MapLibreParticleLab/include/mln/style/layer.hpp

#pragma once

#include <mln/style/conversion.hpp>
#include <mln/style/style_property.hpp>
#include <mln/style/types.hpp>
#include <mln/util/immutable.hpp>

#include <mapbox/std/weak.hpp>
#include <mapbox/util/type_wrapper.hpp>

#include <cassert>
#include <memory>
#include <optional>
#include <string>

namespace mln {
namespace style {
namespace expression {
enum class Dependency : uint32_t;
} // namespace expression

class LayerObserver;
class Filter;

/**
 * @brief Holds static data for a certain layer type.
 */
struct LayerTypeInfo {
    /**
     * @brief contains the layer type as defined in the style specification;
     */
    const char* type;

    /**
     * @brief contains \c Source::Required if the corresponding layer type
     * requires source. Contains \c Source::NotRequired otherwise.
     */
    const enum class Source {
        Required,
        NotRequired
    } source;

    /**
     * @brief contains \c Pass3D::Required if the corresponding layer type
     * requires 3D rendering pass. Contains \c Pass3D::NotRequired otherwise.
     */
    const enum class Pass3D {
        Required,
        NotRequired
    } pass3d;

    /**
     * @brief contains \c Layout::Required if the corresponding layer type
     * requires layouting. * contains \c Layout::NotRequired otherwise.
     */
    const enum class Layout {
        Required,
        NotRequired
    } layout;

    /**
     * @brief contains \c FadingTiles::Required if the corresponding layer type
     * requires rendering on fading tiles. Contains \c FadingTiles::NotRequired otherwise.
     */
    const enum class FadingTiles {
        Required,
        NotRequired
    } fadingTiles;

    /**
     * @brief contains \c CrossTileIndex::Required if the corresponding layer
     * type requires cross-tile indexing and placement. Contains \c
     * CrossTileIndex::NotRequired otherwise.
     */
    const enum class CrossTileIndex {
        Required,
        NotRequired
    } crossTileIndex;

    /**
     * @brief contains the Id of the supported tile type. Used for internal
     * checks. The contained values correspond to \c Tile::Kind enum.
     */
    const enum class TileKind : uint8_t {
        Geometry,
        Raster,
        RasterDEM,
        NotRequired
    } tileKind;
};

// Added this to support plugins and that their LayerTypeInfo isn't the same point
// across the board
bool layerTypeInfoEquals(const mln::style::LayerTypeInfo* one, const mln::style::LayerTypeInfo* other);

/**
 * The runtime representation of a [layer](https://maplibre.org/maplibre-style-spec/#layers)
 * from the MapLibre Style Spec.
 *
 * `Layer` is an abstract base class; concrete derived classes are provided for
 * each layer type. `Layer` contains functionality that is common to all layer types:
 *
 * * Runtime type information: type predicates and casting
 * * Accessors for properties common to all layer types: ID, visibility, etc.
 * * Cloning and copying
 *
 * All other functionality lives in the derived classes. To instantiate a layer,
 * create an instance of the desired type, calling `LayerManager`:
 *
 *     auto circleLayer = LayerManager::get()->createLayer("circle", ...);
 *
 * NOTE: Derived class must invalidate `weakFactory` in their destructor
 */
class Layer {
public:
    Layer(const Layer&) = delete;
    Layer& operator=(const Layer&) = delete;

    virtual ~Layer();

    std::string getID() const;
    // Source
    std::string getSourceID() const;
    std::string getSourceLayer() const;
    void setSourceLayer(const std::string& sourceLayer);
    void setSourceID(const std::string& sourceID);

    // Filter
    const Filter& getFilter() const;
    void setFilter(const Filter&);

    // Visibility
    VisibilityType getVisibility() const;
    void setVisibility(VisibilityType);

    // Zoom range
    float getMinZoom() const;
    float getMaxZoom() const;
    void setMinZoom(float);
    void setMaxZoom(float);

    // Dynamic properties
    std::optional<conversion::Error> setProperty(const std::string& name, const conversion::Convertible& value);

    virtual StyleProperty getProperty(const std::string&) const = 0;
    virtual Value serialize() const;

    // Private implementation
    /// @cond FALSE

    // TODO : We should not have public mutable data members.
    class Impl;
    Immutable<Impl> baseImpl;

    // Create a layer, copying all properties except id and paint properties from this layer.
    virtual std::unique_ptr<Layer> cloneRef(const std::string& id) const = 0;

    void setObserver(LayerObserver*);

    // For use in SDK bindings, which store a reference to a platform-native
    // peer object here, so that separately-obtained references to this object
    // share identical platform-native peers.
    mapbox::base::TypeWrapper peer;
    Layer(Immutable<Impl>);

    const LayerTypeInfo* getTypeInfo() const noexcept;

    mapbox::base::WeakPtr<Layer> makeWeakPtr() { return weakFactory.makeWeakPtr(); }

    /// Collect dependencies
    expression::Dependency getDependencies() const noexcept;

private:
    std::optional<conversion::Error> setVisibility(const conversion::Convertible& value);
    std::optional<conversion::Error> setMinZoom(const conversion::Convertible& value);
    std::optional<conversion::Error> setMaxZoom(const conversion::Convertible& value);

protected:
    virtual Mutable<Impl> mutableBaseImpl() const = 0;
    void serializeProperty(Value&, const StyleProperty&, const char* propertyName, bool isPaint) const;
    virtual std::optional<conversion::Error> setPropertyInternal(const std::string& name,
                                                                 const conversion::Convertible& value) = 0;
    LayerObserver* observer;
    mapbox::base::WeakPtrFactory<Layer> weakFactory{this};
    // Do not add members here, see `WeakPtrFactory`
};

} // namespace style
} // namespace mln