#include "list_model.h"

namespace roro {

void ListModel::setCount(int count) {
    count_ = count < 0 ? 0 : count;
    if (count_ == 0) {
        selected_ = -1;
        first_ = 0;
        return;
    }
    select(selected_ < 0 ? 0 : selected_);
}

void ListModel::select(int index) {
    if (count_ == 0) return;
    selected_ = index < 0 ? 0 : index >= count_ ? count_ - 1 : index;
    scrollToSelection();
}

void ListModel::up() {
    if (count_ == 0) return;
    select(selected_ == 0 ? count_ - 1 : selected_ - 1);
}

void ListModel::down() {
    if (count_ == 0) return;
    select(selected_ == count_ - 1 ? 0 : selected_ + 1);
}

void ListModel::pageUp() { select(selected_ - rows_); }
void ListModel::pageDown() { select(selected_ + rows_); }

void ListModel::scrollToSelection() {
    if (selected_ < first_) first_ = selected_;
    if (selected_ >= first_ + rows_) first_ = selected_ - rows_ + 1;
    int maxFirst = count_ > rows_ ? count_ - rows_ : 0;
    if (first_ > maxFirst) first_ = maxFirst;
}

}  // namespace roro