# Copyright (c) 2026 Beijing Volcano Engine Technology Co., Ltd.
# SPDX-License-Identifier: AGPL-3.0
"""Server configuration for OpenViking HTTP Server."""

import sys
from typing import Dict, List, Literal, Optional

from pydantic import BaseModel, Field, ValidationError, field_validator

# Import auth plugin registry for config validation
from openviking.server.auth.ldap_config import LDAPConfig
from openviking.server.auth.oidc_config import OIDCConfig
from openviking.server.auth.registry import get_registry
from openviking.server.identity import AuthMode
from openviking_cli.utils import get_logger
from openviking_cli.utils.config.config_loader import (
    load_json_config,
    resolve_config_path,
)
from openviking_cli.utils.config.config_utils import format_validation_error
from openviking_cli.utils.config.consts import (
    DEFAULT_CONFIG_DIR,
    DEFAULT_OV_CONF,
    OPENVIKING_CONFIG_ENV,
    SYSTEM_CONFIG_DIR,
)

logger = get_logger(__name__)


def _normalize_config_uri(value: Optional[str], field_name: str) -> Optional[str]:
    if value is None:
        return None
    if not isinstance(value, str):
        raise ValueError(f"{field_name} must be a string")
    uri = value.strip().rstrip("/")
    if not uri:
        raise ValueError(f"{field_name} must not be empty")
    return uri


class AddTargetsConfig(BaseModel):
    """Add targets for resource and skill writes."""

    resource_uri: Optional[str] = None
    skill_uri: Optional[str] = None

    model_config = {"extra": "forbid"}

    @field_validator("resource_uri")
    @classmethod
    def validate_resource_uri(cls, value: Optional[str]) -> Optional[str]:
        uri = _normalize_config_uri(value, "resource_uri")
        if uri is None:
            return None
        from openviking.core.namespace import classify_uri, uri_parts
        from openviking.core.uri_validation import validate_viking_uri
        from openviking_cli.utils.uri import VikingURI

        validate_viking_uri(uri, field_name="resource_uri")
        normalized = VikingURI.normalize(uri).rstrip("/")
        parts = uri_parts(normalized)
        classification = classify_uri(normalized)
        if parts[:1] == ["resources"] or (
            parts[:1] == ["user"]
            and classification.context_type == "resource"
            and classification.content_index is not None
        ):
            return normalized
        raise ValueError("resource_uri must be a resource directory URI")

    @field_validator("skill_uri")
    @classmethod
    def validate_skill_uri(cls, value: Optional[str]) -> Optional[str]:
        uri = _normalize_config_uri(value, "skill_uri")
        if uri is None:
            return None
        from openviking_cli.utils.uri import VikingURI

        normalized = VikingURI.normalize(uri).rstrip("/")
        if normalized in {"viking://user/skills", "viking://agent/skills"}:
            return normalized
        raise ValueError("skill_uri must be viking://user/skills or viking://agent/skills")


class AgentEvolutionConfig(BaseModel):
    """Default Agent Evolution setting for accounts without an override."""

    enabled: bool = False

    model_config = {"extra": "forbid"}


class DeprecatedUserAgentEvolutionConfig(BaseModel):
    """Parse-only compatibility for legacy per-user configuration files."""

    enabled: Optional[bool] = None

    model_config = {"extra": "forbid"}


class UserConfig(BaseModel):
    """User configuration values that can be defaulted or initialized."""

    add_targets: AddTargetsConfig = Field(default_factory=AddTargetsConfig)
    agent_evolution: DeprecatedUserAgentEvolutionConfig = Field(
        default_factory=DeprecatedUserAgentEvolutionConfig,
        exclude=True,
    )

    model_config = {"extra": "forbid"}


class MetricsAccountDimensionConfig(BaseModel):
    """Account-dimension configuration for metrics label injection."""

