"""
Local IPC client — sends commands to native host relay endpoint.
Used by both CLI and public Python API.

Profile selection order:
  1. Explicit `profile` argument to send_command()
  2. BROWSER_CLI_PROFILE environment variable
  3. First entry in runtime registry
  4. Otherwise, no browser can be resolved automatically
"""
import json
import os
import socket
import struct
import uuid
from dataclasses import dataclass
from multiprocessing.connection import Client as PipeClient
from pathlib import Path
from typing import Any

from browser_cli.platform import endpoint_for_alias, is_windows, registry_path
from browser_cli.registry import load_registry
from browser_cli.version_manager import USER_AGENT as _USER_AGENT

# Re-exported for backward compatibility — these used to live here and are still
# referenced as ``browser_cli.client.<name>`` by callers, serve.py, and tests.
from browser_cli.errors import BrowserNotConnected  # noqa: F401
from browser_cli.endpoints import (  # noqa: F401
    _DEFAULT_REMOTE_PORT,
    _looks_like_domain,
    _normalize_endpoint,
    _remote_display_name,
    _resolve_connect_endpoint,
    display_browser_name,
)
from browser_cli.remote_transport import _recv_all, _recv_exact, _send_remote  # noqa: F401

REGISTRY_PATH = registry_path()
REMOTE_REGISTRY_PATH = Path(os.environ.get("XDG_CONFIG_HOME", Path.home() / ".config")) / "browser-cli" / "remotes.json"
_DEFAULT_KEY_PATH = Path(os.environ.get("XDG_CONFIG_HOME", str(Path.home() / ".config"))) / "browser-cli" / "client.key.pem"

@dataclass(frozen=True)
class BrowserTarget:
    profile: str
    display_name: str
    socket_path: str
    remote: str | None = None

def _is_reachable_unix_endpoint(endpoint: str) -> bool:
    """Return True when a Unix socket path exists and accepts connections."""
    path = Path(endpoint)
    if not path.exists():
        return False
    try:
        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
            sock.settimeout(0.2)
            sock.connect(endpoint)
        return True
    except OSError:
        return False

def _active_endpoints(reg: dict) -> dict:
    """Return only entries whose endpoint appears reachable."""
    if is_windows():
        return dict(reg)
    return {k: v for k, v in reg.items() if _is_reachable_unix_endpoint(v)}

def _load_remotes() -> dict[str, dict[str, str]]:
    if not REMOTE_REGISTRY_PATH.exists():
        return {}
    try:
        data = json.loads(REMOTE_REGISTRY_PATH.read_text(encoding="utf-8"))
    except Exception:
        return {}
    if not isinstance(data, dict):
        return {}
    # normalize keys so old entries stored as "domain:443" match current lookups
    return {_normalize_endpoint(str(endpoint)): cfg for endpoint, cfg in data.items() if isinstance(cfg, dict)}

def _is_valid_key_spec(s: str) -> bool:
    """Return True if s looks like a usable key spec: 'agent', 'agent:<sel>', or a file path."""
    return s == "agent" or s.startswith("agent:") or (not s.startswith("<") and ("/" in s or Path(s).suffix in {".pem", ".key"}))

def save_remote_key(endpoint: str, key_spec: str) -> None:
    """Persist the key spec (e.g. 'agent' or a file path) for a remote endpoint."""
    if not endpoint or not key_spec:
        return
    if not _is_valid_key_spec(key_spec):
        return  # refuse to save serialized objects or other garbage
    remotes = _load_remotes()
    current = remotes.get(endpoint, {})
    current["key"] = key_spec
    remotes[endpoint] = current
    REMOTE_REGISTRY_PATH.parent.mkdir(parents=True, exist_ok=True)
    fd = os.open(str(REMOTE_REGISTRY_PATH), os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
    with os.fdopen(fd, "w", encoding="utf-8") as f:
        f.write(json.dumps(remotes, indent=2, sort_keys=True))

def key_for_remote(endpoint: str | None) -> str | None:
    if not endpoint:
        return None
    cfg = _load_remotes().get(endpoint) or {}
    key = cfg.get("key")
    if not key:
        return None
    key_str = str(key)
    # reject corrupted values (e.g. str(AgentKey(...)) saved by an older bug)
    if not _is_valid_key_spec(key_str):
        return None
    return key_str

