#pragma once

#include <ikarus/macros.h>
#include <ikarus/stdtypes.h>

/// \file entity.h
/// \author Folling <folling@ikarus.world>

/// \defgroup entities Entities
/// \brief Entities are the core building blocks of Ikarus.

IKARUS_BEGIN_HEADER

/// \brief Entities are the core building blocks of Ikarus.
/// \detials Blueprints and Properties define the structure of the data.
/// Entities define the data itself.
///
/// Properties can be associated with Entities in two ways:
/// - Directly: The property is linked to the entity.
/// - Indirectly: The property is linked to a blueprint the entity is linked to.
///
/// For each property an entity is linked to, it has a value. These values depend on the property's type.
/// For more information on the types see the property documentation.
///
/// Values are the core type of data within Ikarus.
/// Each value is associated with one page and one property.
///
/// \remark Values are typed, the type of a value is specified by its associated property.
/// For more information on the types see the property documentation.
///
/// \remark Values are guaranteed to be in valid format for a given type
/// but not guaranteed to be valid under the settings of the property.
/// This is because changing the settings can invalidate existing values without resetting them.
struct IkarusEntity;

/// \brief Creates an entity.
/// \param project The project the entity is part of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param parent The parent folder of the entity.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param position The position of the entity in the parent folder. \see #FolderPosition
/// \pre \li Must be within bounds for the parent folder.
/// \param name The name of the entity.
/// \pre \li Must not be null.
/// \pre \li Must not be empty.
/// \param blueprints Blueprints to link the entity to (0..n). Null is treated as an empty array.
/// \param blueprints_count The number of blueprints.
/// \return The created entity or null if an error occurs.
/// \remark Must be freed using #ikarus_free.
IKA_API IkarusEntity * ikarus_entity_create(
    struct IkarusProject * project,
    struct IkarusEntityFolder * parent,
    size_t position,
    char const * name,
    struct IkarusBlueprint ** blueprints,
    size_t blueprints_count
);

/// \brief Copies an entity.
/// \details Creates a deep copy of the entity including all of its properties & associated values.
/// \param entity The entity to copy.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param parent The parent folder of the entity.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param position The position of the entity in the parent folder. \see #FolderPosition
/// \pre \li Must be within bounds for the parent folder.
/// \param name The name of the entity.
/// \pre \li Must not be null.
/// \pre \li Must not be empty.
/// \return The created entity or null if an error occurs.
/// \remark Must be freed using #ikarus_free.
IKA_API IkarusEntity * ikarus_entity_copy(
    struct IkarusEntity * entity, struct IkarusEntityFolder * parent, size_t position, char const * name
);

/// \brief Deletes an entity.
/// \param entity The entity to delete.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \remark The entity must not be accessed after deletion.
IKA_API void ikarus_entity_delete(IkarusEntity * entity);

IKA_API bool ikarus_entity_is_linked_to_blueprint(IkarusEntity const * entity, struct IkarusBlueprint const * blueprint);

/// \brief Checks if an entity has a specific property.
/// \param entity The entity to check.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param property The property to check.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return True if the entity has the property, false otherwise.
IKA_API bool ikarus_entity_has_property(IkarusEntity const * entity, struct IkarusProperty const * property);

/// \brief Links an entity to a blueprint.
/// \param entity The entity to link.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param blueprint The blueprint to link the entity to.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \remark No-op if the entity is already linked to the blueprint.
IKA_API void ikarus_entity_link_to_blueprint(IkarusEntity * entity, struct IkarusBlueprint * blueprint);

/// \brief Unlinks an entity from a blueprint. All values of the properties of the blueprint the entity is linked with will be
/// deleted.
/// \param entity The entity to unlink.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param blueprint The blueprint to unlink the entity from.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \remark No-op if the entity is not linked to the blueprint.
IKA_API void ikarus_entity_unlink_from_blueprint(IkarusEntity * entity, struct IkarusBlueprint * blueprint);

/// \brief Gets the project of an entity.
/// \param entity The entity to get the project of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The project of the entity or null if an error occurs.
IKA_API struct IkarusProject * ikarus_entity_get_project(IkarusEntity const * entity);

