"use strict";

(function (global) {
  const STORAGE_PREFIX = "tarinai_save_slot_v1_";
  const EXPORT_PREFIX = "TARINAI_SAVE_V1:";
  const EXPORT_PREFIX_COMPRESSED = "TARINAI-SAVE-V11:";
  // Alpha note: save/import compatibility is not guaranteed yet.
  // Hash imports intentionally accept only the current V11 format during alpha.
  // V11 stores compact semantic early-game saves when possible, falls back to the V10 binary packet for complex states, and encodes bytes with printable ASCII excluding \, *, ' and _.
  const SLOT_COUNT = 9;
  const Snapshot = global.TarinaiSnapshot;
  if (!Snapshot) throw new Error("TarinaiSnapshot is not available for save_system.js");
  const createSnapshot = (...args) => Snapshot.createSnapshot(...args);
  const restoreSnapshot = (...args) => Snapshot.restoreSnapshot(...args);
  const htmlEscape = global.TarinaiUIHelpers?.htmlEscape || ((v) => String(v ?? "").replace(/[&<>"]/g, c => ({ "&": "&amp;", "<": "&lt;", ">": "&gt;", '"': "&quot;" }[c])));


  const BASE94_ALPHABET = (() => {
    const excluded = new Set(["\\", "*", "'", "_"]);
    let out = "";
    for (let i = 33; i <= 126; i++) {
      const ch = String.fromCharCode(i);
      if (!excluded.has(ch)) out += ch;
    }
    return out;
  })();
  const BASE94_RADIX = BASE94_ALPHABET.length;
  const BASE94_DECODE = (() => {
    const map = Object.create(null);
    for (let i = 0; i < BASE94_ALPHABET.length; i++) map[BASE94_ALPHABET[i]] = i;
    return map;
  })();

  function bytesToBase94(bytes) {
    if (!bytes || !bytes.length) return "!";
    let zeros = 0;
    while (zeros < bytes.length && bytes[zeros] === 0) zeros++;
    const digits = [0];
    for (let i = zeros; i < bytes.length; i++) {
      let carry = bytes[i];
      for (let j = 0; j < digits.length; j++) {
        const x = digits[j] * 256 + carry;
        digits[j] = x % BASE94_RADIX;
        carry = Math.floor(x / BASE94_RADIX);
      }
      while (carry > 0) {
        digits.push(carry % BASE94_RADIX);
        carry = Math.floor(carry / BASE94_RADIX);
      }
    }
    let out = BASE94_ALPHABET[0].repeat(zeros);
    for (let i = digits.length - 1; i >= 0; i--) out += BASE94_ALPHABET[digits[i]];
    return out || BASE94_ALPHABET[0];
  }

  function base94ToBytes(text) {
    const str = String(text || "").replace(/\s/g, "");
    if (!str) return new Uint8Array();
    let zeros = 0;
    while (zeros < str.length && str[zeros] === BASE94_ALPHABET[0]) zeros++;
    const bytes = [0];
    for (let i = zeros; i < str.length; i++) {
      const digit = BASE94_DECODE[str[i]];
      if (digit === undefined) throw new Error("invalid base94 character");
      let carry = digit;
      for (let j = 0; j < bytes.length; j++) {
        const x = bytes[j] * BASE94_RADIX + carry;
        bytes[j] = x & 255;
        carry = x >> 8;
      }
      while (carry > 0) {
        bytes.push(carry & 255);
        carry >>= 8;
      }
    }
    const out = new Uint8Array(zeros + bytes.length);
    for (let i = 0; i < zeros; i++) out[i] = 0;
    for (let i = 0; i < bytes.length; i++) out[out.length - 1 - i] = bytes[i];
    return out;
  }

  function bytesToBase64(bytes) {
    let binary = "";
    const chunk = 0x8000;
    for (let i = 0; i < bytes.length; i += chunk) binary += String.fromCharCode(...bytes.subarray(i, i + chunk));
    return btoa(binary).replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/g, "");
  }

  function stripExportPrefix(text, prefixes) {
    let value = String(text || "").trim();
    const hashless = value.replace(/^#+/, "");
    if (prefixes.some(prefix => hashless.startsWith(prefix))) value = hashless;
    for (const prefix of prefixes) {
      if (value.startsWith(prefix)) return value.slice(prefix.length);
    }
    return value;
  }

