import { json } from './json.js';
import { createETag, setCharset } from './utils.js';
/**
 * Sends the HTTP response.
 *
 * The body parameter can be a Buffer object, a string, an object, or an array.
 *
 * This method performs many useful tasks for simple non-streaming responses.
 * For example, it automatically assigns the Content-Length HTTP response header field (unless previously defined) and provides automatic HEAD and HTTP cache freshness support.
 *
 * @param req Request
 * @param res Response
 */
export const send = (req, res) => (body) => {
    let bodyToSend = body;
    if (Buffer.isBuffer(body)) {
        bodyToSend = body;
    }
    else if (typeof body === 'object' && body !== null) {
        // in case of object - turn it to json
        bodyToSend = JSON.stringify(body, null, 2);
    }
    else if (typeof body === 'string') {
        // reflect this in content-type
        const type = res.getHeader('Content-Type');
        if (type && typeof type === 'string') {
            res.setHeader('Content-Type', setCharset(type, 'utf-8'));
        }
        else
            res.setHeader('Content-Type', setCharset('text/html', 'utf-8'));
    }
    // Set encoding
    const encoding = 'utf8';
    // populate ETag
    let etag;
    if (body && !res.getHeader('etag') && (etag = createETag(bodyToSend, encoding))) {
        res.setHeader('etag', etag);
    }
    // freshness
    if (req.fresh)
        res.statusCode = 304;
    // strip irrelevant headers
    if (res.statusCode === 204 || res.statusCode === 304) {
        res.removeHeader('Content-Type');
        res.removeHeader('Content-Length');
        res.removeHeader('Transfer-Encoding');
        bodyToSend = '';
    }
    if (req.method === 'HEAD') {
        res.end('');
        return res;
    }
    if (typeof body === 'object') {
        if (body == null) {
            res.end('');
            return res;
        }
        if (Buffer.isBuffer(body)) {
            if (!res.getHeader('Content-Type'))
                res.setHeader('content-type', 'application/octet-stream');
            res.end(bodyToSend);
        }
        else
            json(res)(bodyToSend, encoding);
    }
    else {
        if (typeof bodyToSend !== 'string')
            bodyToSend = bodyToSend.toString();
        res.end(bodyToSend, encoding);
    }
    return res;
};
//# sourceMappingURL=send.js.map