/**
 * Payload Builder - Assembling the Final Form
 *
 * Takes all our crafted components and stitches them into
 * the exact structure hCaptcha expects.
 *
 * From h.html source, the payload object (s) contains:
 * {v, sitekey, host, hl, motionData, n, c, rqdata, pst, pd, pdc, pem...}
 *
 * IMPORTANT: The 'c' field is included in the payload object but gets
 * REMOVED before encryption. The encrypted body is then packed as:
 *   msgpack.encode([JSON.stringify(c), encrypted_payload_without_c])
 */

export class PayloadBuilder {
    /**
     * Build the getcaptcha request payload
     *
     * The returned object includes 'c' - the caller is responsible for
     * cloning and deleting 'c' before encryption (matching h.html behavior).
     */
    static build({ siteKey, host, n, c, motionData, rqdata = '' }) {
        const now = Date.now();

        return {
            v: '1',                           // Protocol version
            sitekey: siteKey,
            host,
            hl: 'en',                         // Language

            // Challenge response
            n,                                // Proof of work from hsw.js

            // c field — will be stripped before encryption,
            // then used separately in body packing as msgpack([c_string, encrypted])
            c: typeof c === 'string' ? c : JSON.stringify(c),

            // Motion telemetry
            motionData: typeof motionData === 'string'
                ? motionData
                : JSON.stringify(motionData),

            // Additional fields from h.html source
            rqdata,                           // Request data from checksiteconfig
            pst: false,                       // Previous success token

            // Performance / detection data
            pd: JSON.stringify({
                si: now - 5000,               // Script init
                ce: now - 4500,               // Challenge end
                cs: now - 4000,               // Challenge start
                re: now - 500,                // Response end
                rs: now - 1000,               // Response start
            }),
            pdc: JSON.stringify({}),          // Performance data cached
            pem: JSON.stringify({}),          // Performance event map

            // Previous state
            prev: JSON.stringify({
                escaped: false,
                passed: false,
                expiredChallenge: false,
                expiredResponse: false,
            }),
        };
    }

    /**
     * Build form-encoded payload (alternative format for non-encrypted requests)
     */
    static buildFormData(data) {
        const params = new URLSearchParams();

        for (const [key, value] of Object.entries(data)) {
            if (typeof value === 'object') {
                params.append(key, JSON.stringify(value));
            } else {
                params.append(key, String(value));
            }
        }

        return params.toString();
    }
}