"""CustomerServiceGuardrail — v0.1 Customer Service ruleset (D-019, TASK-03-04).

Pluggable implementation of the Guardrail interface. Enforces the RESEARCH.md
safety baseline for the Customer Service path:
  - system-prompt constraints: no legal/financial/medical advice, no real-company
    impersonation, stay-in-role, concise-for-voice
  - debrief output filter: block recommendations that the learner advise legal action
  - session-start disclaimer audio (defined text)
  - no PII collection beyond the hardcoded profile

Selected via PRAXIS_GUARDRAIL=customer_service (default). Replaces the
SLICE-02 NoOpGuardrail with no pipeline change (D-019).
"""

from __future__ import annotations

import re

from server.services.base import Guardrail, GuardrailContext, GuardrailVerdict

# The session-start disclaimer (RESEARCH.md §Safety). Played as the first AI
# utterance of every session.
DISCLAIMER_TEXT = (
    "This is an AI practice session for training purposes. "
    "It is not a real conversation and no real company is involved."
)

# Patterns that indicate the model is giving advice it shouldn't (per D-019).
_LEGAL_ADVICE_RE = re.compile(
    r"\b(sue|lawsuit|take legal action|small claims|hire a lawyer|attorney|"
    r"file a complaint with .* tribun|legal rights)\b",
    re.IGNORECASE,
)
_FINANCIAL_ADVICE_RE = re.compile(
    r"\b(invest|stock|bond|crypto|retirement fund|tax write-?off|bankruptcy)\b",
    re.IGNORECASE,
)
_MEDICAL_ADVICE_RE = re.compile(
    r"\b(diagnosis|prescribe|medication|therapy|see a doctor|medical condition|"
    r"mental health condition)\b",
    re.IGNORECASE,
)
_IMPERSONATION_RE = re.compile(
    # Claiming to work for a real named company — heuristic.
    r"\b(I (?:work|am employed) (?:at|for|with))\b.*\b(Inc\.|Corp\.|LLC|Ltd\.|"
    r"Amazon|Apple|Google|Microsoft|Walmart|Costco|Telus|Rogers|Bell|Shopify)\b",
    re.IGNORECASE,
)
# Debrief-specific: block recommendations that the learner tell a real customer
# to take legal action. Catches "sue them", "take legal action", "file a lawsuit",
# "small claims", etc. when phrased as advice to the customer.
_DEBRIEF_LEGAL_ACTION_RE = re.compile(
    r"\b(tell (?:the |a )?customer to (?:sue|take legal action|file a lawsuit)|"
    r"advise.*(?:sue|legal action|lawsuit|small claims)|"
    r"recommend.*(?:sue|legal action|lawsuit|small claims)|"
    r"(?:suggest|tell|recommend).*sue them|"
    r"customer should (?:sue|take legal action|file a lawsuit))\b",
    re.IGNORECASE,
)


class CustomerServiceGuardrail(Guardrail):
    """Customer Service ruleset (D-019). Low-risk domain, baseline guardrails."""

    name = "customer_service"

    async def check(
        self, text: str, context: GuardrailContext | None = None
    ) -> GuardrailVerdict:
        ctx = context or GuardrailContext()
        role = ctx.role

        # Debrief output filter — block legal-action recommendations.
        if role == "debrief":
            if _DEBRIEF_LEGAL_ACTION_RE.search(text):
                return GuardrailVerdict(
                    allowed=False,
                    reason="blocked: debrief recommends legal action (D-019 debrief filter)",
                    category="blocked_legal",
                    filtered_text=self._filter_legal(text),
                )
            return GuardrailVerdict(allowed=True, reason="debrief ok", category="ok")

        # System / assistant / user content checks.
        if _LEGAL_ADVICE_RE.search(text):
            return GuardrailVerdict(
                allowed=False,
                reason="blocked: legal advice (D-019 no-legal-advice)",
                category="blocked_legal",
            )
        if _FINANCIAL_ADVICE_RE.search(text):
            return GuardrailVerdict(
                allowed=False,
                reason="blocked: financial advice (D-019 no-financial-advice)",
                category="blocked_financial",
            )
        if _MEDICAL_ADVICE_RE.search(text):
            return GuardrailVerdict(
                allowed=False,
                reason="blocked: medical advice (D-019 no-medical-advice)",
                category="blocked_medical",
            )
        if _IMPERSONATION_RE.search(text):
            return GuardrailVerdict(
                allowed=False,
                reason="blocked: real-company impersonation (D-019)",
                category="blocked_impersonation",
            )

        return GuardrailVerdict(allowed=True, reason="ok", category="ok")

    @property
    def session_start_disclaimer(self) -> str:
        return DISCLAIMER_TEXT

    @staticmethod
    def _filter_legal(text: str) -> str:
        """Replace legal-action recommendations with a coaching redirect."""
        return _DEBRIEF_LEGAL_REDIRECT if _DEBRIEF_LEGAL_REDIRECT else text


# Coaching redirect used when a debrief recommends legal action (D-019).
_DEBRIEF_LEGAL_REDIRECT = (
    "Focus your coaching on the learner's communication performance, "
    "not on advising the customer to take legal action."
)


__all__ = ["CustomerServiceGuardrail", "DISCLAIMER_TEXT"]