"""
AI provider route matrix snapshot.

Loads the latest committed, read-only AI Router / Ollama / OpenClaw /
Nemotron / Gemini provider route matrix. This module never switches providers,
calls paid APIs, probes external providers, reads secrets, changes runtime
routes, enters shadow/canary, triggers workflows, or executes runtime actions.
"""

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 = "ai_provider_route_matrix_*.json"
_SCHEMA_VERSION = "ai_provider_route_matrix_v1"


def load_latest_ai_provider_route_matrix(
    evaluations_dir: Path | None = None,
) -> dict[str, Any]:
    """Load the newest committed AI provider route matrix snapshot."""
    directory = evaluations_dir or _DEFAULT_EVALUATIONS_DIR
    candidates = sorted(directory.glob(_SNAPSHOT_PATTERN))
    if not candidates:
        raise FileNotFoundError(f"no AI provider route 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_route_evidence(payload, str(latest))
    _require_candidate_gates(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 = {
        "provider_switch_allowed",
        "production_routing_change_allowed",
        "use_ai_router_toggle_allowed",
        "fallback_order_change_allowed",
        "ollama_endpoint_change_allowed",
        "paid_api_call_allowed",
        "paid_api_frequency_increase_allowed",
        "external_provider_probe_allowed",
        "live_benchmark_allowed",
        "shadow_or_canary_allowed",
        "openclaw_replacement_allowed",
        "nemotron_shadow_allowed",
        "gemini_direct_call_allowed",
        "secret_read_allowed",
        "secret_plaintext_allowed",
        "notification_send_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:
    routes = payload.get("provider_routes") or []
    gates = payload.get("candidate_gates") or []
    gaps = payload.get("source_gaps") or []
    rollups = payload.get("rollups") or {}

    if rollups.get("total_routes") != len(routes):
        raise ValueError(f"{label}: rollups.total_routes must match provider_routes")
    if rollups.get("by_kind") != _count_by(routes, "kind"):
        raise ValueError(f"{label}: rollups.by_kind must match provider_routes")
    if rollups.get("by_status") != _count_by(routes, "status"):
        raise ValueError(f"{label}: rollups.by_status must match provider_routes")
    if rollups.get("by_route_gate") != _count_by(routes, "route_gate"):
        raise ValueError(f"{label}: rollups.by_route_gate must match provider_routes")

    requiring_action = sorted(
        route.get("route_id")
        for route in routes
        if route.get("status") == "action_required"
    )
    if sorted(rollups.get("route_ids_requiring_action") or []) != requiring_action:
        raise ValueError(f"{label}: rollups.route_ids_requiring_action must match routes")

    approval_gates = sorted(
        gate.get("gate_id")
        for gate in gates
        if gate.get("approval_required") is True
    )
    if sorted(rollups.get("candidate_gate_ids_requiring_approval") or []) != approval_gates:
        raise ValueError(
            f"{label}: rollups.candidate_gate_ids_requiring_approval must match candidate_gates"
        )

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

    zero_count_fields = {
        "provider_switch_allowed_count",
        "paid_api_call_allowed_count",
        "shadow_or_canary_allowed_count",
        "runtime_route_change_allowed_count",
    }
    non_zero = sorted(field for field in zero_count_fields if rollups.get(field) != 0)
    if non_zero:
        raise ValueError(f"{label}: route permission rollup counts must remain 0: {non_zero}")


def _require_route_evidence(payload: dict[str, Any], label: str) -> None:
    routes = payload.get("provider_routes") or []
    missing = sorted(
        route.get("route_id")
        for route in routes
        if not route.get("current_policy")
        or not route.get("provider_order")
        or not route.get("fallback_policy")
        or not route.get("evidence_refs")
        or not route.get("next_action")
    )
    if missing:
        raise ValueError(f"{label}: provider_routes must include policy, order, evidence, next_action: {missing}")

    required_route_ids = {
        "ai_router_execution_policy",
        "ollama_global_endpoint_order",
        "alert_ai_ollama_first_lane",
        "openclaw_nemo_rca_lane",
        "nemotron_tool_calling_candidate",
        "gemini_final_fallback_policy",
    }
    present = {route.get("route_id") for route in routes}
    missing_required = sorted(required_route_ids - present)
    if missing_required:
        raise ValueError(f"{label}: missing required provider routes: {missing_required}")

    blocked_candidates = sorted(
        route.get("route_id")
        for route in routes
        if route.get("kind") == "nemotron_candidate" and route.get("status") != "blocked"
    )
    if blocked_candidates:
        raise ValueError(f"{label}: Nemotron candidates must remain blocked: {blocked_candidates}")


def _require_candidate_gates(payload: dict[str, Any], label: str) -> None:
    gates = payload.get("candidate_gates") or []
    required_ids = {
        "provider_switch_gate",
        "nemotron_replay_gate",
        "paid_provider_call_gate",
    }
    present = {gate.get("gate_id") for gate in gates}
    missing = sorted(required_ids - present)
    if missing:
        raise ValueError(f"{label}: missing required candidate gates: {missing}")

    not_approval_required = sorted(
        gate.get("gate_id")
        for gate in gates
        if gate.get("approval_required") is not True
    )
    if not_approval_required:
        raise ValueError(f"{label}: candidate gates must require approval: {not_approval_required}")


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 = {
        "provider 切換批准",
        "production routing change 批准",
        "Gemini / Claude / NVIDIA 付費呼叫批准",
        "OpenClaw 取代或降級批准",
        "Nemotron 進 shadow / canary 批准",
        "fallback order 修改批准",
        "Ollama endpoint / ConfigMap 修改批准",
        "Secret payload 已讀取或可輸出",
        "外部 live probe 或 benchmark 批准",
        "workflow / deploy / reload 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")

    provider_switch_policy = str(contract.get("provider_switch_policy") or "")
    if "P1-004" not in provider_switch_policy or "只能盤點與顯示" not in provider_switch_policy:
        raise ValueError(f"{label}: provider_switch_policy must preserve P1-004 read-only boundary")


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",
            "gemini_api_key_value",
            "nvidia_api_key_value",
            "claude_api_key_value",
        }
        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