"""Change acceptance governance for AIOS.

Every feature change must provide matching tests. Every architecture change must
be reviewed by an independent architecture agent. User-facing changes must be
validated by an independent user acceptance agent.
"""

from __future__ import annotations

from dataclasses import asdict, dataclass, field
from datetime import datetime, timezone
from typing import Any


def utc_now() -> str:
    return datetime.now(timezone.utc).isoformat()


@dataclass(frozen=True)
class ChangeDescriptor:
    change_id: str
    change_type: str
    title: str
    files_changed: list[str]
    tests: list[str] = field(default_factory=list)
    user_facing: bool = False
    architecture_impact: bool = False
    risk: str = "low"

    def to_dict(self) -> dict[str, Any]:
        return asdict(self)


@dataclass(frozen=True)
class AcceptanceFinding:
    check: str
    status: str
    detail: str
    required: bool = True

    def passed(self) -> bool:
        return self.status == "pass" or not self.required

    def to_dict(self) -> dict[str, Any]:
        return asdict(self)


@dataclass(frozen=True)
class AcceptanceDecision:
    status: str
    findings: list[AcceptanceFinding]
    decided_at: str = field(default_factory=utc_now)

    def to_dict(self) -> dict[str, Any]:
        return {
            "status": self.status,
            "findings": [f.to_dict() for f in self.findings],
            "decided_at": self.decided_at,
        }


class ChangeAcceptanceGate:
    def evaluate(self, change: ChangeDescriptor) -> AcceptanceDecision:
        findings: list[AcceptanceFinding] = []
        findings.append(self._tests_required(change))
        findings.append(self._user_acceptance_required(change))
        findings.append(self._architecture_review_required(change))
        findings.append(self._risk_gate(change))
        status = "pass" if all(f.passed() for f in findings) else "blocked"
        return AcceptanceDecision(status, findings)

    def _tests_required(self, change: ChangeDescriptor) -> AcceptanceFinding:
        if change.tests:
            return AcceptanceFinding("tests_present", "pass", "matching tests declared")
        return AcceptanceFinding("tests_present", "fail", "every feature change requires tests")

    def _user_acceptance_required(self, change: ChangeDescriptor) -> AcceptanceFinding:
        if not change.user_facing:
            return AcceptanceFinding("user_acceptance", "pass", "not user-facing")
        has_user_test = any("user" in t.lower() or "acceptance" in t.lower() for t in change.tests)
        return AcceptanceFinding(
            "user_acceptance",
            "pass" if has_user_test else "fail",
            "user-facing change requires user acceptance test",
        )

    def _architecture_review_required(self, change: ChangeDescriptor) -> AcceptanceFinding:
        if not change.architecture_impact:
            return AcceptanceFinding("architecture_review", "pass", "no architecture impact")
        has_arch_test = any("arch" in t.lower() or "architecture" in t.lower() for t in change.tests)
        return AcceptanceFinding(
            "architecture_review",
            "pass" if has_arch_test else "fail",
            "architecture change requires independent architect review artifact/test",
        )

    def _risk_gate(self, change: ChangeDescriptor) -> AcceptanceFinding:
        if change.risk in {"low", "medium", "high"}:
            return AcceptanceFinding("risk_classified", "pass", f"risk={change.risk}")
        return AcceptanceFinding("risk_classified", "fail", "risk must be low/medium/high")


__all__ = ["ChangeDescriptor", "AcceptanceFinding", "AcceptanceDecision", "ChangeAcceptanceGate"]