self.importScripts('../coherentpdf.browser.min.js');

self.onmessage = function (e) {
    const { command, files, jobs } = e.data;

    if (command === 'merge') {
        mergePDFs(files, jobs);
    }
};

function mergePDFs(files, jobs) {
    try {
        const loadedPdfs = {};
        const pdfsToMerge = [];
        const rangesToMerge = [];

        for (const file of files) {
            const uint8Array = new Uint8Array(file.data);
            const pdfDoc = coherentpdf.fromMemory(uint8Array, "");
            loadedPdfs[file.name] = pdfDoc;
        }

        for (const job of jobs) {
            const sourcePdf = loadedPdfs[job.fileName];
            if (!sourcePdf) continue;

            let range;
            if (job.rangeType === 'all') {
                range = coherentpdf.all(sourcePdf);
            } else if (job.rangeType === 'specific') {
                if (coherentpdf.validatePagespec(job.rangeString)) {
                    range = coherentpdf.parsePagespec(sourcePdf, job.rangeString);
                } else {
                    range = coherentpdf.all(sourcePdf);
                }
            } else if (job.rangeType === 'single') {
                const pageNum = job.pageIndex + 1;
                range = coherentpdf.range(pageNum, pageNum);
            } else if (job.rangeType === 'range') {
                range = coherentpdf.range(job.startPage, job.endPage);
            }

            pdfsToMerge.push(sourcePdf);
            rangesToMerge.push(range);
        }

        if (pdfsToMerge.length === 0) {
            throw new Error('No valid files or pages to merge.');
        }

        const mergedPdf = coherentpdf.mergeSame(pdfsToMerge, true, true, rangesToMerge);

        const mergedPdfBytes = coherentpdf.toMemory(mergedPdf, false, true);
        const buffer = mergedPdfBytes.buffer;

        coherentpdf.deletePdf(mergedPdf);
        Object.values(loadedPdfs).forEach(pdf => coherentpdf.deletePdf(pdf));

        self.postMessage({
            status: 'success',
            pdfBytes: buffer
        }, [buffer]);

    } catch (error) {
        self.postMessage({
            status: 'error',
            message: error.message || 'Unknown error during merge'
        });
    }
}