'use strict';

// ── Helpers ────────────────────────────────────────────────────────────────

function formatBytes(n) {
  if (n < 1024) return n + ' B';
  if (n < 1024 ** 2) return (n / 1024).toFixed(1) + ' KB';
  if (n < 1024 ** 3) return (n / 1024 ** 2).toFixed(1) + ' MB';
  return (n / 1024 ** 3).toFixed(2) + ' GB';
}

function copyToClipboard(text, btn) {
  navigator.clipboard.writeText(text).then(() => {
    const orig = btn.textContent;
    btn.textContent = 'Copied!';
    setTimeout(() => (btn.textContent = orig), 1500);
  });
}

// ── DOM refs ───────────────────────────────────────────────────────────────

const tabBtns       = document.querySelectorAll('.tab-btn');
const tabContents   = document.querySelectorAll('.tab-content');

const formView      = document.getElementById('formView');
const resultView    = document.getElementById('resultView');

const dropZone      = document.getElementById('dropZone');
const fileInput     = document.getElementById('fileInput');
const dzIcon        = document.getElementById('dzIcon');
const dzMain        = document.getElementById('dzMain');
const dzHint        = document.getElementById('dzHint');
const dzName        = document.getElementById('dzName');
const dzSize        = document.getElementById('dzSize');

const textArea      = document.getElementById('textArea');
const ttlSelect     = document.getElementById('ttlSelect');
const passwordIn    = document.getElementById('passwordInput');
const burnToggle    = document.getElementById('burnToggle');

const uploadBtn     = document.getElementById('uploadBtn');
const progressWrap  = document.getElementById('progressWrap');
const progressFill  = document.getElementById('progressFill');
const progressLbl   = document.getElementById('progressLbl');
const alertBox      = document.getElementById('alertBox');

const resultUrl     = document.getElementById('resultUrl');
const copyUrlBtn    = document.getElementById('copyUrlBtn');
const resultPwWrap  = document.getElementById('resultPwWrap');
const resultPw      = document.getElementById('resultPw');
const copyPwBtn     = document.getElementById('copyPwBtn');
const shareAgainBtn = document.getElementById('shareAgainBtn');

let selectedFile = null;
let activeTab = 'file';

// ── Tabs ───────────────────────────────────────────────────────────────────

tabBtns.forEach(btn => {
  btn.addEventListener('click', () => {
    activeTab = btn.dataset.tab;
    tabBtns.forEach(b => b.classList.toggle('active', b === btn));
    tabContents.forEach(c => c.classList.toggle('active', c.id === 'tab-' + activeTab));
    clearAlert();
  });
});

// ── Drop zone ──────────────────────────────────────────────────────────────

dropZone.addEventListener('dragover', e => { e.preventDefault(); dropZone.classList.add('dragover'); });
dropZone.addEventListener('dragleave', () => dropZone.classList.remove('dragover'));
dropZone.addEventListener('drop', e => {
  e.preventDefault();
  dropZone.classList.remove('dragover');
  if (e.dataTransfer.files.length) setFile(e.dataTransfer.files[0]);
});
fileInput.addEventListener('change', () => {
  if (fileInput.files.length) setFile(fileInput.files[0]);
});

function setFile(file) {
  selectedFile = file;
  dropZone.classList.add('has-file');
  dzIcon.textContent = '📄';
  dzMain.textContent = '';
  dzHint.textContent = '';
  dzName.textContent = file.name;
  dzSize.textContent = formatBytes(file.size);
}

// ── Alerts ─────────────────────────────────────────────────────────────────

function showAlert(msg, type = 'error') {
  alertBox.className = `alert alert-${type}`;
  alertBox.textContent = msg;
  alertBox.classList.remove('hidden');
}
function clearAlert() { alertBox.classList.add('hidden'); }

