#include "spells.hpp"

#include <components/debug/debuglog.hpp>
#include <components/esm3/loadspel.hpp>
#include <components/esm3/spellstate.hpp>

#include <components/esm3/loadmgef.hpp>

#include "../mwbase/environment.hpp"
#include "../mwbase/world.hpp"

#include "../mwworld/class.hpp"
#include "../mwworld/esmstore.hpp"

#include "actorutil.hpp"
#include "creaturestats.hpp"
#include "stat.hpp"

namespace MWMechanics
{
    Spells::Spells() {}

    Spells::Spells(const Spells& spells)
        : mSpellList(spells.mSpellList)
        , mSpells(spells.mSpells)
        , mSelectedSpell(spells.mSelectedSpell)
        , mUsedPowers(spells.mUsedPowers)
    {
        if (mSpellList)
            mSpellList->addListener(this);
    }

    Spells::Spells(Spells&& spells)
        : mSpellList(std::move(spells.mSpellList))
        , mSpells(std::move(spells.mSpells))
        , mSelectedSpell(std::move(spells.mSelectedSpell))
        , mUsedPowers(std::move(spells.mUsedPowers))
    {
        if (mSpellList)
            mSpellList->updateListener(&spells, this);
    }

    std::vector<const ESM::Spell*>::const_iterator Spells::begin() const
    {
        return mSpells.begin();
    }

    std::vector<const ESM::Spell*>::const_iterator Spells::end() const
    {
        return mSpells.end();
    }

    bool Spells::hasSpell(const ESM::RefId& spell) const
    {
        return hasSpell(SpellList::getSpell(spell));
    }

    bool Spells::hasSpell(const ESM::Spell* spell) const
    {
        return std::find(mSpells.begin(), mSpells.end(), spell) != mSpells.end();
    }

    void Spells::add(const ESM::Spell* spell, bool modifyBase)
    {
        if (modifyBase)
            mSpellList->add(spell);
        else
            addSpell(spell);
    }

    void Spells::add(const ESM::RefId& spellId, bool modifyBase)
    {
        add(SpellList::getSpell(spellId), modifyBase);
    }

    void Spells::addSpell(const ESM::Spell* spell)
    {
        if (!hasSpell(spell))
            mSpells.emplace_back(spell);
    }

    void Spells::remove(const ESM::RefId& spellId, bool modifyBase)
    {
        remove(SpellList::getSpell(spellId), modifyBase);
    }

    void Spells::remove(const ESM::Spell* spell, bool modifyBase)
    {
        removeSpell(spell);
        if (modifyBase)
            mSpellList->remove(spell);
        if (spell->mId == mSelectedSpell)
            mSelectedSpell = ESM::RefId();
    }

    void Spells::removeSpell(const ESM::Spell* spell)
    {
        const auto it = std::find(mSpells.begin(), mSpells.end(), spell);
        if (it != mSpells.end())
            mSpells.erase(it);
    }

    void Spells::removeAllSpells()
    {
        mSpells.clear();
    }

    void Spells::clear(bool modifyBase)
    {
        removeAllSpells();
        if (modifyBase)
            mSpellList->clear();
    }

    void Spells::setSelectedSpell(const ESM::RefId& spellId)
    {
        mSelectedSpell = spellId;
    }

    const ESM::RefId& Spells::getSelectedSpell() const
    {
        return mSelectedSpell;
    }

    bool Spells::hasSpellType(const ESM::Spell::SpellType type) const
    {
        auto it = std::find_if(std::begin(mSpells), std::end(mSpells),
            [=](const ESM::Spell* spell) { return spell->mData.mType == type; });
        return it != std::end(mSpells);
    }

    bool Spells::hasCommonDisease() const
    {
        return hasSpellType(ESM::Spell::ST_Disease);
    }

    bool Spells::hasBlightDisease() const
    {
        return hasSpellType(ESM::Spell::ST_Blight);
    }

    void Spells::purge(const SpellFilter& filter)
    {
        std::vector<ESM::RefId> purged;
        for (auto iter = mSpells.begin(); iter != mSpells.end();)
        {
            const ESM::Spell* spell = *iter;
            if (filter(spell))
            {
                iter = mSpells.erase(iter);
                purged.push_back(spell->mId);
            }
            else
                ++iter;
        }
        if (!purged.empty())
            mSpellList->removeAll(purged);
    }

    void Spells::purgeCommonDisease()
    {
        purge([](auto spell) { return spell->mData.mType == ESM::Spell::ST_Disease; });
    }

    void Spells::purgeBlightDisease()
    {
        purge([](auto spell) { return spell->mData.mType == ESM::Spell::ST_Blight && !hasCorprusEffect(spell); });
    }

    void Spells::purgeCorprusDisease()
    {
        purge(&hasCorprusEffect);
    }

    void Spells::purgeCurses()
    {
        purge([](auto spell) { return spell->mData.mType == ESM::Spell::ST_Curse; });
    }

    bool Spells::hasCorprusEffect(const ESM::Spell* spell)
    {
        for (const auto& effectIt : spell->mEffects.mList)
        {
            if (effectIt.mData.mEffectID == ESM::MagicEffect::Corprus)
            {
                return true;
            }
        }
        return false;
    }