  function base64ToBytes(text) {
    let b64 = stripExportPrefix(text, [EXPORT_PREFIX]).replace(/-/g, "+").replace(/_/g, "/");
    while (b64.length % 4) b64 += "=";
    const binary = atob(b64);
    const bytes = new Uint8Array(binary.length);
    for (let i = 0; i < binary.length; i++) bytes[i] = binary.charCodeAt(i);
    return bytes;
  }

  async function gzipBytes(bytes) {
    if (typeof CompressionStream !== "function") return null;
    const stream = new Blob([bytes]).stream().pipeThrough(new CompressionStream("gzip"));
    return new Uint8Array(await new Response(stream).arrayBuffer());
  }

  async function gunzipBytes(bytes) {
    if (typeof DecompressionStream !== "function") throw new Error("compressed import is not supported in this browser");
    const stream = new Blob([bytes]).stream().pipeThrough(new DecompressionStream("gzip"));
    return new Uint8Array(await new Response(stream).arrayBuffer());
  }

  function encodeSnapshotLegacy(snapshot) {
    const json = JSON.stringify(snapshot);
    const bytes = new TextEncoder().encode(json);
    return EXPORT_PREFIX + bytesToBase64(bytes);
  }

  async function encodeSnapshot(snapshot) {
    if (snapshot?.__tarinaiCompactBytes && snapshot.bytes) {
      const raw = snapshot.bytes instanceof Uint8Array ? snapshot.bytes : new Uint8Array(snapshot.bytes);
      const compressed = await gzipBytes(raw);
      if (compressed && compressed.length < raw.length) return EXPORT_PREFIX_COMPRESSED + "z" + bytesToBase94(compressed);
      return EXPORT_PREFIX_COMPRESSED + "r" + bytesToBase94(raw);
    }
    const json = JSON.stringify(snapshot);
    const bytes = new TextEncoder().encode(json);
    const compressed = await gzipBytes(bytes);
    if (compressed && compressed.length < bytes.length) return EXPORT_PREFIX_COMPRESSED + "z" + bytesToBase94(compressed);
    return EXPORT_PREFIX_COMPRESSED + "r" + bytesToBase94(bytes);
  }

  async function decodeSnapshot(text) {
    const raw = String(text || "").trim();
    const normalized = raw.replace(/^#+/, "");
    if (!normalized) throw new Error("empty import text");
    if (!normalized.startsWith(EXPORT_PREFIX_COMPRESSED)) throw new Error("unsupported save hash version");
    const body = stripExportPrefix(normalized, [EXPORT_PREFIX_COMPRESSED]);
    const mode = body[0] || "r";
    const payload = body.slice(1);
    const bytes = base94ToBytes(payload);
    const packet = mode === "z" ? await gunzipBytes(bytes) : bytes;
    if (!Snapshot.decodeV11SnapshotBytes) throw new Error("V11 decoder is not available");
    return Snapshot.decodeV11SnapshotBytes(packet);
  }

  function slotKey(slot) { return `${STORAGE_PREFIX}${slot}`; }

  function makeThumbnail() {
    const source = global.canvas || document.getElementById("gameCanvas");
    if (!source || !source.width || !source.height) return "";
    try {
      const tw = 168;
      const th = 96;
      const c = document.createElement("canvas");
      c.width = tw;
      c.height = th;
      const ctx = c.getContext("2d", { alpha: false });
      if (!ctx) return "";
      ctx.fillStyle = "#f6efe3";
      ctx.fillRect(0, 0, tw, th);
      const scale = Math.min(tw / source.width, th / source.height);
      const w = Math.max(1, Math.round(source.width * scale));
      const h = Math.max(1, Math.round(source.height * scale));
      const x = Math.floor((tw - w) / 2);
      const y = Math.floor((th - h) / 2);
      ctx.imageSmoothingEnabled = true;
      ctx.drawImage(source, x, y, w, h);
      return c.toDataURL("image/jpeg", 0.58);
    } catch (_) {
      return "";
    }
  }

  function makeSaveSnapshot() {
    const snapshot = createSnapshot(global.world);
    snapshot.thumbnail = makeThumbnail();
    return snapshot;
  }

  function saveSlot(slot) {
    const snapshot = makeSaveSnapshot();
    localStorage.setItem(slotKey(slot), JSON.stringify(snapshot));
    return snapshot;
  }

  function loadSlot(slot) {
    const raw = localStorage.getItem(slotKey(slot));
    if (!raw) throw new Error("empty slot");
    return restoreSnapshot(JSON.parse(raw), global.world);
  }

  function deleteSlot(slot) { localStorage.removeItem(slotKey(slot)); }

  function readSlot(slot) {
    const raw = localStorage.getItem(slotKey(slot));
    if (!raw) return null;
    try { return JSON.parse(raw); } catch (_) { return null; }
  }

