"""Domain counters, defined here so the numbers on a dashboard are the
numbers the domain actually decided.

Kept behind a tiny protocol rather than importing `prometheus_client` into
`rag/`: the domain records that a generation was refused for an ungrounded
number, and the process that happens to expose Prometheus does the exporting.
`NullMetrics` is the default, so tests and any deployment without a metrics
stack run unchanged.

The counter that matters is `generation_rejected` — it is the measured form of
the claim that the answer layer cannot state a figure the book does not.
"""
from __future__ import annotations

from typing import Protocol


class Metrics(Protocol):
    def increment(self, name: str, **labels: str) -> None: ...


class NullMetrics:
    def increment(self, name: str, **labels: str) -> None:  # noqa: ARG002
        # Deliberately inert: the default when no metrics stack is configured.
        return None


class InMemoryMetrics:
    """Reference implementation of the contract; also what tests assert on."""

    def __init__(self) -> None:
        self.counts: dict[tuple[str, tuple[tuple[str, str], ...]], int] = {}

    def increment(self, name: str, **labels: str) -> None:
        key = (name, tuple(sorted(labels.items())))
        self.counts[key] = self.counts.get(key, 0) + 1

    def total(self, name: str, **labels: str) -> int:
        if labels:
            return self.counts.get((name, tuple(sorted(labels.items()))), 0)
        return sum(count for (n, _), count in self.counts.items() if n == name)


RETRIEVAL_ROUTE = "duocthu_retrieval_route_total"
ABSTENTION = "duocthu_abstention_total"
GENERATION_REJECTED = "duocthu_generation_rejected_total"
GENERATION_SERVED = "duocthu_generation_served_total"
ANSWER_EXTRACTIVE = "duocthu_answer_extractive_total"

# Conversational loop. `CLARIFY_ASKED` is the counter that shows the system
# asking instead of guessing — the behaviour a reviewer will probe first.
CLARIFY_ASKED = "duocthu_clarify_asked_total"
LOOP_ROUNDS = "duocthu_loop_retrieval_rounds_total"
LOOP_REFINED = "duocthu_loop_refined_total"
LOOP_REPAIRED = "duocthu_loop_repaired_total"
FOLLOWUP_INHERITED = "duocthu_followup_inherited_total"