cellWidget(row, int(E::Language)));
  SOFT_ASSERT(combo, return {});

  if (combo->currentText().isEmpty())
    return {};

  const auto langId = LanguageCodes::idForName(combo->currentText());
  SOFT_ASSERT(!langId.isEmpty(), return {});

  Substitution sub;
  auto sourceItem = item(row, int(E::Source));
  SOFT_ASSERT(sourceItem, return {});
  sub.source = sourceItem->text();

  auto targetItem = item(row, int(E::Target));
  SOFT_ASSERT(targetItem, return {});
  sub.target = targetItem->text();

  return std::make_pair(langId, sub);
}

void SubstitutionsTable::handleItemChange(QTableWidgetItem *item)
{
  if (item->column() != int(Column::Source))
    return;

  const auto lastRow = rowCount() - 1;
  if (!item->text().isEmpty() && item->row() == lastRow) {
    addRow();
    return;
  }

  if (item->text().isEmpty() && item->row() != lastRow) {
    removeRow(item->row());
    return;
  }
}