"""
Runtime surface inventory snapshot.

Loads the latest committed, read-only API / Web / Worker / K8s runtime surface
inventory. This module never calls the live cluster, reads Secret payloads,
executes rollouts, changes routing, or enables active scans.
"""

from __future__ import annotations

import json
from pathlib import Path
from typing import Any

from src.services.snapshot_paths import default_evaluations_dir

_DEFAULT_EVALUATIONS_DIR = default_evaluations_dir(Path(__file__))
_SNAPSHOT_PATTERN = "runtime_surface_inventory_*.json"
_SCHEMA_VERSION = "runtime_surface_inventory_v1"


def load_latest_runtime_surface_inventory(
    evaluations_dir: Path | None = None,
) -> dict[str, Any]:
    """Load the newest committed runtime surface inventory snapshot."""
    directory = evaluations_dir or _DEFAULT_EVALUATIONS_DIR
    candidates = sorted(directory.glob(_SNAPSHOT_PATTERN))
    if not candidates:
        raise FileNotFoundError(f"no runtime surface inventory snapshots found in {directory}")

    latest = candidates[-1]
    with latest.open(encoding="utf-8") as handle:
        payload = json.load(handle)

    if not isinstance(payload, dict):
        raise ValueError(f"{latest}: expected JSON object")
    _require_schema(payload, _SCHEMA_VERSION, str(latest))
    _require_read_only_boundaries(payload, str(latest))
    _require_operation_boundaries(payload, str(latest))
    _require_rollup_consistency(payload, str(latest))
    _require_operator_denials(payload, str(latest))
    _require_surface_evidence(payload, str(latest))
    return payload


def _require_schema(payload: dict[str, Any], expected: str, label: str) -> None:
    actual = payload.get("schema_version")
    if actual != expected:
        raise ValueError(f"{label}: expected schema_version={expected}, got {actual!r}")


def _require_read_only_boundaries(payload: dict[str, Any], label: str) -> None:
    program_status = payload.get("program_status") or {}
    if program_status.get("read_only_mode") is not True:
        raise ValueError(f"{label}: program_status.read_only_mode must be true")

    approval_boundaries = payload.get("approval_boundaries") or {}
    allowed = sorted(key for key, value in approval_boundaries.items() if value is not False)
    if allowed:
        raise ValueError(f"{label}: approval boundaries must remain false: {allowed}")


def _require_operation_boundaries(payload: dict[str, Any], label: str) -> None:
    boundaries = payload.get("operation_boundaries") or {}
    if boundaries.get("read_only_api_allowed") is not True:
        raise ValueError(f"{label}: read_only_api_allowed must be true")

    blocked_flags = {
        "live_k8s_query_allowed",
        "kubectl_allowed",
        "rollout_allowed",
        "restart_allowed",
        "scale_allowed",
        "delete_allowed",
        "secret_read_allowed",
        "secret_plaintext_allowed",
        "active_scan_allowed",
        "production_route_change_allowed",
    }
    allowed = sorted(flag for flag in blocked_flags if boundaries.get(flag) is not False)
    if allowed:
        raise ValueError(f"{label}: operation boundaries must remain false: {allowed}")


def _require_rollup_consistency(payload: dict[str, Any], label: str) -> None:
    surfaces = payload.get("runtime_surfaces") or []
    components = payload.get("source_runtime_components") or []
    rollups = payload.get("rollups") or {}

    if rollups.get("total_surfaces") != len(surfaces):
        raise ValueError(f"{label}: rollups.total_surfaces must match runtime_surfaces")

    if rollups.get("by_kind") != _count_by(surfaces, "kind"):
        raise ValueError(f"{label}: rollups.by_kind must match runtime_surfaces")
    if rollups.get("by_status") != _count_by(surfaces, "status"):
        raise ValueError(f"{label}: rollups.by_status must match runtime_surfaces")
    if rollups.get("by_evidence_level") != _count_by(surfaces, "evidence_level"):
        raise ValueError(f"{label}: rollups.by_evidence_level must match runtime_surfaces")

    action_required = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if surface.get("status") != "manifest_mapped"
    )
    if sorted(rollups.get("action_required_surface_ids") or []) != action_required:
        raise ValueError(f"{label}: rollups.action_required_surface_ids must match surfaces")

    secret_surfaces = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if surface.get("kind") == "secret" or surface.get("secret_exposure") != "none"
    )
    if sorted(rollups.get("secret_surface_ids") or []) != secret_surfaces:
        raise ValueError(f"{label}: rollups.secret_surface_ids must match secret surfaces")

    live_check_required = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if surface.get("live_check_status") == "required"
    )
    if sorted(rollups.get("live_check_missing_surface_ids") or []) != live_check_required:
        raise ValueError(f"{label}: rollups.live_check_missing_surface_ids must match surfaces")

    if rollups.get("total_source_components") != len(components):
        raise ValueError(f"{label}: rollups.total_source_components must match source_runtime_components")

    bound_components = sum(1 for component in components if component.get("status") == "bound")
    if rollups.get("source_components_with_runtime_binding") != bound_components:
        raise ValueError(
            f"{label}: rollups.source_components_with_runtime_binding must match source_runtime_components"
        )


def _require_operator_denials(payload: dict[str, Any], label: str) -> None:
    contract = payload.get("operator_contract") or {}
    must_not_interpret_as = set(contract.get("must_not_interpret_as") or [])
    required_denials = {
        "runtime 執行授權",
        "rollout / restart / scale / delete 批准",
        "Secret 已驗證或可讀取",
        "Ingress / DNS 可修改",
    }
    if not required_denials.issubset(must_not_interpret_as):
        raise ValueError(f"{label}: operator_contract.must_not_interpret_as is missing required denials")


def _require_surface_evidence(payload: dict[str, Any], label: str) -> None:
    surfaces = payload.get("runtime_surfaces") or []
    missing_evidence = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if not surface.get("manifest_ref") or not surface.get("evidence_refs")
    )
    if missing_evidence:
        raise ValueError(f"{label}: runtime surfaces must include manifest_ref and evidence_refs: {missing_evidence}")

    plaintext_secret = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if surface.get("kind") == "secret"
        and surface.get("secret_exposure") not in {"template_only", "name_only", "payload_redacted"}
    )
    if plaintext_secret:
        raise ValueError(f"{label}: secret surfaces must stay redacted: {plaintext_secret}")


def _count_by(items: list[dict[str, Any]], key: str) -> dict[str, int]:
    counts: dict[str, int] = {}
    for item in items:
        value = item.get(key)
        counts[value] = counts.get(value, 0) + 1
    return counts