// =============================================================================
// ANZ Statement Download Helper
// =============================================================================
// PASTE + ENTER, then click Download buttons normally.
// The blob tab still opens (just close it), BUT you also get a properly
// named PDF file downloaded automatically.
//
// TO STOP: just refresh the page (F5)
// =============================================================================

(function () {
    'use strict';

    let downloadCount = 0;
    let lastClickedFilename = null;

    // Track which button was clicked
    document.addEventListener('click', function (e) {
        const btn = e.target.closest('button[data-clicktrack="Download"]');
        if (btn) {
            const label = btn.getAttribute('aria-label') || '';
            const match = label.match(
                /Download the statement issued on (\d{2}) (\w{3}) (\d{4}) (\w+) \d{4}/
            );
            if (match) {
                const [, , monthShort, year, monthFull] = match;
                const monthNum = new Date(`${monthShort} 1, 2000`).getMonth() + 1;
                lastClickedFilename = `ANZ-Statement-${year}-${String(monthNum).padStart(2, '0')}-${monthFull}.pdf`;
            } else {
                lastClickedFilename = `ANZ-Statement-${Date.now()}.pdf`;
            }
            console.log(`⏳ ${lastClickedFilename}...`);
        }
    }, true);

    // Intercept XHR — READ ONLY, don't modify anything
    const origOpen = XMLHttpRequest.prototype.open;
    const origSend = XMLHttpRequest.prototype.send;

    XMLHttpRequest.prototype.open = function (method, url, ...rest) {
        this._url = url;
        return origOpen.call(this, method, url, ...rest);
    };

    XMLHttpRequest.prototype.send = function (body) {
        if (this._url && this._url.includes('download-statement')) {
            // Just listen — don't modify anything. ANZ's code runs normally.
            this.addEventListener('load', function () {
                try {
                    const text = typeof this.response === 'string' ? this.response : this.responseText;
                    const json = JSON.parse(text);
                    const pdf = findPdfData(json);
                    if (pdf) {
                        const fn = lastClickedFilename || `ANZ-Statement-${Date.now()}.pdf`;
                        savePdf(pdf, fn);
                        downloadCount++;
                        console.log(`✅ #${downloadCount} ${fn} (${(pdf.length * 3 / 4 / 1024).toFixed(0)} KB)`);
                        console.log(`   Close the blob tab, then click next Download button.`);
                    }
                } catch (e) {
                    // Silently ignore — ANZ's handler still runs fine
                }
            });
        }
        return origSend.call(this, body);
    };

    function findPdfData(obj, depth) {
        if ((depth || 0) > 5) return null;
        if (typeof obj === 'string' && obj.length > 1000) {
            if (obj.startsWith('JVBERi')) return obj;
            if (obj.match(/^[A-Za-z0-9+/=]+$/) && obj.length > 10000) return obj;
        }
        if (Array.isArray(obj)) {
            for (const item of obj) { const r = findPdfData(item, (depth || 0) + 1); if (r) return r; }
        }
        if (obj && typeof obj === 'object') {
            for (const key of Object.keys(obj)) { const r = findPdfData(obj[key], (depth || 0) + 1); if (r) return r; }
        }
        return null;
    }

    function savePdf(base64, filename) {
        const bin = atob(base64);
        const bytes = new Uint8Array(bin.length);
        for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
        const blob = new Blob([bytes], { type: 'application/pdf' });
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url; a.download = filename;
        document.body.appendChild(a); a.click(); document.body.removeChild(a);
        setTimeout(() => URL.revokeObjectURL(url), 2000);
    }

    console.log('');
    console.log('✅ Download helper active!');
    console.log('👆 Click Download buttons normally.');
    console.log('   Each click: PDF saves as file + blob tab opens (close it).');
    console.log('   To stop: refresh (F5)');
    console.log('');
})();