from __future__ import annotations

import asyncio
import dataclasses
import importlib.metadata
import inspect
import os
import threading
import time
from collections.abc import Awaitable, Callable
from typing import Any, Protocol, runtime_checkable

from ..workspace.policy import CloudWorkspacePolicy, SingleWorkspacePolicy
from .directory import DirectoryProjectionProvider, directory_projection_limits_from_config
from .entitlements import EntitlementProvider, OpenSourceEntitlementProvider


CLOUD_BOOTSTRAP_ENTRY_POINT = 'langbot.cloud_bootstrap'
REQUIRED_TENANT_ISOLATION_VERSION = 2
SUPPORTED_PGVECTOR_DIMENSIONS = frozenset({384, 512, 768, 1024, 1536})


class CloudBootstrapError(RuntimeError):
    """Fail-closed Cloud bootstrap validation error."""


class CloudRuntimeUnavailableError(CloudBootstrapError):
    """The verified Cloud receipt no longer admits runtime work."""


@runtime_checkable
class CloudManifestProvider(Protocol):
    """Closed adapter responsible for renewing the signed deployment receipt."""

    async def refresh_manifest(self) -> VerifiedCloudDeployment:
        """Fetch, verify, and return the newest deployment receipt."""

    async def aclose(self) -> None:
        """Release control-plane transport resources."""


@dataclasses.dataclass(frozen=True, slots=True)
class OpenSourceDeployment:
    """Default deployment selected when no closed bootstrap is installed."""

    mode: str = 'oss'
    workspace_policy: SingleWorkspacePolicy = dataclasses.field(default_factory=SingleWorkspacePolicy)
    entitlement_provider: OpenSourceEntitlementProvider = dataclasses.field(
        default_factory=OpenSourceEntitlementProvider
    )
    directory_provider: None = None
    manifest_provider: None = None
    persistence_mode: str = 'oss_compat'
    required_vector_backend: str | None = None

    @property
    def multi_workspace_enabled(self) -> bool:
        return False

    def validate_instance_config(self, config: dict[str, Any]) -> None:
        del config


@dataclasses.dataclass(frozen=True, slots=True)
class VerifiedCloudDeployment:
    """Receipt returned only after the closed package verifies a Manifest.

    Core deliberately does not accept a config flag as a substitute for this
    object.  The closed entry point owns root-key/JWS verification and the
    entitlement adapter; open Core validates the receipt's runtime invariants.
    """

    instance_uuid: str
    manifest_jti: str
    manifest_generation: int
    expires_at: int
    release: str
    capabilities: frozenset[str]
    tenant_isolation_version: int
    entitlement_provider: EntitlementProvider
    directory_provider: DirectoryProjectionProvider
    manifest_provider: CloudManifestProvider
    verification_key_id: str
    mode: str = dataclasses.field(default='cloud', init=False)
    workspace_policy: CloudWorkspacePolicy = dataclasses.field(default_factory=CloudWorkspacePolicy, init=False)
    persistence_mode: str = dataclasses.field(default='cloud_runtime', init=False)
    required_vector_backend: str = dataclasses.field(default='pgvector', init=False)

    @property
    def multi_workspace_enabled(self) -> bool:
        return True

    def validate(self, expected_instance_uuid: str, *, now: int | None = None) -> None:
        current_time = int(time.time()) if now is None else now
        if not self.instance_uuid or self.instance_uuid != expected_instance_uuid:
            raise CloudBootstrapError('Verified Cloud Manifest targets another LangBot instance')
        if not self.manifest_jti or not self.verification_key_id:
            raise CloudBootstrapError('Verified Cloud Manifest receipt is incomplete')
        if isinstance(self.manifest_generation, bool) or self.manifest_generation <= 0:
            raise CloudBootstrapError('Verified Cloud Manifest generation must be positive')
        if self.expires_at <= current_time:
            raise CloudBootstrapError('Verified Cloud Manifest is expired')
        if self.tenant_isolation_version < REQUIRED_TENANT_ISOLATION_VERSION:
            raise CloudBootstrapError('Verified Cloud Manifest requires an unsupported tenant isolation version')
        if 'multi_workspace_v2' not in self.capabilities:
            raise CloudBootstrapError('Verified Cloud Manifest does not grant multi_workspace_v2')
        if not isinstance(self.entitlement_provider, EntitlementProvider):
            raise CloudBootstrapError('Verified Cloud bootstrap did not provide an entitlement adapter')
        if not isinstance(self.directory_provider, DirectoryProjectionProvider):
            raise CloudBootstrapError('Verified Cloud bootstrap did not provide a directory adapter')
        if not isinstance(self.manifest_provider, CloudManifestProvider):
            raise CloudBootstrapError('Verified Cloud bootstrap did not provide a Manifest renewal adapter')

