#ifndef LIBMPV_QTHELPER_H_
#define LIBMPV_QTHELPER_H_

#include <mpv/client.h>

#include <cstring>

#include <QHash>
#include <QList>
#include <QMetaType>
#include <QSharedPointer>
#include <QString>
#include <QVariant>

namespace mpv {
namespace qt {

    // Wrapper around mpv_handle. Does refcounting under the hood.
    class Handle {
        struct container {
            container(mpv_handle* h)
                : mpv(h)
            {
            }
            ~container() { mpv_terminate_destroy(mpv); }
            mpv_handle* mpv;
        };
        QSharedPointer<container> sptr;

    public:
        // Construct a new Handle from a raw mpv_handle with refcount 1. If the
        // last Handle goes out of scope, the mpv_handle will be destroyed with
        // mpv_terminate_destroy().
        // Never destroy the mpv_handle manually when using this wrapper. You
        // will create dangling pointers. Just let the wrapper take care of
        // destroying the mpv_handle.
        // Never create multiple wrappers from the same raw mpv_handle; copy the
        // wrapper instead (that's what it's for).
        static Handle FromRawHandle(mpv_handle* handle)
        {
            Handle h;
            h.sptr = QSharedPointer<container>(new container(handle));
            return h;
        }

        // Return the raw handle; for use with the libmpv C API.
        operator mpv_handle*() const { return sptr ? (*sptr).mpv : 0; }
    };

    static inline QVariant node_to_variant(const mpv_node* node)
    {
        switch (node->format) {
        case MPV_FORMAT_STRING:
            return QVariant(QString::fromUtf8(node->u.string));
        case MPV_FORMAT_FLAG:
            return QVariant(static_cast<bool>(node->u.flag));
        case MPV_FORMAT_INT64:
            return QVariant(static_cast<qlonglong>(node->u.int64));
        case MPV_FORMAT_DOUBLE:
            return QVariant(node->u.double_);
        case MPV_FORMAT_NODE_ARRAY: {
            mpv_node_list* list = node->u.list;
            QVariantList qlist;
            for (int n = 0; n < list->num; n++)
                qlist.append(node_to_variant(&list->values[n]));
            return QVariant(qlist);
        }
        case MPV_FORMAT_NODE_MAP: {
            mpv_node_list* list = node->u.list;
            QVariantMap qmap;
            for (int n = 0; n < list->num; n++) {
                qmap.insert(QString::fromUtf8(list->keys[n]),
                    node_to_variant(&list->values[n]));
            }
            return QVariant(qmap);
        }
        default: // MPV_FORMAT_NONE, unknown values (e.g. future extensions)
            return QVariant();
        }
    }

    struct node_builder {
        node_builder(const QVariant& v)
        {
            set(&node_, v);
        }
        ~node_builder()
        {
            free_node(&node_);
        }
        mpv_node* node() { return &node_; }

    private:
        Q_DISABLE_COPY(node_builder)
        mpv_node node_;
        mpv_node_list* create_list(mpv_node* dst, bool is_map, int num)
        {
            dst->format = is_map ? MPV_FORMAT_NODE_MAP : MPV_FORMAT_NODE_ARRAY;
            mpv_node_list* list = new mpv_node_list();
            dst->u.list = list;
            if (!list)
                goto err;
            list->values = new mpv_node[num]();
            if (!list->values)
                goto err;
            if (is_map) {
                list->keys = new char*[num]();
                if (!list->keys)
                    goto err;
            }
            return list;
        err:
            free_node(dst);
            return NULL;
        }
        char* dup_qstring(const QString& s)
        {
            QByteArray b = s.toUtf8();
            char* r = new char[b.size() + 1];
            if (r)
                std::memcpy(r, b.data(), b.size() + 1);
            return r;
        }
        bool test_type(const QVariant& v, QMetaType::Type t)
        {
            // The Qt docs say: "Although this function is declared as returning
            // "QVariant::Type(obsolete), the return value should be interpreted
            // as QMetaType::Type."
            // So a cast really seems to be needed to avoid warnings (urgh).
            return static_cast<int>(v.type()) == static_cast<int>(t);
        }
        void set(mpv_node* dst, const QVariant& src)
        {
            if (test_type(src, QMetaType::QString)) {
                dst->format = MPV_FORMAT_STRING;
                dst->u.string = dup_qstring(src.toString());
                if (!dst->u.string)
                    goto fail;
            } else if (test_type(src, QMetaType::Bool)) {
                dst->format = MPV_FORMAT_FLAG;
                dst->u.flag = src.toBool() ? 1 : 0;
            } else if (test_type(src, QMetaType::Int) || test_type(src, QMetaType::LongLong) || test_type(src, QMetaType::UInt) || test_type(src, QMetaType::ULongLong)) {
                dst->format = MPV_FORMAT_INT64;
                dst->u.int64 = src.toLongLong();
            } else if (test_type(src, QMetaType::Double)) {
                dst->format = MPV_FORMAT_DOUBLE;
                dst->u.double_ = src.toDouble();
            } else if (src.canConvert<QVariantList>()) {
                QVariantList qlist = src.toList();
                mpv_node_list* list = create_list(dst, false, qlist.size());
                if (!list)
                    goto fail;
                list->num = qlist.size();
                for (int n = 0; n < qlist.size(); n++)
                    set(&list->values[n], qlist[n]);
            } else if (src.canConvert<QVariantMap>()) {
                QVariantMap qmap = src.toMap();
                mpv_node_list* list = create_list(dst, true, qmap.size());
                if (!list)
                    goto fail;
                list->num = qmap.size();
                for (int n = 0; n < qmap.size(); n++) {
                    list->keys[n] = dup_qstring(qmap.keys()[n]);
                    if (!list->keys[n]) {
                        free_node(dst);
                        goto fail;
                    }
                    set(&list->values[n], qmap.values()[n]);
                }
            } else {
                goto fail;
            }
            return;
        fail:
            dst->format = MPV_FORMAT_NONE;
        }
        void free_node(mpv_node* dst)
        {
            switch (dst->format) {
            case MPV_FORMAT_STRING:
                delete[] dst->u.string;
                break;
            case MPV_FORMAT_NODE_ARRAY:
            case MPV_FORMAT_NODE_MAP: {
                mpv_node_list* list = dst->u.list;
                if (list) {
                    for (int n = 0; n < list->num; n++) {
                        if (list->keys)
                            delete[] list->keys[n];
                        if (list->values)
                            free_node(&list->values[n]);
                    }
                    delete[] list->keys;
                    delete[] list->values;
                }
                delete list;
                break;
            }
            default:;
            }
            dst->format = MPV_FORMAT_NONE;
        }
    };

