"""Minimal Mumble protocol client — vendored/adapted from the recipe-maintainer corpus
`recipe-info/mumble/tests/mumble_connect.py` (zero external deps; stdlib ssl/socket/struct only).

Mumble has no HTTP API for its voice server, so the canonical "is it really working" check is the
control-channel TLS handshake: connect, send Version + Authenticate, and read messages until the
server completes the handshake with a ServerSync. This module performs that handshake and returns a
structured result the cc-ci functional tests (parity port + recipe-specific) assert against.

On cc-ci the recipe is deployed with `compose.host-ports.yml`, which publishes 64738 directly on the
cc-ci host (`mode: host`); tests run on-host via cc-ci-run, so they connect to 127.0.0.1:64738.
"""

from __future__ import annotations

import socket
import ssl
import struct
import time

PORT = 64738

# Message types (Mumble.proto)
MSG_VERSION = 0
MSG_AUTHENTICATE = 2
MSG_REJECT = 4
MSG_SERVERSYNC = 5
MSG_CHANNELSTATE = 7
MSG_USERSTATE = 9
MSG_SERVERCONFIG = 24

REJECT_TYPES = {
    0: "None", 1: "WrongVersion", 2: "InvalidUsername", 3: "WrongUserPW",
    4: "WrongServerPW", 5: "UsernameInUse", 6: "ServerFull", 7: "NoCertificate",
    8: "AuthenticatorFail",
}

_HEADER = ">HI"
_HEADER_SIZE = 6


def _enc_varint(value: int) -> bytes:
    out = bytearray()
    while value > 0x7F:
        out.append((value & 0x7F) | 0x80)
        value >>= 7
    out.append(value & 0x7F)
    return bytes(out)


def _enc_field_varint(field: int, value: int) -> bytes:
    return _enc_varint(field << 3) + _enc_varint(value)


def _enc_field_string(field: int, value: str) -> bytes:
    raw = value.encode("utf-8")
    return _enc_varint((field << 3) | 2) + _enc_varint(len(raw)) + raw


def _dec_varint(data: bytes, off: int) -> tuple[int, int]:
    result = shift = 0
    while off < len(data):
        b = data[off]
        result |= (b & 0x7F) << shift
        off += 1
        if not (b & 0x80):
            break
        shift += 7
    return result, off


def _dec_fields(data: bytes) -> dict:
    fields: dict = {}
    off = 0
    while off < len(data):
        tag, off = _dec_varint(data, off)
        field, wire = tag >> 3, tag & 0x07
        if wire == 0:
            value, off = _dec_varint(data, off)
        elif wire == 1:
            value = struct.unpack_from("<Q", data, off)[0]
            off += 8
        elif wire == 2:
            length, off = _dec_varint(data, off)
            raw = data[off:off + length]
            off += length
            try:
                value = raw.decode("utf-8")
            except UnicodeDecodeError:
                value = raw
        elif wire == 5:
            value = struct.unpack_from("<I", data, off)[0]
            off += 4
        else:
            raise ValueError(f"unknown wire type {wire}")
        fields[field] = value
    return fields


def _send(sock, msg_type: int, payload: bytes = b"") -> None:
    sock.sendall(struct.pack(_HEADER, msg_type, len(payload)) + payload)


def _recv(sock, timeout: float) -> tuple[int, bytes]:
    sock.settimeout(timeout)
    header = b""
    while len(header) < _HEADER_SIZE:
        chunk = sock.recv(_HEADER_SIZE - len(header))
        if not chunk:
            raise ConnectionError("connection closed reading header")
        header += chunk
    msg_type, length = struct.unpack(_HEADER, header)
    payload = b""
    while len(payload) < length:
        chunk = sock.recv(length - len(payload))
        if not chunk:
            raise ConnectionError("connection closed reading payload")
        payload += chunk
    return msg_type, payload


def _build_version() -> bytes:
    v = (1 << 16) | (5 << 8) | 0  # pretend client 1.5.0
    return (_enc_field_varint(1, v)
            + _enc_field_string(2, "cc-ci mumble probe 1.0")
            + _enc_field_string(3, "Linux"))


def _build_authenticate(username: str, password: str = "") -> bytes:
    payload = _enc_field_string(1, username)
    if password:
        payload += _enc_field_string(2, password)
    payload += _enc_field_varint(5, 1)  # opus = true
    return payload


def handshake(host: str = "127.0.0.1", port: int = PORT, username: str = "cc-ci-probe",
              password: str = "", timeout: float = 20.0) -> dict:
    """Full Mumble control-channel handshake. Returns a result dict:

