"use strict";

const $ = (id) => document.getElementById(id);

const STORAGE_KEY = "filehost.uploads";

const dropzone = $("dropzone");
const fileInput = $("fileInput");
const pwInput = $("pwInput");
const progress = $("progress");
const progressBar = $("progressBar");
const progressPct = $("progressPct");
const progressName = $("progressName");
const result = $("result");
const resultUrl = $("resultUrl");
const resultName = $("resultName");
const resultSize = $("resultSize");
const resultLock = $("resultLock");
const copyBtn = $("copyBtn");
const deleteBtn = $("deleteBtn");
const againBtn = $("againBtn");
const notice = $("notice");
const fileListWrap = $("fileListWrap");
const fileList = $("fileList");
const clearListBtn = $("clearListBtn");

let current = null;
let uploading = false;

function formatBytes(bytes) {
  if (bytes < 1024) return `${bytes} B`;
  const units = ["KB", "MB", "GB", "TB"];
  let value = bytes;
  let i = -1;
  do {
    value /= 1024;
    i += 1;
  } while (value >= 1024 && i < units.length - 1);
  return `${value.toFixed(value >= 100 ? 0 : 1)} ${units[i]}`;
}

function showNotice(message, kind) {
  notice.textContent = message;
  notice.className = kind;
}

function clearNotice() {
  notice.className = "hidden";
  notice.textContent = "";
}

function setProgress(loaded, total) {
  const pct = total > 0 ? Math.round((loaded / total) * 100) : 0;
  progressBar.style.width = `${pct}%`;
  progressPct.textContent = `${pct}%`;
}

function reset() {
  uploading = false;
  current = null;
  result.classList.add("hidden");
  resultLock.classList.add("hidden");
  progress.classList.add("hidden");
  progressBar.style.width = "0%";
  progressPct.textContent = "0%";
  fileInput.value = "";
  pwInput.value = "";
  clearNotice();
}

// ---- client-side upload history (localStorage) ----

function loadUploads() {
  try {
    const raw = localStorage.getItem(STORAGE_KEY);
    const parsed = raw ? JSON.parse(raw) : [];
    return Array.isArray(parsed) ? parsed : [];
  } catch {
    return [];
  }
}

function saveUploads(list) {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(list));
  } catch {
    /* storage unavailable (e.g. private mode) — ignore */
  }
}

function addUpload(record) {
  const list = loadUploads();
  const idx = list.findIndex((item) => item.id === record.id);
  if (idx !== -1) list[idx] = record;
  else list.unshift(record);
  saveUploads(list);
  renderList();
}

function removeUpload(id) {
  saveUploads(loadUploads().filter((item) => item.id !== id));
  renderList();
}

function downloadUrl(item) {
  return new URL(item.url, window.location.origin).href;
}

async function copyText(text) {
  const fallback = () => {
    const ta = document.createElement("textarea");
    ta.value = text;
    ta.style.position = "fixed";
    ta.style.opacity = "0";
    document.body.appendChild(ta);
    ta.select();
    let ok = false;
    try {
      ok = document.execCommand("copy");
    } catch {
      ok = false;
    }
    ta.remove();
    return ok;
  };
  if (navigator.clipboard) {
    try {
      await navigator.clipboard.writeText(text);
      return true;
    } catch {
      return fallback();
    }
  }
  return fallback();
}

function setCopyFeedback(btn, label) {
  const original = btn.textContent;
  btn.textContent = label;
  setTimeout(() => {
    btn.textContent = original;
  }, 1500);
}

function renderList() {
  const list = loadUploads();
  if (list.length === 0) {
    fileListWrap.classList.add("hidden");
    fileList.innerHTML = "";
    return;
  }
  fileListWrap.classList.remove("hidden");
  fileList.innerHTML = "";

  for (const item of list) {
    const li = document.createElement("li");
    li.className = "file-item";

    const meta = document.createElement("div");
    meta.className = "file-item-meta";

    const name = document.createElement("span");
    name.className = "file-item-name";
    name.textContent = item.originalName;
    name.title = item.originalName;

    if (item.protected) {
      const lock = document.createElement("span");
      lock.className = "lock";
      lock.textContent = "Password protected";
      name.appendChild(lock);
    }

    const sub = document.createElement("span");
    sub.className = "file-item-sub";
    let subText = formatBytes(item.size || 0);
    if (item.createdAt) {
      try {
        subText += ` \u00b7 ${new Date(item.createdAt).toLocaleString()}`;
      } catch {
        /* ignore date formatting */
      }
    }
    sub.textContent = subText;

    meta.appendChild(name);
    meta.appendChild(sub);

    const actions = document.createElement("div");
    actions.className = "file-item-actions";

    const dl = document.createElement("a");
    dl.className = "btn-link";
    dl.href = downloadUrl(item);
    dl.textContent = "Download";
    dl.title = "Open download link";

    const copy = document.createElement("button");
    copy.type = "button";
    copy.textContent = "Copy";
    copy.addEventListener("click", async () => {
      const ok = await copyText(downloadUrl(item));
      setCopyFeedback(copy, ok ? "Copied" : "Copy failed");
    });

