function AnnotationPlugin(options) {

  const { onChange } = options

  return {

    onSelect(event, data, state, editor) {

      event.preventDefault()

      const selection = data.selection;

      const startOffset = selection.startOffset;

      const endOffset = selection.endOffset;

      if (selection.isCollapsed) {

        return;

      }

      let nodes = [];

      let hasStarted = false;

      let hasEnded = false;

      // Keep only the relevant nodes,

      // i.e. nodes which are contained within selection

      state.document.nodes.forEach((node) => {

        if (selection.hasStartIn(node)) {

          hasStarted = true;

        }

        if (hasStarted && !hasEnded) {

          nodes.push(node);

        }

        if (selection.hasEndIn(node)) {

          hasEnded = true;

        }

      });

      let text = '';

      // Concatenate the nodes text

      if (nodes.length === 1) {

        text = nodes[0].text.substring(startOffset, endOffset);

      } else {

        text = nodes.map((node) => {

          if (selection.hasStartIn(node)) return node.text.substring(startOffset);

          if (selection.hasEndIn(node)) return node.text.substring(0, endOffset);

          return node.text;

        }).join('\n');

      }

      if (onChange) {

        onChange(text);

      }

    }

  };

}

export default AnnotationPlugin;