    bool Spells::canUsePower(const ESM::Spell* spell) const
    {
        const auto it = std::find_if(
            std::begin(mUsedPowers), std::end(mUsedPowers), [&](auto& pair) { return pair.first == spell; });
        return it == mUsedPowers.end() || it->second + 24 <= MWBase::Environment::get().getWorld()->getTimeStamp();
    }

    void Spells::usePower(const ESM::Spell* spell)
    {
        // Updates or inserts a new entry with the current timestamp.
        const auto it = std::find_if(
            std::begin(mUsedPowers), std::end(mUsedPowers), [&](auto& pair) { return pair.first == spell; });
        const auto timestamp = MWBase::Environment::get().getWorld()->getTimeStamp();
        if (it == mUsedPowers.end())
            mUsedPowers.emplace_back(spell, timestamp);
        else
            it->second = timestamp;
    }

    void Spells::readState(const ESM::SpellState& state, CreatureStats* creatureStats)
    {
        const auto& baseSpells = mSpellList->getSpells();

        for (const ESM::RefId& id : state.mSpells)
        {
            // Discard spells that are no longer available due to changed content files
            const ESM::Spell* spell = MWBase::Environment::get().getESMStore()->get<ESM::Spell>().search(id);
            if (spell)
            {
                addSpell(spell);

                if (id == state.mSelectedSpell)
                    mSelectedSpell = id;
            }
        }
        // Add spells from the base record
        for (const ESM::RefId& id : baseSpells)
        {
            const ESM::Spell* spell = MWBase::Environment::get().getESMStore()->get<ESM::Spell>().search(id);
            if (spell)
                addSpell(spell);
        }

        for (auto it = state.mUsedPowers.begin(); it != state.mUsedPowers.end(); ++it)
        {
            const ESM::Spell* spell = MWBase::Environment::get().getESMStore()->get<ESM::Spell>().search(it->first);
            if (!spell)
                continue;
            mUsedPowers.emplace_back(spell, MWWorld::TimeStamp(it->second));
        }

        // Permanent effects are used only to keep the custom magnitude of corprus spells effects (after cure too), and
        // only in old saves. Convert data to the new approach.
        for (auto it = state.mPermanentSpellEffects.begin(); it != state.mPermanentSpellEffects.end(); ++it)
        {
            const ESM::Spell* spell = MWBase::Environment::get().getESMStore()->get<ESM::Spell>().search(it->first);
            if (!spell)
                continue;

            // Import data only for player, other actors should not suffer from corprus worsening.
            MWWorld::Ptr player = getPlayer();
            if (creatureStats->getActorId() != player.getClass().getCreatureStats(player).getActorId())
                return;

            // Note: if target actor has the Restore attribute effects, stats will be restored.
            for (const ESM::SpellState::PermanentSpellEffectInfo& info : it->second)
            {
                // Applied corprus effects are already in loaded stats modifiers
                if (info.mId == ESM::MagicEffect::FortifyAttribute)
                {
                    auto id = ESM::Attribute::indexToRefId(info.mArg);
                    AttributeValue attr = creatureStats->getAttribute(id);
                    attr.setModifier(attr.getModifier() - info.mMagnitude);
                    attr.damage(-info.mMagnitude);
                    creatureStats->setAttribute(id, attr);
                }
                else if (info.mId == ESM::MagicEffect::DrainAttribute)
                {
                    auto id = ESM::Attribute::indexToRefId(info.mArg);
                    AttributeValue attr = creatureStats->getAttribute(id);
                    attr.setModifier(attr.getModifier() + info.mMagnitude);
                    attr.damage(info.mMagnitude);
                    creatureStats->setAttribute(id, attr);
                }
            }
        }
    }

    void Spells::writeState(ESM::SpellState& state) const
    {
        const auto& baseSpells = mSpellList->getSpells();
        for (const auto spell : mSpells)
        {
            // Don't save spells and powers stored in the base record
            if ((spell->mData.mType != ESM::Spell::ST_Spell && spell->mData.mType != ESM::Spell::ST_Power)
                || std::find(baseSpells.begin(), baseSpells.end(), spell->mId) == baseSpells.end())
            {
                state.mSpells.emplace_back(spell->mId);
            }
        }

        state.mSelectedSpell = mSelectedSpell;

        for (const auto& it : mUsedPowers)
            state.mUsedPowers[it.first->mId] = it.second.toEsm();
    }

    bool Spells::setSpells(const ESM::RefId& actorId)
    {
        bool result;
        std::tie(mSpellList, result) = MWBase::Environment::get().getESMStore()->getSpellList(actorId);
        mSpellList->addListener(this);
        addAllToInstance(mSpellList->getSpells());
        return result;
    }

    void Spells::addAllToInstance(const std::vector<ESM::RefId>& spells)
    {
        for (const ESM::RefId& id : spells)
        {
            const ESM::Spell* spell = MWBase::Environment::get().getESMStore()->get<ESM::Spell>().search(id);
            if (spell)
                addSpell(spell);
            else
                Log(Debug::Warning) << "Warning: ignoring nonexistent spell " << id;
        }
    }

    Spells::~Spells()
    {
        if (mSpellList)
            mSpellList->removeListener(this);
    }
}