    def validate_instance_config(self, config: dict[str, Any]) -> None:
        try:
            directory_projection_limits_from_config(config)
        except (TypeError, ValueError) as exc:
            raise CloudBootstrapError(f'Cloud directory limits are invalid: {exc}') from exc
        if config.get('database', {}).get('use') != 'postgresql':
            raise CloudBootstrapError('Cloud runtime requires database.use=postgresql')
        if config.get('vdb', {}).get('use') != self.required_vector_backend:
            raise CloudBootstrapError('Cloud runtime requires vdb.use=pgvector')
        pgvector_config = config.get('vdb', {}).get('pgvector', {})
        if pgvector_config.get('use_business_database') is not True:
            raise CloudBootstrapError('Cloud runtime requires vdb.pgvector.use_business_database=true')
        dimensions = pgvector_config.get('allowed_dimensions')
        if (
            not isinstance(dimensions, list)
            or not dimensions
            or any(isinstance(item, bool) or not isinstance(item, int) for item in dimensions)
            or not set(dimensions).issubset(SUPPORTED_PGVECTOR_DIMENSIONS)
        ):
            supported = ', '.join(str(item) for item in sorted(SUPPORTED_PGVECTOR_DIMENSIONS))
            raise CloudBootstrapError(f'Cloud pgvector allowed_dimensions must be a non-empty subset of: {supported}')
        if config.get('mcp', {}).get('stdio', {}).get('enabled', True) is not False:
            raise CloudBootstrapError('Cloud runtime requires mcp.stdio.enabled=false')
        plugin_worker = config.get('plugin', {}).get('worker', {})
        if plugin_worker.get('require_hard_limits') is not True:
            raise CloudBootstrapError('Cloud Runtime requires plugin.worker.require_hard_limits=true')
        box_config = config.get('box', {})
        if box_config.get('enabled') is not True:
            raise CloudBootstrapError('Cloud runtime requires box.enabled=true')
        if box_config.get('backend') != 'nsjail':
            raise CloudBootstrapError('Cloud runtime requires box.backend=nsjail')
        runtime_endpoint = str(box_config.get('runtime', {}).get('endpoint', '') or '').strip()
        if not runtime_endpoint:
            raise CloudBootstrapError('Cloud runtime requires a shared external box.runtime.endpoint')
        admission = box_config.get('admission', {})
        required_admission = {
            'required': True,
            'logical_session_id': 'global',
            'required_backend': 'nsjail',
            'max_sessions': 1,
            'max_managed_processes': 0,
        }
        if any(admission.get(name) != value for name, value in required_admission.items()):
            raise CloudBootstrapError(
                'Cloud runtime requires grant-enforced Box admission with one global session and zero managed processes'
            )
        grant_ttl = admission.get('max_grant_ttl_sec')
        if isinstance(grant_ttl, bool) or not isinstance(grant_ttl, int) or not 1 <= grant_ttl <= 300:
            raise CloudBootstrapError('Cloud Box admission max_grant_ttl_sec must be between 1 and 300')
        workspace_quota_mb = admission.get('workspace_quota_mb')
        if isinstance(workspace_quota_mb, bool) or not isinstance(workspace_quota_mb, int) or workspace_quota_mb <= 0:
            raise CloudBootstrapError('Cloud Box admission workspace_quota_mb must be a positive integer')
        local_config = box_config.get('local', {})
        host_root = str(local_config.get('host_root', '') or '').strip()
        default_workspace = str(local_config.get('default_workspace', '') or '').strip()
        allowed_mount_roots = local_config.get('allowed_mount_roots')
        if not host_root or not os.path.isabs(host_root):
            raise CloudBootstrapError('Cloud Box local.host_root must be an absolute shared-volume path')
        if not default_workspace or not os.path.isabs(default_workspace):
            raise CloudBootstrapError('Cloud Box local.default_workspace must be an absolute shared-volume path')
        if (
            not isinstance(allowed_mount_roots, list)
            or not allowed_mount_roots
            or any(not isinstance(root, str) or not os.path.isabs(root) for root in allowed_mount_roots)
        ):
            raise CloudBootstrapError('Cloud Box local.allowed_mount_roots must contain absolute shared-volume paths')
        resolved_workspace = os.path.realpath(default_workspace)
        if not any(
            resolved_workspace == os.path.realpath(root)
            or resolved_workspace.startswith(f'{os.path.realpath(root)}{os.sep}')
            for root in allowed_mount_roots
        ):
            raise CloudBootstrapError('Cloud Box local.default_workspace must be under allowed_mount_roots')


