import string
import socket
import stdio
import stdlib
import requests
import openssl
import json
import memhub


# ============================================================
# requests/https.vp - HTTPS client (openssl SSL/TLS + certificate verification)
#
# Same API names as requests (HTTP), but over TLS and by default it verifies the peer certificate:
#     import requests.https as rhttps
#     resp = rhttps.get("https://example.com/", verify=True)
#     if resp is not None:
#         print(resp.status_code)
#         print(resp.text)
#     requests.release(resp)
#
# Notes:
#   - with verify=True it verifies the certificate chain + hostname (hostname check via SSL_set1_host),
#     provide ca_file pointing to a PEM CA bundle; if not provided it uses the system default path
#     (on Windows this is usually empty, so real sites fail with "unable to verify certificate chain" and return None).
#   - on failure returns None; use last_error() to get the reason text.
#   - after a successful handshake, use last_tls_info() to view the TLS version / cipher suite / peer certificate subject.
# ============================================================

define HTTPS_PORT = 443

# Module-internal state
_ossl_ready: bool = False
_socket_ready: bool = False
_err_store: [512]char      # last failure reason (static buffer)
_info_store: [512]char     # TLS metadata of last successful handshake
_scratch_store: [512]char  # scratch concat buffer
_last_verify_val: int = -1              # last SSL_get_verify_result (0=ok; -1=disabled)
_last_verify_flag: int = -1             # last request verify flag (1=on; 0=off; -1=unknown)

# ============================================================
# SSE streaming receive area (post_stream only; single request, polled by UI thread).
#   _st_len written bytes; _st_consumed consumed cursor; _st_state 0=running 1=done(2xx) 2=fail; _st_status HTTP code.
# ============================================================
define STREAM_CAP = 262144
_st_buf: [STREAM_CAP]char
_st_len: sizet = 0
_st_consumed: sizet = 0
_st_state: int = 0
_st_status: int = 0
_st_err: [512]char


def stream_begin():
    """Start a new streaming receive: reset buffer/cursor/state."""
    global _st_len, _st_consumed, _st_state, _st_status
    _st_len = 0
    _st_consumed = 0
    _st_state = 0
    _st_status = 0
    _st_err[0] = 0


def stream_pull(out: str, cap: int) -> int:
    """Copy unconsumed delta into out (NUL-terminated); return bytes copied."""
    global _st_consumed
    if out is None or cap <= 1:
        return 0
    avail: int = 0
    if _st_len > _st_consumed:
        avail = int(_st_len - _st_consumed)
    if avail > cap - 1:
        avail = cap - 1
    for i in range(int(sizet(avail))):
        out[i] = _st_buf[_st_consumed + i]
    out[sizet(avail)] = 0
    _st_consumed += sizet(avail)
    return avail


def stream_state() -> int:
    """0=running 1=done(2xx) 2=failed."""
    return _st_state


def stream_status() -> int:
    """HTTP status code; negative means network/parse error."""
    return _st_status


def stream_error_text() -> str:
    """Failure reason text (when _st_state==2)."""
    return _st_err


def last_verify_result() -> int:
    """Last cert verify result: 0=ok; >0=failure code; -1=verify disabled."""
    return _last_verify_val


def last_verify_enabled() -> int:
    """Whether last request enabled verify (1=yes; 0=no; -1=unknown)."""
    return _last_verify_flag


# ============================================================
# internal helpers
# ============================================================

def last_error() -> str:
    """Last failure reason text (empty string if none)."""
    return _err_store


def last_tls_info() -> str:
    """Last successful handshake TLS info (version/cipher/peer subject), empty if none."""
    return _info_store


def _RecordErrorText(text: str):
    """Write failure reason into static buffer _err_store."""
    if text is None: return
    _err_store[0] = 0
    stdio.snprintf(_err_store, 512, "%s", text)


def _RecordInfoText(text: str):
    """Write TLS metadata into static buffer _info_store."""
    if text is None: return
    _info_store[0] = 0
    stdio.snprintf(_info_store, 512, "%s", text)


def _EnsureReady() -> int:
    """Initialize socket and openssl (both idempotent)."""
    global _socket_ready, _ossl_ready
    if not _socket_ready:
        if socket.SocketInit() != 0:
            _RecordErrorText("socket init failed")
            return -1
        _socket_ready = True
    if not _ossl_ready:
        if openssl.OPENSSL_init_ssl(0, None) != 1:
            _RecordErrorText("OPENSSL_init_ssl failed")
            return -1
        _ossl_ready = True
    return 0


