const socket = io();
const $ = (selector) => document.querySelector(selector);
const sessionKey = "materia-medica-session";
const cardValues = [2, 3, 4, 5];
let state = null;
let actionMode = "one";
let toastTimer;

const showToast = (message) => {
  const toast = $("#toast");
  toast.textContent = message;
  toast.classList.add("show");
  clearTimeout(toastTimer);
  toastTimer = setTimeout(() => toast.classList.remove("show"), 2600);
};

const emit = (event, payload = {}) => socket.emit(event, payload);
const options = (values = cardValues) => values.map((value) => `<option value="${value}">${value}</option>`).join("");
const player = (id) => state?.players.find((item) => item.id === id);

socket.on("connect", () => {
  $("#connection").textContent = "已连接";
  $("#connection").classList.add("online");
  const saved = JSON.parse(localStorage.getItem(sessionKey) || "null");
  if (saved) emit("session:resume", saved);
});

socket.on("disconnect", () => {
  $("#connection").textContent = "正在重连";
  $("#connection").classList.remove("online");
});

socket.on("session", (session) => {
  localStorage.setItem(sessionKey, JSON.stringify(session));
});

socket.on("room:state", (room) => {
  state = room;
  $("#entry").classList.add("hidden");
  $("#game").classList.remove("hidden");
  render();
});

socket.on("error:message", showToast);
socket.on("private:message", showToast);

$("#create").addEventListener("click", () => emit("room:create", { name: $("#name").value }));
$("#join").addEventListener("click", () =>
  emit("room:join", { name: $("#name").value, roomId: $("#room-code").value.trim().toUpperCase() })
);
$("#start").addEventListener("click", () => emit("game:start"));
$("#copy-room").addEventListener("click", async () => {
  await navigator.clipboard?.writeText(state.id);
  showToast("房间码已复制");
});

function render() {
  const self = player(state.selfId);
  const current = player(state.currentPlayerId);
  $("#copy-room").textContent = state.id;
  $("#start").classList.toggle("hidden", state.phase !== "waiting" || state.hostId !== state.selfId);

  const titles = {
    waiting: state.players.length < 3 ? `等待玩家 ${state.players.length}/3` : "三人到齐，可以开始",
    playing: current ? `${current.name} 的回合` : "牌局进行中",
    finished: state.winnerId ? `${player(state.winnerId)?.name ?? "玩家"} 获胜` : "游戏结束"
  };
  $("#status-title").textContent = titles[state.phase];

  $("#players").innerHTML = state.players.map((item) => `
    <article class="player ${item.id === state.selfId ? "self" : ""} ${item.id === state.currentPlayerId ? "current" : ""} ${item.eliminated ? "eliminated" : ""}">
      <div class="player-head">
        <span class="player-name">${escapeHtml(item.name)}${item.id === state.selfId ? "（你）" : ""}</span>
        <span class="player-score">${item.score} 分</span>
      </div>
      <div class="player-meta">
        <span>${item.eliminated ? "已淘汰" : `${item.cardCount} 张牌`}</span>
        <span><i class="dot ${item.connected ? "online" : ""}"></i> ${item.connected ? "在线" : "离线"}</span>
      </div>
    </article>
  `).join("");

  const hand = self?.hand ?? [];
  $("#hand-total").textContent = `${hand.length} 张`;
  $("#hand").innerHTML = hand.length
    ? hand.map((value) => `<div class="card" aria-label="数字 ${value}">${value}</div>`).join("")
    : `<span class="empty">${state.phase === "waiting" ? "游戏开始后发牌" : "没有手牌"}</span>`;

  $("#logs").innerHTML = [...state.logs].reverse().map((log) => `
    <li>${escapeHtml(log.message)}<time>${new Date(log.at).toLocaleTimeString([], { hour: "2-digit", minute: "2-digit" })}</time></li>
  `).join("");

  renderActions();
}

function renderActions() {
  const area = $("#actions");
  const self = player(state.selfId);
  const myTurn = state.currentPlayerId === state.selfId;
  $("#turn-note").textContent = state.phase === "playing" ? (myTurn ? "轮到你行动" : "等待其他玩家") : "";

  if (state.phase === "waiting") {
    area.innerHTML = `<p class="empty">${state.players.length === 3 ? "由房主开始游戏" : "分享房间码，邀请另外两名玩家"}</p>`;
    return;
  }
  if (state.phase === "finished") {
    area.innerHTML = `<div class="response-box"><p class="response-copy">隐藏牌是 <strong>${state.hidden?.join("、")}</strong>。</p></div>`;
    return;
  }
  if (self.eliminated) {
    area.innerHTML = `<p class="empty">你已被淘汰，可以继续观看牌局。</p>`;
    return;
  }
  if (state.pending?.type === "request") {
    renderRequestResponse(area);
    return;
  }
  if (state.pending?.type === "guess") {
    renderGuessResponse(area);
    return;
  }
  if (!myTurn) {
    area.innerHTML = `<p class="empty">观察各玩家手牌数量的变化，等待你的回合。</p>`;
    return;
  }

