ifc-structural 0.4.0

use ifc_model::{EntityId, Model, Transaction, Value};
use ifc_schema::{Schema, TypeKind};

use super::item::{root_fields, validate_root, StructuralRootDraft};
use super::{build_named, optional_ref, validate_optional_ref, validate_ref, validate_ref_select};
use crate::action::CoordinateSystem;
use crate::error::{StructuralError, StructuralResult};

/// Value of `IfcProjectedOrTrueLengthEnum` naming how a linear/planar action's magnitude is measured.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ProjectedOrTrue {
    /// `PROJECTED_LENGTH`: magnitude given per unit of the projected length/area.
    ProjectedLength,
    /// `TRUE_LENGTH`: magnitude given per unit of the true (unprojected) length/area.
    TrueLength,
}

impl ProjectedOrTrue {
    fn token(self) -> &'static str {
        match self {
            Self::ProjectedLength => "PROJECTED_LENGTH",
            Self::TrueLength => "TRUE_LENGTH",
        }
    }
}

/// Staged action subtype for [`ActionDraft::kind`].
#[derive(Debug, Clone)]
pub enum ActionDraftKind {
    /// Stages an `IfcStructuralPointAction`.
    Point,
    /// Stages an `IfcStructuralLinearAction`.
    Linear {
        /// `ProjectedOrTrue`; staged only when the target schema declares the attribute.
        projected_or_true: Option<ProjectedOrTrue>,
    },
    /// Stages an `IfcStructuralPlanarAction`.
    Planar {
        /// `ProjectedOrTrue`; staged only when the target schema declares the attribute.
        projected_or_true: Option<ProjectedOrTrue>,
    },
    /// Stages an `IfcStructuralCurveAction`.
    ///
    /// IFC4 replaced the linear/planar pair with curve/surface forms that
    /// additionally carry a mandatory `PredefinedType`.
    Curve {
        /// `ProjectedOrTrue`; staged only when the target schema declares it.
        projected_or_true: Option<ProjectedOrTrue>,
        /// `PredefinedType`, an `IfcStructuralCurveActivityTypeEnum` token.
        predefined_type: &'static str,
    },
    /// Stages an `IfcStructuralSurfaceAction`.
    Surface {
        /// `ProjectedOrTrue`; staged only when the target schema declares it.
        projected_or_true: Option<ProjectedOrTrue>,
        /// `PredefinedType`, an `IfcStructuralSurfaceActivityTypeEnum` token.
        predefined_type: &'static str,
    },
}

/// Staged fields for creating an `IfcStructuralAction` via [`stage_action`].
#[derive(Debug, Clone)]
#[non_exhaustive]
pub struct ActionDraft {
    /// `IfcRoot` attributes shared with other staged structural entities.
    pub root: StructuralRootDraft,
    /// `AppliedLoad`; must reference a load type compatible with `kind`.
    pub applied_load: EntityId,
    /// `GlobalOrLocal`.
    pub coordinate_system: CoordinateSystem,
    /// `DestabilizingLoad`; required when the target schema (IFC2X3) declares it mandatory.
    pub destabilizing_load: Option<bool>,
    /// `CausedBy`; only staged when the target schema declares the attribute.
    pub caused_by: Option<EntityId>,
    /// Which `IfcStructuralAction` subtype to create, and its subtype-specific attributes.
    pub kind: ActionDraftKind,
    /// Varying-load attributes; when set, a [`ActionDraftKind::Linear`] or
    /// [`ActionDraftKind::Planar`] kind stages the IFC2X3 varying subtype.
    pub varying: Option<VaryingActionDraft>,
}