  function formatSlotSummary(snapshot) {
    if (!snapshot) return "空き";
    const d = snapshot.summary || {};
    const date = snapshot.createdAt ? new Date(snapshot.createdAt).toLocaleString("ja-JP", { month: "2-digit", day: "2-digit", hour: "2-digit", minute: "2-digit" }) : "日時不明";
    return `${date}\n${d.fieldType || "庭"} / ${d.day || 1}日目 ${d.time || ""}\n${d.population || 0}匹 / 道具${d.items || 0}`;
  }

  function ensureDialog() {
    let dialog = document.getElementById("saveDialog");
    if (dialog) return dialog;
    dialog = document.createElement("div");
    dialog.id = "saveDialog";
    dialog.className = "field-dialog hidden";
    dialog.setAttribute("role", "dialog");
    dialog.setAttribute("aria-modal", "true");
    dialog.innerHTML = `
      <div class="field-dialog-panel save-dialog-panel">
        <h2 id="saveDialogTitle">セーブ / ロード</h2>
        <p class="hint">9つのスロットに現在のコロニーを保存できます。ハッシュテキストは圧縮して短く書き出します。</p>
        <div id="saveSlotList" class="save-slot-list save-slot-grid"></div>
        <div class="save-export-panel">
          <div class="save-export-actions">
            <button id="saveExportBtn" class="btn" type="button">現在の状態を書き出し</button>
            <button id="saveImportBtn" class="btn primary" type="button">ハッシュテキストを読み込み</button>
          </div>
          <textarea id="saveHashText" class="save-hash-text" spellcheck="false" placeholder="ここに短縮ハッシュテキストが表示されます。読み込む場合はここに貼り付けてください。"></textarea>
        </div>
        <div id="saveConfirmBox" class="save-confirm-box hidden" role="alertdialog" aria-modal="false">
          <div class="save-confirm-message"></div>
          <div class="save-confirm-actions">
            <button class="btn" data-save-confirm="cancel" type="button">やめる</button>
            <button class="btn danger" data-save-confirm="ok" type="button">実行</button>
          </div>
        </div>
        <div class="field-dialog-actions">
          <button id="saveCloseBtn" class="btn" type="button">閉じる</button>
        </div>
      </div>`;
    document.body.appendChild(dialog);
    return dialog;
  }

  function confirmInGame(message, okLabel = "実行") {
    const dialog = ensureDialog();
    const box = dialog.querySelector("#saveConfirmBox");
    if (!box) return Promise.resolve(false);
    box.querySelector(".save-confirm-message").textContent = message;
    const ok = box.querySelector('[data-save-confirm="ok"]');
    if (ok) ok.textContent = okLabel;
    box.classList.remove("hidden");
    return new Promise(resolve => {
      const finish = (value) => {
        box.classList.add("hidden");
        box.removeEventListener("click", onClick);
        resolve(value);
      };
      const onClick = (e) => {
        const btn = e.target.closest("[data-save-confirm]");
        if (!btn) return;
        finish(btn.dataset.saveConfirm === "ok");
      };
      box.addEventListener("click", onClick);
    });
  }

  function slotThumbnailHtml(snapshot) {
    const src = snapshot?.thumbnail || "";
    if (src) return `<img src="${htmlEscape(src)}" alt="" loading="lazy">`;
    return `<div class="save-slot-thumb-empty">No Image</div>`;
  }

  function renderSlotList() {
    const dialog = ensureDialog();
    const list = dialog.querySelector("#saveSlotList");
    if (!list) return;
    list.innerHTML = "";
    for (let i = 1; i <= SLOT_COUNT; i++) {
      const snapshot = readSlot(i);
      const row = document.createElement("div");
      row.className = `save-slot-card ${snapshot ? "filled" : "empty"}`;
      row.innerHTML = `
        <div class="save-slot-thumb">${slotThumbnailHtml(snapshot)}</div>
        <div class="save-slot-title">スロット ${i}</div>
        <div class="save-slot-meta">${htmlEscape(formatSlotSummary(snapshot)).replace(/\n/g, "<br>")}</div>
        <div class="save-slot-actions">
          <button class="btn mini" data-save-slot="${i}" type="button">保存</button>
          <button class="btn mini" data-load-slot="${i}" type="button" ${snapshot ? "" : "disabled"}>読込</button>
          <button class="btn mini danger" data-delete-slot="${i}" type="button" ${snapshot ? "" : "disabled"}>削除</button>
        </div>`;
      list.appendChild(row);
    }
  }

