1 files changed, 163 insertions, 0 deletions
diff --git a/core/src/Model/Workflow/Workflow.hpp b/core/src/Model/Workflow/Workflow.hpp
new file mode 100644
index 0000000..a7b2c31
--- /dev/null
+++ b/core/src/Model/Workflow/Workflow.hpp
@@ -0,0 +1,163 @@
+#pragma once
+
+#include "Value.hpp"
+#include "cplt_fwd.hpp"
+
+#include <cstddef>
+#include <cstdint>
+#include <limits>
+#include <memory>
+#include <span>
+#include <string>
+#include <vector>
+
+class WorkflowConnection {
+public:
+	static constexpr auto kInvalidId = std::numeric_limits<size_t>::max();
+
+	enum Direction {
+		ManyToOne,
+		OneToMany,
+	};
+
+	struct ConnectionPoint {
+		size_t Node;
+		int Pin;
+
+		bool operator==(const ConnectionPoint&) const = default;
+	};
+
+	std::vector<ConnectionPoint> MultiConnections;
+	ConnectionPoint SingleConnection;
+	Direction ConnectionDirection;
+
+public:
+	WorkflowConnection();
+
+	bool IsValid() const;
+	std::span<ConnectionPoint> GetSourcePoints();
+	std::span<const ConnectionPoint> GetSourcePoints() const;
+	std::span<ConnectionPoint> GetDestinationPoints();
+	std::span<const ConnectionPoint> GetDestinationPoints() const;
+};
+
+class WorkflowNode {
+public:
+	static constexpr auto kInvalidId = std::numeric_limits<size_t>::max();
+
+	enum Type {
+		InputType,
+		TransformType,
+		OutputType,
+	};
+
+	enum Kind {
+		KD_NumericAddition,
+		KD_NumericSubtraction,
+		KD_NumericMultiplication,
+		KD_NumericDivision,
+		KD_NumericExpression,
+		KD_TextFormatting,
+		KD_DocumentTemplateExpansion,
+		KD_FormInput,
+		KD_DatabaseRowsInput,
+
+		InvalidKind,
+		KindCount = InvalidKind,
+	};
+
+protected:
+	struct InputPin {
+		size_t Connection = WorkflowConnection::kInvalidId;
+		BaseValue::Kind MatchingType = BaseValue::KindInvalid;
+		bool ConnectionToConst = false;
+		bool AllowsMultipleConnections = false;
+
+		/// A constant connection connects from a user-specified constant value, feeding to a valid \c Destination and \c DestinationPin (i.e. input pins).
+		bool IsConstantConnection() const;
+		bool IsConnected() const;
+		BaseValue::Kind GetMatchingType() const;
+		WorkflowConnection::Direction GetSupportedDirection() const;
+	};
+
+	struct OutputPin {
+		size_t Connection = WorkflowConnection::kInvalidId;
+		BaseValue::Kind MatchingType = BaseValue::KindInvalid;
+		bool AllowsMultipleConnections = false;
+
+		bool IsConnected() const;
+		BaseValue::Kind GetMatchingType() const;
+		WorkflowConnection::Direction GetSupportedDirection() const;
+	};
+
+	friend class Workflow;
+	friend class WorkflowEvaluationContext;
+
+	Workflow* mWorkflow;
+	size_t mId;
+	std::vector<InputPin> mInputs;
+	std::vector<OutputPin> mOutputs;
+	Type mType;
+	Kind mKind;
+
+public:
+	WorkflowNode(Type type, Kind kind);
+	virtual ~WorkflowNode() = default;
+
+	WorkflowNode(const WorkflowNode&) = delete;
+	WorkflowNode& operator=(const WorkflowNode&) = delete;
+	WorkflowNode(WorkflowNode&&) = default;
+	WorkflowNode& operator=(WorkflowNode&&) = default;
+
+	size_t GetId() const;
+	Type GetType() const;
+	Kind GetKind() const;
+
+	void ConnectInput(int nodeId, WorkflowNode& output, int outputNodeId);
+	void DisconnectInput(int nodeId);
+	bool IsInputConnected(int nodeId) const;
+
+	void ConnectOutput(int nodeId, WorkflowNode& input, int inputNodeId);
+	void DisconnectOutput(int nodeId);
+	bool IsOutputConnected(int nodeId) const;
+
+	virtual void Evaluate(WorkflowEvaluationContext& ctx) = 0;
+
+protected:
+	InputPin& InsertInputPin(int atIdx);
+	void RemoveInputPin(int pin);
+	void SwapInputPin(int a, int b);
+	OutputPin& InsertOutputPin(int atIdx);
+	void RemoveOutputPin(int pin);
+	void SwapOutputPin(int a, int b);
+
+	/* For \c Workflow to invoke, override by implementations */
+
+	void OnAttach(Workflow& workflow, size_t newId) {}
+	void OnDetach() {}
+};
+
+class Workflow {
+private:
+	friend class WorkflowEvaluationContext;
+
+	std::vector<WorkflowConnection> mConnections;
+	std::vector<std::unique_ptr<WorkflowNode>> mNodes;
+	std::vector<std::unique_ptr<BaseValue>> mConstants;
+
+public:
+	WorkflowConnection* GetConnectionById(size_t id);
+	WorkflowNode* GetStepById(size_t id);
+	BaseValue* GetConstantById(size_t id);
+
+	void AddStep(std::unique_ptr<WorkflowNode> step);
+	void RemoveStep(size_t id);
+
+	bool Connect(WorkflowNode& sourceNode, int sourcePin, WorkflowNode& destinationNode, int destinationPin);
+	bool DisconnectBySource(WorkflowNode& sourceNode, int sourcePin);
+	bool DisconnectByDestination(WorkflowNode& destinationNode, int destinationPin);
+
+private:
+	std::pair<WorkflowConnection&, size_t> AllocWorkflowConnection();
+	std::pair<std::unique_ptr<WorkflowNode>&, size_t> AllocWorkflowStep();
+};