def _ParseHttpsUrl(url: str, host_buf: str, host_size: int, path_buf: str, path_size: int, port: int*) -> int:
    """Parse https://host[:port][/path]; default port 443."""
    if url is None: return -1
    if host_buf is None or path_buf is None or port is None: return -1

    p: str = url

    # Skip "https://" (8 bytes)
    if string.strncmp(p, "https://", 8) == 0:
        p += 8

    # Parse host
    host_start: str = p
    host_len: int = 0
    while p[0] != '\0' and p[0] != ':' and p[0] != '/':
        host_len += 1
        p += 1

    if host_len == 0 or host_len >= host_size: return -1
    string.strncpy(host_buf, host_start, host_len)
    host_buf[host_len] = 0

    # Parse port
    if p[0] == ':':
        p += 1
        port_val: int = 0
        while p[0] >= '0' and p[0] <= '9':
            port_val = port_val * 10 + int(p[0] - '0')
            p += 1
        *port = port_val
    else:
        *port = HTTPS_PORT

    # Parse path
    if p[0] == '/':
        path_start: str = p
        path_len: int = 0
        while p[0] != '\0':
            path_len += 1
            p += 1
        if path_len >= path_size: return -1
        string.strncpy(path_buf, path_start, path_len)
        path_buf[path_len] = 0
    else:
        if path_size < 2: return -1
        path_buf[0] = '/'
        path_buf[1] = 0

    return 0


def _ScratchBuf() -> str:
    """Return static concat buffer (512B, reused)."""
    return _scratch_store


def _TlsErrText():
    """Write last openssl error-queue text into static scratch buffer."""
    e: uint32 = openssl.ERR_get_error()
    if e == 0:
        _scratch_store[0] = 0
        string.strncpy(_scratch_store, "openssl error (no detail)", 26)
        return
    openssl.ERR_error_string_n(e, _scratch_store, 512)


# ============================================================
# Core request
# ============================================================

def _HttpsRequest(method: str, url: str, verify: bool, ca_file: str, data: str, content_type: str, auth: str = None) -> requests.Response*:
    """HTTPS GET/POST core. verify=False skips cert chain/hostname checks (not recommended);
    verify=True uses ca_file PEM bundle (else system default); auth adds Authorization header on POST only.
    """
    global _last_verify_val, _last_verify_flag
    if requests._mbuddy is None: return None

    _last_verify_flag = 1 if verify else 0

    resp: requests.Response* = requests.create_response()
    if resp is None: return None

    if _EnsureReady() != 0:
        requests.release(resp)
        return None

    # Temp buffer for error text; openssl details go to module scratch.
    errmsg: str = requests._mbuddy.alloc(512)
    if errmsg is None:
        requests.release(resp)
        return None

    # ---- Parse URL ----
    host_buf: [256]char
    path_buf: [1024]char
    port: int = 0

    if _ParseHttpsUrl(url, host_buf, 256, path_buf, 1024, &port) != 0:
        stdio.snprintf(errmsg, 512, "bad https url: %s", url)
        _RecordErrorText(errmsg)
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    # ---- Establish TCP connection ----
    sock = socket.Socket(socket.AF_INET, socket.SOCK_STREAM)
    if sock.fd == socket.INVALID_SOCKET:
        _RecordErrorText("socket() failed")
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    if sock.connect(host_buf, port) != 0:
        stdio.snprintf(errmsg, 512, "connect %s:%d failed", host_buf, port)
        _RecordErrorText(errmsg)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    # ---- SSL_CTX / SSL ----
    ctx: openssl.SslCtxPtr = openssl.SSL_CTX_new(openssl.TLS_client_method())
    if ctx is None:
        _RecordErrorText("SSL_CTX_new failed")
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    if verify:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyPeer, None)
        if ca_file is not None and ca_file[0] != 0:
            if openssl.SSL_CTX_load_verify_locations(ctx, ca_file, None) != 1:
                _TlsErrText()
                stdio.snprintf(errmsg, 512, "load CA file failed: %s (%s)", ca_file, _ScratchBuf())
                _RecordErrorText(errmsg)
                openssl.SSL_CTX_free(ctx)
                sock.close()
                requests._mbuddy.free(errmsg)
                requests.release(resp)
                return None
        else:
            # System default paths (usually empty on Windows; cert chain check will fail).
            openssl.SSL_CTX_set_default_verify_paths(ctx)
    else:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyNone, None)