      tls_connect (bool), server_version (dict|None), auth_accepted (bool), channels (list[str]),
      users (list[str]), server_sync (bool), welcome_text (str|None), server_config (dict),
      error (str|None).
    """
    result = {
        "tls_connect": False, "server_version": None, "auth_accepted": False,
        "channels": [], "users": [], "server_sync": False, "welcome_text": None,
        "server_config": {}, "error": None,
    }
    raw = tls = None
    try:
        raw = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        raw.settimeout(timeout)
        ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
        ctx.check_hostname = False
        ctx.verify_mode = ssl.CERT_NONE
        ctx.minimum_version = ssl.TLSVersion.TLSv1_2
        tls = ctx.wrap_socket(raw, server_hostname=host)
        tls.connect((host, port))
        result["tls_connect"] = True

        _send(tls, MSG_VERSION, _build_version())
        _send(tls, MSG_AUTHENTICATE, _build_authenticate(username, password))

        channels: dict = {}
        users: dict = {}
        deadline = time.time() + timeout
        # Murmur usually sends ServerConfig around ServerSync; the exact order varies by version.
        # So we don't stop at ServerSync — once it arrives we keep reading for a short grace window
        # to also capture ServerConfig (used by the recipe-specific config round-trip tests), then
        # stop. If both arrive we stop immediately.
        grace_deadline = None
        while time.time() < deadline:
            if grace_deadline is not None and time.time() >= grace_deadline:
                break
            if result["server_sync"] and result["server_config"]:
                break
            remaining = deadline - time.time()
            if grace_deadline is not None:
                remaining = min(remaining, grace_deadline - time.time())
            if remaining <= 0:
                break
            try:
                msg_type, payload = _recv(tls, timeout=remaining)
            except (socket.timeout, ConnectionError):
                break
            if msg_type == MSG_VERSION:
                f = _dec_fields(payload)
                v1 = f.get(1, 0)
                result["server_version"] = {
                    "string": f"{(v1 >> 16) & 0xFF}.{(v1 >> 8) & 0xFF}.{v1 & 0xFF}",
                    "release": f.get(2, ""), "os": f.get(3, ""),
                }
            elif msg_type == MSG_REJECT:
                f = _dec_fields(payload)
                result["error"] = (f"Rejected: {REJECT_TYPES.get(f.get(1, 0), 'Unknown')} "
                                   f"— {f.get(2, '')}")
                return result
            elif msg_type == MSG_CHANNELSTATE:
                f = _dec_fields(payload)
                ch_id = f.get(1, 0)
                channels[ch_id] = f.get(3, f"channel-{ch_id}")
            elif msg_type == MSG_USERSTATE:
                f = _dec_fields(payload)
                name = f.get(3, "")
                if name:
                    users[f.get(1, 0)] = name
            elif msg_type == MSG_SERVERCONFIG:
                f = _dec_fields(payload)
                # ServerConfig fields: 1 max_bandwidth, 2 welcome_text, 3 allow_html,
                # 4 message_length, 5 image_message_length, 6 max_users
                result["server_config"] = {
                    "max_bandwidth": f.get(1), "welcome_text": f.get(2),
                    "allow_html": f.get(3), "message_length": f.get(4),
                    "image_message_length": f.get(5), "max_users": f.get(6),
                }
            elif msg_type == MSG_SERVERSYNC:
                f = _dec_fields(payload)
                result["welcome_text"] = f.get(3, "")
                result["server_sync"] = True
                result["auth_accepted"] = True
                # keep reading a short grace window to catch a trailing ServerConfig
                if grace_deadline is None:
                    grace_deadline = time.time() + 3.0

        result["channels"] = list(channels.values())
        result["users"] = list(users.values())
        if not result["server_sync"] and not result["error"]:
            result["error"] = "timed out waiting for ServerSync"
    except (ConnectionError, ssl.SSLError, OSError) as e:
        result["error"] = f"{type(e).__name__}: {e}"
    finally:
        if tls is not None:
            try:
                tls.shutdown(socket.SHUT_RDWR)
            except OSError:
                pass
            tls.close()
        elif raw is not None:
            raw.close()
    return result


def retry_handshake(attempts: int = 12, interval: float = 5.0, **kwargs) -> dict:
    """Retry the handshake until ServerSync completes (cold-boot readiness) or attempts exhaust.
    Returns the last result (caller asserts on it)."""
    last: dict = {}
    for _ in range(attempts):
        last = handshake(**kwargs)
        if last.get("server_sync"):
            return last
        time.sleep(interval)
    return last