Angelmaneuver/unit-converter

import {
    CancellationToken,
    Hover,
    HoverProvider,
    Position,
    ProviderResult,
    TextDocument,
    MarkdownString
}                           from 'vscode';
import { ExtensionSetting } from '../../../settings/extension';

export abstract class AbstractHoverProvider implements HoverProvider {
    protected settings: ExtensionSetting;
    protected regex:    RegExp;

    constructor(settings: ExtensionSetting, regex: RegExp) {
        this.settings = settings;
        this.regex    = regex;
    }

    public provideHover(document: TextDocument, position: Position, token: CancellationToken): ProviderResult<Hover> {
        const wordRange = document.getWordRangeAtPosition(position, this.regex);

        if (undefined === wordRange) {
            return Promise.reject();
        } else {
            const word     = document.lineAt(position.line).text.slice(wordRange.start.character, wordRange.end.character);
            const contents = this.analyze(word);

            return Promise.resolve(new Hover(contents));
        }
    }

    protected abstract analyze(word: string): MarkdownString;
}