class CloudBootstrapProvider(Protocol):
    def bootstrap(
        self,
        *,
        instance_uuid: str,
        instance_config: dict[str, Any],
    ) -> VerifiedCloudDeployment | Awaitable[VerifiedCloudDeployment]: ...


class DeploymentAdmissionGuard:
    """Continuously enforce one verified deployment receipt.

    Startup verification alone is insufficient because a long-running process
    could otherwise keep serving after the signed Manifest expires. The guard
    tracks both wall-clock expiry and a monotonic deadline so moving the system
    clock backwards cannot extend an already admitted receipt.

    A closed bootstrap may atomically replace the receipt with a strictly newer
    Manifest generation after performing its own signature verification. The
    logical instance and deployment mode cannot change during the process.
    """

    def __init__(
        self,
        instance_uuid: str,
        deployment: OpenSourceDeployment | VerifiedCloudDeployment,
        *,
        wall_time: Callable[[], float] = time.time,
        monotonic_time: Callable[[], float] = time.monotonic,
    ) -> None:
        self.instance_uuid = instance_uuid
        self._wall_time = wall_time
        self._monotonic_time = monotonic_time
        self._lock = threading.Lock()
        self._deployment = deployment
        self._deadline: float | None = None
        self._install_initial(deployment)

    @property
    def deployment(self) -> OpenSourceDeployment | VerifiedCloudDeployment:
        with self._lock:
            return self._deployment

    def _install_initial(self, deployment: OpenSourceDeployment | VerifiedCloudDeployment) -> None:
        now = int(self._wall_time())
        if isinstance(deployment, VerifiedCloudDeployment):
            deployment.validate(self.instance_uuid, now=now)
            self._deadline = self._monotonic_time() + (deployment.expires_at - now)
        elif not isinstance(deployment, OpenSourceDeployment):
            raise TypeError('Deployment admission requires a verified deployment object')

    @staticmethod
    def _receipt_identity(deployment: VerifiedCloudDeployment) -> tuple[Any, ...]:
        return (
            deployment.instance_uuid,
            deployment.manifest_jti,
            deployment.manifest_generation,
            deployment.expires_at,
            deployment.release,
            tuple(sorted(deployment.capabilities)),
            deployment.tenant_isolation_version,
            deployment.verification_key_id,
        )

    def replace(self, deployment: VerifiedCloudDeployment) -> None:
        """Atomically install a verified, non-rollback Cloud receipt."""

        now = int(self._wall_time())
        deployment.validate(self.instance_uuid, now=now)
        with self._lock:
            current = self._deployment
            if not isinstance(current, VerifiedCloudDeployment):
                raise CloudRuntimeUnavailableError('Deployment mode cannot change while LangBot is running')
            if deployment.manifest_generation < current.manifest_generation:
                raise CloudRuntimeUnavailableError('Cloud Manifest generation rolled back')
            if deployment.manifest_generation == current.manifest_generation and self._receipt_identity(
                deployment
            ) != self._receipt_identity(current):
                raise CloudRuntimeUnavailableError('Cloud Manifest generation has conflicting contents')
            self._deployment = deployment
            self._deadline = self._monotonic_time() + (deployment.expires_at - now)

    def require_active(self) -> OpenSourceDeployment | VerifiedCloudDeployment:
        """Return the active deployment or fail closed after Manifest expiry."""

        now = int(self._wall_time())
        monotonic_now = self._monotonic_time()
        with self._lock:
            deployment = self._deployment
            deadline = self._deadline
        if isinstance(deployment, OpenSourceDeployment):
            return deployment
        try:
            deployment.validate(self.instance_uuid, now=now)
        except CloudBootstrapError as exc:
            raise CloudRuntimeUnavailableError(str(exc)) from exc
        if deadline is None or monotonic_now >= deadline:
            raise CloudRuntimeUnavailableError('Verified Cloud Manifest is expired')
        return deployment


class CloudManifestRefreshService:
    """Renew a short-lived verified Manifest before runtime admission expires."""