    ssl: openssl.SslPtr = openssl.SSL_new(ctx)
    if ssl is None:
        _RecordErrorText("SSL_new failed")
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    openssl.SSL_set_fd(ssl, sock.fd)
    # SNI (SSL_set_tlsext_host_name is a macro -> call SSL_ctrl directly)
    openssl.SSL_ctrl(ssl, openssl.SslCtrlSetTlsextHostname, openssl.TlsextNametypeHostName, host_buf)
    # Hostname verification (TLS core compares cert SAN/CN against host)
    if verify:
        openssl.SSL_set1_host(ssl, host_buf)

    # ---- Handshake ----
    hret: int = openssl.SSL_connect(ssl)
    if hret <= 0:
        want: int = openssl.SSL_get_error(ssl, hret)
        _TlsErrText()
        stdio.snprintf(errmsg, 512, "SSL_connect failed (want=%d): %s", want, _ScratchBuf())
        _RecordErrorText(errmsg)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    # ---- Record last cert verify result (for last_verify_result) ----
    if verify:
        _last_verify_val = int(openssl.SSL_get_verify_result(ssl))
    else:
        _last_verify_val = -1

    # ---- Re-check cert chain verify result ----
    if verify:
        vres: int32 = openssl.SSL_get_verify_result(ssl)
        if vres != 0:
            reason: str = openssl.X509_verify_cert_error_string(vres)
            if reason is None:
                stdio.snprintf(errmsg, 512, "SSL certificate verify failed: error %d", int(vres))
            else:
                stdio.snprintf(errmsg, 512, "SSL certificate verify failed (%d): %s", int(vres), reason)
            _RecordErrorText(errmsg)
            openssl.SSL_free(ssl)
            openssl.SSL_CTX_free(ctx)
            sock.close()
            requests._mbuddy.free(errmsg)
            requests.release(resp)
            return None

    # ---- Record TLS metadata (version / cipher / peer subject) ----
    name_buf: str = requests._mbuddy.alloc(512)
    if name_buf is not None:
        peer: openssl.X509Ptr = openssl.SSL_get1_peer_certificate(ssl)
        if peer is not None:
            subj: openssl.X509NamePtr = openssl.X509_get_subject_name(peer)
            if subj is not None:
                name_buf[0] = 0
                openssl.X509_NAME_oneline(subj, name_buf, 512)
                name_buf[511] = 0
            openssl.X509_free(peer)
        else:
            name_buf[0] = 0
            string.strncpy(name_buf, "(no peer certificate)", 21)
            name_buf[21] = 0
        ver: str = openssl.SSL_get_version(ssl)
        cipher: str = openssl.SSL_CIPHER_get_name(openssl.SSL_get_current_cipher(ssl))
        stdio.snprintf(errmsg, 512, "%s | cipher %s | peer: %s",
            ver if ver is not None else "?", cipher if cipher is not None else "?", name_buf)
        _RecordInfoText(errmsg)
        requests._mbuddy.free(name_buf)

    # ---- Build request headers and send ----
    req_buf: str = requests._mbuddy.alloc(requests.HTTP_BUFSIZ)
    if req_buf is None:
        _RecordErrorText("alloc request buffer failed")
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    body_len: int = 0
    is_post: bool = string.strcmp(method, "POST") == 0
    if is_post:
        body_len = int(string.strlen(data)) if data is not None else 0
        ct: str = content_type if content_type is not None else "application/x-www-form-urlencoded"
        # Build header in stages so Authorization can be inserted on demand (only when auth non-empty).
        hdr_off: int = 0
        hdr_cap: int = requests.HTTP_BUFSIZ
        stdio.snprintf(req_buf, hdr_cap, "POST %s HTTP/1.1\r\nHost: %s\r\n", path_buf, host_buf)
        hdr_off = int(string.strlen(req_buf))
        if auth is not None and auth[0] != 0:
            stdio.snprintf(req_buf + hdr_off, hdr_cap - hdr_off, "Authorization: %s\r\n", auth)
            hdr_off = int(string.strlen(req_buf))
        stdio.snprintf(req_buf + hdr_off, hdr_cap - hdr_off,
            "Content-Type: %s\r\nContent-Length: %d\r\nAccept-Encoding: gzip\r\nConnection: close\r\n\r\n",
            ct, body_len)
    else:
        stdio.snprintf(req_buf, requests.HTTP_BUFSIZ,
            "GET %s HTTP/1.1\r\nHost: %s\r\nAccept-Encoding: gzip\r\nConnection: close\r\n\r\n",
            path_buf, host_buf)

