#include "UsernameSet.hpp"

#include <tuple>

namespace chatterino {

//
// UsernameSet
//

UsernameSet::ConstIterator UsernameSet::begin() const
{
    return this->items.begin();
}

UsernameSet::ConstIterator UsernameSet::end() const
{
    return this->items.end();
}

UsernameSet::Range UsernameSet::subrange(const Prefix &prefix) const
{
    auto it = this->firstKeyForPrefix.find(prefix);
    if (it != this->firstKeyForPrefix.end())
    {
        auto start = this->items.find(it->second);
        auto end = start;

        while (end != this->items.end() && prefix.isStartOf(*end))
        {
            end++;
        }
        return {start, end};
    }

    return {this->items.end(), this->items.end()};
}

std::set<QString>::size_type UsernameSet::size() const
{
    return this->items.size();
}

std::pair<UsernameSet::Iterator, bool> UsernameSet::insert(const QString &value)
{
    this->insertPrefix(value);

    return this->items.insert(value);
}

std::pair<UsernameSet::Iterator, bool> UsernameSet::insert(QString &&value)
{
    this->insertPrefix(value);

    return this->items.insert(std::move(value));
}

void UsernameSet::insertPrefix(const QString &value)
{
    auto &string = this->firstKeyForPrefix[Prefix(value)];

    if (string.isNull() || value < string)
        string = value;
}

//
// Range
//

UsernameSet::Range::Range(ConstIterator start, ConstIterator end)
    : start_(start)
    , end_(end)
{
}

UsernameSet::ConstIterator UsernameSet::Range::begin()
{
    return this->start_;
}

UsernameSet::ConstIterator UsernameSet::Range::end()
{
    return this->end_;
}

//
// Prefix
//

Prefix::Prefix(const QString &string)
    : first(string.size() >= 1 ? string[0].toLower() : '\0')
    , second(string.size() >= 2 ? string[1].toLower() : '\0')
{
}

bool Prefix::operator==(const Prefix &other) const
{
    return std::tie(this->first, this->second) ==
           std::tie(other.first, other.second);
}

bool Prefix::isStartOf(const QString &string) const
{
    if (string.size() == 0)
    {
        return this->first == QChar('\0') && this->second == QChar('\0');
    }
    else if (string.size() == 1)
    {
        return this->first == string[0].toLower() &&
               this->second == QChar('\0');
    }
    else
    {
        return this->first == string[0].toLower() &&
               this->second == string[1].toLower();
    }
}

}  // namespace chatterino