from __future__ import annotations

import json
from dataclasses import asdict, dataclass
from pathlib import Path
from typing import Any


CRITERIA_SCHEMA_VERSION = "quality-criteria-registry/v1"
DEFAULT_CRITERIA_PATH = (
    Path(__file__).resolve().parents[3]
    / "docs"
    / "quality-criteria"
    / "acceptance-quality-criteria.v1.json"
)
REQUIRED_CRITERION_FIELDS = {
    "id",
    "title",
    "category",
    "severity",
    "applies_to",
    "description",
    "deterministic_action",
    "deterministic_action_when",
    "reviewer_guidance",
}


@dataclass(frozen=True)
class QualityCriterion:
    id: str
    title: str
    category: str
    severity: str
    applies_to: list[str]
    description: str
    deterministic_action: str
    deterministic_action_when: str
    reviewer_guidance: str
    agentic_guidance: str = ""
    examples: list[str] | None = None


@dataclass(frozen=True)
class QualityCriteriaRegistry:
    schema_version: str
    criteria_version: str
    status: str
    updated_at: str
    criteria: list[QualityCriterion]


def load_quality_criteria(path: str | Path | None = None) -> QualityCriteriaRegistry:
    criteria_path = Path(path) if path is not None else DEFAULT_CRITERIA_PATH
    payload = json.loads(criteria_path.read_text(encoding="utf-8"))
    return _registry_from_payload(payload)


def active_quality_criteria_version(path: str | Path | None = None) -> str:
    return load_quality_criteria(path).criteria_version


def criteria_registry_dict(registry: QualityCriteriaRegistry) -> dict[str, Any]:
    return asdict(registry)


def criteria_registry_json(registry: QualityCriteriaRegistry) -> str:
    return json.dumps(criteria_registry_dict(registry), indent=2, sort_keys=True) + "\n"


def criteria_registry_markdown(registry: QualityCriteriaRegistry) -> str:
    lines = [
        f"# Quality Criteria Registry: {registry.criteria_version}",
        "",
        f"- Schema: `{registry.schema_version}`",
        f"- Status: `{registry.status}`",
        f"- Updated: `{registry.updated_at}`",
        "",
    ]
    for criterion in registry.criteria:
        lines.extend(
            [
                f"## {criterion.id}: {criterion.title}",
                "",
                f"- Category: `{criterion.category}`",
                f"- Severity: `{criterion.severity}`",
                f"- Applies to: `{', '.join(criterion.applies_to)}`",
                f"- Deterministic action: `{criterion.deterministic_action}`",
                "",
                criterion.description,
                "",
                f"Deterministic trigger: {criterion.deterministic_action_when}",
                "",
                f"Reviewer guidance: {criterion.reviewer_guidance}",
                "",
            ]
        )
    return "\n".join(lines)


def _registry_from_payload(payload: dict[str, Any]) -> QualityCriteriaRegistry:
    if payload.get("schema_version") != CRITERIA_SCHEMA_VERSION:
        raise ValueError(
            "unsupported quality criteria schema: "
            f"{payload.get('schema_version', '<missing>')}"
        )
    criteria_payload = payload.get("criteria")
    if not isinstance(criteria_payload, list) or not criteria_payload:
        raise ValueError("quality criteria registry must contain criteria")
    criteria = [_criterion_from_payload(item) for item in criteria_payload]
    ids = [criterion.id for criterion in criteria]
    if len(ids) != len(set(ids)):
        raise ValueError("quality criteria ids must be unique")
    return QualityCriteriaRegistry(
        schema_version=str(payload.get("schema_version", "")),
        criteria_version=str(payload.get("criteria_version", "")),
        status=str(payload.get("status", "")),
        updated_at=str(payload.get("updated_at", "")),
        criteria=criteria,
    )


def _criterion_from_payload(payload: dict[str, Any]) -> QualityCriterion:
    missing = sorted(REQUIRED_CRITERION_FIELDS - set(payload))
    if missing:
        raise ValueError(
            f"quality criterion {payload.get('id', '<unknown>')} missing fields: "
            f"{', '.join(missing)}"
        )
    applies_to = payload.get("applies_to")
    if not isinstance(applies_to, list) or not applies_to:
        raise ValueError(
            f"quality criterion {payload.get('id', '<unknown>')} must list applies_to"
        )
    examples = payload.get("examples") or []
    return QualityCriterion(
        id=str(payload["id"]),
        title=str(payload["title"]),
        category=str(payload["category"]),
        severity=str(payload["severity"]),
        applies_to=[str(item) for item in applies_to],
        description=str(payload["description"]),
        deterministic_action=str(payload["deterministic_action"]),
        deterministic_action_when=str(payload["deterministic_action_when"]),
        reviewer_guidance=str(payload["reviewer_guidance"]),
        agentic_guidance=str(payload.get("agentic_guidance", "")),
        examples=[str(item) for item in examples],
    )