// Copyright (C) 2016 Jochen Becher
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#pragma once

#include "handle.h"
#include "qmt/infrastructure/qmtassert.h"

#include <QList>
#include <QHash>

namespace qmt {

template<typename T>
class Handles
{
public:
    typedef QList<Handle<T>> value_type;
    typedef typename value_type::iterator iterator;
    typedef typename value_type::const_iterator const_iterator;

    explicit Handles(bool takeOwnership = false) : m_takesOwnership(takeOwnership) { }

    Handles(const Handles<T> &rhs)
        : m_handleList(rhs.m_handleList)
    {
    }

    Handles(const Handles<T> &rhs, bool takeOwnership)
        : m_handleList(rhs.m_handleList),
          m_takesOwnership(takeOwnership)
    {
        if (m_takesOwnership && rhs.m_takesOwnership)
            const_cast<Handles<T> &>(rhs).m_handleList.clear();
    }

    ~Handles()
    {
        reset();
    }

    Handles<T> operator=(const Handles<T> &rhs)
    {
        if (this != &rhs) {
            m_handleList = rhs.m_handleList;
            if (m_takesOwnership && rhs.m_takesOwnership)
                const_cast<Handles<T> &>(rhs).m_handleList.clear();
        }
        return *this;
    }

    bool takesOwnership() const { return m_takesOwnership; }
    bool isEmpty() const { return m_handleList.empty(); }
    int size() const { return m_handleList.size(); }

    bool contains(const Uid &uid) const
    {
        for (const Handle<T> &handle : std::as_const(m_handleList)) {
            if (handle.uid() == uid)
                return true;
        }
        return false;
    }

    bool contains(const T *t) const
    {
        QMT_ASSERT(t, return false);
        return contains(t->uid());
    }

    T *find(const Uid &uid) const
    {
        for (const Handle<T> &handle : std::as_const(m_handleList)) {
            if (handle.uid() == uid)
                return handle.target();
        }
        return nullptr;
    }

    T *at(int index) const
    {
        QMT_ASSERT(index >= 0 && index < m_handleList.size(), return nullptr);
        return m_handleList.at(index).target();
    }

    T *at(int index)
    {
        QMT_ASSERT(index >= 0 && index < m_handleList.size(), return nullptr);
        return m_handleList.at(index);
    }

    int indexOf(const Uid &uid) const
    {
        int index = 0;
        for (const Handle<T> &handle : std::as_const(m_handleList)) {
            if (handle.uid() == uid)
                return index;
            ++index;
        }
        return -1;
    }

    int indexOf(const T *t) const
    {
        QMT_ASSERT(t, return -1);
        return indexOf(t->uid());
    }

    const value_type &get() const { return m_handleList; }

    value_type take()
    {
        value_type handles = m_handleList;
        m_handleList.clear();
        return handles;
    }

    void set(const value_type &handles) {
        reset();
        m_handleList = handles;
    }

    void reset()
    {
        if (m_takesOwnership) {
            for (const Handle<T> &handle : std::as_const(m_handleList))
                delete handle.target();
        }
        m_handleList.clear();
    }

    iterator begin() { return m_handleList.begin(); }
    iterator end() { return m_handleList.end(); }
    const_iterator begin() const { return m_handleList.begin(); }
    const_iterator end() const { return m_handleList.end(); }

    void add(const Uid &uid)
    {
        QMT_CHECK(uid.isValid());
        m_handleList.append(Handle<T>(uid));
    }

    void add(T *t)
    {
        QMT_ASSERT(t, return);
        m_handleList.append(Handle<T>(t));
    }

    void insert(int beforeIndex, const Uid &uid)
    {
        QMT_ASSERT(beforeIndex >= 0 && beforeIndex <= m_handleList.size(), return);
        QMT_ASSERT(uid.isValid(), return);
        m_handleList.insert(beforeIndex, Handle<T>(uid));
    }

    void insert(int beforeIndex, T *t)
    {
        QMT_ASSERT(beforeIndex >= 0 && beforeIndex <= m_handleList.size(), return);
        QMT_ASSERT(t, return);
        m_handleList.insert(beforeIndex, Handle<T>(t));
    }

    void remove(int index)
    {
        QMT_ASSERT(index >= 0 && index < size(), return);
        if (m_takesOwnership) {
            T *t = m_handleList.at(index).target();
            m_handleList.removeAt(index);
            delete t;
        } else {
            m_handleList.removeAt(index);
        }
    }

    void remove(const Uid &uid)
    {
        remove(indexOf(uid));
    }

    void remove(T *t)
    {
        QMT_ASSERT(t, return);
        remove(indexOf(t));
    }

    T * take(int index)
    {
        QMT_ASSERT(index >= 0 && index < size(), return nullptr);
        T *t = m_handleList.at(index).target();
        m_handleList.removeAt(index);
        return t;
    }

    T *take(const Uid &uid)
    {
        return take(indexOf(uid));
    }

    T *take(T *t)
    {
        QMT_ASSERT(t, return nullptr);
        return take(indexOf(t));
    }

    friend bool operator==(const Handles<T> &lhs, const Handles<T> &rhs)
    {
        return lhs.get() == rhs.get();
    }

    friend bool operator!=(const Handles &lhs, const Handles &rhs) { return !(lhs == rhs); }

private:
    value_type m_handleList;
    bool m_takesOwnership = false;
};

} // namespace qmt