/// IFC2X3 varying-action attributes for [`ActionDraft::varying`].
///
/// With [`ActionDraftKind::Linear`] it stages an
/// `IfcStructuralLinearActionVarying` (`SubsequentAppliedLoads : LIST [1:?]`);
/// with [`ActionDraftKind::Planar`] an `IfcStructuralPlanarActionVarying`
/// (`LIST [2:?]`). IFC4 and IFC4X3 declare neither entity.
#[derive(Debug, Clone, PartialEq, Eq)]
#[non_exhaustive]
pub struct VaryingActionDraft {
    /// `VaryingAppliedLoadLocation`, an `IfcShapeAspect` reference.
    pub varying_applied_load_location: EntityId,
    /// `SubsequentAppliedLoads`, `IfcStructuralLoad` references in list
    /// order after the action's `AppliedLoad`. Repeats are allowed (LIST).
    pub subsequent_applied_loads: Vec<EntityId>,
}

impl VaryingActionDraft {
    /// Starts a draft from its two required attributes.
    #[must_use]
    pub fn new(
        varying_applied_load_location: EntityId,
        subsequent_applied_loads: Vec<EntityId>,
    ) -> Self {
        Self {
            varying_applied_load_location,
            subsequent_applied_loads,
        }
    }
}

impl ActionDraft {
    /// Starts a draft from its required fields; every other field is unset.
    #[must_use]
    pub fn new(
        root: StructuralRootDraft,
        applied_load: EntityId,
        coordinate_system: CoordinateSystem,
        kind: ActionDraftKind,
    ) -> Self {
        Self {
            root,
            applied_load,
            coordinate_system,
            destabilizing_load: None,
            caused_by: None,
            kind,
            varying: None,
        }
    }

    /// Sets `destabilizing_load`: `DestabilizingLoad`; required when the target
    /// schema (IFC2X3) declares it mandatory.
    #[must_use]
    pub fn destabilizing_load(mut self, value: bool) -> Self {
        self.destabilizing_load = Some(value);
        self
    }

    /// Sets `caused_by`: `CausedBy`; only staged when the target schema
    /// declares the attribute.
    #[must_use]
    pub fn caused_by(mut self, value: EntityId) -> Self {
        self.caused_by = Some(value);
        self
    }

    /// Sets `varying`: stage the IFC2X3 varying subtype of a linear or
    /// planar action with these attributes.
    #[must_use]
    pub fn varying(mut self, value: VaryingActionDraft) -> Self {
        self.varying = Some(value);
        self
    }
}

/// Stage an `IfcStructuralAction` create edit on `tx`.
///
/// Fails with [`StructuralError::WrongReferenceType`] if `draft.applied_load`
/// is not one of the load types `kind` permits, [`StructuralError::SemanticViolation`]
/// if `ProjectedOrTrue` is `PROJECTED_LENGTH` while `coordinate_system` is not
/// `Global`, and [`StructuralError::MissingRequired`] if `destabilizing_load`
/// is unset while the target schema requires it.
///
/// With [`ActionDraft::varying`] set, a linear kind stages
/// `IfcStructuralLinearActionVarying` and a planar kind
/// `IfcStructuralPlanarActionVarying`. That fails with
/// [`StructuralError::EntityNotInSchema`] outside IFC2X3, with
/// [`StructuralError::InvalidDraftValue`] for any other kind or a
/// `SubsequentAppliedLoads` list below its minimum (1 linear, 2 planar),
/// and with the reference errors when the location is not an
/// `IfcShapeAspect` or a subsequent load not an `IfcStructuralLoad`.
/// Every refusal stages nothing. Returns the id staged for the new entity.
pub fn stage_action(
    tx: &mut Transaction,
    model: &Model,
    schema: &Schema,
    draft: ActionDraft,
) -> StructuralResult<EntityId> {
    let varying = validate_varying(tx, model, schema, &draft)?;
    validate_root(tx, model, schema, &draft.root)?;
    let (entity_type, projected_or_true, load_members): (&str, Option<ProjectedOrTrue>, &[&str]) =
        match draft.kind {
            ActionDraftKind::Point => (
                "IfcStructuralPointAction",
                None,
                &[
                    "IfcStructuralLoadSingleForce",
                    "IfcStructuralLoadSingleDisplacement",
                ],
            ),
            ActionDraftKind::Linear { projected_or_true } => (
                "IfcStructuralLinearAction",
                projected_or_true,
                &[
                    "IfcStructuralLoadLinearForce",
                    "IfcStructuralLoadTemperature",
                ],
            ),
            ActionDraftKind::Planar { projected_or_true } => (
                "IfcStructuralPlanarAction",
                projected_or_true,
                &[
                    "IfcStructuralLoadPlanarForce",
                    "IfcStructuralLoadTemperature",
                ],
            ),
            ActionDraftKind::Curve {
                projected_or_true, ..
            } => (
                "IfcStructuralCurveAction",
                projected_or_true,
                &[
                    "IfcStructuralLoadLinearForce",
                    "IfcStructuralLoadTemperature",
                ],
            ),
            ActionDraftKind::Surface {
                projected_or_true, ..
            } => (
                "IfcStructuralSurfaceAction",
                projected_or_true,
                &[
                    "IfcStructuralLoadPlanarForce",
                    "IfcStructuralLoadTemperature",
                ],
            ),
        };
    let entity_type = varying.as_ref().map_or(entity_type, |(name, _)| *name);
    validate_ref_select(
        tx,
        model,
        schema,
        draft.applied_load,
        "compatible structural load",
        load_members,
    )?;
    validate_optional_ref(tx, model, schema, draft.caused_by, "IfcStructuralReaction")?;
    if projected_or_true == Some(ProjectedOrTrue::ProjectedLength)
        && draft.coordinate_system != CoordinateSystem::Global
    {
        return Err(StructuralError::SemanticViolation {
            entity: None,
            rule: "PROJECTED_LENGTH structural action requires GLOBAL_COORDS",
        });
    }
    let attributes = schema.attributes(entity_type);