    const del = document.createElement("button");
    del.type = "button";
    del.className = "danger";
    del.textContent = "Delete";
    del.addEventListener("click", () => deleteFile(item, () => removeUpload(item.id)));

    actions.appendChild(dl);
    actions.appendChild(copy);
    actions.appendChild(del);

    li.appendChild(meta);
    li.appendChild(actions);
    fileList.appendChild(li);
  }
}

async function deleteFile(item, onSuccess) {
  const ok = window.confirm(`Delete "${item.originalName}" permanently? This cannot be undone.`);
  if (!ok) return;
  try {
    const res = await fetch(`/api/files/${item.id}`, {
      method: "DELETE",
      headers: { "X-Delete-Key": item.key },
    });
    if (res.ok) {
      onSuccess();
      showNotice(`"${item.originalName}" was deleted.`, "info");
    } else {
      let message = "Deletion failed.";
      try {
        const data = await res.json();
        if (data && data.error) message = data.error;
      } catch {
        /* keep fallback message */
      }
      showNotice(message, "error");
    }
  } catch {
    showNotice("Deletion failed: network error.", "error");
  }
}

// ---- upload flow ----

function showResult(data) {
  progress.classList.add("hidden");
  result.classList.remove("hidden");
  resultName.textContent = data.originalName;
  resultSize.textContent = formatBytes(data.size);
  resultUrl.value = downloadUrl(data);
  resultLock.classList.toggle("hidden", !data.protected);
  current = data;
  addUpload({
    id: data.id,
    key: data.key,
    url: data.url,
    originalName: data.originalName,
    size: data.size,
    protected: !!data.protected,
    createdAt: new Date().toISOString(),
  });
}

function startUpload(file) {
  if (uploading) return;
  clearNotice();
  progress.classList.remove("hidden");
  progressName.textContent = file.name;
  setProgress(0, file.size);
  uploading = true;

  const xhr = new XMLHttpRequest();
  const form = new FormData();
  if (pwInput.value) form.append("password", pwInput.value);
  form.append("file", file);

  xhr.upload.addEventListener("progress", (e) => {
    if (e.lengthComputable) setProgress(e.loaded, e.total);
  });

  xhr.addEventListener("load", () => {
    uploading = false;
    if (xhr.status >= 200 && xhr.status < 300) {
      try {
        showResult(JSON.parse(xhr.responseText));
      } catch {
        progress.classList.add("hidden");
        showNotice("Invalid server response.", "error");
      }
      return;
    }
    progress.classList.add("hidden");
    let message = `Upload failed (HTTP ${xhr.status})`;
    try {
      const data = JSON.parse(xhr.responseText);
      if (data && data.error) message = data.error;
    } catch {
      /* keep fallback message */
    }
    showNotice(message, "error");
  });

  xhr.addEventListener("error", () => {
    uploading = false;
    progress.classList.add("hidden");
    showNotice("Network error during upload.", "error");
  });

  xhr.addEventListener("abort", () => {
    uploading = false;
    progress.classList.add("hidden");
  });

  xhr.open("POST", "/api/upload");
  xhr.send(form);
}

function handleFile(file) {
  if (!file) return;
  if (file.size === 0) {
    showNotice("Empty files are not supported.", "error");
    return;
  }
  startUpload(file);
}

dropzone.addEventListener("click", () => {
  if (!uploading) fileInput.click();
});

dropzone.addEventListener("keydown", (e) => {
  if ((e.key === "Enter" || e.key === " ") && !uploading) {
    e.preventDefault();
    fileInput.click();
  }
});

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

let dragDepth = 0;
document.addEventListener("dragenter", (e) => {
  e.preventDefault();
  if (!uploading) {
    dragDepth += 1;
    dropzone.classList.add("drag");
  }
});
document.addEventListener("dragover", (e) => e.preventDefault());
document.addEventListener("dragleave", (e) => {
  e.preventDefault();
  dragDepth = Math.max(0, dragDepth - 1);
  if (dragDepth === 0) dropzone.classList.remove("drag");
});
document.addEventListener("drop", (e) => {
  e.preventDefault();
  dragDepth = 0;
  dropzone.classList.remove("drag");
  if (uploading) return;
  const file = e.dataTransfer && e.dataTransfer.files ? e.dataTransfer.files[0] : null;
  if (file) handleFile(file);
});

copyBtn.addEventListener("click", async () => {
  const ok = await copyText(resultUrl.value);
  setCopyFeedback(copyBtn, ok ? "Copied" : "Copy failed");
});

deleteBtn.addEventListener("click", () => {
  if (!current) return;
  deleteFile(current, () => {
    removeUpload(current.id);
    reset();
  });
});

againBtn.addEventListener("click", reset);

clearListBtn.addEventListener("click", () => {
  if (loadUploads().length === 0) return;
  const ok = window.confirm(
    "Clear this list? This only removes the entries from THIS browser. The uploaded files remain on the server.",
  );
  if (!ok) return;
  saveUploads([]);
  renderList();
  showNotice("List cleared. Files on the server were not touched.", "info");
});

renderList();