    hdr_len: int = int(string.strlen(req_buf))
    sent: int = openssl.SSL_write(ssl, req_buf, hdr_len)
    if sent <= 0:
        _TlsErrText()
        stdio.snprintf(errmsg, 512, "SSL_write header failed: %s", _ScratchBuf())
        _RecordErrorText(errmsg)
        requests._mbuddy.free(req_buf)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    if is_post and body_len > 0 and data is not None:
        openssl.SSL_write(ssl, data, body_len)

    requests._mbuddy.free(req_buf)

    # ---- Receive response (buffer auto-doubles, supports MB bodies) ----
    resp_cap: int = requests.HTTP_BUFSIZ
    resp_buf: str = requests._mbuddy.alloc(sizet(resp_cap))
    if resp_buf is None:
        _RecordErrorText("alloc response buffer failed")
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        requests.release(resp)
        return None

    total: int = 0
    while True:
        room: int = resp_cap - 1 - total
        if room <= 0:
            # Buffer full but more data may follow: double capacity (hard cap 256MB, runaway-guard).
            if resp_cap >= 268435456:
                break
            resp_cap = resp_cap * 2
            nb: rawptr = requests._mbuddy.realloc(resp_buf, sizet(resp_cap))
            if nb is None:
                _RecordErrorText("realloc response buffer failed")
                requests._mbuddy.free(resp_buf)
                openssl.SSL_free(ssl)
                openssl.SSL_CTX_free(ctx)
                sock.close()
                requests._mbuddy.free(errmsg)
                requests.release(resp)
                return None
            resp_buf = bytes(uint64(nb))
            room = resp_cap - 1 - total
        n: int = openssl.SSL_read(ssl, resp_buf + total, room)
        if n <= 0:
            break
        total += n

    resp_buf[total] = 0

    # Close TLS and TCP
    openssl.SSL_shutdown(ssl)
    openssl.SSL_free(ssl)
    openssl.SSL_CTX_free(ctx)
    sock.close()

    resp._raw_buf = resp_buf
    requests.parse_response(resp, total)

    requests._mbuddy.free(errmsg)
    return resp


# ============================================================
# Public API
# ============================================================

def _HttpsRedirectLoop(method: str, url: str, verify: bool, ca_file: str, data: str, content_type: str, auth: str = None) -> requests.Response*:
    """HTTPS GET/POST with redirect following (cross http/https, max 5 hops).
    auth is passed through to _HttpsRequest; note Authorization also follows cross-host redirects.
    """
    if requests._mbuddy is None: return None

    cur: str = requests._mbuddy.alloc(2048)
    if cur is None: return None
    if int(string.strlen(url)) >= 2047:
        _RecordErrorText("url too long")
        requests._mbuddy.free(cur)
        return None
    string.strcpy(cur, url)

    for hop in range(5):
        resp: requests.Response* = _HttpsRequest(method, cur, verify, ca_file, data, content_type, auth)
        if resp is None:
            requests._mbuddy.free(cur)
            return None

        code: int = resp.status_code
        if not (code >= 300 and code < 400):
            requests._mbuddy.free(cur)
            return resp

        loc: str = requests._mbuddy.alloc(2048)
        if loc is None:
            requests._mbuddy.free(cur)
            return resp
        if requests.header_value(resp, "Location", loc, 2048) != 0:
            requests._mbuddy.free(loc)
            requests._mbuddy.free(cur)
            return resp

        nxt: str = requests._mbuddy.alloc(2048)
        if nxt is None:
            requests._mbuddy.free(loc)
            requests._mbuddy.free(cur)
            return resp
        if requests._ResolveRedirectUrl(cur, loc, nxt, 2048) != 0:
            _RecordErrorText("unresolvable redirect Location")
            requests.release(resp)
            requests._mbuddy.free(nxt)
            requests._mbuddy.free(loc)
            requests._mbuddy.free(cur)
            return None
        requests.release(resp)