  const targets = state.players.filter((item) => item.id !== state.selfId && !item.eliminated);
  area.innerHTML = `
    <div class="action-tabs">
      <button data-mode="one" class="${actionMode === "one" ? "active" : ""}">取一张</button>
      <button data-mode="all" class="${actionMode === "all" ? "active" : ""}">取同号全部</button>
      <button data-mode="guess" class="${actionMode === "guess" ? "active" : ""}">猜隐藏牌</button>
    </div>
    ${actionMode === "guess" ? guessForm() : `
      <form id="request-form" class="action-form">
        <label>目标<select name="targetId">${targets.map((item) => `<option value="${item.id}">${escapeHtml(item.name)}</option>`).join("")}</select></label>
        <label>牌号一<select name="first">${options()}</select></label>
        <label>牌号二<select name="second">${options()}</select></label>
        <button class="primary">发出请求</button>
      </form>
    `}
  `;
  area.querySelectorAll("[data-mode]").forEach((button) => {
    button.addEventListener("click", () => {
      actionMode = button.dataset.mode;
      renderActions();
    });
  });
  $("#request-form")?.addEventListener("submit", (event) => {
    event.preventDefault();
    const form = new FormData(event.currentTarget);
    emit("game:request", {
      targetId: form.get("targetId"),
      values: [Number(form.get("first")), Number(form.get("second"))],
      mode: actionMode
    });
  });
  $("#guess-form")?.addEventListener("submit", sendGuess);
}

function renderRequestResponse(area) {
  const pending = state.pending;
  if (pending.targetId !== state.selfId) {
    area.innerHTML = `<p class="empty">等待 ${escapeHtml(player(pending.targetId)?.name ?? "目标玩家")} 回应要牌请求。</p>`;
    return;
  }
  area.innerHTML = `
    <div class="response-box">
      <p class="response-copy">${escapeHtml(player(pending.requesterId)?.name)} 请求数字 <strong>${pending.values.join(" 或 ")}</strong> 的${pending.mode === "one" ? "一张牌" : "其中一种全部牌"}。</p>
      <div class="response-actions">
        ${pending.values.map((value) => `<button class="primary" data-give="${value}">交出数字 ${value}</button>`).join("")}
        <button class="danger" data-decline>不给</button>
      </div>
    </div>
  `;
  area.querySelectorAll("[data-give]").forEach((button) =>
    button.addEventListener("click", () => emit("game:request-answer", { value: Number(button.dataset.give) }))
  );
  area.querySelector("[data-decline]").addEventListener("click", () => emit("game:request-answer", { value: null }));
}

function renderGuessResponse(area) {
  const pending = state.pending;
  const expectedPlayerId = pending.forcedPlayerId ?? pending.responderIds[pending.responseIndex];
  const guessList = pending.guesses.map((guess) => `
    <div class="guess-option">
      <span><strong>${escapeHtml(player(guess.playerId)?.name)}</strong>：${guess.values.join("、")}</span>
      ${expectedPlayerId === state.selfId && guess.playerId !== state.selfId
        ? `<button class="primary" data-agree="${guess.playerId}">认同</button>`
        : ""}
    </div>
  `).join("");

  if (expectedPlayerId !== state.selfId) {
    const waitingFor = player(expectedPlayerId)?.name ?? "其他玩家";
    area.innerHTML = `
      <div class="response-box">
        <div class="guess-list">${guessList}</div>
        <p class="empty">等待 ${escapeHtml(waitingFor)} 回应。</p>
      </div>
    `;
    return;
  }

  const forced = pending.forcedPlayerId === state.selfId;
  area.innerHTML = `
    <div class="response-box">
      <div class="guess-list">${guessList}</div>
      ${forced ? `<p class="response-copy">你是本轮唯一放弃者，必须选择认同一项猜测或提出自己的猜测。</p>` : ""}
      <div class="response-actions">
        <button data-counter>另猜</button>
        ${forced ? "" : `<button class="danger" data-choice="abandon">放弃</button>`}
      </div>
      <form id="counter-form" class="guess-pair hidden">
        <select name="first">${options()}</select>
        <select name="second">${options()}</select>
        <button class="primary">提交新猜测</button>
      </form>
    </div>
  `;
  area.querySelectorAll("[data-agree]").forEach((button) =>
    button.addEventListener("click", () =>
      emit("game:guess-answer", { choice: "agree", guesserId: button.dataset.agree })
    )
  );
  area.querySelectorAll("[data-choice]").forEach((button) =>
    button.addEventListener("click", () => emit("game:guess-answer", { choice: button.dataset.choice }))
  );
  area.querySelector("[data-counter]").addEventListener("click", () => $("#counter-form").classList.remove("hidden"));
  $("#counter-form").addEventListener("submit", (event) => {
    event.preventDefault();
    const form = new FormData(event.currentTarget);
    emit("game:guess-answer", {
      choice: "counter",
      values: [Number(form.get("first")), Number(form.get("second"))]
    });
  });
}

function guessForm() {
  return `
    <form id="guess-form" class="action-form">
      <label>第一张<select name="first">${options()}</select></label>
      <label>第二张<select name="second">${options()}</select></label>
      <button class="primary">提出猜测</button>
    </form>
  `;
}

function sendGuess(event) {
  event.preventDefault();
  const form = new FormData(event.currentTarget);
  emit("game:guess", { values: [Number(form.get("first")), Number(form.get("second"))] });
}

function escapeHtml(value = "") {
  return String(value).replace(/[&<>"']/g, (character) => ({
    "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;", "'": "&#039;"
  })[character]);
}