{% extends "base.html" %}

{% block title %}Upload a CSV to {{ database_name }}{% endblock %}

{% block extra_head %}
<style type="text/css">
#file-drop {
    border: 2px dashed #aaa;
    border-radius: 1em;
    width: 80%;
    font-family: sans-serif;
    padding: 1em;
    box-sizing: border-box;
}
#file-drop.highlight {
    border-color: purple;
    background-color: #8000801f;
}
#file-drop label {
    margin: 0;
    padding: 1em;
    font-style: italic;
    text-align: center;
    display: block;
    width: 100%;
}
input[type=file] {
    display: none;
}
progress {
    -webkit-appearance: none;
    appearance: none;
    border: none;
    width: 80%;
    height: 2em;
    margin-top: 1em;
}
progress::-webkit-progress-bar {
    background-color: #ddd;
}
progress::-webkit-progress-value {
    background-color: #124d77;
}
</style>
{% endblock %}

{% block content %}
<h1>Upload a CSV</h1>
<p>CSV will be imported into <strong>{{ database_name }}</strong></p>
<form action="/-/upload-csvs" method="post" enctype="multipart/form-data">
<div id="file-drop">
    <input type="file" name="csv" id="csvUpload">
    <label for="csvUpload">Select a file to upload or drag and drop one here</label>
</div>
<p style="margin-bottom: -0.8em;font-size: 0.8em; display: none;" id="progress-label">Uploading...</p>
<progress class="progress" value="0" max="100">Uploading...</progress>
</form>
</div>

<script>
var fileInput = document.getElementsByName("csv")[0];
var dropArea = document.getElementById("file-drop");
var progress = document.getElementsByTagName("progress")[0];
var progressLabel = document.getElementById("progress-label");
var label = dropArea.getElementsByTagName("label")[0];
progress.style.display = "none";
fileInput.addEventListener("change", () => {
  uploadFile(fileInput.files[0]);
});
["dragenter", "dragover", "dragleave", "drop"].forEach(eventName => {
  dropArea.addEventListener(
    eventName,
    e => {
      e.preventDefault();
      e.stopPropagation();
    },
    false
  );
});
["dragenter", "dragover"].forEach(eventName => {
  dropArea.addEventListener(
    eventName,
    () => {
      dropArea.classList.add("highlight");
    },
    false
  );
});

["dragleave", "drop"].forEach(eventName => {
  dropArea.addEventListener(
    eventName,
    () => {
      dropArea.classList.remove("highlight");
    },
    false
  );
});

dropArea.addEventListener(
  "drop",
  e => {
    uploadFile(e.dataTransfer.files[0]);
  },
  false
);

function uploadFile(file) {
  label.innerText = file.name;
  var xhr = new XMLHttpRequest();
  var formData = new FormData();
  dropArea.style.display = "none";
  progressLabel.style.display = "block";
  xhr.open("POST", fileInput.form.action, true);

  // Add following event listener
  xhr.upload.addEventListener("progress", function(e) {
    progress.value = (e.loaded * 100.0) / e.total || 100;
  });
  progress.style.display = "block";

  xhr.addEventListener("readystatechange", function(e) {
    if (xhr.readyState == 4 && xhr.status == 200) {
      var data = JSON.parse(xhr.responseText);
      // Show server-side processing progress bar
      progressLabel.innerHTML = "Processing...";
      progress.value = 0;
      var url = `/${data.database_path}/_csv_progress_.json?id=${data.task_id}&_shape=array`;
      function pollForProgress() {
          fetch(url).then(d => d.json()).then(rows => {
              if (rows[0].error) {
                alert("An error occurred processing that file:\n\n" + rows[0].error);
                location.href = location.href;
              }
              progress.value = (rows[0].bytes_done * 100.0) / rows[0].bytes_todo;
              progressLabel.innerHTML = `Processing... ${Number(rows[0].rows_done).toLocaleString()} rows imported`;
              if (rows[0].bytes_done == rows[0].bytes_todo) {
                  document.location = JSON.parse(xhr.responseText).url;
              } else {
                  setTimeout(pollForProgress, 1000);
              }
          });
      }
      pollForProgress();
    } else if (xhr.readyState == 4 && xhr.status != 200) {
      alert("Error!");
    }
  });

  formData.append("xhr", "1");
  formData.append("csrftoken", "{{ csrftoken() }}");
  formData.append("csv", file);
  xhr.send(formData);
}
</script>
{% endblock %}