        # Cross-scheme dispatch: https -> continue loop; http -> hand to requests (http) chain
        if string.strncmp(nxt, "https://", 8) != 0:
            requests._mbuddy.free(loc)
            requests._mbuddy.free(cur)
            http_resp: requests.Response* = requests.get(nxt)
            requests._mbuddy.free(nxt)
            return http_resp

        requests._mbuddy.free(loc)
        requests._mbuddy.free(cur)
        cur = nxt

    _RecordErrorText("too many redirects")
    requests._mbuddy.free(cur)
    return None


def get(url: str, verify: bool = True, ca_file: str = None) -> requests.Response*:
    """HTTPS GET (follows 3xx redirects, max 5 hops). verify checks cert chain + hostname;
    ca_file is a PEM CA bundle path, None uses system default. Returns Response* or None.
    """
    return _HttpsRedirectLoop("GET", url, verify, ca_file, None, None)


def post(url: str, data: str = None, content_type: str = "application/x-www-form-urlencoded",
         verify: bool = True, ca_file: str = None, auth: str = None) -> requests.Response*:
    """HTTPS POST (follows 3xx redirects, max 5 hops). verify checks cert chain + hostname;
    ca_file PEM CA bundle (None = system default); auth optional "Bearer <key>", sent when non-empty.
    """
    return _HttpsRedirectLoop("POST", url, verify, ca_file, data, content_type, auth)


# ============================================================
# SSE streaming Chat Completions (post_stream): sends Accept: text/event-stream and extracts
# choices[0].delta.content from data:{json} lines into _st_buf; blocking, returns HTTP status or -1/-2.
# ============================================================

def _SseDeltaContent(root: json.JsonValue*) -> str:
    """Extract choices[0].delta.content from a stream data event; None if absent."""
    if root is None or not root.is_object():
        return None
    cv: json.JsonValue* = root["choices"]
    if cv is None or not cv.is_array():
        return None
    m0: json.JsonValue* = cv.get_item(0)
    if m0 is None or not m0.is_object():
        return None
    dv: json.JsonValue* = m0["delta"]
    if dv is None or not dv.is_object():
        return None
    content_v: json.JsonValue* = dv["content"]
    if content_v is None or not content_v.is_string():
        return None
    return content_v.as_string()


def _StreamAppendContent(txt: str):
    """Append delta content to _st_buf (truncate on overflow)."""
    global _st_len
    if txt is None:
        return
    pos: sizet = _st_len
    i: sizet = 0
    while txt[i] != 0:
        if pos >= sizet(STREAM_CAP) - 1:
            break
        _st_buf[pos] = txt[i]
        pos += 1
        i += 1
    _st_len = pos


def _SetStreamFail(rc: int):
    """Finish stream failure: copy reason from _err_store and set state."""
    global _st_state, _st_status
    _st_state = 2
    _st_status = rc
    stdio.snprintf(_st_err, 512, "%s", _err_store)


def post_stream(url: str, data: str, content_type: str = "application/json",
                verify: bool = True, ca_file: str = None, auth: str = None) -> int:
    """SSE streaming POST (blocking; call from a background thread). data must be a JSON body
    containing "stream":true. Returns HTTP status; negative means network/parse failure.
    """
    global _st_state, _st_status
    if requests._mbuddy is None:
        return -1

    _st_state = 0
    _st_status = 0

    # Winsock/openssl init (idempotent; first call may run on a background thread)
    if _EnsureReady() != 0:
        _SetStreamFail(-1)
        return -1

    # ---- Connect/TLS (same as _HttpsRequest) ----
    errmsg: str = requests._mbuddy.alloc(512)
    if errmsg is None:
        return -1

    host_buf: [256]char
    path_buf: [1024]char
    port: int = 0
    if _ParseHttpsUrl(url, host_buf, 256, path_buf, 1024, &port) != 0:
        stdio.snprintf(errmsg, 512, "bad https url: %s", url)
        _RecordErrorText(errmsg)
        _SetStreamFail(-1)
        requests._mbuddy.free(errmsg)
        return -1