/// \brief Gets the parent folder of an entity.
/// \param entity The entity to get the parent folder of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The parent folder of the entity or null if an error occurs.
IKA_API struct IkarusEntityFolder * ikarus_entity_get_parent(IkarusEntity const * entity);

/// \brief Gets the position of an entity within its parent folder.
/// \param entity The entity to get the position of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The position of the entity or undefined if an error occurs.
IKA_API size_t ikarus_entity_get_position(IkarusEntity const * entity);

/// \brief Gets the name of an entity.
/// \param entity The entity to get the name of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The name of the entity or null if an error occurs.
/// \remark The returned pointer is valid until the entity is freed but may be invalidated by other operations.
IKA_API char const * ikarus_entity_get_name(IkarusEntity const * entity);

/// \brief Gets the property root folder of an entity.
/// \param entity The entity to get the root folder of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The root folder of all properties of the entity or null if an error occurs.
/// \remark Must be freed using #ikarus_free.
IKA_API struct IkarusPropertyFolder * ikarus_entity_get_property_root_folder(IkarusEntity const * entity);

/// \brief Gets the number of properties of an entity.
/// \param entity The entity to get the number of properties of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The number of properties or undefined if an error occurs.
IKA_API size_t ikarus_entity_get_property_count(IkarusEntity const * entity);

/// \brief Gets the properties of an entity.
/// \param entity The entity to get the properties of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param properties_out The buffer to write the properties to.
/// \pre \li Must not be null.
/// \param properties_out_size The size of the buffer.
IKA_API void ikarus_entity_get_properties(
    IkarusEntity const * entity, struct IkarusProperty ** properties_out, size_t properties_out_size
);

/// \brief Gets the value of a property of an entity.
/// \details If the entity has never set the value of the property, the default value is returned (which may be indeterminate).
/// \param entity The entity to get the value of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param property The property to get the value of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return The value of the property or null if the entity does not have the property or an error occurs.
/// \remark Must be freed using #ikarus_free.
IKA_API struct IkarusEntityValue * get_value(IkarusEntity const * entity, struct IkarusProperty const * property);

/// \brief Sets the parent folder of an entity.
/// \param entity The entity to set the parent folder of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param new_parent The new parent folder of the entity.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param new_position The new position of the entity in the parent folder. \see #FolderPosition
/// \pre \li Must be within bounds for the parent folder.
/// \remark This adjusts the positions of old and new siblings.
IKA_API void ikarus_entity_set_parent(IkarusEntity * entity, struct IkarusEntityFolder * new_parent, size_t new_position);

/// \brief Sets the position of an entity within its parent folder.
/// \param entity The entity to set the position of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param new_position The new position of the entity. \see #FolderPosition
/// \pre \li Must be within bounds for the parent folder.
/// \remark This adjusts the positions of siblings.
IKA_API void ikarus_entity_set_position(IkarusEntity * entity, size_t new_position);

/// \brief Sets the name of an entity.
/// \param entity The entity to set the name of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param new_name The new name of the entity.
/// \pre \li Must not be null.
/// \pre \li Must not be empty.
IKA_API void ikarus_entity_set_name(IkarusEntity * entity, char const * new_name);

/// \brief Sets the value of a property of an entity.
/// \param entity The entity to set the value of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param property The property to set the value of.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param value The new value of the property.
/// \pre \li Must not be null.
/// \pre \li Must be of the same type as the property.
/// \param validate_settings If set, this function fails not only if the type of the value is invalid, but also if it's not
/// valid under the properties settings. \see property.h
/// \remark If the entity does not have the property, this function fails.
IKA_API void ikarus_entity_set_value(
    IkarusEntity * entity, struct IkarusProperty const * property, struct IkarusValue * value, bool validate_settings
);

/// \brief Compares two entities.
/// \param left The left entity to compare.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \param right The right entity to compare.
/// \pre \li Must not be null.
/// \pre \li Must exist.
/// \return True if the two entities are equal, false otherwise.
/// \remark This neither performs a pointer comparison nor a deep comparison. When we say "equal" we mean that the two
/// entities reference the same entity in the same project.
IKA_API bool ikarus_entity_is_equal(IkarusEntity const * left, IkarusEntity const * right);

IKARUS_END_HEADER

// @}