import {
    CodeLensProvider,
    TextDocument,
    CodeLens,
    Range,
    Command
} from "vscode";

export interface Reference {
    document: TextDocument;
    citekey: string;
    pagenr: number | null;
    range: Range;
}

// TODO match citations in brackets [@citation] inline @citatinon,
// but also page number in [see @citation p.23] and
// inlince @citation [p.23] (so brackets after inline)
// TODO possibly use https://github.com/martinring/markdown-it-citations/blob/ba82a511de047a2438b4ac060c4c71b5a5c82da9/src/index.ts#L43
export function findReferences(document: TextDocument): Reference[] {
    const matches: Reference[] = [];
    for (let lineNr = 0; lineNr < document.lineCount; lineNr++) {
        const line = document.lineAt(lineNr);
        let match: RegExpExecArray | null;
        let regex = /(?<=@)([\w\.]+)[, ]*\[?(?:[p]{0,2}\.)?(\d+)?(?:-+\d+)?\]?/g;
        regex.lastIndex = 0;
        const text = line.text;//.substring(0, 1000);
        while ((match = regex.exec(text))) {
            const result = {
                document: document,
                citekey: match[1],
                pagenr: match[2] ? parseInt(match[2]) : null,
                range: new Range(lineNr, match.index, lineNr, match.index + match[0].length)
            } as Reference;
            // if (result) {
            matches.push(result);
            // }
        }
    }
    return matches;
}