    sock = socket.Socket(socket.AF_INET, socket.SOCK_STREAM)
    if sock.fd == socket.INVALID_SOCKET:
        _RecordErrorText("socket() failed")
        _SetStreamFail(-1)
        requests._mbuddy.free(errmsg)
        return -1
    if sock.connect(host_buf, port) != 0:
        stdio.snprintf(errmsg, 512, "connect %s:%d failed", host_buf, port)
        _RecordErrorText(errmsg)
        _SetStreamFail(-1)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    ctx: openssl.SslCtxPtr = openssl.SSL_CTX_new(openssl.TLS_client_method())
    if ctx is None:
        _RecordErrorText("SSL_CTX_new failed")
        _SetStreamFail(-1)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    if verify:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyPeer, None)
        if ca_file is not None and ca_file[0] != 0:
            if openssl.SSL_CTX_load_verify_locations(ctx, ca_file, None) != 1:
                _TlsErrText()
                stdio.snprintf(errmsg, 512, "load CA file failed: %s (%s)", ca_file, _ScratchBuf())
                _RecordErrorText(errmsg)
                _SetStreamFail(-1)
                openssl.SSL_CTX_free(ctx)
                sock.close()
                requests._mbuddy.free(errmsg)
                return -1
        else:
            openssl.SSL_CTX_set_default_verify_paths(ctx)
    else:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyNone, None)

    ssl: openssl.SslPtr = openssl.SSL_new(ctx)
    if ssl is None:
        _RecordErrorText("SSL_new failed")
        _SetStreamFail(-1)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    openssl.SSL_set_fd(ssl, sock.fd)
    openssl.SSL_ctrl(ssl, openssl.SslCtrlSetTlsextHostname, openssl.TlsextNametypeHostName, host_buf)
    if verify:
        openssl.SSL_set1_host(ssl, host_buf)

    hret: int = openssl.SSL_connect(ssl)
    if hret <= 0:
        want: int = openssl.SSL_get_error(ssl, hret)
        _TlsErrText()
        stdio.snprintf(errmsg, 512, "SSL_connect failed (want=%d): %s", want, _ScratchBuf())
        _RecordErrorText(errmsg)
        _SetStreamFail(-1)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    if verify:
        vres: int32 = openssl.SSL_get_verify_result(ssl)
        if vres != 0:
            reason: str = openssl.X509_verify_cert_error_string(vres)
            if reason is None:
                stdio.snprintf(errmsg, 512, "SSL certificate verify failed: error %d", int(vres))
            else:
                stdio.snprintf(errmsg, 512, "SSL certificate verify failed (%d): %s", int(vres), reason)
            _RecordErrorText(errmsg)
            _SetStreamFail(-1)
            openssl.SSL_free(ssl)
            openssl.SSL_CTX_free(ctx)
            sock.close()
            requests._mbuddy.free(errmsg)
            return -1

    # ---- Build request headers (POST + Accept: text/event-stream) and send ----
    req_buf: str = requests._mbuddy.alloc(requests.HTTP_BUFSIZ)
    if req_buf is None:
        _RecordErrorText("alloc request buffer failed")
        _SetStreamFail(-1)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    body_len: int = int(string.strlen(data)) if data is not None else 0
    ct: str = content_type if content_type is not None else "application/json"
    hdr_off: int = 0
    stdio.snprintf(req_buf, requests.HTTP_BUFSIZ, "POST %s HTTP/1.1\r\nHost: %s\r\n", path_buf, host_buf)
    hdr_off = int(string.strlen(req_buf))
    if auth is not None and auth[0] != 0:
        stdio.snprintf(req_buf + hdr_off, requests.HTTP_BUFSIZ - hdr_off, "Authorization: %s\r\n", auth)
        hdr_off = int(string.strlen(req_buf))
    stdio.snprintf(req_buf + hdr_off, requests.HTTP_BUFSIZ - hdr_off,
        "Content-Type: %s\r\nContent-Length: %d\r\nAccept: text/event-stream\r\nConnection: close\r\n\r\n",
        ct, body_len)

    hdr_len: int = int(string.strlen(req_buf))
    sent: int = openssl.SSL_write(ssl, req_buf, hdr_len)
    if sent <= 0:
        _TlsErrText()
        stdio.snprintf(errmsg, 512, "SSL_write header failed: %s", _ScratchBuf())
        _RecordErrorText(errmsg)
        _SetStreamFail(-1)
        requests._mbuddy.free(req_buf)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1
    if body_len > 0 and data is not None:
        openssl.SSL_write(ssl, data, body_len)
    requests._mbuddy.free(req_buf)

    # ---- Read response: skip headers -> parse SSE lines -> extract delta.content ----
    rd: str = requests._mbuddy.alloc(16384)
    if rd is None:
        _RecordErrorText("alloc stream buffer failed")
        _SetStreamFail(-1)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1