def remote_browser_targets(endpoint: str, key=None) -> list[BrowserTarget]:
    """Return browser targets advertised by a single remote endpoint."""
    remote_targets = send_command("browser-cli.targets", remote=endpoint, key=key)
    targets: list[BrowserTarget] = []
    for item in remote_targets or []:
        profile = str(item.get("profile") or "default")
        display = str(item.get("displayName") or profile)
        targets.append(
            BrowserTarget(
                profile=profile,
                display_name=_remote_display_name(endpoint, profile, display),
                socket_path="",
                remote=endpoint,
            )
        )
    return targets

def _remote_browser_targets(key=None) -> list[BrowserTarget]:
    targets: list[BrowserTarget] = []
    for endpoint in _load_remotes():
        try:
            targets.extend(remote_browser_targets(endpoint, key=key))
        except (BrowserNotConnected, RuntimeError):
            continue
    return targets

def remote_target_for_alias(alias: str | None) -> BrowserTarget | None:
    """Resolve a user-facing remote alias such as 'host:profile' to a target."""
    if not alias:
        return None
    targets = _remote_browser_targets()
    for target in targets:
        endpoint_profile = f"{target.remote}:{target.profile}" if target.remote else None
        if alias in {target.display_name, endpoint_profile}:
            return target

    endpoint_matches = []
    for target in targets:
        if not target.remote:
            continue
        remote_host, sep, _remote_port = target.remote.rpartition(":")
        if alias == target.remote or (sep and alias == remote_host):
            endpoint_matches.append(target)
    if len(endpoint_matches) == 1:
        return endpoint_matches[0]
    if len(endpoint_matches) > 1:
        aliases = [target.profile for target in endpoint_matches]
        endpoint = endpoint_matches[0].remote or alias
        examples = "\n".join(
            f"  browser-cli --remote {endpoint} --browser {a} ..."
            for a in aliases
        )
        display_aliases = [target.display_name for target in endpoint_matches]
        shorthand_examples = "\n".join(
            f"  browser-cli --browser {a} ..."
            for a in display_aliases
        )
        raise BrowserNotConnected(
            f"Multiple remote browser instances are active on {alias}: {', '.join(aliases)}\n"
            f"Use --browser <alias> with --remote to select one:\n{examples}\n"
            f"Or use the full remote browser alias:\n{shorthand_examples}"
        )
    return None

def active_browser_targets(*, include_remotes: bool = True, key=None) -> list[BrowserTarget]:
    targets: list[BrowserTarget] = []
    if REGISTRY_PATH.exists():
        reg = load_registry(REGISTRY_PATH)
        targets.extend(
            BrowserTarget(profile=profile, display_name=display_browser_name(profile, sock_path), socket_path=sock_path)
            for profile, sock_path in _active_endpoints(reg).items()
        )
    if include_remotes:
        targets.extend(_remote_browser_targets(key=key))
    return targets

def _is_active_local_profile(profile: str | None) -> bool:
    """Return True when profile names a reachable local browser endpoint."""
    if not profile:
        return False
    if REGISTRY_PATH.exists():
        reg = load_registry(REGISTRY_PATH)
        if profile in _active_endpoints(reg):
            return True
    if not is_windows():
        try:
            return Path(endpoint_for_alias(profile)).exists()
        except Exception:
            return False
    return False

def _resolve_socket(profile: str | None = None) -> str:
    """Return the socket path for the given profile (or auto-detect)."""
    target = profile or os.environ.get("BROWSER_CLI_PROFILE")

    if target:
        if REGISTRY_PATH.exists():
            reg = load_registry(REGISTRY_PATH)
            if target in reg:
                return reg[target]
        return endpoint_for_alias(target)

    # Auto-detect: error when multiple browser instances are active
    try:
        active = active_browser_targets(include_remotes=False)
        if len(active) > 1:
            aliases = [target.profile for target in active]
            examples = "\n".join(f"  browser-cli --browser {a} ..." for a in aliases)
            raise BrowserNotConnected(
                f"Multiple browser instances are active: {', '.join(aliases)}\n"
                f"Use --browser <alias> to select one:\n{examples}"
            )
        if active:
            return active[0].socket_path
    except BrowserNotConnected:
        raise
    except Exception:
        pass

    raise BrowserNotConnected(
        "Cannot resolve a browser socket automatically.\n"
        "Make sure the browser is running with the browser-cli extension enabled,\n"
        "or pass --browser <alias> / set BROWSER_CLI_PROFILE to a known alias."
    )

def _load_private_key(key_path: "Path | str | None" = None):
    """Load an Ed25519 signing key.