    def __init__(
        self,
        admission: DeploymentAdmissionGuard,
        provider: CloudManifestProvider,
        logger: Any,
        *,
        wall_time: Callable[[], float] = time.time,
        refresh_margin_seconds: int = 180,
        maximum_sleep_seconds: int = 300,
    ) -> None:
        if not isinstance(provider, CloudManifestProvider):
            raise TypeError('Cloud Manifest refresh requires a CloudManifestProvider')
        if refresh_margin_seconds < 120:
            raise ValueError('Cloud Manifest refresh margin must be at least 120 seconds')
        if maximum_sleep_seconds <= 0:
            raise ValueError('Cloud Manifest refresh maximum sleep must be positive')
        self.admission = admission
        self.provider = provider
        self.logger = logger
        self._wall_time = wall_time
        self.refresh_margin_seconds = refresh_margin_seconds
        self.maximum_sleep_seconds = maximum_sleep_seconds

    def next_refresh_delay(self) -> float:
        deployment = self.admission.deployment
        if not isinstance(deployment, VerifiedCloudDeployment):
            return float(self.maximum_sleep_seconds)
        remaining = deployment.expires_at - self._wall_time()
        return max(
            5.0,
            min(
                float(self.maximum_sleep_seconds),
                remaining - self.refresh_margin_seconds,
            ),
        )

    async def refresh_once(self) -> VerifiedCloudDeployment:
        candidate = await self.provider.refresh_manifest()
        if not isinstance(candidate, VerifiedCloudDeployment):
            raise CloudBootstrapError('Cloud Manifest provider returned an invalid deployment receipt')
        self.admission.replace(candidate)
        return candidate

    async def run(self) -> None:
        retry_delay = 5.0
        while True:
            try:
                await asyncio.sleep(self.next_refresh_delay())
                await self.refresh_once()
                retry_delay = 5.0
            except asyncio.CancelledError:
                raise
            except Exception:
                self.logger.exception('Cloud Manifest refresh failed')
                await asyncio.sleep(retry_delay)
                retry_delay = min(retry_delay * 2, 30.0)


async def _invoke_provider(
    loaded: Any,
    *,
    instance_uuid: str,
    instance_config: dict[str, Any],
) -> VerifiedCloudDeployment:
    provider = loaded() if inspect.isclass(loaded) else loaded
    bootstrap = getattr(provider, 'bootstrap', None)
    if not callable(bootstrap):
        raise CloudBootstrapError('Cloud bootstrap entry point must expose bootstrap()')
    result = bootstrap(instance_uuid=instance_uuid, instance_config=instance_config)
    if inspect.isawaitable(result):
        result = await result
    if not isinstance(result, VerifiedCloudDeployment):
        raise CloudBootstrapError('Cloud bootstrap must return VerifiedCloudDeployment')
    return result


async def resolve_deployment(
    *,
    instance_uuid: str,
    instance_config: dict[str, Any],
    entry_points: Callable[[], Any] | None = None,
    now: int | None = None,
) -> OpenSourceDeployment | VerifiedCloudDeployment:
    """Discover the optional closed bootstrap and validate its receipt.

    Absence selects OSS singleton mode.  Presence is fail-closed: duplicate,
    broken, invalid, or expired providers never fall back to an OSS Workspace.
    """

    discover = entry_points or importlib.metadata.entry_points
    discovered = discover()
    if hasattr(discovered, 'select'):
        candidates = list(discovered.select(group=CLOUD_BOOTSTRAP_ENTRY_POINT))
    else:  # Python/importlib compatibility for dict-like EntryPoints
        candidates = list(discovered.get(CLOUD_BOOTSTRAP_ENTRY_POINT, ()))
    if not candidates:
        deployment = OpenSourceDeployment()
        deployment.validate_instance_config(instance_config)
        return deployment
    if len(candidates) != 1:
        raise CloudBootstrapError('Exactly one Cloud bootstrap provider may be installed')

    try:
        loaded = candidates[0].load()
        deployment = await _invoke_provider(
            loaded,
            instance_uuid=instance_uuid,
            instance_config=instance_config,
        )
        deployment.validate(instance_uuid, now=now)
        deployment.validate_instance_config(instance_config)
        return deployment
    except CloudBootstrapError:
        raise
    except Exception as exc:
        raise CloudBootstrapError('Closed Cloud bootstrap failed') from exc