import { useReducer, type ActionDispatch } from "react";
import {
  playingGrid,
  reduce,
  type Action,
  type Initial,
  type ReductionError,
} from "sudoku-rust";

const isReductionError = (val: unknown): val is ReductionError =>
  val === "LockedCell" ||
  (typeof val === "object" &&
    val !== null &&
    "ValidationError" in val &&
    typeof val.ValidationError === "object" &&
    val.ValidationError !== null &&
    "row" in val.ValidationError &&
    "column" in val.ValidationError &&
    "box" in val.ValidationError &&
    typeof val.ValidationError.row === "boolean" &&
    typeof val.ValidationError.column == "boolean" &&
    typeof val.ValidationError.box === "boolean");

export default function useGrid(): [
  [Initial, ReductionError | null],
  ActionDispatch<[Action]>,
] {
  return useReducer(
    ([{ playing, solution }], action) => {
      let reduction = reduce(playing, solution, action);
      if ("Invalid" in reduction)
        return [{ playing, solution }, reduction.Invalid];
      return [
        {
          solution,
          playing: reduction.Valid,
        },
        null,
      ];
    },
    [],
    // oxlint-disable-next-line
    (_) => [playingGrid.makeInitial("Medium"), null],
  );
}