    /**
 * RAII wrapper that calls mpv_free_node_contents() on the pointer.
 */
    struct node_autofree {
        mpv_node* ptr;
        node_autofree(mpv_node* a_ptr)
            : ptr(a_ptr)
        {
        }
        ~node_autofree() { mpv_free_node_contents(ptr); }
    };

    /**
 * Return the given property as mpv_node converted to QVariant, or QVariant()
 * on error.
 *
 * @deprecated use get_property() instead
 *
 * @param name the property name
 */
    static inline QVariant get_property_variant(mpv_handle* ctx, const QString& name)
    {
        mpv_node node;
        if (mpv_get_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, &node) < 0)
            return QVariant();
        node_autofree f(&node);
        return node_to_variant(&node);
    }

    /**
 * Set the given property as mpv_node converted from the QVariant argument.

 * @deprecated use set_property() instead
 */
    static inline int set_property_variant(mpv_handle* ctx, const QString& name,
        const QVariant& v)
    {
        node_builder node(v);
        return mpv_set_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
    }

    /**
 * Set the given option as mpv_node converted from the QVariant argument.
 *
 * @deprecated use set_property() instead
 */
    static inline int set_option_variant(mpv_handle* ctx, const QString& name,
        const QVariant& v)
    {
        node_builder node(v);
        return mpv_set_option(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
    }

    /**
 * mpv_command_node() equivalent. Returns QVariant() on error (and
 * unfortunately, the same on success).
 *
 * @deprecated use command() instead
 */
    static inline QVariant command_variant(mpv_handle* ctx, const QVariant& args)
    {
        node_builder node(args);
        mpv_node res;
        if (mpv_command_node(ctx, node.node(), &res) < 0)
            return QVariant();
        node_autofree f(&res);
        return node_to_variant(&res);
    }

    /**
 * This is used to return error codes wrapped in QVariant for functions which
 * return QVariant.
 *
 * You can use get_error() or is_error() to extract the error status from a
 * QVariant value.
 */
    struct ErrorReturn {
        /**
     * enum mpv_error value (or a value outside of it if ABI was extended)
     */
        int error;

        ErrorReturn()
            : error(0)
        {
        }
        explicit ErrorReturn(int err)
            : error(err)
        {
        }
    };

    /**
 * Return the mpv error code packed into a QVariant, or 0 (success) if it's not
 * an error value.
 *
 * @return error code (<0) or success (>=0)
 */
    static inline int get_error(const QVariant& v)
    {
        if (!v.canConvert<ErrorReturn>())
            return 0;
        return v.value<ErrorReturn>().error;
    }

    /**
 * Return whether the QVariant carries a mpv error code.
 */
    static inline bool is_error(const QVariant& v)
    {
        return get_error(v) < 0;
    }

    /**
 * Return the given property as mpv_node converted to QVariant, or QVariant()
 * on error.
 *
 * @param name the property name
 * @return the property value, or an ErrorReturn with the error code
 */
    static inline QVariant get_property(mpv_handle* ctx, const QString& name)
    {
        mpv_node node;
        int err = mpv_get_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, &node);
        if (err < 0)
            return QVariant::fromValue(ErrorReturn(err));
        node_autofree f(&node);
        return node_to_variant(&node);
    }

    /**
 * Set the given property as mpv_node converted from the QVariant argument.
 *
 * @return mpv error code (<0 on error, >= 0 on success)
 */
    static inline int set_property(mpv_handle* ctx, const QString& name,
        const QVariant& v)
    {
        node_builder node(v);
        return mpv_set_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
    }

    /**
 * mpv_command_node() equivalent.
 *
 * @param args command arguments, with args[0] being the command name as string
 * @return the property value, or an ErrorReturn with the error code
 */
    static inline QVariant command(mpv_handle* ctx, const QVariant& args)
    {
        node_builder node(args);
        mpv_node res;
        int err = mpv_command_node(ctx, node.node(), &res);
        if (err < 0)
            return QVariant::fromValue(ErrorReturn(err));
        node_autofree f(&res);
        return node_to_variant(&res);
    }
}
}

Q_DECLARE_METATYPE(mpv::qt::ErrorReturn)

#endif