"""Optimistic fraud validator for completed inference requests."""

import json
import math
import random
import threading
import time
import urllib.request
from typing import Any

__version__ = "0.1.0"


class ValidatorProcess:
    """Separate validator loop that samples completed requests and submits slashes."""

    def __init__(
        self,
        *,
        contracts: Any,
        reference_node_url: str,
        sample_rate: float = 0.05,
        tolerance: float = 1e-6,
        slash_amount: int = 100,
        strike_threshold: int = 3,
        random_seed: int | None = None,
        webhook_url: str | None = None,
        interval_seconds: float = 1.0,
        billing: Any | None = None,
    ) -> None:
        if not 0.0 <= sample_rate <= 1.0:
            raise ValueError("sample_rate must be between 0 and 1")
        if tolerance < 0:
            raise ValueError("tolerance must be non-negative")
        if slash_amount <= 0:
            raise ValueError("slash_amount must be positive")
        if strike_threshold <= 0:
            raise ValueError("strike_threshold must be positive")
        if interval_seconds <= 0:
            raise ValueError("interval_seconds must be positive")

        self._contracts = contracts
        self._billing = billing
        self._reference_node_url = reference_node_url.rstrip("/")
        self._sample_rate = sample_rate
        self._tolerance = tolerance
        self._slash_amount = slash_amount
        self._strike_threshold = strike_threshold
        self._webhook_url = webhook_url
        self._interval_seconds = interval_seconds
        self._random = random.Random(random_seed)
        self._last_event_index = -1
        self._running = False
        self._thread: threading.Thread | None = None
        self.sampled_count = 0

    def validate_once(self) -> list[Any]:
        """Run one validation cycle and return slash receipts submitted this cycle."""
        receipts: list[Any] = []
        events = self._contracts.validation.list_completed_inferences(
            after_index=self._last_event_index,
        )
        for event in events:
            self._last_event_index = max(self._last_event_index, event.index)
            if self._random.random() >= self._sample_rate:
                continue
            self.sampled_count += 1
            reference_output = self._run_reference(event.messages)
            if _outputs_match(event.observed_output, reference_output, self._tolerance):
                continue
            receipts.extend(self._slash_route(event.route_nodes, event.observed_output, reference_output))
        return receipts

    def start(self) -> None:
        if self._running:
            raise RuntimeError("ValidatorProcess is already running")
        self._running = True
        self._thread = threading.Thread(target=self._run_loop, daemon=True)
        self._thread.start()

    def stop(self) -> None:
        self._running = False
        if self._thread is not None:
            self._thread.join(timeout=2)
        self._thread = None

    def _run_loop(self) -> None:
        while self._running:
            self.validate_once()
            time.sleep(self._interval_seconds)

    def _run_reference(self, messages: list[dict]) -> str:
        response = _post_json(
            f"{self._reference_node_url}/v1/infer",
            {"messages": messages},
        )
        text = response.get("text")
        if not isinstance(text, str):
            raise ValueError("reference node response did not contain text")
        return text

    def _slash_route(
        self,
        route_nodes: list[dict],
        observed_output: str,
        reference_output: str,
    ) -> list[Any]:
        receipts: list[Any] = []
        node = _final_text_node(route_nodes)
        wallet_address = node.get("wallet_address") if node else None
        if not wallet_address:
            return receipts
        if self._contracts.registry.get_wallet(wallet_address).banned:
            return receipts
        receipts.append(self._contracts.registry.submit_slash_proof(
            wallet_address=wallet_address,
            slash_amount=self._slash_amount,
            strike_threshold=self._strike_threshold,
            reason=(
                "reference output diverged "
                f"(observed={observed_output!r}, reference={reference_output!r})"
            ),
            webhook_url=self._webhook_url,
        ))
        # ADR-0015: the pending balance is the collateral — forfeit it in the
        # same validation cycle as the strike.
        if self._billing is not None:
            forfeit = self._billing.forfeit_pending(wallet_address, reason="fraud-divergence")
            print(
                f"[validator] forfeited pending balance of {wallet_address}: "
                f"{forfeit['amount']:.6f} USDT (fraud-divergence)",
                flush=True,
            )
        return receipts


def _final_text_node(route_nodes: list[dict]) -> dict | None:
    if not route_nodes:
        return None
    return max(route_nodes, key=lambda node: int(node.get("shard_end", 0)))


def _outputs_match(observed: str, reference: str, tolerance: float) -> bool:
    observed_float = _parse_float(observed)
    reference_float = _parse_float(reference)
    if observed_float is not None and reference_float is not None:
        return math.isclose(observed_float, reference_float, rel_tol=tolerance, abs_tol=tolerance)
    return observed == reference


def _parse_float(value: str) -> float | None:
    try:
        return float(value)
    except ValueError:
        return None


def _post_json(url: str, payload: dict, timeout: float = 5.0) -> dict:
    data = json.dumps(payload).encode()
    req = urllib.request.Request(
        url,
        data=data,
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with urllib.request.urlopen(req, timeout=timeout) as response:
        return json.loads(response.read())


__all__ = ["ValidatorProcess"]