"use strict";

(function () {
  const $ = (sel) => document.querySelector(sel);
  const $$ = (sel) => Array.from(document.querySelectorAll(sel));

  const dropZone = $("#dropZone");
  const fileInput = $("#fileInput");
  const searchInput = $("#searchInput");
  const clearBtn = $("#clearBtn");
  const downloadAllBtn = $("#downloadAllBtn");

  const statusEl = $("#status");
  const progressEl = $("#progress");
  const progressBar = $("#progressBar");
  const fileNameEl = $("#fileName");
  const fileSizeEl = $("#fileSize");

  const fileListEl = $("#fileList");
  const countEl = $("#count");

  const previewSection = $("#previewSection");
  const previewContent = $("#previewContent");
  const closePreviewBtn = $("#closePreviewBtn");

  const state = {
    zip: null,
    entries: [],   // { name, file, size, type, lastModDate, url? }
    objectUrls: [],
    totalBytes: 0,
    loadedBytes: 0,
    currentZipFile: null
  };

  // Utils
  function bytesToSize(bytes) {
    if (bytes === 0) return "0 B";
    const k = 1024;
    const sizes = ["B", "KB", "MB", "GB", "TB"];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    const val = parseFloat((bytes / Math.pow(k, i)).toFixed(2));
    return `${val} ${sizes[i]}`;
  }

  function sanitizeName(name) {
    // Avoid path traversal and invalid characters
    const cleaned = name.replace(/^(\.*\/)+/, "").replace(/\.\./g, "");
    return cleaned || "file";
  }

  function setStatus(text, type = "info") {
    statusEl.textContent = text;
    statusEl.className = "status";
    if (type === "error") {
      statusEl.style.color = "#ef4444";
    } else if (type === "success") {
      statusEl.style.color = "#22c55e";
    } else {
      statusEl.style.color = "var(--muted)";
    }
  }

  function setProgress(percent) {
    if (percent <= 0 || percent >= 100) {
      progressEl.style.display = "none";
      progressEl.setAttribute("aria-hidden", "true");
    } else {
      progressEl.style.display = "block";
      progressEl.setAttribute("aria-hidden", "false");
    }
    progressBar.style.width = `${Math.max(0, Math.min(100, percent))}%`;
  }

  function clearObjectUrls() {
    state.objectUrls.forEach((url) => URL.revokeObjectURL(url));
    state.objectUrls = [];
  }

  function resetAll() {
    state.zip = null;
    state.entries = [];
    state.totalBytes = 0;
    state.loadedBytes = 0;
    state.currentZipFile = null;
    clearObjectUrls();
    fileListEl.innerHTML = "";
    countEl.textContent = "0";
    fileNameEl.textContent = "";
    fileSizeEl.textContent = "";
    setStatus("No file loaded.");
    setProgress(0);
    clearBtn.disabled = true;
    downloadAllBtn.disabled = true;
    hidePreview();
  }

  function hidePreview() {
    previewSection.hidden = true;
    previewContent.innerHTML = "";
  }

  function showPreviewFor(entry) {
    previewSection.hidden = false;
    previewContent.innerHTML = "";

    const type = (entry.type || "").toLowerCase();
    const name = entry.name;

    // Text preview
    if (type.startsWith("text/") || /\.(txt|md|csv|json|js|ts|jsx|tsx|html|css|scss|sass|less|yml|yaml|xml|log)$/i.test(name)) {
      const pre = document.createElement("pre");
      pre.textContent = "Loading preview...";
      entry.file.text().then((txt) => {
        pre.textContent = txt;
      }).catch(() => {
        pre.textContent = "Unable to preview this text file.";
      });
      previewContent.appendChild(pre);
      return;
    }

    // Image preview
    if (type.startsWith("image/") || /\.(png|jpe?g|gif|webp|svg|bmp|ico)$/i.test(name)) {
      const img = document.createElement("img");
      img.alt = name;
      const url = URL.createObjectURL(entry.file);
      state.objectUrls.push(url);
      img.src = url;
      img.onload = () => {
        // Keep object URL for preview lifetime; will be revoked on clear/reset
      };
      previewContent.appendChild(img);
      return;
    }

    // PDF preview
    if (type === "application/pdf" || /\.pdf$/i.test(name)) {
      const embed = document.createElement("embed");
      embed.type = "application/pdf";
      const url = URL.createObjectURL(entry.file);
      state.objectUrls.push(url);
      embed.src = url;
      previewContent.appendChild(embed);
      return;
    }

    // Fallback message
    const p = document.createElement("p");
    p.textContent = "Preview is not available for this file type.";
    previewContent.appendChild(p);
  }

  function renderList(entries) {
    fileListEl.innerHTML = "";
    const frag = document.createDocumentFragment();

    entries.forEach((entry) => {
      const li = document.createElement("li");
      li.className = "file";

      const nameCol = document.createElement("div");
      nameCol.className = "file__name";
      const badge = document.createElement("span");
      badge.className = "badge";
      badge.textContent = entry.type || "file";
      const path = document.createElement("span");
      path.className = "path";
      path.textContent = entry.name;

      nameCol.appendChild(badge);
      nameCol.appendChild(path);

      const size = document.createElement("div");
      size.className = "file__size";
      size.textContent = bytesToSize(entry.size);

      const actions = document.createElement("div");
      actions.className = "file__actions";

