import { FIGHTER, SPAWN } from "../constants.js";

const STORAGE_KEYS = {
  names: "arena.match.playerNames",
  spawnPlacement: "arena.match.spawnPlacement",
};

export function createMatchForm() {
  const form = getElement("#fighter-form");
  const namesInput = getElement("#player-names");
  const namesWarningNode = getElement("#player-names-warning");
  const namesWarningTitleNode = getElement("[data-player-names-warning-title]");
  const namesWarningCountNode = getElement("[data-player-names-warning-count]");
  const namesWarningLimitNode = getElement("[data-player-names-warning-limit]");
  const namesWarningReasonNode = getElement("[data-player-names-warning-reason]");
  const appNode = document.querySelector("#app");
  const statusNode = document.querySelector("#match-status");
  const statusTextNodes = document.querySelectorAll("[data-status-text]");
  const spawnPlacementInputs = getElements('input[name="spawnPlacement"]');
  const setPlayerNamesWarning = (warning = null) => {
    const hasWarning = Boolean(warning);

    if (!hasWarning) {
      namesWarningNode.hidden = true;
      namesInput.removeAttribute("aria-invalid");
      return;
    }

    namesWarningTitleNode.textContent = warning.title;
    namesWarningCountNode.textContent = warning.fighterCount.toLocaleString("ko-KR");
    namesWarningLimitNode.textContent = warning.maxFighterCount.toLocaleString("ko-KR");
    namesWarningReasonNode.textContent = warning.reason ?? "";
    namesWarningReasonNode.hidden = !warning.reason;
    namesWarningNode.hidden = false;
    namesInput.setAttribute("aria-invalid", "true");
  };

  const readMatchConfig = () => ({
    names: nicknameValues(namesInput.value),
    spawnPlacement: selectedSpawnPlacement(spawnPlacementInputs),
  });

  restoreSavedMatchSettings(namesInput, spawnPlacementInputs);
  namesInput.addEventListener("input", () => {
    setPlayerNamesWarning();
    saveMatchSettings(namesInput, spawnPlacementInputs);
  });
  spawnPlacementInputs.forEach((input) => {
    input.addEventListener("change", () => {
      saveMatchSettings(namesInput, spawnPlacementInputs);
    });
  });

  return {
    onSubmit(handler) {
      form.addEventListener("submit", (event) => {
        event.preventDefault();
        handler(readMatchConfig());
      });
    },
    readMatchConfig,
    setPlayerNamesWarning,
    setStatus(message) {
      if (statusNode) {
        statusNode.setAttribute("aria-hidden", "false");
        statusNode.title = message;
      }

      statusTextNodes.forEach((node) => {
        node.textContent = message;
      });

      appNode?.classList.add("status-active");
    },
  };
}

function getElement(selector) {
  const element = document.querySelector(selector);

  if (!element) {
    throw new Error(`Missing required element: ${selector}`);
  }

  return element;
}

function getElements(selector) {
  const elements = [...document.querySelectorAll(selector)];

  if (elements.length === 0) {
    throw new Error(`Missing required elements: ${selector}`);
  }

  return elements;
}

function nicknameValues(value) {
  return value
    .split(/\r?\n|,/)
    .map((name) => name.trim().slice(0, FIGHTER.NICKNAME_LENGTH))
    .filter(Boolean);
}

function restoreSavedMatchSettings(namesInput, spawnPlacementInputs) {
  const storage = getLocalStorage();

  if (!storage) {
    return;
  }

  try {
    const savedNames = storage.getItem(STORAGE_KEYS.names);
    const savedSpawnPlacement = storage.getItem(STORAGE_KEYS.spawnPlacement);

    if (savedNames !== null) {
      namesInput.value = savedNames;
    }

    setSpawnPlacement(spawnPlacementInputs, savedSpawnPlacement);
  } catch {
    // Storage may be unavailable in private or restricted browser contexts.
  }
}

function saveMatchSettings(namesInput, spawnPlacementInputs) {
  const storage = getLocalStorage();

  if (!storage) {
    return;
  }

  try {
    storage.setItem(STORAGE_KEYS.names, namesInput.value);
    storage.setItem(STORAGE_KEYS.spawnPlacement, selectedSpawnPlacement(spawnPlacementInputs));
  } catch {
    // Ignore storage failures so the match form remains usable.
  }
}

function selectedSpawnPlacement(inputs) {
  return inputs.find((input) => input.checked)?.value ?? SPAWN.DEFAULT_PLACEMENT;
}

function setSpawnPlacement(inputs, value) {
  const savedInput = inputs.find((input) => input.value === value);
  const defaultInput = inputs.find((input) => input.value === SPAWN.DEFAULT_PLACEMENT);
  const nextInput = savedInput ?? defaultInput;

  if (nextInput) {
    nextInput.checked = true;
  }
}

function getLocalStorage() {
  try {
    return window.localStorage;
  } catch {
    return null;
  }
}