    # JSON pool (reset per event, sized for one data event)
    pmem: str = stdlib.malloc(524288)
    if pmem is None:
        _RecordErrorText("alloc json pool failed")
        _SetStreamFail(-1)
        requests._mbuddy.free(rd)
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        requests._mbuddy.free(errmsg)
        return -1
    jpool: memhub.MemPool* = memhub.MemPool(pmem, 524288)

    leftover: [16384]char
    llen: int = 0
    header_done: int = 0
    status_code: int = 0
    had_read: int = 0

    while True:
        n: int = openssl.SSL_read(ssl, rd, 16384)
        if n <= 0:
            break
        had_read = 1
        # 1) Append to leftover
        ai: int = 0
        while ai < n and llen < 16383:
            leftover[llen] = rd[ai]
            llen += 1
            ai += 1
        # 2) Process line by line
        while True:
            # Find line end \n
            nl: int = -1
            for k in range(int(llen)):
                if leftover[k] == 10:
                    nl = k
                    break
            if nl < 0:
                break
            e: int = nl
            if e > 0 and leftover[e - 1] == 13:
                e -= 1
            leftover[e] = 0
            line: str = leftover
            if header_done == 0:
                if string.strncmp(line, "HTTP/", 5) == 0:
                    # Status code: HTTP/1.1 200 OK
                    sp: int = 0
                    while line[sp] != 0 and line[sp] != ' ':
                        sp += 1
                    if line[sp] == ' ':
                        sp += 1
                        code_val: int = 0
                        while line[sp] >= '0' and line[sp] <= '9':
                            code_val = code_val * 10 + int(line[sp] - '0')
                            sp += 1
                        status_code = code_val
                if e == 0:
                    header_done = 1
            else:
                if e > 0 and line[0] != ':':
                    if string.strncmp(line, "data:", 5) == 0:
                        pl: str = line + 5
                        while pl[0] == ' ':
                            pl += 1
                        if pl[0] != 0:
                            if string.strncmp(pl, "[DONE]", 6) != 0 or pl[6] != 0:
                                jpool.reset()
                                ev: json.JsonValue* = json.parse(jpool, pl)
                                dtx: str = _SseDeltaContent(ev)
                                if dtx is not None:
                                    _StreamAppendContent(dtx)
            # 3) Remove processed line
            rem: int = llen - (nl + 1)
            for j2 in range(int(rem)):
                leftover[j2] = leftover[nl + 1 + j2]
            llen = rem

    # ---- Wrap up ----
    openssl.SSL_shutdown(ssl)
    openssl.SSL_free(ssl)
    openssl.SSL_CTX_free(ctx)
    sock.close()
    requests._mbuddy.free(rd)
    stdlib.free(pmem)
    requests._mbuddy.free(errmsg)

    if status_code == 0:
        if had_read == 0:
            _RecordErrorText("no response data")
        else:
            _RecordErrorText("missing HTTP status line")
        _SetStreamFail(-2)
        return -2

    _st_status = status_code
    if status_code >= 200 and status_code < 300:
        _st_state = 1
    else:
        _st_state = 2
        stdio.snprintf(_st_err, 512, "HTTP %d (check Key/model/address or account quota)", status_code)
    return status_code


# ============================================================
# Large-file Range download primitive for requests.download. Thread-safe: no _mbuddy,
# independent SSL_CTX/SSL/socket per connection. Returns body bytes>=0; -1 arg; -2 redirect; -3 failure.
# ============================================================

def _DlOnce(url: str, start: sizet, count: int, verify: bool, ca_file: str,
            dst: str, dst_cap: int, out_status: int*,
            out_loc: str, out_loccap: int,
            out_total: sizet*) -> int:
    """HTTPS single Range fetch (thread-safe; see module comment)."""
    global _last_verify_val, _last_verify_flag
    if url is None or dst is None or dst_cap <= 0 \
            or out_status is None or out_total is None:
        return -1
    *out_status = 0
    *out_total = 0
    if out_loc is not None and out_loccap > 0:
        out_loc[0] = 0
    _last_verify_flag = 1 if verify else 0

    if _EnsureReady() != 0:
        return -3

    host_buf: [256]char
    path_buf: [1024]char
    port: int = 0
    if _ParseHttpsUrl(url, host_buf, 256, path_buf, 1024, &port) != 0:
        _RecordErrorText("bad https url")
        return -3