      const previewBtn = document.createElement("button");
      previewBtn.className = "btn btn-secondary";
      previewBtn.textContent = "Preview";
      previewBtn.addEventListener("click", () => showPreviewFor(entry));

      const downloadBtn = document.createElement("button");
      downloadBtn.className = "btn btn-primary";
      downloadBtn.textContent = "Download";
      downloadBtn.addEventListener("click", () => {
        const a = document.createElement("a");
        const url = URL.createObjectURL(entry.file);
        state.objectUrls.push(url);
        a.href = url;
        a.download = entry.name.split("/").pop();
        document.body.appendChild(a);
        a.click();
        a.remove();
      });

      actions.appendChild(previewBtn);
      actions.appendChild(downloadBtn);

      li.appendChild(nameCol);
      li.appendChild(size);
      li.appendChild(actions);

      frag.appendChild(li);
    });

    fileListEl.appendChild(frag);
    countEl.textContent = String(entries.length);
  }

  async function handleZipFile(file) {
    resetAll();
    state.currentZipFile = file;
    fileNameEl.textContent = file.name || "ZIP archive";
    fileSizeEl.textContent = bytesToSize(file.size);

    setStatus("Loading ZIP...");
    setProgress(2);

    try {
      const zip = await JSZip.loadAsync(file);
      state.zip = zip;

      const entries = [];
      let processed = 0;
      const total = Object.keys(zip.files).length;

      for (const [path, entry] of Object.entries(zip.files)) {
        // Skip directories
        if (entry.dir) {
          processed++;
          setProgress(Math.round((processed / total) * 100));
          continue;
        }

        const safeName = sanitizeName(path);
        // Obtain as Blob
        const blob = await entry.async("blob");
        const fileObj = new File([blob], safeName, { type: blob.type || "application/octet-stream", lastModified: entry.date?.getTime?.() || Date.now() });

        entries.push({
          name: safeName,
          file: fileObj,
          size: fileObj.size,
          type: fileObj.type || "application/octet-stream",
          lastModDate: entry.date
        });

        processed++;
        if (processed % 5 === 0) {
          setProgress(Math.round((processed / total) * 100));
          await new Promise((r) => setTimeout(r, 0)); // Yield to UI
        }
      }

      // Sort by path then size desc for consistent order
      entries.sort((a, b) => a.name.localeCompare(b.name) || b.size - a.size);
      state.entries = entries;
      state.totalBytes = entries.reduce((acc, e) => acc + e.size, 0);
      state.loadedBytes = state.totalBytes;

      renderList(entries);
      setStatus(`Loaded ${entries.length} files from "${file.name}".`);
      setProgress(100);
      clearBtn.disabled = false;
      downloadAllBtn.disabled = entries.length === 0;
    } catch (err) {
      console.error(err);
      setStatus("Failed to read the ZIP file. It may be corrupted or unsupported.", "error");
      setProgress(0);
    }
  }

  function filterEntries(query) {
    const q = query.trim().toLowerCase();
    if (!q) return state.entries;
    return state.entries.filter((e) => e.name.toLowerCase().includes(q));
  }

  async function downloadAll() {
    if (!state.entries.length) return;
    const zip = new JSZip();
    for (const e of state.entries) {
      zip.file(e.name, e.file);
    }
    setStatus("Preparing ZIP for download...");
    setProgress(3);

    try {
      const blob = await zip.generateAsync(
        { type: "blob", compression: "DEFLATE", compressionOptions: { level: 6 } },
        (metadata) => {
          setProgress(Math.max(3, Math.min(99, Math.round(metadata.percent))));
        }
      );
      const a = document.createElement("a");
      const url = URL.createObjectURL(blob);
      a.href = url;
      a.download = (state.currentZipFile?.name?.replace(/\.zip$/i, "") || "extracted") + "-extracted.zip";
      document.body.appendChild(a);
      a.click();
      a.remove();
      URL.revokeObjectURL(url);
      setStatus("ZIP ready for download.", "success");
      setProgress(100);
    } catch (err) {
      console.error(err);
      setStatus("Failed to create ZIP for download.", "error");
      setProgress(0);
    }
  }

  // Event handlers
  dropZone.addEventListener("click", () => fileInput.click());
  dropZone.addEventListener("keydown", (e) => {
    if (e.key === "Enter" || e.key === " ") {
      e.preventDefault();
      fileInput.click();
    }
  });

  ["dragenter", "dragover"].forEach((evt) => {
    dropZone.addEventListener(evt, (e) => {
      e.preventDefault();
      e.stopPropagation();
      dropZone.classList.add("is-dragover");
    });
  });
  ["dragleave", "drop"].forEach((evt) => {
    dropZone.addEventListener(evt, (e) => {
      e.preventDefault();
      e.stopPropagation();
      if (evt === "drop") {
        const dt = e.dataTransfer;
        const file = dt?.files?.[0];
        if (file) handleZipFile(file);
      }
      dropZone.classList.remove("is-dragover");
    });
  });

  fileInput.addEventListener("change", () => {
    const file = fileInput.files?.[0];
    if (file) handleZipFile(file);
  });

  searchInput.addEventListener("input", () => {
    renderList(filterEntries(searchInput.value));
  });

  clearBtn.addEventListener("click", () => {
    fileInput.value = "";
    resetAll();
  });

  downloadAllBtn.addEventListener("click", () => {
    downloadAll();
  });

  closePreviewBtn.addEventListener("click", () => {
    hidePreview();
  });

  // Init
  resetAll();
})();