#pragma once


#include <wfr/common/types/WfsTypes.h>
#include <atomic>
#include <vector>


namespace wfr {

// Forward declarations
namespace enactment {
class WepBuilder;
}

namespace wfs {

// Forward declarations
class Workflow;
class ActivityInstance;
class ActivityTemplate;


class Activity {
friend class ActivityTemplate;
friend class Workflow;
friend class enactment::WepBuilder;

// Static non-public properties
private:
	/**
	 * Static variable holding the next free activityID.
	 **/
	static std::atomic<wfr_id_t> nextActivityID;

	/**
	 * Returns the next free activityID.
	 *
	 * @return next free activityID.
	 */
	static wfr_id_t getNextActivityID() { return nextActivityID.fetch_add(1); }

// Mutable properties that need to be accessed via getter-/setter-functions.
private:
	/** Status of this activity object. **/
	ActivityStatus status;

	/** Vector holding references to instances of this workflow activity. **/
	std::vector<ActivityInstance*> instanceList;

	/** Reference to the parent of this activity object (structure-wise). **/
	Activity* parent = nullptr;

	std::vector<Activity*> successors;

	std::vector<Activity*> predecessors;

// Invariant properties that can be accessed directly.
public:
	/**  Unique ID of this workflow activity. **/
	const wfr_id_t activityID;

	/** Parent workflow instance of this activity object. **/
	Workflow& workflow;

	/** Parent activitiy template of this activity object. **/
	ActivityTemplate& baseTemplate;


// Non-public functions
private:
	/**
	 * Constructor.
	 *
	 * @param workflow workflow instance this activity object belongs to.
	 * @param baseTemplate activity template this object is associated with.
	 * @param parent the parent activity of this object (structure-wise).
	 */
	Activity( Workflow& workflow, ActivityTemplate& baseTemplate );

	/**
	 * Initialises this activity object.
	 *
	 * @param activities list of activities for successor/predecessor lists generation.
	 **/
	void initActivity();

	/**
	 * Creates a new activity instance of this activity object.
	 *
	 * @return new activity instance.
	 **/
	ActivityInstance* createNewInstance(wfr_id_t iterationID = 0);

// Public functions
public:
	/** Destructor. **/
	~Activity() noexcept;

	ActivityType activityType() const noexcept;

	bool isCompositeActivity() const noexcept;

	bool isLoop() const noexcept;

	bool isConditional() const noexcept;

	/**
	 * Returns the number of activity instances of this activity object.
	 *
	 * @return number of activity instances.
	 **/
	wfr_size_t getInstanceCount() const noexcept { return instanceList.size(); }

	/**
	 * Returns a reference to the vector holding the activity instance references.
	 *
	 * @return reference to the vector holding the activity instance references.
	 **/
	const std::vector<ActivityInstance*>& getInstanceList() const noexcept { return instanceList; }

	/**
	 * Returns the parent activity of this object (structure-wise).
	 *
	 * @return parent activity.
	 **/
	Activity* getParent() const noexcept { return parent; }

	wfr_size_t getChildrenCount(wfr_id_t branchID = 0) const noexcept;

	std::vector<Activity*> getChildren(wfr_id_t branchID = 0) const noexcept;


	/**
	 * Returns the number of successors.
	 *
	 * @return number of successors.
	 **/
	wfr_size_t getSuccessorCount() const noexcept { return successors.size(); }

	/**
	 * Returns a reference to the array holding the successors.
	 *
	 * @return reference to the array holding the successors.
	 **/
	const std::vector<Activity*> getSuccessors() const noexcept { return successors; }

	/**
	 * Returns whether the given activityID belongs to a successor.
	 *
	 * @param aid activityID to test.
	 * @return true if successor, false otherwise.
	 */
	bool isSuccessor(wfr_id_t aid) const noexcept;

	/**
	 * Returns whether the given reference is a successor.
	 *
	 * @param act reference to test
	 * @return true if successor, false otherwise.
	 */
	bool isSuccessor(Activity& act) const noexcept;


	/**
	 * Returns the number of predecessors.
	 *
	 * @return number of predecessors.
	 **/
	wfr_size_t getPredecessorCount() const noexcept { return predecessors.size(); }

	/**
	 * Returns a reference to the array holding the predecessors.
	 *
	 * @return reference to the array holding the predecessors.
	 **/
	const std::vector<Activity*> getPredecessors() { return predecessors; }

	/**
	 * Returns whether the given activityID belongs to a predecessor.
	 *
	 * @param aid activityID to test.
	 * @return true if predecessor, false otherwise.
	 */
	bool isPredecessor(wfr_id_t aid) const noexcept;

	/**
	 * Returns whether the given reference is a predecessor.
	 *
	 * @param act reference to test
	 * @return true if predecessor, false otherwise.
	 */
	bool isPredecessor(Activity& act) const noexcept;

	/**
	 * Returns the status of this activity.
	 *
	 * @return activity status.
	 **/
	ActivityStatus getActivityStatus() const noexcept { return status; }

	void setActivityStatus(ActivityStatus status);

};

} /* namespace wfs */
} /* namespace wfr */