from typing import List, Dict, Any


class PolicyEngine:
    def __init__(self):
        self._policies: List[Dict[str, Any]] = []

    def load_policies(self, dsl: str) -> None:
        # Very small DSL parser for a single-line policy per call.
        # Example:
        # allow subject="traderA" venue="venue1" signal="price" action="read" latency_ms=5 volume_cap=1000 regulatory="none"
        for line in [l.strip() for l in dsl.splitlines() if l.strip()]:
            if not line:
                continue
            if not line.startswith("allow"):
                continue
            # Remove leading 'allow'
            rest = line[len("allow"):].strip()
            policy: Dict[str, Any] = {}
            # Split by spaces, then parse key=value parts
            parts = rest.split()
            for part in parts:
                if "=" not in part:
                    continue
                k, v = part.split("=", 1)
                v = v.strip().strip('"')
                # cast common types
                if v.isdigit():
                    policy[k] = int(v)
                else:
                    policy[k] = v
            # Normalize some keys
            policy.setdefault("latency_ms", 0)
            policy.setdefault("volume_cap", None)
            self._policies.append(policy)

    def check_access(self, subject: str, venue: str, signal: str, action: str) -> bool:
        # Simple matcher: any policy that matches all provided fields grants access
        for p in self._policies:
            if (
                p.get("subject") in (subject, "any")
                and p.get("venue") in (venue, "any")
                and p.get("signal") == signal
                and p.get("action") == action
            ):
                return True
        return False