// Shared helpers for the admin panel.

function requireAuth() {
  if (!Auth.isAuthed()) {
    location.href = "index.html";
  }
}

function slugify(s) {
  return (s || "")
    .toLowerCase()
    .trim()
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");
}

function uid(prefix) {
  return prefix + "-" + Math.random().toString(36).slice(2, 8);
}

const ADMIN_LOGO_SVG = `
  <svg class="brand-mark" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg" aria-hidden="true">
    <circle cx="50" cy="50" r="50" fill="#6b3d8f"/>
    <g fill="#ffffff" font-family="'Cormorant Garamond','Playfair Display','Times New Roman',serif" font-weight="500" font-style="italic">
      <text x="37" y="70" text-anchor="middle" font-size="60">J</text>
      <text x="63" y="70" text-anchor="middle" font-size="60">M</text>
    </g>
  </svg>
`;

function sidebarHtml(active) {
  const items = [
    ["dashboard.html", t("admin.sidebar.dashboard"), "dashboard"],
    ["artists.html", t("admin.sidebar.artists"), "artists"],
    ["exhibitions.html", t("admin.sidebar.exhibitions"), "exhibitions"],
    ["news.html", t("admin.sidebar.news"), "news"],
    ["settings.html", t("admin.sidebar.settings"), "settings"]
  ];
  const curLang = getLang();
  return `
    <aside class="sidebar">
      <div class="brand-row">
        <a class="brand" href="dashboard.html">
          ${ADMIN_LOGO_SVG}
          <div class="brand-text">
            <div class="brand-word">Jimi Gallery</div>
            <div class="brand-sub">${t("admin.login.title")}</div>
          </div>
        </a>
        <div class="lang-controls">
          <select class="lang-select" id="sidebar-lang" aria-label="${t("admin.sidebar.language")}">
            ${SUPPORTED_LANGS.map(
              (l) =>
                `<option value="${l}"${l === curLang ? " selected" : ""}>${LANG_LABELS[l]}</option>`
            ).join("")}
          </select>
          ${
            hasLangOverride()
              ? `<button type="button" class="lang-reset" id="lang-reset" title="${t("lang.auto_hint")}" aria-label="${t("lang.auto_hint")}">↺</button>`
              : ""
          }
        </div>
      </div>
      <nav>
        ${items
          .map(
            ([h, l, k]) =>
              `<a href="${h}" class="${active === k ? "active" : ""}">${l}</a>`
          )
          .join("")}
      </nav>
      <div class="sidebar-foot">
        <a href="../index.html" target="_blank">${t("admin.sidebar.view_site")}</a>
        <a href="#" id="export-data">${t("admin.sidebar.export")}</a>
        <a href="#" id="import-data">${t("admin.sidebar.import")}</a>
        <input type="file" id="import-file" accept="application/json,.json" style="display:none" />
        <a href="#" id="logout">${t("admin.sidebar.logout")}</a>
        <a href="#" id="reset-data" style="color:var(--danger)">${t("admin.sidebar.reset")}</a>
      </div>
    </aside>
  `;
}

function mountSidebar(active) {
  const host = document.getElementById("sidebar-slot");
  if (host) host.outerHTML = sidebarHtml(active);
  document.getElementById("sidebar-lang")?.addEventListener("change", (e) => {
    setLang(e.target.value);
  });
  document.getElementById("lang-reset")?.addEventListener("click", (e) => {
    e.preventDefault();
    clearLangOverride();
  });
  document.getElementById("logout")?.addEventListener("click", (e) => {
    e.preventDefault();
    Auth.logout();
    location.href = "index.html";
  });
  document.getElementById("reset-data")?.addEventListener("click", async (e) => {
    e.preventDefault();
    if (!confirm(t("admin.confirm.reset"))) return;
    try {
      await Store.reset();
      toast(t("admin.toast.data_reset"));
      setTimeout(() => location.reload(), 400);
    } catch (err) {
      alert(err.message || err);
    }
  });
  document.getElementById("export-data")?.addEventListener("click", (e) => {
    e.preventDefault();
    exportData();
  });
  document.getElementById("import-data")?.addEventListener("click", (e) => {
    e.preventDefault();
    document.getElementById("import-file")?.click();
  });
  document.getElementById("import-file")?.addEventListener("change", (e) => {
    const f = e.target.files && e.target.files[0];
    if (f) importDataFromFile(f);
    e.target.value = "";
  });
}

