aot24.ts

type Alley = "  ";
type MazeItem = "🎄" | "🎅" | Alley;
type DELICIOUS_COOKIES = "🍪";
type MazeMatrix = MazeItem[][];
type Directions = "up" | "down" | "left" | "right";

type As<From, To> = From extends To? From : never;

type Num = 1[]
type i<num extends Num> = num['length']
type zero = []
type ten = inc<inc<inc<inc<inc<inc<inc<inc<inc<inc<zero>>>>>>>>>>
type inc<i extends Num> = [1, ...i]
type dec<i extends Num> = i extends [1, ...infer rest] ? rest : never

type Coords = [Num, Num]
type zero2 = [zero, zero]

type applyDirection<xy extends Coords, dir extends Directions> = 
	dir extends 'up' ? [xy[0], dec<xy[1]>] : 
	dir extends 'down' ? [xy[0], inc<xy[1]>] : 
	dir extends 'left' ? [dec<xy[0]>, xy[1]] : 
	dir extends 'right' ? [inc<xy[0]>, xy[1]] : never

type getAt<board extends MazeMatrix, xy extends Coords> 
	= board[i<xy[1]>][i<xy[0]>]

type setAtList<list extends any[], item, i extends any[], acc extends any[] = [], result extends any[] = []> =
  list extends [infer head, ...infer rest] 
    ? acc extends i 
      ? [...result, item, ...rest]
      : setAtList<rest, item, i, inc<acc>, [...result, head]>
    : never

type setAt<list extends any[][], item, xy extends Coords> =
  setAtList<list, setAtList<list[i<xy[1]>], item, xy[0]>, xy[1]>

type findSanta<board extends MazeMatrix, xy extends Coords = zero2>
	= getAt<board, xy> extends undefined ? findSanta<board, [zero, inc<xy[1]>]>
	: getAt<board, xy> extends '🎅' ? xy : findSanta<board, [inc<xy[0]>, xy[1]]>

type winCondition<xy extends Coords, dir extends Directions> =
	dir extends 'up' ? (xy[1] extends zero ? true : false) : 
	dir extends 'down' ? (xy[1] extends ten ? true : false) : 
	dir extends 'left' ? (xy[0] extends zero ? true : false) : 
	dir extends 'right' ? (xy[0] extends ten ? true : false) : never




type Move<board extends MazeMatrix, dir extends Directions> = Move_2<board, dir,findSanta<board>>

type Move_2<board extends MazeMatrix, dir extends Directions, santa extends Coords> =
	winCondition<santa, dir> extends true ? MazeWin : 
		Move_3<board, santa, As<applyDirection<santa, dir>, Coords>>

type Move_3<board extends MazeMatrix, santa extends Coords, destination extends Coords> =
	getAt<board, destination> extends Alley
		?	setAt<As<setAt<board, '🎅', destination>, any[][]>, Alley, santa>
		: board
;