  function openDialog() {
    const dialog = ensureDialog();
    renderSlotList();
    dialog.classList.remove("hidden");
  }

  function closeDialog() {
    document.getElementById("saveDialog")?.classList.add("hidden");
  }

  function bindSaveSystem() {
    const btn = document.getElementById("saveBtn") || global.ui?.saveBtn;
    if (!btn || btn.dataset.saveBound === "1") return;
    btn.dataset.saveBound = "1";
    btn.addEventListener("click", () => {
      global.audio?.uiClick?.();
      openDialog();
    });
    const dialog = ensureDialog();
    dialog.addEventListener("click", async (e) => {
      if (e.target === dialog) { closeDialog(); return; }
      if (e.target.closest("#saveConfirmBox")) return;
      const saveBtn = e.target.closest("[data-save-slot]");
      const loadBtn = e.target.closest("[data-load-slot]");
      const deleteBtn = e.target.closest("[data-delete-slot]");
      if (saveBtn) {
        const slot = Number(saveBtn.dataset.saveSlot);
        try {
          saveSlot(slot);
          renderSlotList();
          global.audio?.notify?.();
          global.showToast?.(`スロット${slot}に保存しました。`);
        } catch (error) {
          console.warn(error);
          global.showToast?.("保存に失敗しました。空き容量を確認してください。");
        }
        return;
      }
      if (loadBtn) {
        const slot = Number(loadBtn.dataset.loadSlot);
        if (!await confirmInGame(`スロット${slot}を読み込みます。現在の状態は上書きされます。`, "読み込む")) return;
        try {
          loadSlot(slot);
          closeDialog();
          global.audio?.notify?.();
          global.showToast?.(`スロット${slot}を読み込みました。`);
        } catch (error) {
          console.warn(error);
          global.showToast?.("読み込みに失敗しました。");
        }
        return;
      }
      if (deleteBtn) {
        const slot = Number(deleteBtn.dataset.deleteSlot);
        if (!await confirmInGame(`スロット${slot}を削除しますか？`, "削除")) return;
        deleteSlot(slot);
        renderSlotList();
        global.audio?.delete?.();
        global.showToast?.(`スロット${slot}を削除しました。`);
        return;
      }
      if (e.target.closest("#saveCloseBtn")) closeDialog();
      if (e.target.closest("#saveExportBtn")) {
        const area = dialog.querySelector("#saveHashText");
        const exportBtn = dialog.querySelector("#saveExportBtn");
        try {
          if (exportBtn) exportBtn.disabled = true;
          if (area) {
            area.value = "書き出し中…";
            const fullSnapshot = createSnapshot(global.world);
            const exportSnapshot = Snapshot.createCompactSnapshot ? Snapshot.createCompactSnapshot(global.world) : fullSnapshot;
            const text = await encodeSnapshot(exportSnapshot);
            area.value = text;
            area.focus();
            area.select();
            const legacy = encodeSnapshotLegacy(fullSnapshot);
            const rate = legacy.length ? Math.round((1 - text.length / legacy.length) * 100) : 0;
            global.showToast?.(rate > 0 ? `軽量ハッシュを書き出しました（約${rate}%短縮）。` : "現在の状態を書き出しました。");
          }
        } catch (error) {
          console.warn(error);
          global.showToast?.("書き出しに失敗しました。");
        } finally {
          if (exportBtn) exportBtn.disabled = false;
        }
      }
      if (e.target.closest("#saveImportBtn")) {
        const area = dialog.querySelector("#saveHashText");
        const text = area?.value || "";
        if (!text.trim()) { global.showToast?.("読み込むハッシュテキストを貼り付けてください。"); return; }
        if (!await confirmInGame("ハッシュテキストを読み込みます。現在の状態は上書きされます。", "読み込む")) return;
        try {
          restoreSnapshot(await decodeSnapshot(text), global.world);
          closeDialog();
          global.audio?.notify?.();
          global.showToast?.("ハッシュテキストから読み込みました。");
        } catch (error) {
          console.warn(error);
          global.showToast?.("読み込みに失敗しました。テキストを確認してください。");
        }
      }
    });
  }

  global.TarinaiSaveSystem = {
    createSnapshot,
    restoreSnapshot,
    encodeSnapshot,
    decodeSnapshot,
    saveSlot,
    loadSlot,
    deleteSlot,
    readSlot,
    bindSaveSystem,
    openDialog,
  };
})(typeof window !== "undefined" ? window : globalThis);