{% extends 'base.html' %}

{% block title %}Upscale Image — WebTools{% endblock %}

{% block content %}
<div class="container py-5">

  <!-- Breadcrumb -->
  <nav aria-label="breadcrumb" class="mb-4">
    <ol class="breadcrumb">
      <li class="breadcrumb-item"><a href="{{ url_for('main.index') }}">Home</a></li>
      <li class="breadcrumb-item"><a href="{{ url_for('main.index') }}#image">Image Tools</a></li>
      <li class="breadcrumb-item active" aria-current="page">Upscale Image</li>
    </ol>
  </nav>

  <!-- Page Header -->
  <div class="row mb-4">
    <div class="col">
      <h1 class="h2 fw-bold"><i class="fa-solid fa-magnifying-glass-plus me-2 text-primary"></i>Upscale Image</h1>
      <p class="text-muted">Enlarge your image by 2x, 3x, or 4x while maintaining the best possible quality.</p>
    </div>
  </div>

  <div class="row g-4">
    <!-- Left column: form -->
    <div class="col-lg-6">
      <div class="card shadow-sm border-0">
        <div class="card-body p-4">

          <!-- Drop zone -->
          <div id="dropZone" class="border border-2 rounded-3 text-center p-5 mb-4 position-relative"
               style="border-style:dashed!important;cursor:pointer;transition:background .2s;">
            <i class="fa-solid fa-cloud-arrow-up fa-2x text-muted mb-2"></i>
            <p class="mb-1 fw-semibold">Drag &amp; drop an image here</p>
            <p class="text-muted small mb-3">or click to browse</p>
            <input type="file" id="imageInput" name="image" accept="image/*"
                   class="position-absolute top-0 start-0 w-100 h-100 opacity-0" style="cursor:pointer;">
          </div>

          <!-- Preview -->
          <div id="previewWrap" class="mb-4 d-none text-center">
            <img id="imagePreview" src="" alt="Preview" class="img-fluid rounded shadow-sm" style="max-height:180px;">
            <p id="previewInfo" class="small text-muted mt-2 mb-0"></p>
          </div>

          <!-- Scale factor -->
          <div class="mb-4">
            <label class="form-label fw-semibold">Scale Factor</label>
            <div class="row g-3">
              <div class="col-4">
                <input type="radio" class="btn-check" name="scale" id="scale2x" value="2" checked>
                <label class="btn btn-outline-primary w-100 py-3" for="scale2x">
                  <span class="d-block h4 mb-1">2x</span>
                  <small>Double</small>
                </label>
              </div>
              <div class="col-4">
                <input type="radio" class="btn-check" name="scale" id="scale3x" value="3">
                <label class="btn btn-outline-primary w-100 py-3" for="scale3x">
                  <span class="d-block h4 mb-1">3x</span>
                  <small>Triple</small>
                </label>
              </div>
              <div class="col-4">
                <input type="radio" class="btn-check" name="scale" id="scale4x" value="4">
                <label class="btn btn-outline-primary w-100 py-3" for="scale4x">
                  <span class="d-block h4 mb-1">4x</span>
                  <small>Quadruple</small>
                </label>
              </div>
            </div>
          </div>

          <!-- Expected output -->
          <div id="dimsPreview" class="alert alert-light border mb-4 d-none">
            <i class="fa-solid fa-ruler-combined me-2 text-primary"></i>
            Original: <strong id="origDimsText">—</strong>
            &rarr; Upscaled: <strong id="newDimsText" class="text-success">—</strong>
          </div>

          <!-- Notice -->
          <div class="alert alert-warning mb-4">
            <i class="fa-solid fa-triangle-exclamation me-2"></i>
            <strong>Note:</strong> Quality improvement depends on the original image resolution.
            Very small or low-quality images may not show significant detail enhancement.
          </div>

          <!-- Submit -->
          <div class="d-grid">
            <button id="submitBtn" type="button" class="btn btn-primary btn-lg" disabled>
              <i class="fa-solid fa-magnifying-glass-plus me-2"></i>Upscale Image
            </button>
          </div>

        </div>
      </div>
    </div>

    <!-- Right column: results -->
    <div class="col-lg-6">
      <div id="errorAlert" class="alert alert-danger d-none" role="alert">
        <i class="fa-solid fa-circle-xmark me-2"></i><span id="errorMsg"></span>
      </div>

      <div id="loadingCard" class="card shadow-sm border-0 d-none">
        <div class="card-body p-5 text-center">
          <div class="spinner-border text-primary mb-3" style="width:3rem;height:3rem;" role="status">
            <span class="visually-hidden">Processing...</span>
          </div>
          <p class="fw-semibold mb-0">Upscaling image…</p>
          <p class="small text-muted">This may take a moment for larger images.</p>
        </div>
      </div>

