"""Request middleware chain — auth, audit, rate limiting for all routes.

Every route handler passes through this chain. Security attributes are
declared per-route at registration time, so developers can't accidentally
skip auth or audit.
"""

from __future__ import annotations

import logging
from typing import Dict, Optional

log = logging.getLogger(__name__)

# ── Route security metadata ──

# auth levels: "none" (public), "optional" (check if token present), "required"
# audit: True/False — log this request to audit trail
# rate: None or "user" or "ip" — rate limit scope


class RoutePolicy:
    """Security policy for a single route."""

    __slots__ = ("auth", "audit", "csrf", "rate")

    def __init__(self, auth: str = "required", audit: bool = True, csrf: bool = False, rate: Optional[str] = None):
        self.auth = auth  # "none" | "optional" | "required"
        self.audit = audit  # log to audit trail
        self.csrf = csrf  # require CSRF token (POST)
        self.rate = rate  # None | "user" | "ip"


# Default policies by route pattern
_ROUTE_POLICIES: Dict[str, RoutePolicy] = {}

# Well-known public routes (no auth needed)
_PUBLIC_ROUTES = frozenset(
    {
        "/",
        "/setup",
        "/unlock",
        "/health",
        "/api/health",
        "/static/app.js",
        "/static/index.html",
        "/icon-192.svg",
        "/icon-512.svg",
        "/manifest.json",
        "/api/auth/login",
        "/api/auth/status",
        "/favicon.ico",
    }
)

# Routes that MUST have auth even on loopback
_SENSITIVE_ROUTES = frozenset(
    {
        "/api/vault/unlock",
        "/api/vault/lock",
        "/api/admin/restart",
        "/api/admin/shutdown",
        "/bash",
    }
)


def get_route_policy(path: str, method: str = "GET") -> RoutePolicy:
    """Get security policy for a route. Returns sensible defaults."""
    if path in _ROUTE_POLICIES:
        return _ROUTE_POLICIES[path]

    # Public routes
    if path in _PUBLIC_ROUTES:
        return RoutePolicy(auth="none", audit=False, csrf=False)

    # Static files
    if path.startswith("/static/"):
        return RoutePolicy(auth="none", audit=False, csrf=False)

    # Sensitive routes — always require auth
    if path in _SENSITIVE_ROUTES:
        return RoutePolicy(auth="required", audit=True, csrf=True)

    # API routes default to auth required
    if path.startswith("/api/"):
        is_write = method in ("POST", "PUT", "DELETE", "PATCH")
        return RoutePolicy(
            auth="required",
            audit=is_write,
            csrf=is_write,
            rate="user" if is_write else None,
        )

    # Default: require auth, audit writes
    return RoutePolicy(auth="required", audit=method != "GET")


def register_route_policy(path: str, policy: RoutePolicy) -> None:
    """Register custom security policy for a route."""
    _ROUTE_POLICIES[path] = policy


# ── Rate limiter ──
# Unified rate limiter lives in auth.py (RateLimiter class with token bucket).
# Legacy per-IP sliding window removed in v0.18.50 to eliminate duplication.
# Use: from salmalm.web.auth import rate_limiter


# ── External exposure safety checks ──


def check_external_exposure_safety(bind_addr: str, handler) -> list:
    """When binding to 0.0.0.0, verify safety requirements are met.
    Returns list of warning strings. Empty = safe."""
    if bind_addr == "127.0.0.1":
        return []

    warnings = []

    # Check if auth is configured
    import os
    from salmalm.constants import DATA_DIR

    # Use the canonical auth DB (same source as auth.py)
    try:
        from salmalm.web.auth import AUTH_DB

        auth_db_path = AUTH_DB
    except ImportError:
        auth_db_path = DATA_DIR / "auth.db"

    has_admin = False
    for db_candidate in (auth_db_path, DATA_DIR / "salmalm.db"):
        if db_candidate.exists():
            try:
                import sqlite3

                conn = sqlite3.connect(str(db_candidate))
                cur = conn.execute("SELECT COUNT(*) FROM users WHERE password_hash IS NOT NULL")
                count = cur.fetchone()[0]
                conn.close()
                if count > 0:
                    has_admin = True
                    break
            except Exception:
                continue

    if not has_admin:
        warnings.append(
            "⚠️  SECURITY: No admin password set! Run 'salmalm' and set a password "
            "before exposing to network. Anyone can access all tools including exec/write_file/browser."
        )

    # Check if dangerous tools should be restricted
    if not os.environ.get("SALMALM_EXTERNAL_TOOLS_OK"):
        warnings.append(
            "ℹ️  Dangerous tools (exec, bash, file_write, browser) require authentication "
            "when bound to 0.0.0.0. Set SALMALM_EXTERNAL_TOOLS_OK=1 to suppress this warning."
        )

    return warnings


# ── Tool risk tiers ──

TOOL_TIER_CRITICAL = frozenset(
    {
        # Actual registered tool names (verified from tool_registry._HANDLERS)
        "exec",
        "exec_session",
        "write_file",
        "edit_file",
        "python_eval",
        "sandbox_exec",
        "browser",
        "email_send",
        "gmail",
        "google_calendar",
        "calendar_delete",
        "calendar_add",
        "node_manage",
        "plugin_manage",
    }
)
TOOL_TIER_HIGH = frozenset(
    {
        "http_request",
        "read_file",
        "memory_write",
        "mesh",
        "sub_agent",
        "cron_manage",
        "screenshot",
        "tts",
        "stt",
    }
)
TOOL_TIER_NORMAL = frozenset()  # everything else


def get_tool_tier(tool_name: str) -> str:
    """Get risk tier for a tool: 'critical', 'high', or 'normal'."""
    if tool_name in TOOL_TIER_CRITICAL:
        return "critical"
    if tool_name in TOOL_TIER_HIGH:
        return "high"
    return "normal"


def is_tool_allowed_external(tool_name: str, is_authenticated: bool, bind_addr: str) -> bool:
    """Check if a tool can be used given current context.
    Critical tools require auth when externally exposed."""
    if bind_addr == "127.0.0.1":
        return True  # Loopback = trusted
    tier = get_tool_tier(tool_name)
    if tier == "critical" and not is_authenticated:
        return False
    return True
