"""
Observability contract and noise-reduction matrix snapshot.

Loads the latest committed, read-only Prometheus / Alertmanager / SigNoz /
Grafana observability contract matrix. This module never mutates alert rules,
routes, receivers, silences, dashboards, webhooks, collectors, secrets,
notifications, workflows, or runtime state.
"""

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 = "observability_contract_matrix_*.json"
_SCHEMA_VERSION = "observability_contract_matrix_v1"


def load_latest_observability_contract_matrix(
    evaluations_dir: Path | None = None,
) -> dict[str, Any]:
    """Load the newest committed observability contract matrix snapshot."""
    directory = evaluations_dir or _DEFAULT_EVALUATIONS_DIR
    candidates = sorted(directory.glob(_SNAPSHOT_PATTERN))
    if not candidates:
        raise FileNotFoundError(f"no observability contract matrix 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_surface_evidence(payload, str(latest))
    _require_noise_opportunities(payload, str(latest))
    _require_operator_denials(payload, str(latest))
    _require_no_plaintext_secret_payload_keys(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 = {
        "prometheus_rule_write_allowed",
        "prometheus_reload_allowed",
        "alertmanager_route_write_allowed",
        "alertmanager_receiver_change_allowed",
        "alertmanager_to_openclaw_allowed",
        "silence_create_allowed",
        "grafana_dashboard_write_allowed",
        "grafana_api_write_allowed",
        "signoz_query_mutation_allowed",
        "signoz_webhook_change_allowed",
        "sentry_webhook_change_allowed",
        "otel_collector_deploy_allowed",
        "event_exporter_restart_allowed",
        "secret_read_allowed",
        "secret_plaintext_allowed",
        "notification_send_allowed",
        "external_api_call_allowed",
        "live_prometheus_query_allowed",
        "workflow_trigger_allowed",
        "deploy_trigger_allowed",
        "reload_trigger_allowed",
        "runtime_execution_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("observability_surfaces") or []
    opportunities = payload.get("noise_reduction_opportunities") or []
    gaps = payload.get("classification_gaps") or []
    rollups = payload.get("rollups") or {}

    if rollups.get("total_surfaces") != len(surfaces):
        raise ValueError(f"{label}: rollups.total_surfaces must match observability_surfaces")
    if rollups.get("by_kind") != _count_by(surfaces, "kind"):
        raise ValueError(f"{label}: rollups.by_kind must match observability_surfaces")
    if rollups.get("by_status") != _count_by(surfaces, "status"):
        raise ValueError(f"{label}: rollups.by_status must match observability_surfaces")
    if rollups.get("by_evidence_status") != _count_by(surfaces, "evidence_status"):
        raise ValueError(f"{label}: rollups.by_evidence_status must match observability_surfaces")
    if rollups.get("by_noise_policy_status") != _count_by(surfaces, "noise_policy_status"):
        raise ValueError(f"{label}: rollups.by_noise_policy_status must match observability_surfaces")

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

    proposal_only_surfaces = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if surface.get("noise_policy_status") == "proposal_only"
    )
    if sorted(rollups.get("surface_ids_with_proposal_only_noise_policy") or []) != proposal_only_surfaces:
        raise ValueError(
            f"{label}: rollups.surface_ids_with_proposal_only_noise_policy must match surfaces"
        )

    approval_required = sorted(
        opportunity.get("opportunity_id")
        for opportunity in opportunities
        if opportunity.get("status") == "approval_required"
    )
    if rollups.get("noise_reduction_opportunities_total") != len(opportunities):
        raise ValueError(f"{label}: rollups.noise_reduction_opportunities_total must match opportunities")
    if sorted(rollups.get("approval_required_opportunity_ids") or []) != approval_required:
        raise ValueError(f"{label}: rollups.approval_required_opportunity_ids must match opportunities")

    if sorted(rollups.get("classification_gap_ids") or []) != sorted(gap.get("gap_id") for gap in gaps):
        raise ValueError(f"{label}: rollups.classification_gap_ids must match classification_gaps")


def _require_surface_evidence(payload: dict[str, Any], label: str) -> None:
    surfaces = payload.get("observability_surfaces") or []
    missing = sorted(
        surface.get("surface_id")
        for surface in surfaces
        if not surface.get("coverage_contract")
        or not surface.get("evidence_refs")
        or not surface.get("next_action")
    )
    if missing:
        raise ValueError(f"{label}: observability_surfaces must include contract, evidence, next_action: {missing}")


def _require_noise_opportunities(payload: dict[str, Any], label: str) -> None:
    opportunities = payload.get("noise_reduction_opportunities") or []
    non_proposal = sorted(
        opportunity.get("opportunity_id")
        for opportunity in opportunities
        if opportunity.get("proposal_only") is not True
    )
    if non_proposal:
        raise ValueError(f"{label}: noise opportunities must stay proposal_only: {non_proposal}")

    required_ids = {
        "prometheus_noise_rule_tuning",
        "alertmanager_grouping_inhibit_tuning",
        "success_notification_quiet_policy",
    }
    present = {opportunity.get("opportunity_id") for opportunity in opportunities}
    if not required_ids.issubset(present):
        raise ValueError(f"{label}: missing required noise-reduction opportunities")


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 = {
        "Prometheus alert rule 修改批准",
        "Alertmanager receiver / route 修改批准",
        "Alertmanager 指向 OpenClaw receiver 批准",
        "Silence 建立或維護窗口批准",
        "Grafana dashboard 寫入批准",
        "SigNoz / Sentry webhook 設定修改批准",
        "Secret 已讀取或可輸出",
        "Telegram 測試通知批准",
        "deploy / reload / workflow 觸發批准",
        "runtime execution 授權",
    }
    if not required_denials.issubset(must_not_interpret_as):
        raise ValueError(f"{label}: operator_contract.must_not_interpret_as is missing required denials")

    route_policy = str(contract.get("alertmanager_route_policy") or "")
    if "OpenClaw" not in route_policy or "不接收 Alertmanager webhook" not in route_policy:
        raise ValueError(f"{label}: operator_contract.alertmanager_route_policy must block OpenClaw receiver use")


def _require_no_plaintext_secret_payload_keys(value: Any, label: str, path: str = "$") -> None:
    if isinstance(value, dict):
        forbidden_key_fragments = {
            "secret_value",
            "token_value",
            "authorization_header",
            "private_key",
            "webhook_secret",
            "runner_token",
            "signoz_token",
            "sentry_dsn",
        }
        for key, nested in value.items():
            lowered = str(key).lower()
            if any(fragment in lowered for fragment in forbidden_key_fragments):
                raise ValueError(f"{label}: forbidden secret payload key at {path}.{key}")
            _require_no_plaintext_secret_payload_keys(nested, label, f"{path}.{key}")
    elif isinstance(value, list):
        for index, nested in enumerate(value):
            _require_no_plaintext_secret_payload_keys(nested, label, f"{path}[{index}]")


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