    let destabilizing_required = attributes
        .iter()
        .find(|a| a.name.eq_ignore_ascii_case("DestabilizingLoad"))
        .is_some_and(|attribute| !attribute.optional);
    if destabilizing_required && draft.destabilizing_load.is_none() {
        return Err(StructuralError::MissingRequired {
            entity_type: entity_type.into(),
            attribute: "DestabilizingLoad".into(),
        });
    }
    let has_object_type = draft.root.object_type.is_some();
    let mut fields = root_fields(draft.root);
    fields.push(("AppliedLoad", Value::Ref(draft.applied_load)));
    fields.push((
        "GlobalOrLocal",
        Value::Enum(match draft.coordinate_system {
            CoordinateSystem::Global => "GLOBAL_COORDS".into(),
            CoordinateSystem::Local => "LOCAL_COORDS".into(),
        }),
    ));
    if attributes
        .iter()
        .any(|a| a.name.eq_ignore_ascii_case("DestabilizingLoad"))
    {
        fields.push((
            "DestabilizingLoad",
            draft.destabilizing_load.map_or(Value::Null, Value::Bool),
        ));
    }
    if attributes
        .iter()
        .any(|a| a.name.eq_ignore_ascii_case("CausedBy"))
    {
        fields.push(("CausedBy", optional_ref(draft.caused_by)));
    }
    if attributes
        .iter()
        .any(|a| a.name.eq_ignore_ascii_case("ProjectedOrTrue"))
    {
        fields.push((
            "ProjectedOrTrue",
            projected_or_true.map_or(Value::Null, |value| Value::Enum(value.token().into())),
        ));
    }
    if attributes
        .iter()
        .any(|a| a.name.eq_ignore_ascii_case("PredefinedType"))
    {
        // IFC4 makes PredefinedType mandatory on the curve and surface
        // forms. USERDEFINED without an ObjectType names nothing, which
        // is the same trap the element types carry.
        let token = match draft.kind {
            ActionDraftKind::Curve {
                predefined_type, ..
            }
            | ActionDraftKind::Surface {
                predefined_type, ..
            } => predefined_type,
            _ => "NOTDEFINED",
        };
        if token.eq_ignore_ascii_case("USERDEFINED") && !has_object_type {
            return Err(StructuralError::SemanticViolation {
                entity: None,
                rule: "USERDEFINED PredefinedType requires an ObjectType",
            });
        }
        // SuitablePredefinedType: the curve form alone excludes
        // EQUIDISTANT. The token exists in the enum because the
        // activity-type enum is shared with curve *reactions*, where
        // equidistant results are meaningful; an applied action
        // cannot be equidistant.
        if matches!(draft.kind, ActionDraftKind::Curve { .. })
            && token.eq_ignore_ascii_case("EQUIDISTANT")
        {
            return Err(StructuralError::SemanticViolation {
                entity: None,
                rule: "IfcStructuralCurveAction.SuitablePredefinedType",
            });
        }
        // The token must be one the target schema declares for this
        // attribute: a surface token on a curve action resolves to a
        // slot that accepts it structurally and means nothing.
        validate_activity_token(schema, entity_type, token)?;
        fields.push(("PredefinedType", Value::Enum(token.into())));
    }
    if let Some((_, varying)) = varying {
        fields.push((
            "VaryingAppliedLoadLocation",
            Value::Ref(varying.varying_applied_load_location),
        ));
        fields.push((
            "SubsequentAppliedLoads",
            Value::List(
                varying
                    .subsequent_applied_loads
                    .into_iter()
                    .map(Value::Ref)
                    .collect(),
            ),
        ));
    }
    Ok(tx.create(build_named(schema, entity_type, fields)?))
}