// ── Upload ─────────────────────────────────────────────────────────────────

uploadBtn.addEventListener('click', handleUpload);

async function handleUpload() {
  clearAlert();

  const isFile = activeTab === 'file';
  const password = passwordIn.value.trim();

  if (isFile && !selectedFile) { showAlert('Please select a file first.'); return; }
  if (!isFile && !textArea.value.trim()) { showAlert('Please enter some text first.'); return; }

  uploadBtn.disabled = true;
  progressWrap.classList.remove('hidden');
  setProgress(0, 'Preparing…');

  try {
    const form = new FormData();

    if (isFile) {
      form.append('file', selectedFile, selectedFile.name);
      form.append('share_type', 'file');
      form.append('original_filename', selectedFile.name);
      form.append('mimetype', selectedFile.type || 'application/octet-stream');
    } else {
      const blob = new Blob([textArea.value], { type: 'text/plain' });
      form.append('file', blob, 'text.txt');
      form.append('share_type', 'text');
      form.append('mimetype', 'text/plain');
    }

    form.append('ttl_hours', ttlSelect.value);
    form.append('burn_after_read', burnToggle.checked);
    if (password) form.append('password', password);

    setProgress(10, 'Uploading…');

    const data = await xhrUpload('/api/upload', form, pct => {
      setProgress(10 + Math.round(pct * 0.88), `Uploading… ${Math.round(pct)}%`);
    });

    setProgress(100, 'Done');

    const shareUrl = `${location.origin}/s/${data.share_id}`;
    switchToResult(shareUrl, password || null);

  } catch (err) {
    showAlert(err.message || 'Upload failed. Please try again.');
    uploadBtn.disabled = false;
    progressWrap.classList.add('hidden');
  }
}

function setProgress(pct, label) {
  progressFill.style.width = pct + '%';
  progressLbl.textContent = label;
}

function xhrUpload(url, formData, onProgress) {
  return new Promise((resolve, reject) => {
    const xhr = new XMLHttpRequest();
    xhr.open('POST', url);
    xhr.upload.onprogress = e => {
      if (e.lengthComputable) onProgress((e.loaded / e.total) * 100);
    };
    xhr.onload = () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        resolve(JSON.parse(xhr.responseText));
      } else {
        let msg = 'Upload failed';
        try { msg = JSON.parse(xhr.responseText).detail || msg; } catch {}
        reject(new Error(msg));
      }
    };
    xhr.onerror = () => reject(new Error('Network error'));
    xhr.send(formData);
  });
}

// ── View crossfade ─────────────────────────────────────────────────────────

function switchToResult(url, pw) {
  resultUrl.value = url;
  copyUrlBtn.onclick = () => copyToClipboard(url, copyUrlBtn);

  if (pw) {
    resultPwWrap.classList.remove('hidden');
    resultPw.value = pw;
    copyPwBtn.onclick = () => copyToClipboard(pw, copyPwBtn);
  } else {
    resultPwWrap.classList.add('hidden');
  }

  // Re-trigger SVG check animation
  ['.check-circle', '.check-mark'].forEach(sel => {
    const el = resultView.querySelector(sel);
    el.style.animation = 'none';
    el.getBoundingClientRect();
    el.style.animation = '';
  });

  formView.classList.add('view-exiting');
  setTimeout(() => {
    formView.classList.add('hidden');
    formView.classList.remove('view-exiting');
    progressWrap.classList.add('hidden');
    resultView.classList.remove('hidden');
    resultView.classList.add('view-entering');
    setTimeout(() => resultView.classList.remove('view-entering'), 350);
  }, 260);
}

function switchToForm() {
  resultView.classList.add('view-exiting');
  setTimeout(() => {
    resultView.classList.add('hidden');
    resultView.classList.remove('view-exiting');
    resetForm();
    formView.classList.remove('hidden');
    formView.classList.add('view-entering');
    setTimeout(() => formView.classList.remove('view-entering'), 350);
  }, 260);
}

function resetForm() {
  selectedFile = null;
  fileInput.value = '';
  dropZone.classList.remove('has-file');
  dzIcon.textContent = '📂';
  dzMain.textContent = 'Drop a file or click to browse';
  dzHint.textContent = '1 GB recommended · up to 6 GB accepted';
  dzName.textContent = '';
  dzSize.textContent = '';
  textArea.value = '';
  passwordIn.value = '';
  burnToggle.checked = false;
  ttlSelect.value = '24';
  clearAlert();
  uploadBtn.disabled = false;
}

shareAgainBtn.addEventListener('click', switchToForm);