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#include "qxsdstatemachinebuilder_p.h"

#include "qxsdelement_p.h"
#include "qxsdmodelgroup_p.h"
#include "qxsdschemahelper_p.h"

QT_BEGIN_NAMESPACE

using namespace QPatternist;

/*
 * This methods takes a list of objects and returns a list of list
 * of all combinations the objects can be ordered.
 *
 * e.g. input = [ 1, 2, 3 ]
 *      output = [
 *                  [ 1, 2, 3 ],
 *                  [ 1, 3, 2 ],
 *                  [ 2, 1, 3 ],
 *                  [ 2, 3, 1 ],
 *                  [ 3, 1, 2 ],
 *                  [ 3, 2, 1 ]
 *               ]
 *
 * The method is used to create all possible combinations for the particles
 * in an <all> model group.
 */
template <typename T>
QList< QList<T> > allCombinations(const QList<T> &input)
{
    if (input.count() == 1)
        return (QList< QList<T> >() << input);

    QList< QList<T> > result;
    for (int i = 0; i < input.count(); ++i) {
        QList<T> subList = input;
        T value = subList.takeAt(i);

        QList< QList<T> > subLists = allCombinations(subList);
        for (int j = 0; j < subLists.count(); ++j) {
            subLists[j].prepend(value);
        }
        result << subLists;
    }

    return result;
}

XsdStateMachineBuilder::XsdStateMachineBuilder(XsdStateMachine<XsdTerm::Ptr> *machine, const NamePool::Ptr &namePool, Mode mode)
    : m_stateMachine(machine), m_namePool(namePool), m_mode(mode)
{
}

XsdStateMachine<XsdTerm::Ptr>::StateId XsdStateMachineBuilder::reset()
{
    Q_ASSERT(m_stateMachine);

    m_stateMachine->clear();

    return m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::EndState);
}

XsdStateMachine<XsdTerm::Ptr>::StateId XsdStateMachineBuilder::addStartState(XsdStateMachine<XsdTerm::Ptr>::StateId state)
{
    const XsdStateMachine<XsdTerm::Ptr>::StateId startState = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::StartState);
    m_stateMachine->addEpsilonTransition(startState, state);

    return startState;
}

/*
 * Create the FSA according to Algorithm Tp(S) from http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html
 */
XsdStateMachine<XsdTerm::Ptr>::StateId XsdStateMachineBuilder::buildParticle(const XsdParticle::Ptr &particle, XsdStateMachine<XsdTerm::Ptr>::StateId endState)
{
    XsdStateMachine<XsdTerm::Ptr>::StateId currentStartState = endState;
    XsdStateMachine<XsdTerm::Ptr>::StateId currentEndState = endState;

    // 2
    if (particle->maximumOccursUnbounded()) {
        const XsdStateMachine<XsdTerm::Ptr>::StateId t = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::InternalState);
        const XsdStateMachine<XsdTerm::Ptr>::StateId n = buildTerm(particle->term(), t);

        m_stateMachine->addEpsilonTransition(t, n);
        m_stateMachine->addEpsilonTransition(n, endState);

        currentEndState = t;
        currentStartState = t;
    } else { // 3
        int count = (particle->maximumOccurs() - particle->minimumOccurs());
        if (count > 100)
            count = 100;

        for (int i = 0; i < count; ++i) {
            currentStartState = buildTerm(particle->term(), currentEndState);
            m_stateMachine->addEpsilonTransition(currentStartState, endState);
            currentEndState = currentStartState;
        }
    }

    int minOccurs = particle->minimumOccurs();
    if (minOccurs > 100)
        minOccurs = 100;

    for (int i = 0; i < minOccurs; ++i) {
        currentStartState = buildTerm(particle->term(), currentEndState);
        currentEndState = currentStartState;
    }

    return currentStartState;
}

/*
 * Create the FSA according to Algorithm Tt(S) from http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html
 */
XsdStateMachine<XsdTerm::Ptr>::StateId XsdStateMachineBuilder::buildTerm(const XsdTerm::Ptr &term, XsdStateMachine<XsdTerm::Ptr>::StateId endState)
{
    if (term->isWildcard()) { // 1
        const XsdStateMachine<XsdTerm::Ptr>::StateId b = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::InternalState);
        m_stateMachine->addTransition(b, term, endState);
        return b;
    } else if (term->isElement()) { // 2
        const XsdStateMachine<XsdTerm::Ptr>::StateId b = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::InternalState);
        m_stateMachine->addTransition(b, term, endState);

