{% extends "base.html" %}

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

{% block extra_head %}
{{ super() }}
<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>A table will be created in database "<strong><a href="{{ urls.database(database_name) }}">{{ database_name }}</a></strong>".</p>
<form action="/-/upload-csvs" id="uploadForm" method="post" enctype="multipart/form-data">
<div id="file-drop">
    <input type="hidden" name="csrftoken" value="{{ csrftoken() }}">
    <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>
<p style="margin-top: 1em">
    <label for="id_table_name">Table name</label>
    <input required id="id_table_name" type="text" name="table_name">
</p>
<p><input type="submit" value="Upload file" class="button"></p>
</form>
</div>

<script>
var uploadForm = document.getElementById("uploadForm");
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];
var tableName = document.getElementById("id_table_name");

// State that holds the most-recent uploaded File, from a FileList
let currentFile = null;

progress.style.display = "none";
fileInput.addEventListener("change", () => {
  setFile(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 => {
    setFile(e.dataTransfer.files[0]);
  },
  false
);

function formattedBytes(bytes) {
  if (bytes < 1024) {
    return bytes + " bytes";
  }
  if (bytes < 1024 * 1024) {
    return (bytes / 1024).toFixed(1) + " KB";
  }
  if (bytes < 1024 * 1024 * 1024) {
    return (bytes / 1024 / 1024).toFixed(1) + " MB";
  }
  if (bytes < 1024 * 1024 * 1024 * 1024) {
    return (bytes / 1024 / 1024 / 1024).toFixed(1) + " GB";
  }
}

function setFile(file) {
  if (currentFile != file) {
    currentFile = file;
  }
  label.innerText = file.name;
  label.innerHTML += '<br><span style="font-size: 0.9em">' + formattedBytes(file.size) + '</span>';
  if (!tableName.value.trim()) {
    tableName.value = file.name.replace(/\.csv$/i, "").trim();
  }
}

// Onsubmit handler
uploadForm.addEventListener("submit", ev => {
  ev.preventDefault();
  if (!tableName.value.trim()) {
    alert("Please enter a table name");
    return;
  }
  if (!currentFile) {
    alert("Please select a file");
    return;
  }
  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", currentFile);
  formData.append("table", tableName.value);
  xhr.send(formData);
});
</script>
{% endblock %}