/// <summary>
    /// Runs in a state loop until either the battle is lost or won.
    /// It will cycle thought each units turn from friendly unit to enemy unit.
    /// If a unit is missing or dead it will skip that unit and go to the next.
    /// </summary>
    /// <returns>Not sure.</returns>
    private IEnumerator Battle()
    {
        bool ongoingBattle = true;

        while (ongoingBattle)
        {
            CheckForUnitsWithDot();
            switch (state)
            {
            case BattleState.START:
                SetupBattle();
                yield return(new WaitForSeconds(2f));

                state = BattleState.FRIENDLY1TURN;
                break;

            case BattleState.FRIENDLY1TURN:
                unitsTurn = friendlyUnit1;
                BattleHUD.SetBattleStationToDark(enemy3BattleStation);
                BattleHUD.SetBattleStationToLight(friendly1BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(FriendlyTurn());
                }
                if (IsAllEnemiesDead())
                {
                    state = BattleState.WON;
                }
                else
                {
                    state = BattleState.ENEMY1TURN;
                }
                break;

            case BattleState.ENEMY1TURN:
                unitsTurn = enemyUnit1;
                BattleHUD.SetBattleStationToDark(friendly1BattleStation);
                BattleHUD.SetBattleStationToLight(enemy1BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(DoEnemyAI());
                }
                if (IsAllFriendlyDead())
                {
                    state = BattleState.LOST;
                }
                else
                {
                    state = BattleState.FRIENDLY2TURN;
                }
                break;

            case BattleState.FRIENDLY2TURN:
                unitsTurn = friendlyUnit2;
                BattleHUD.SetBattleStationToDark(enemy1BattleStation);
                BattleHUD.SetBattleStationToLight(friendly2BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(FriendlyTurn());
                }
                if (IsAllEnemiesDead())
                {
                    state = BattleState.WON;
                }
                else
                {
                    state = BattleState.ENEMY2TURN;
                }
                break;

            case BattleState.ENEMY2TURN:
                unitsTurn = enemyUnit2;
                BattleHUD.SetBattleStationToDark(friendly2BattleStation);
                BattleHUD.SetBattleStationToLight(enemy2BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(DoEnemyAI());
                }
                if (IsAllFriendlyDead())
                {
                    state = BattleState.LOST;
                }
                else
                {
                    state = BattleState.FRIENDLY3TURN;
                }
                break;

            case BattleState.FRIENDLY3TURN:
                unitsTurn = friendlyUnit3;
                BattleHUD.SetBattleStationToDark(enemy2BattleStation);
                BattleHUD.SetBattleStationToLight(friendly3BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(FriendlyTurn());
                }
                if (IsAllEnemiesDead())
                {
                    state = BattleState.WON;
                }
                else
                {
                    state = BattleState.ENEMY3TURN;
                }
                break;

            case BattleState.ENEMY3TURN:
                unitsTurn = enemyUnit3;
                BattleHUD.SetBattleStationToDark(friendly3BattleStation);
                BattleHUD.SetBattleStationToLight(enemy3BattleStation);
                BattleHUD.showPortrait(unitsTurn);
                if (!unitsTurn.isDead)
                {
                    yield return(DoEnemyAI());
                }
                if (IsAllFriendlyDead())
                {
                    state = BattleState.LOST;
                }
                else
                {
                    state = BattleState.FRIENDLY1TURN;
                }
                break;

            case BattleState.LOST:
                EnableDisableAttackButtons(false);
                EnableDisableTargetButtons(false);
                ongoingBattle = false;
                EndBattle();
                break;

            case BattleState.WON:
                EnableDisableAttackButtons(false);
                EnableDisableTargetButtons(false);
                ongoingBattle = false;
                EndBattle();
                break;

            default:
                ongoingBattle = false;
                break;
            }
        }
    }