        const XsdElement::Ptr element(term);
        if (m_mode == CheckingMode) {
            const XsdElement::List substGroups = element->substitutionGroups();
            for (int i = 0; i < substGroups.count(); ++i)
                m_stateMachine->addTransition(b, substGroups.at(i), endState);
        } else if (m_mode == ValidatingMode) {
            const XsdElement::List substGroups = element->substitutionGroups();
            for (int i = 0; i < substGroups.count(); ++i) {
                if (XsdSchemaHelper::substitutionGroupOkTransitive(element, substGroups.at(i), m_namePool))
                    m_stateMachine->addTransition(b, substGroups.at(i), endState);
            }
        }

        return b;
    } else if (term->isModelGroup()) {
        const XsdModelGroup::Ptr group(term);

        if (group->compositor() == XsdModelGroup::ChoiceCompositor) { // 3
            const XsdStateMachine<XsdTerm::Ptr>::StateId b = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::InternalState);

            for (int i = 0; i < group->particles().count(); ++i) {
                const XsdParticle::Ptr particle(group->particles().at(i));
                if (particle->maximumOccurs() != 0) {
                    const XsdStateMachine<XsdTerm::Ptr>::StateId state = buildParticle(particle, endState);
                    m_stateMachine->addEpsilonTransition(b, state);
                }
            }

            return b;
        } else if (group->compositor() == XsdModelGroup::SequenceCompositor) { // 4
            XsdStateMachine<XsdTerm::Ptr>::StateId currentStartState = endState;
            XsdStateMachine<XsdTerm::Ptr>::StateId currentEndState = endState;

            for (int i = (group->particles().count() - 1); i >= 0; --i) { // iterate reverse
                const XsdParticle::Ptr particle(group->particles().at(i));
                if (particle->maximumOccurs() != 0) {
                    currentStartState = buildParticle(particle, currentEndState);
                    currentEndState = currentStartState;
                }
            }

            return currentStartState;
        } else if (group->compositor() == XsdModelGroup::AllCompositor) {
            const XsdStateMachine<XsdTerm::Ptr>::StateId newStartState = m_stateMachine->addState(XsdStateMachine<XsdTerm::Ptr>::InternalState);

            const QList<XsdParticle::List> list = allCombinations(group->particles());

            for (int i = 0; i < list.count(); ++i) {
                XsdStateMachine<XsdTerm::Ptr>::StateId currentStartState = endState;
                XsdStateMachine<XsdTerm::Ptr>::StateId currentEndState = endState;

                const XsdParticle::List particles = list.at(i);
                for (int j = (particles.count() - 1); j >= 0; --j) { // iterate reverse
                    const XsdParticle::Ptr particle(particles.at(j));
                    if (particle->maximumOccurs() != 0) {
                        currentStartState = buildParticle(particle, currentEndState);
                        currentEndState = currentStartState;
                    }
                }
                m_stateMachine->addEpsilonTransition(newStartState, currentStartState);
            }

            if (list.isEmpty())
                return endState;
            else
                return newStartState;
        }
    }

    Q_ASSERT(false);
    return 0;
}

static void internalParticleLookupMap(const XsdParticle::Ptr &particle, QHash<XsdTerm::Ptr, XsdParticle::Ptr> &hash)
{
    hash.insert(particle->term(), particle);

    if (particle->term()->isModelGroup()) {
        const XsdModelGroup::Ptr group(particle->term());
        const XsdParticle::List particles = group->particles();
        for (int i = 0; i < particles.count(); ++i)
            internalParticleLookupMap(particles.at(i), hash);
    }
}

QHash<XsdTerm::Ptr, XsdParticle::Ptr> XsdStateMachineBuilder::particleLookupMap(const XsdParticle::Ptr &particle)
{
    QHash<XsdTerm::Ptr, XsdParticle::Ptr> result;
    internalParticleLookupMap(particle, result);

    return result;
}

QT_END_NAMESPACE