    sock = socket.Socket(socket.AF_INET, socket.SOCK_STREAM)
    if sock.fd == socket.INVALID_SOCKET:
        _RecordErrorText("socket() failed")
        return -3
    if sock.connect(host_buf, port) != 0:
        _RecordErrorText("connect failed")
        sock.close()
        return -3

    ctx: openssl.SslCtxPtr = openssl.SSL_CTX_new(openssl.TLS_client_method())
    if ctx is None:
        _RecordErrorText("SSL_CTX_new failed")
        sock.close()
        return -3

    if verify:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyPeer, None)
        if ca_file is not None and ca_file[0] != 0:
            if openssl.SSL_CTX_load_verify_locations(ctx, ca_file, None) != 1:
                _RecordErrorText("load CA file failed")
                openssl.SSL_CTX_free(ctx)
                sock.close()
                return -3
        else:
            openssl.SSL_CTX_set_default_verify_paths(ctx)
    else:
        openssl.SSL_CTX_set_verify(ctx, openssl.SslVerifyNone, None)

    ssl: openssl.SslPtr = openssl.SSL_new(ctx)
    if ssl is None:
        _RecordErrorText("SSL_new failed")
        openssl.SSL_CTX_free(ctx)
        sock.close()
        return -3

    openssl.SSL_set_fd(ssl, sock.fd)
    openssl.SSL_ctrl(ssl, openssl.SslCtrlSetTlsextHostname, openssl.TlsextNametypeHostName, host_buf)
    if verify:
        openssl.SSL_set1_host(ssl, host_buf)

    hret: int = openssl.SSL_connect(ssl)
    if hret <= 0:
        _RecordErrorText("SSL_connect failed")
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        return -3

    if verify:
        _last_verify_val = int(openssl.SSL_get_verify_result(ssl))
        if _last_verify_val != 0:
            _RecordErrorText("SSL certificate verify failed")
            openssl.SSL_free(ssl)
            openssl.SSL_CTX_free(ctx)
            sock.close()
            return -3
    else:
        _last_verify_val = -1

    # Build Range request header (no Accept-Encoding, so response is raw bytes)
    req: str = stdlib.malloc(1024)
    if req is None:
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        return -3
    cnt: int = count
    if cnt < 0:
        cnt = 0
    end: sizet = start + sizet(cnt) - 1
    if cnt <= 0:
        end = start
    stdio.snprintf(req, 1024,
        "GET %s HTTP/1.1\r\nHost: %s\r\nRange: bytes=%zu-%zu\r\nConnection: close\r\n\r\n",
        path_buf, host_buf, start, end)
    sent: int = openssl.SSL_write(ssl, req, int(string.strlen(req)))
    stdlib.free(req)
    if sent <= 0:
        _RecordErrorText("SSL_write failed")
        openssl.SSL_free(ssl)
        openssl.SSL_CTX_free(ctx)
        sock.close()
        return -3

    total: int = 0
    tgt: int = -1
    while total < dst_cap - 1:
        room: int = dst_cap - 1 - total
        if room > 4096:
            room = 4096
        n: int = openssl.SSL_read(ssl, dst + total, room)
        if n <= 0:
            break
        total += n
        if tgt < 0:
            bo: int = requests._FindBodyStart(dst, total)
            if bo >= 0:
                cl: int = requests._CLenOf(dst, total)
                if cl >= 0:
                    tgt = bo + cl
        if tgt >= 0 and total >= tgt:
            break

    openssl.SSL_shutdown(ssl)
    openssl.SSL_free(ssl)
    openssl.SSL_CTX_free(ctx)
    sock.close()
    dst[total] = 0

    st: int = requests._StatusRaw(dst)
    *out_status = st
    if st == 0:
        _RecordErrorText("empty response")
        return -3
    if requests._IsHttpRedirect(st):
        if out_loc is not None and out_loccap > 0:
            if requests._RawHeaderValue(dst, total, "Location", out_loc, out_loccap) != 0:
                out_loc[0] = 0
        return -2
    if st != 200 and st != 206:
        _RecordErrorText("http status not 200/206")
        return -3

    if st == 206:
        *out_total = requests._CRTotalOf(dst, total)
    else:
        cl2: int = requests._CLenOf(dst, total)
        if cl2 > 0:
            *out_total = sizet(cl2)
    bo: int = requests._FindBodyStart(dst, total)
    if bo < 0 or bo >= total:
        return 0
    blen: int = total - bo
    if blen > cnt and cnt > 0:
        blen = cnt
    return blen