pavlitsky/vscode-yard

"use strict";
import { EndOfLine, Position, TextEditor, TextLine, window } from "vscode";
import { Builder } from "./builder";

// Generate YARD comment
export default class YardDocumenter {
  private editor: TextEditor;
  private position: Position;
  private line: TextLine;
  private lineText: string;
  private eol: string;

  // Build and insert documentation snippet
  public generate() {
    // Update current editor, line, cursor position
    this.updateContext();

    // Check if documenter should run
    if (!this.shouldRun()) { return; }

    // Resolve documenter by current line's content
    const snippet = (new Builder(this.lineText, this.eol)).build();
    if (!snippet) { return; }

    // Insert documentation snippet
    return this.editor.insertSnippet(snippet, this.snippetPosition());
  }

  private updateContext(textEditor?: TextEditor) {
    this.editor = textEditor || window.activeTextEditor;
    if (this.editor) {
      this.position = this.editor.selection.active;
      this.line = this.editor.document.lineAt(this.position);
      this.lineText = this.line.text;
      this.eol = this.editor.document.eol === EndOfLine.LF ? "\n" : "\r\n";
    }
  }

  // Get position for a snippet
  private snippetPosition(): Position {
    return this.position.with({character: this.line.firstNonWhitespaceCharacterIndex});
  }

  // Check if previous line already has some comment
  private commentExists(): boolean {
    if (this.line.lineNumber === 0) { return false; }
    const prevLinePosition = this.position.with({line: this.line.lineNumber - 1});
    const prevLine = this.editor.document.lineAt(prevLinePosition);
    return prevLine.text.trim().startsWith("#");
  }

  // Is documenter should run
  private shouldRun(): boolean {
    return this.editor && !this.commentExists();
  }
}