// Fill out your copyright notice in the Description page of Project Settings.


#include "PresidentAIController.h"
#include "EngineUtils.h"
#include "Util.h"

#define LogInfo(Msg) Util::log_info(TEXT("APresidentAIController"), Msg)
#define LogError(Msg) Util::log_error(TEXT("APresidentAIController"), Msg)

void APresidentAIController::BeginPlay()  
{
    Super::BeginPlay();

	/*
	 * Initialize random stream.
	 */
	random.Initialize(FMath::Rand());
}

void APresidentAIController::Tick(float delta)  
{
    Super::Tick(delta);

	switch (current_state)
	{
	case state_t::init:
	{
		// Without this offset, the path finding to return to starting location will fail with
		// invalid. I'm too sleepy to dig further.
		const FVector offset(1.0, 1.0, 0);
		starting_location = GetPawn()->GetActorLocation() + offset;
		target_location = starting_location;
		marker_locations = get_markers();

		// Update state.
		current_state = state_t::idle;
	}
		break;
	case state_t::idle:
	{
		const bool should_wait = random.GetFraction() > .5;
		const bool is_home = target_location == starting_location;
		if (should_wait && is_home)
		{
			current_state = state_t::waiting;
		}
		else
		{
			target_location = is_home ? get_random_mark() : starting_location;
			MoveToLocation(target_location);
			current_state = state_t::moving;
		}
	}
		break;
	case state_t::moving:
		if (move_completed)
		{
			move_completed = false;
			current_state = state_t::waiting;
		}
		break;
	case state_t::waiting:
		waiting_time += delta;
		if (waiting_time > wait_threshold)
		{
			waiting_time = 0;
			current_state = state_t::idle;
		}
		break;
	default:
		/*
		 * Do nothing.
		 */
		break;
	}
}

void APresidentAIController::OnMoveCompleted(FAIRequestID request_id, const FPathFollowingResult& result)
{
	move_completed = true;
}


/**
 * Helper function to load all the markers in the level.
 */
TArray<FVector> APresidentAIController::get_markers() const
{
	TArray<FVector> locations;
	for (TActorIterator<AActor> iterator(GetWorld()); iterator; ++iterator)
	{
		AActor* actor = *iterator;
		if (actor && actor != this)
		{
			UClass* actor_class = actor->GetClass();

			if (actor_class == marker_class)
			{
				locations.Add(actor->GetActorLocation());
			}
		}
	}
	
	if (locations.Num() == 0)
	{
		LogError("No markers");
	}

	return locations;
}

/**
 * Helper function for returning world location of randomly selected mark.
 * 
 * @return World location vector of mark.
 */
FVector APresidentAIController::get_random_mark() const
{
	if (marker_locations.Num() == 0)
	{
		LogError("No markers");
		return FVector();
	}

	const int index = random.RandRange(0, marker_locations.Num() - 1);
	return marker_locations[index];
}