async function exportData() {
  let data;
  try {
    data = await Store.exportAll();
  } catch (e) {
    alert(e.message || e);
    return;
  }
  const json = JSON.stringify(data, null, 2);
  const blob = new Blob([json], { type: "application/json" });
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  const ts = new Date().toISOString().slice(0, 10);
  a.download = `jimi-gallery-${ts}.json`;
  document.body.appendChild(a);
  a.click();
  a.remove();
  URL.revokeObjectURL(url);
  toast(t("admin.toast.exported"));
}

function importDataFromFile(file) {
  const reader = new FileReader();
  reader.onerror = () => alert(t("admin.error.invalid_file"));
  reader.onload = async () => {
    let parsed;
    try {
      parsed = JSON.parse(reader.result);
    } catch (e) {
      alert(t("admin.error.invalid_file"));
      return;
    }
    if (
      !parsed ||
      typeof parsed !== "object" ||
      !parsed.settings ||
      !Array.isArray(parsed.artists) ||
      !Array.isArray(parsed.exhibitions) ||
      !Array.isArray(parsed.news)
    ) {
      alert(t("admin.error.invalid_file"));
      return;
    }
    if (!confirm(t("admin.confirm.import"))) return;
    try {
      await Store.importAll(parsed);
      toast(t("admin.toast.imported"));
      setTimeout(() => location.reload(), 400);
    } catch (err) {
      alert(err.message || err);
    }
  };
  reader.readAsText(file);
}

let _toastTimer;
function toast(msg) {
  let el = document.querySelector(".toast");
  if (!el) {
    el = document.createElement("div");
    el.className = "toast";
    document.body.appendChild(el);
  }
  el.textContent = msg;
  requestAnimationFrame(() => el.classList.add("show"));
  clearTimeout(_toastTimer);
  _toastTimer = setTimeout(() => el.classList.remove("show"), 1800);
}

function openModal() {
  document.getElementById("modal")?.classList.add("open");
}
function closeModal() {
  document.getElementById("modal")?.classList.remove("open");
}

function fmtDateShort(iso) {
  if (!iso) return "—";
  return new Date(iso + "T00:00:00").toLocaleDateString(
    typeof getLocale === "function" ? getLocale() : "en-US",
    { month: "short", day: "numeric", year: "numeric" }
  );
}

// Mount a multilingual text field with EN/KO/JA tabs. Returns a handle with
// .get() returning the { en, ko, ja } object. Pair this with form submit:
//   const bio = mountMultilingualField(el, { value: a.bio });
//   // later: item.bio = bio.get();
function mountMultilingualField(container, opts = {}) {
  const { value = {}, type = "textarea", placeholder = "", minHeight = "" } = opts;
  const initial =
    typeof value === "string"
      ? { en: value, ko: "", ja: "" }
      : { en: (value && value.en) || "", ko: (value && value.ko) || "", ja: (value && value.ja) || "" };
  const state = { ...initial };
  const langs = SUPPORTED_LANGS;
  let current = getLang();
  if (!langs.includes(current)) current = "en";

  container.classList.add("ml-field");
  const inputEl =
    type === "input"
      ? `<input type="text" class="ml-input" placeholder="${escapeAttr(placeholder)}" />`
      : `<textarea class="ml-input" placeholder="${escapeAttr(placeholder)}"${
          minHeight ? ` style="min-height:${minHeight}"` : ""
        }></textarea>`;
  container.innerHTML = `
    <div class="ml-tabs">
      ${langs
        .map(
          (l) =>
            `<button type="button" class="ml-tab" data-lang="${l}">${LANG_LABELS[l]}</button>`
        )
        .join("")}
    </div>
    ${inputEl}
  `;

  const input = container.querySelector(".ml-input");
  const tabs = container.querySelectorAll(".ml-tab");

  function switchTo(lang) {
    state[current] = input.value;
    current = lang;
    input.value = state[lang] || "";
    tabs.forEach((tb) => tb.classList.toggle("active", tb.dataset.lang === lang));
  }

  tabs.forEach((tb) => tb.addEventListener("click", () => switchTo(tb.dataset.lang)));