/// Resolve and check [`ActionDraft::varying`] before anything is staged.
///
/// Returns the varying entity type with its attributes, or `None` when the
/// draft is not varying.
fn validate_varying(
    tx: &Transaction,
    model: &Model,
    schema: &Schema,
    draft: &ActionDraft,
) -> StructuralResult<Option<(&'static str, VaryingActionDraft)>> {
    let Some(varying) = &draft.varying else {
        return Ok(None);
    };
    let (entity_type, minimum, expected) = match draft.kind {
        ActionDraftKind::Linear { .. } => (
            "IfcStructuralLinearActionVarying",
            1,
            "LIST [1:?] of IfcStructuralLoad references",
        ),
        ActionDraftKind::Planar { .. } => (
            "IfcStructuralPlanarActionVarying",
            2,
            "LIST [2:?] of IfcStructuralLoad references",
        ),
        _ => {
            return Err(StructuralError::InvalidDraftValue {
                entity_type: "IfcStructuralAction",
                attribute: "SubsequentAppliedLoads",
                expected: "a Linear or Planar action kind (only those have varying subtypes)",
            })
        }
    };
    if schema.entity(entity_type).is_none() {
        return Err(StructuralError::EntityNotInSchema {
            entity: entity_type,
            schema: schema.name().to_owned(),
        });
    }
    if varying.subsequent_applied_loads.len() < minimum {
        return Err(StructuralError::InvalidDraftValue {
            entity_type,
            attribute: "SubsequentAppliedLoads",
            expected,
        });
    }
    validate_ref(
        tx,
        model,
        schema,
        varying.varying_applied_load_location,
        "IfcShapeAspect",
    )?;
    for load in &varying.subsequent_applied_loads {
        validate_ref(tx, model, schema, *load, "IfcStructuralLoad")?;
    }
    Ok(Some((entity_type, varying.clone())))
}

/// Refuse a `PredefinedType` token the schema does not declare
/// for `entity_type`.
///
/// The curve and surface forms carry different activity enums
/// with overlapping tokens (`CONST`, `DISCRETE`), so a wrong-form
/// token is not always visibly wrong.
pub(super) fn validate_activity_token(
    schema: &Schema,
    entity_type: &'static str,
    token: &str,
) -> StructuralResult<()> {
    let declared = schema
        .attributes(entity_type)
        .iter()
        .find(|a| a.name.eq_ignore_ascii_case("PredefinedType"))
        .and_then(|a| schema.type_def(&a.type_name))
        .is_some_and(|def| {
            matches!(&def.kind, TypeKind::Enumeration(values)
                if values.iter().any(|v| v.eq_ignore_ascii_case(token)))
        });
    if declared {
        return Ok(());
    }
    Err(StructuralError::InvalidDraftValue {
        entity_type,
        attribute: "PredefinedType",
        expected: "a token this action's activity enum declares",
    })
}