import TurndownService from "turndown";

export function removeInvisibleCharacters(str: string): string {
    // See: https://www.utf8-chartable.de/unicode-utf8-table.pl
    //      https://stackoverflow.com/a/13836410
    // /[^\u0000-\u007E]/g
    // /\u00AD/g - soft hyphen
    // /[^\u0020-\u007E\u00A1-\u00AC\u00AE-\u00FF]/g
    return str
        .replace(/[\u0000-\u0009\u000B\u000C\u000E-\u001F\u007F-\u009F]/g, "") // Control characters
        .replace(/[\u00AD\u2007\u200C\u2028-\u202F\u2060-\u206F\uFEFF]/g, "") // Invisible characters, such as ­ or "Zero Width Non-Joiner"
        .replace(/\u00A0/g, " ")
        .replace(/\u2002/g, " ")
        .replace(/\u2003/g, " ")
        .replace(/\u2009/g, " ");
    //.replace(/[\u0378\u0379\u0380-\u0383\u038B\u038D\u03A2\u0530\u0557\u0558\u058B\u058C\u0590\u05C8-\u05CF\u05EB-\u05EE\u05F5-\u05FF\u070E\u074B\u074C\u07B2-\u07BF\u07FB\u07FC\u082E\u082F\u083F]/g, ""); // Weird characters
}

/**
 * Returns a TurndownService object configured for my own taste...
 * (of course, if you don't like it, you can configure it to fit your needs)
 */
export function getTurndownService(): TurndownService {
    const turndownService = new TurndownService({
        headingStyle: "atx",
        hr: "---",
        bulletListMarker: "-",
        codeBlockStyle: "fenced",
        fence: "```",
        emDelimiter: "*",
        strongDelimiter: "**",
        linkStyle: "inlined",
        linkReferenceStyle: "full",
    });

    // Add strikethrough:
    turndownService.addRule("strikethrough", {
        filter: ["del", "s"], // , 'strike'
        replacement: function (content) {
            return "~~" + content + "~~";
        },
    });

    // Add blockquote:
    /*turndownService.addRule('blockquote', {
        filter: ['blockquote'],
        replacement: function (content) {
            return '> ' + content;
        }
    });*/

    // Filter table tags:
    turndownService
        .remove("table")
        .remove("tbody")
        .remove("thead")
        .remove("tr")
        .remove("td")
        .remove("th");

    return turndownService;
}