    Sources (in priority order):
      1. Explicit key_path / --key flag
      2. BROWSER_CLI_KEY environment variable
      3. Default PEM file (~/.config/browser-cli/client.key.pem)

    Pass "agent" or "agent:<selector>" to use a key from the SSH agent
    (works with YubiKey via gpg-agent, TPM, or regular ssh-agent).
    """
    raw = str(key_path) if key_path is not None else os.environ.get("BROWSER_CLI_KEY", str(_DEFAULT_KEY_PATH))

    if raw == "agent" or raw.startswith("agent:"):
        selector = raw[6:] or None  # "agent:cardno:..." → "cardno:..."
        from browser_cli.auth import agent_find_key
        return agent_find_key(selector)

    path = Path(raw)
    if not path.exists():
        return None
    try:
        from browser_cli.auth import load_private_key
        return load_private_key(path)
    except Exception:
        return None

def _auto_route_remote(endpoint: str, key=None) -> str | None:
    targets = remote_browser_targets(endpoint, key=key)
    if len(targets) == 1:
        return targets[0].profile
    if len(targets) > 1:
        aliases = [target.profile for target in targets]
        examples = "\n".join(f"  browser-cli --remote {endpoint} --browser {a} ..." for a in aliases)
        raise BrowserNotConnected(
            f"Multiple remote browser instances are active: {', '.join(aliases)}\n"
            f"Use --browser <alias> to select one:\n{examples}"
        )
    return None

def send_command(command: str, args: dict | None = None, profile: str | None = None, remote: str | None = None, key: "Path | None" = None) -> Any:
    """Send a command to the browser and return the response data."""
    requested_profile = profile or os.environ.get("BROWSER_CLI_PROFILE")
    remote_endpoint = remote or os.environ.get("BROWSER_CLI_REMOTE")
    if remote_endpoint:
        remote_endpoint = _normalize_endpoint(remote_endpoint)
    remote_alias_target = None
    if not remote_endpoint and requested_profile and not _is_active_local_profile(requested_profile):
        remote_alias_target = remote_target_for_alias(requested_profile)
        if remote_alias_target:
            remote_endpoint = remote_alias_target.remote
            requested_profile = remote_alias_target.profile

    msg = {
        "id": str(uuid.uuid4()),
        "command": command,
        "args": args or {},
    }
    if remote_endpoint:
        from browser_cli import transport
        msg["user_agent"] = _USER_AGENT
        msg["accept_encoding"] = transport.client_accept_encoding()
        # key priority: explicit flag > saved per-remote config > BROWSER_CLI_KEY env > default file
        key_spec = key if key is not None else key_for_remote(remote_endpoint)
        private_key = _load_private_key(key_spec)
        # persist explicit key spec so future calls don't need --key
        if key is not None:
            save_remote_key(remote_endpoint, str(key))
        route_profile = requested_profile
        _no_route_commands = {"browser-cli.targets", "browser-cli.auth.keys", "browser-cli.auth.trust"}
        if not route_profile and command not in _no_route_commands:
            route_profile = _auto_route_remote(remote_endpoint, key=key_spec)
        if route_profile:
            msg["_route"] = route_profile
    else:
        private_key = None

    try:
        if remote_endpoint:
            response = _send_remote(remote_endpoint, msg, private_key)
        elif is_windows():
            payload = json.dumps(msg).encode("utf-8")
            sock_path = _resolve_socket(profile)
            with PipeClient(sock_path, family="AF_PIPE") as conn:
                conn.send_bytes(payload)
                response = conn.recv_bytes()
        else:
            payload = json.dumps(msg).encode("utf-8")
            sock_path = _resolve_socket(profile)
            with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
                sock.connect(sock_path)
                sock.sendall(struct.pack("<I", len(payload)) + payload)
                response = _recv_all(sock)
    except (FileNotFoundError, ConnectionRefusedError, OSError):
        if remote_endpoint:
            raise BrowserNotConnected(
                f"Cannot connect to remote browser at {remote_endpoint}.\n"
                "Make sure browser-cli serve is running on the remote host."
            )
        profile_hint = f" (profile: {profile})" if profile else ""
        raise BrowserNotConnected(
            f"Cannot connect to browser{profile_hint}.\n"
            "Make sure:\n"
            "  1. The browser-cli extension is installed and enabled\n"
            "  2. The native host is registered: uv run browser-cli install <browser>\n"
            "  3. Your browser is running\n"
            "  Tip: use BROWSER_CLI_PROFILE=<name> to select a specific profile"
        )

    if response is None:
        raise ConnectionError("Connection closed before full response received")
    from browser_cli import transport
    result = transport.decode_response(response)
    if not result.get("success", True):
        raise RuntimeError(result.get("error", "unknown error from browser"))
    return result.get("data")