"use strict";

(function main() {
  // DOM elements
  var markdown = document.getElementById("markdown");
  var markup = document.getElementById("markup");
  var numbered = document.getElementById("numbered");
  var violations = document.getElementById("violations");
  var form = document.getElementsByTagName("form")[0];
  var openFile = document.getElementById("openFile");

  // Instances
  var markdownit = window.markdownit();
  var newLineRe = /\r\n|\r|\n/;

  // Handle input
  function onMarkdownInput() {
    // Markdown
    var content = markdown.value;
    // Markup
    markup.innerHTML = markdownit.render(content);
    // Numbered
    numbered.innerText = content.split(newLineRe)
      .map(function mapNumberedLine(line, index) {
        return (index + 1) + ": " + line;
      }).join("\n");
    // Violations
    var options = {
      "strings": {
        "content": content
      }
    };
    var results = window.markdownlint.sync(options).toString();
    violations.innerText = results.split(newLineRe)
      .map(function mapResultLine(line) {
        return line.replace(/^content: /, "");
      }).join("\n");
  }

  // Load from a string or File object
  function loadMarkdown(source) {
    // Reset input element
    form.reset();
    if (typeof source === "string") {
      // Update from string
      markdown.value = source;
      onMarkdownInput();
    } else {
      // Update from File object
      var reader = new FileReader();
      reader.onload = function readerOnload(e) {
        markdown.value = e.target.result;
        onMarkdownInput();
      };
      reader.readAsText(source);
    }
  }

  // Handle drag-and-drop
  function onDragOver(e) {
    if (e.dataTransfer && e.dataTransfer.dropEffect) {
      e.dataTransfer.dropEffect = "link";
      e.preventDefault();
    }
  }
  function onDrop(e) {
    if (e.dataTransfer && e.dataTransfer.files) {
      loadMarkdown(e.dataTransfer.files[0]);
      e.preventDefault();
    }
  }

  // Handle file open
  function onOpenFileChange(e) {
    if (e.target && e.target.files) {
      loadMarkdown(e.target.files[0]);
    }
  }

  // Add event listeners
  document.body.addEventListener("dragover", onDragOver);
  document.body.addEventListener("drop", onDrop);
  openFile.addEventListener("change", onOpenFileChange);
  markdown.addEventListener("input", onMarkdownInput);
}());