      <div id="resultsCard" class="card shadow-sm border-0 d-none">
        <div class="card-header bg-success text-white fw-semibold">
          <i class="fa-solid fa-circle-check me-2"></i>Upscale Complete
        </div>
        <div class="card-body p-4">
          <div class="row g-3 mb-4">
            <div class="col-6">
              <div class="p-3 rounded bg-light text-center">
                <p class="small text-muted mb-1">Original</p>
                <p id="resultOrigDims" class="fw-bold mb-0">—</p>
              </div>
            </div>
            <div class="col-6">
              <div class="p-3 rounded bg-light text-center">
                <p class="small text-muted mb-1">Upscaled</p>
                <p id="resultNewDims" class="fw-bold mb-0 text-success">—</p>
              </div>
            </div>
          </div>
          <div class="d-grid">
            <a id="downloadLink" href="#" class="btn btn-success btn-lg" download>
              <i class="fa-solid fa-download me-2"></i>Download Upscaled Image
            </a>
          </div>
        </div>
      </div>

      <div id="placeholderCard" class="card border-0 bg-light">
        <div class="card-body p-5 text-center text-muted">
          <i class="fa-solid fa-magnifying-glass-plus fa-3x mb-3 opacity-25"></i>
          <p class="mb-0">Your upscaled image will appear here after processing.</p>
        </div>
      </div>
    </div>
  </div>
</div>
{% endblock %}

{% block scripts %}
<script>
(function () {
  'use strict';

  const dropZone    = document.getElementById('dropZone');
  const fileInput   = document.getElementById('imageInput');
  const previewWrap = document.getElementById('previewWrap');
  const previewInfo = document.getElementById('previewInfo');
  const submitBtn   = document.getElementById('submitBtn');
  const errorAlert  = document.getElementById('errorAlert');
  const errorMsg    = document.getElementById('errorMsg');
  const loadingCard = document.getElementById('loadingCard');
  const resultsCard = document.getElementById('resultsCard');
  const placeholder = document.getElementById('placeholderCard');
  const dimsPreview = document.getElementById('dimsPreview');

  let selectedFile = null;
  let origW = 0, origH = 0;

  dropZone.addEventListener('dragover', (e) => { e.preventDefault(); dropZone.classList.add('bg-primary','bg-opacity-10'); });
  dropZone.addEventListener('dragleave', () => { dropZone.classList.remove('bg-primary','bg-opacity-10'); });
  dropZone.addEventListener('drop', (e) => {
    e.preventDefault();
    dropZone.classList.remove('bg-primary','bg-opacity-10');
    if (e.dataTransfer.files[0]) handleFile(e.dataTransfer.files[0]);
  });
  fileInput.addEventListener('change', () => { if (fileInput.files[0]) handleFile(fileInput.files[0]); });

  function handleFile(file) {
    selectedFile = file;
    const reader = new FileReader();
    reader.onload = (ev) => {
      const img = document.getElementById('imagePreview');
      img.src = ev.target.result;
      img.onload = () => {
        origW = img.naturalWidth;
        origH = img.naturalHeight;
        previewInfo.textContent = file.name + ' — ' + origW + ' × ' + origH + 'px';
        updateDimsPreview();
        dimsPreview.classList.remove('d-none');
        document.getElementById('resultOrigDims').textContent = origW + ' × ' + origH;
      };
      previewWrap.classList.remove('d-none');
    };
    reader.readAsDataURL(file);
    submitBtn.disabled = false;
    hideResults();
  }

  function updateDimsPreview() {
    const scale = parseInt(document.querySelector('input[name="scale"]:checked').value);
    document.getElementById('origDimsText').textContent  = origW + ' × ' + origH;
    document.getElementById('newDimsText').textContent   = (origW*scale) + ' × ' + (origH*scale);
    document.getElementById('resultNewDims').textContent = (origW*scale) + ' × ' + (origH*scale);
  }

  document.querySelectorAll('input[name="scale"]').forEach(r => {
    r.addEventListener('change', () => { if (origW) updateDimsPreview(); });
  });

  function hideResults() {
    errorAlert.classList.add('d-none');
    loadingCard.classList.add('d-none');
    resultsCard.classList.add('d-none');
    placeholder.classList.remove('d-none');
  }

  submitBtn.addEventListener('click', async () => {
    if (!selectedFile) return;
    errorAlert.classList.add('d-none');
    loadingCard.classList.remove('d-none');
    resultsCard.classList.add('d-none');
    placeholder.classList.add('d-none');
    submitBtn.disabled = true;

    const fd = new FormData();
    fd.append('image', selectedFile);
    fd.append('scale', document.querySelector('input[name="scale"]:checked').value);

    try {
      const resp = await fetch('/tools/image/upscale/process', { method: 'POST', body: fd });
      if (!resp.ok) {
        let msg = 'Server error ' + resp.status;
        try { const j = await resp.json(); msg = j.error || msg; } catch(_) {}
        throw new Error(msg);
      }
      const newW = resp.headers.get('X-Width');
      const newH = resp.headers.get('X-Height');
      if (newW && newH) {
        document.getElementById('resultNewDims').textContent = newW + ' × ' + newH;
      }
      const blob = await resp.blob();
      const url  = URL.createObjectURL(blob);
      const dl   = document.getElementById('downloadLink');
      dl.href     = url;
      dl.download = 'upscaled_' + selectedFile.name;
      loadingCard.classList.add('d-none');
      resultsCard.classList.remove('d-none');
    } catch (err) {
      loadingCard.classList.add('d-none');
      placeholder.classList.remove('d-none');
      errorMsg.textContent = err.message;
      errorAlert.classList.remove('d-none');
    } finally {
      submitBtn.disabled = false;
    }
  });
})();
</script>
{% endblock %}