  // initial active tab
  tabs.forEach((tb) => tb.classList.toggle("active", tb.dataset.lang === current));
  input.value = state[current] || "";

  return {
    get() {
      state[current] = input.value;
      return { en: state.en || "", ko: state.ko || "", ja: state.ja || "" };
    }
  };
}

function escapeAttr(s) {
  return String(s == null ? "" : s)
    .replace(/&/g, "&amp;")
    .replace(/"/g, "&quot;");
}

// Read a File, downscale if large, return a data URL string.
async function fileToDataURL(file, maxDim = 1400, quality = 0.82) {
  const originalDataUrl = await new Promise((resolve, reject) => {
    const r = new FileReader();
    r.onerror = () => reject(r.error || new Error("read failed"));
    r.onload = () => resolve(r.result);
    r.readAsDataURL(file);
  });
  if (file.type === "image/gif" || file.size < 300 * 1024) return originalDataUrl;
  return new Promise((resolve) => {
    const img = new Image();
    img.onerror = () => resolve(originalDataUrl);
    img.onload = () => {
      const scale = Math.min(1, maxDim / Math.max(img.width, img.height));
      if (scale >= 1) return resolve(originalDataUrl);
      const w = Math.round(img.width * scale);
      const h = Math.round(img.height * scale);
      const canvas = document.createElement("canvas");
      canvas.width = w;
      canvas.height = h;
      canvas.getContext("2d").drawImage(img, 0, 0, w, h);
      try {
        resolve(canvas.toDataURL("image/jpeg", quality));
      } catch (e) {
        resolve(originalDataUrl);
      }
    };
    img.src = originalDataUrl;
  });
}

// Mount an image field (preview + URL input + upload + clear) into `container`.
// Returns the URL input element.
function mountImageField(container, opts = {}) {
  const {
    value = "",
    id = "",
    dataK = "",
    placeholder = "Paste image URL",
    compact = false
  } = opts;

  container.className = "image-field" + (compact ? " compact" : "");
  container.innerHTML = `
    <div class="image-field-preview">
      <img alt="" />
      <div class="image-field-empty">No image selected</div>
    </div>
    <div class="image-field-controls">
      <input type="url" class="image-field-url"${id ? ` id="${id}"` : ""}${
    dataK ? ` data-k="${dataK}"` : ""
  } placeholder="${placeholder}" value="${escapeAttr(value)}" />
      <label class="btn ghost btn-small image-field-upload">
        Upload
        <input type="file" accept="image/*" />
      </label>
      <button type="button" class="btn ghost btn-small image-field-clear">Clear</button>
    </div>
  `;

  const urlInput = container.querySelector(".image-field-url");
  const fileInput = container.querySelector('input[type="file"]');
  const previewImg = container.querySelector(".image-field-preview img");
  const emptyEl = container.querySelector(".image-field-empty");
  const clearBtn = container.querySelector(".image-field-clear");

  function updatePreview() {
    const v = urlInput.value.trim();
    if (v) {
      previewImg.src = v;
      previewImg.style.display = "";
      emptyEl.style.display = "none";
    } else {
      previewImg.removeAttribute("src");
      previewImg.style.display = "none";
      emptyEl.style.display = "";
    }
  }

  urlInput.addEventListener("input", updatePreview);
  previewImg.addEventListener("error", () => {
    previewImg.style.display = "none";
    emptyEl.textContent = "Preview unavailable";
    emptyEl.style.display = "";
  });

  fileInput.addEventListener("change", async () => {
    const file = fileInput.files && fileInput.files[0];
    if (!file) return;
    if (!file.type.startsWith("image/")) {
      alert("Please select an image file.");
      fileInput.value = "";
      return;
    }
    if (file.size > 20 * 1024 * 1024) {
      alert("Image too large — please choose a file under 20MB.");
      fileInput.value = "";
      return;
    }
    try {
      const dataUrl = await fileToDataURL(file);
      urlInput.value = dataUrl;
      emptyEl.textContent = "No image selected";
      updatePreview();
    } catch (err) {
      alert("Could not read image: " + (err.message || err));
    }
    fileInput.value = "";
  });

  clearBtn.addEventListener("click", () => {
    urlInput.value = "";
    emptyEl.textContent = "No image selected";
    updatePreview();
  });

  updatePreview();
  return urlInput;
}