"""WebSocket handshake helpers. Keep this module free of ASR/TTS imports."""

import json


def is_websocket_upgrade(headers) -> bool:
    """True when the HTTP request is a WebSocket handshake, not a health check."""
    if headers is None:
        return False
    try:
        connection_hdr = str(headers.get("connection", "") or "")
        upgrade_hdr = str(headers.get("upgrade", "") or "")
    except Exception:
        return False
    return "upgrade" in connection_hdr.lower() or "websocket" in upgrade_hdr.lower()


def is_client_hello(message) -> bool:
    """Device hello must be answered even while private config is still loading."""
    if not isinstance(message, str):
        return False
    try:
        data = json.loads(message)
    except Exception:
        return False
    return isinstance(data, dict) and data.get("type") == "hello"


def merge_hello_audio_params(welcome_params, client_params) -> dict:
    """Keep server TTS output rate. Device hello sample_rate is capture-only."""
    merged = dict(welcome_params or {})
    if not isinstance(client_params, dict):
        return merged
    fmt = client_params.get("format")
    if fmt:
        merged["format"] = fmt
    channels = client_params.get("channels")
    if channels:
        merged["channels"] = channels
    return merged


def is_priority_listen_detect(message) -> bool:
    """Boot/app-task detect must not be dropped while bind config is still loading."""
    if not isinstance(message, str):
        return False
    try:
        data = json.loads(message)
    except Exception:
        return False
    if not isinstance(data, dict) or data.get("type") != "listen":
        return False
    if data.get("state") != "detect":
        return False
    text = str(data.get("text") or "")
    return (
        text.startswith("[app_task]")
        or text.startswith("[voice_entry]")
        or text.startswith("[skill_event]")
        or text.startswith("[lesson_sync]")
    )