<script setup lang="ts">
import * as THREE from "three";
import { useIntervalFn, useLocalStorage } from "@vueuse/core";

const store = useSettingsStore();
const confirmationModal = useConfirmationModal();

const { onRender } = useScreen();
const { assets: atlas } = useAssets();
const assets = atlas.images.settings.bottomScreen;

const highScore = useLocalStorage("snake_high_score", 0);

const handleCancel = () => {
  switch (state.value) {
    case "alive": {
      state.value = "pause";
      // TODO: onClosed should as "choice" as a parameter, like "confirmed" or "canceled"
      let quit = false;
      confirmationModal.open({
        text: $t("settings.user.personalMessage.quitConfirmation"),
        onConfirm: () => {
          quit = true;
        },
        onClosed: () => {
          if (quit) store.closeSubMenu();
        },
        onCancel: () => {
          state.value = "alive";
        },
      });
      break;
    }

    case "dead":
    case "waiting": {
      store.closeSubMenu();
      break;
    }
  }
};

const handleConfirm = () => {
  switch (state.value) {
    case "alive": {
      state.value = "pause";
      confirmationModal.open({
        text: $t("settings.user.personalMessage.restartConfirmation"),
        onConfirm: () => {
          spawn();
        },
        onCancel: () => {
          state.value = "alive";
        },
      });
      break;
    }

    case "waiting":
    case "dead": {
      spawn();
      break;
    }
  }
};

const BOARD_X = 15;
const BOARD_Y = 48;
const BOARD_WIDTH = 13;
const BOARD_HEIGHT = 7;
const CELL_SIZE = 15;
const CELL_PADDING = 1;

const position = new THREE.Vector2();
const direction = new THREE.Vector2();
const nextDirection = new THREE.Vector2();
const tail: THREE.Vector2[] = [];
const food = new THREE.Vector2();

let score = 0;
const state = ref<"waiting" | "alive" | "pause" | "dead">("waiting");

const randomFoodPos = (): THREE.Vector2 => {
  // can't spawn on the head or tail
  const occupiedPositions = [position, ...tail];
  const emptyPositions: THREE.Vector2[] = [];

  for (let x = 0; x < BOARD_WIDTH; x++) {
    for (let y = 0; y < BOARD_HEIGHT; y++) {
      const candidate = new THREE.Vector2(x, y);
      if (!occupiedPositions.find((part) => part.equals(candidate))) {
        emptyPositions.push(candidate);
      }
    }
  }

  return emptyPositions[THREE.MathUtils.randInt(0, emptyPositions.length - 1)]!;
};

const eat = () => {
  highScore.value = Math.max(highScore.value, score);
  food.copy(randomFoodPos());
  score += 1;
};

const die = () => {
  state.value = "dead";
};

const spawn = () => {
  state.value = "alive";
  score = 0;
  tail.length = 0;

  position.set(0, 0);
  direction.set(1, 0);
  nextDirection.set(1, 0);
  food.copy(randomFoodPos());
};

useIntervalFn(() => {
  if (state.value !== "alive") return;

  direction.copy(nextDirection);

  const previousPosition = position.clone();
  position.set(
    (position.x + direction.x + BOARD_WIDTH) % BOARD_WIDTH,
    (position.y + direction.y + BOARD_HEIGHT) % BOARD_HEIGHT,
  );

  if (!position.equals(previousPosition)) {
    if (tail.find((part) => part.equals(position))) {
      die();
    }
    tail.push(previousPosition);
    if (food.equals(position)) {
      eat();
    } else {
      tail.shift();
    }
  }
}, 200);

const cellToBoardPos = (pos: THREE.Vector2) => ({
  x: BOARD_X + CELL_SIZE + 1 + pos.x * (CELL_SIZE + CELL_PADDING),
  y: BOARD_Y + pos.y * (CELL_SIZE + CELL_PADDING),
});

onRender((ctx) => {
  assets.background.draw(ctx, 0, 0);

  // score
  assets.user.snakeScore.draw(ctx, 27, 32);
  ctx.textBaseline = "top";
  ctx.font = "10px NDS10";
  ctx.fillStyle = "#282828";
  fillTextHCentered(
    ctx,
    $t("settings.user.personalMessage.score", { score }),
    27,
    36,
    108,
  );
  fillTextHCentered(
    ctx,
    $t("settings.user.personalMessage.best", { best: highScore.value }),
    135,
    36,
    108,
  );

  // board
  assets.user.snakeBoard.draw(ctx, 15, 48);

  if (state.value === "waiting") {
    ctx.fillStyle = "#fbfbfb";
    const text = `\n\n\n  ${$t("settings.user.personalMessage.startPrompt")}`;
    let x = 15;
    let y = 52;
    for (let i = 0; i < text.length; i += 1, x += 16) {
      while (text[i] === "\n") {
        x = 15;
        y += 16;
        i += 1;
      }
      ctx.fillText(text[i]!, x + 20, y);
    }
  } else {
    // food
    ctx.fillStyle = "#ff2020";
    ctx.fillRect(
      cellToBoardPos(food).x + 1,
      cellToBoardPos(food).y + 1,
      CELL_SIZE,
      CELL_SIZE,
    );

    // snake
    for (const part of tail) {
      ctx.fillStyle = state.value === "dead" ? "#991010" : "#20ff20";
      ctx.fillRect(
        cellToBoardPos(part).x + 1,
        cellToBoardPos(part).y + 1,
        CELL_SIZE,
        CELL_SIZE,
      );
    }
    assets.user.snakeHead.draw(
      ctx,
      cellToBoardPos(position).x + 1,
      cellToBoardPos(position).y,
    );
  }
});

useKeyDown((key) => {
  if (state.value !== "alive") return;

  const newDirection = direction.clone();
  switch (key) {
    case "NDS_UP":
      newDirection.set(0, -1);
      break;
    case "NDS_RIGHT":
      newDirection.set(1, 0);
      break;
    case "NDS_DOWN":
      newDirection.set(0, 1);
      break;
    case "NDS_LEFT":
      newDirection.set(-1, 0);
      break;
  }

  if (newDirection.clone().dot(direction) === 0) {
    nextDirection.copy(newDirection);
  }
});

defineOptions({ render: () => null });
</script>

<template>
  <CommonButtons
    :y-offset="confirmationModal.buttonsYOffset"
    b-label="Quit"
    :a-label="state === 'waiting' ? 'Start' : 'Restart'"
    @activate-b="handleCancel"
    @activate-a="handleConfirm"
  />
</template>
