CREATE OR REPLACE FUNCTION "move"(moving_ship_id integer, new_speed integer, new_direction integer, new_destination_x integer, new_destination_y
integer)
  RETURNS boolean AS
$BODY$
DECLARE
        max_speed integer;
        current_speed integer;
        current_fuel integer;
        current_direction integer;
        fuel_cost integer;
        direction_fuel_cost integer := 0;
        final_speed integer;
        final_direction  integer;
        final_fuel integer;
        distance  bigint;
        distance_x bigint;
        distance_y bigint;
        range integer;
        location_x  integer;
        location_y  integer;
        ship_player_id integer;
BEGIN
        -- Grab current stats of ship
        SELECT INTO max_speed, current_fuel, location_x, location_y, ship_player_id  ship.max_speed, ship.current_fuel, ship.location_x, ship.location_y, player_id from ship WHERE id=moving_ship_id;
        SELECT INTO current_speed, current_direction speed, direction FROM ship_control WHERE ship_id = moving_ship_id;

        IF MOVE_PERMISSION_CHECK(moving_ship_id) THEN
                -- If they don't know what direction they're going, calculate it for them
                IF (final_direction IS NULL) THEN
                    final_direction := getangle(location_x, location_y, new_destination_x, new_destination_y);
                ELSE
                    final_direction := MOD(new_direction, 360);
                END IF;

                -- Make sure they don't travel faster than max_speed!
                SELECT INTO final_speed CASE WHEN new_speed < max_speed THEN new_speed ELSE max_speed END;

                -- Calculate the distance to target (if it exists)
                IF (new_destination_x IS NOT NULL AND new_destination_y IS NOT NULL) THEN
                    distance_x := new_destination_x - location_x;
                    distance_y := new_destination_y - location_y;
                    distance := CAST(SQRT((distance_x * distance_x) + (distance_y * distance_y)) AS bigint);

                    -- If their distance is less than their speed, override it
                    IF (distance < final_speed) THEN
                        IF (distance < 2147483647) THEN
                            final_speed = CAST(distance AS integer);
                        ELSE
                            final_speed := 2147483647;
                        END IF;
                    END IF;
                END IF;

                -- If they're not currently travelling at this speed/direction...
                IF (current_speed <> final_speed OR current_direction <> final_direction) THEN
                    fuel_cost := ABS(final_speed - current_speed); -- Calculate the fuel cost to change speed

                    -- if they're already moving and aren't trying to stop...
                    IF (current_speed <> 0 AND final_speed <> 0) THEN -- add 1 fuel cost per degree changed
                        direction_fuel_cost := ABS(final_direction - current_direction);

                        -- Pythagorus is inexact with integer-only datatypes, so sometimes we're off by 1 degree when calculating the direction.
                        -- Don't let this eat up our fuel!
                        IF (direction_fuel_cost = 1) THEN direction_fuel_cost := 0; END IF;
                        fuel_cost := fuel_cost + direction_fuel_cost;
                    END IF;
                ELSE
                    fuel_cost := 0;
                END IF;

                -- Abort moving if they specified a destination and don't have enough fuel to get/stop there
                IF ((new_destination_x IS NOT NULL AND new_destination_y IS NOT NULL) AND (current_fuel < fuel_cost + direction_fuel_cost + final_speed)) THEN
                    EXECUTE 'NOTIFY ' || get_player_error_channel(GET_PLAYER_USERNAME(ship_player_id)) || ', ''' || GET_SHIP_NAME(moving_ship_id) || ' does not have enough fuel to fly heading ' || final_direction || ', accelerate to ' || final_speed ||' and then stop! To override, specify a NULL destination x and y.'';';
                    RETURN 'f';
                END IF;

                final_fuel := current_fuel - fuel_cost;
                --EXECUTE 'NOTIFY ' || get_player_error_channel(GET_PLAYER_USERNAME(ship_player_id)) || ', ''Ship:' || moving_ship_id || '. Fuel:' || current_fuel || '. Cost:' || fuel_cost || '. DirCost:' || direction_fuel_cost || '. finalspeed: ' || final_speed || ''';';

                -- Move the ship!
                UPDATE
                        ship
                SET
                        current_fuel = final_fuel,
                        location_x = ship.location_x + CAST(COS(RADIANS(final_direction)) * final_speed AS integer),
                        location_y = ship.location_y + CAST(SIN(RADIANS(final_direction)) * final_speed AS integer),
                        last_move_tic = (SELECT last_value FROM tic_seq)
                WHERE
                        id = moving_ship_id;

                -- Update ship_control so future ticks know how to move this ship
                UPDATE
                        ship_control
                SET
                        destination_x=new_destination_x,
                        destination_y=new_destination_y,
                        speed=new_speed,
                        direction=final_direction
                WHERE
                        ship_id = moving_ship_id;


                -- Re-retrieve the current ship stats
                SELECT INTO max_speed, current_fuel, location_x, location_y, range, ship_player_id  ship.max_speed, ship.current_fuel, ship.location_x, ship.location_y, ship.range, player_id FROM ship WHERE id=moving_ship_id;
                SELECT INTO current_speed, current_direction speed, direction FROM ship_control WHERE ship_id = moving_ship_id;

                -- If the ship is in range of its target..
                IF (new_destination_x BETWEEN (location_x - range) AND (location_x + range) AND new_destination_y BETWEEN (location_y - range) AND (location_y + range)) THEN
                    -- calculate how much fuel it would require to stop (or slow down as much as possible)
                    IF (current_fuel >= current_speed) THEN
                        final_fuel := current_fuel - current_speed;
                        final_speed := 0;
                        final_direction := 0;
                    ELSE
                        final_fuel := 0;
                        final_speed := current_speed - current_fuel;
                        final_direction := current_direction;
                    END IF;

                    -- Update the control and ship tables with the stopping results
                    UPDATE ship_control
                    SET speed = final_speed,
                    direction = final_direction
                    WHERE ship_id = moving_ship_id;

                    UPDATE ship
                    SET current_fuel = final_fuel
                    WHERE id = moving_ship_id;
                END IF;

                RETURN 't';
        ELSE
                EXECUTE 'NOTIFY ' || get_player_error_channel(GET_PLAYER_USERNAME(ship_player_id)) ||', ''Ship '|| moving_ship_id || ' did not budge!'';';
                RETURN 'f';
        END IF;
END
$BODY$
  LANGUAGE plpgsql VOLATILE SECURITY DEFINER;