package lib.turtle;

import lib.Pos;
import lib.Pos3;
import kernel.turtle.Turtle;

using tink.CoreApi;

class TurtleExecuter {
	private var instructions:Array<TurtleInstruction>;

	public function new(instructions:Array<TurtleInstruction>) {
		this.instructions = instructions;
	}

	public function getRequiredFuel():Int {
		var fuel = 0;
		for (inst in instructions) {
			if (inst == Forward || inst == Back || inst == Up || inst == Down) {
				fuel++;
			}
		}

		return fuel;
	}

	public function getRequiredBlocks():Int {
		var blocks = 0;
		for (inst in instructions) {
			switch inst {
				case Place(_):
					blocks++;
				default:
			}
		}

		return blocks;
	}

	/**
		Return the offset of the turtle after executing the instructions.
		The origin is the starting position of the turtle.
	**/
	public function getFinalOffset():{offset:Pos3, faceing:Pos} {
		var pos:Pos3 = {x: 0, y: 0, z: 0};
		var forwardVec:Pos3 = {x: 1, y: 0, z: 0};

		for (inst in instructions) {
			switch inst {
				case Forward:
					pos = pos + forwardVec;
				case Back:
					pos = pos - forwardVec;
				case TurnRight:
					forwardVec = {x: -forwardVec.z, z: forwardVec.x, y: forwardVec.y};
				case TurnLeft:
					forwardVec = {x: forwardVec.z, z: -forwardVec.x, y: forwardVec.y};
				default:
			}
		}

		return {offset: pos, faceing: new Pos({x: forwardVec.x, y: forwardVec.z})};
	}

	public function execute() {
		for (inst in instructions) {
			executeInst(inst);
		}
	}

	private function executeInst(instruction:TurtleInstruction):Outcome<Noise, String> {
		switch instruction {
			case Forward:
				return Turtle.forward();
			case Back:
				return Turtle.back();
			case Up:
				return Turtle.up();
			case Down:
				return Turtle.down();
			case TurnLeft:
				return Turtle.turnLeft();
			case TurnRight:
				return Turtle.turnRight();
			case Dig(dir):
				return Turtle.dig(dir);
			case Place(dir):
				return Turtle.place(dir);
			case PlacseSign(dir, text):
				return Turtle.placeSign(dir, text);
			case Select(slot):
				var r = Turtle.selectSlot(slot);
				if (r.isSuccess()) {
					return Outcome.Success(null);
				} else {
					return Outcome.Failure("Failed to select slot");
				}
		}

		return Outcome.Failure("Unknown instruction: " + instruction);
	}
}