    # Enabled by default, but still allowlist-gated to avoid accidental high-cardinality exposure.
    enabled: bool = True
    max_active_accounts: int = 100
    metric_allowlist: List[str] = Field(default_factory=list)

    model_config = {"extra": "forbid"}


class PrometheusExporterConfig(BaseModel):
    """Prometheus exporter configuration."""

    enabled: bool = True

    model_config = {"extra": "forbid"}


class OTelExporterConfig(BaseModel):
    """OpenTelemetry exporter configuration."""

    class TLSConfig(BaseModel):
        """TLS configuration for OTLP exporters."""

        insecure: bool = False

        model_config = {"extra": "forbid"}

    enabled: bool = False
    protocol: str = "grpc"  # "grpc", "http", or "local" for traces
    tls: TLSConfig = Field(default_factory=TLSConfig)
    endpoint: str = "localhost:4317"  # gRPC default: 4317; HTTP default: 4318
    service_name: str = "openviking-server"
    export_interval_ms: int = 10000
    headers: Dict[str, str] = Field(default_factory=dict)
    local_path: str = "~/.openviking/logs/traces.jsonl"
    local_rotation_mb: int = Field(default=40, gt=0)
    local_backup_count: int = Field(default=2, ge=0)

    model_config = {"extra": "forbid"}


class MetricsExportersConfig(BaseModel):
    """Metrics exporters configuration."""

    prometheus: PrometheusExporterConfig = Field(default_factory=PrometheusExporterConfig)
    otel: OTelExporterConfig = Field(default_factory=OTelExporterConfig)

    model_config = {"extra": "forbid"}


class MetricsConfig(BaseModel):
    """Metrics subsystem configuration."""

    enabled: bool = False
    bot_data_path: Optional[str] = None
    account_dimension: MetricsAccountDimensionConfig = Field(
        default_factory=MetricsAccountDimensionConfig
    )
    exporters: MetricsExportersConfig = Field(default_factory=MetricsExportersConfig)

    model_config = {"extra": "forbid"}


class UsageAuditConfig(BaseModel):
    """Product usage and audit projection configuration."""

    enabled: bool = True
    backend: Literal["sqlite"] = "sqlite"
    sqlite_path: Optional[str] = None
    queue_size: int = Field(10_000, gt=0)
    batch_size: int = Field(500, gt=0)
    flush_interval_seconds: float = Field(1.0, gt=0)
    shutdown_flush_timeout_seconds: float = Field(3.0, gt=0)
    usage_retention_days: int = Field(14, ge=0)
    audit_retention_days: int = Field(7, ge=0)
    audit_retention_per_account: int = Field(1000, ge=0)
    timezone: str = "local"
    inventory_ttl_seconds: float = Field(10.0, ge=0)

    model_config = {"extra": "forbid"}


class UsageReporterSinkConfig(BaseModel):
    """Usage reporter sink configuration."""

    type: Literal["custom", "file_log"] = "custom"
    class_path: Optional[str] = None
    config: Dict[str, object] = Field(default_factory=dict)

    model_config = {"extra": "forbid"}


class UsageReporterConfig(BaseModel):
    """Usage event reporter configuration."""

    enabled: bool = False
    extractors: List[Literal["memory_usage"]] = Field(default_factory=lambda: ["memory_usage"])
    sinks: List[UsageReporterSinkConfig] = Field(default_factory=list)

    model_config = {"extra": "forbid"}


class TraceDumpBodyConfig(BaseModel):
    """HTTP body dump configuration.

    Attaches request/response bodies as attributes on the active trace span so
    they can be inspected in trace UIs. Off by default — bodies may contain
    secrets and high-cardinality content.
    """

    enabled: bool = False
    max_bytes: int = 4096

    model_config = {"extra": "forbid"}


class ObservabilityConfig(BaseModel):
    """Server-side observability configuration."""

    metrics: MetricsConfig = Field(default_factory=MetricsConfig)
    usage_audit: UsageAuditConfig = Field(default_factory=UsageAuditConfig)
    traces: OTelExporterConfig = Field(default_factory=OTelExporterConfig)
    logs: OTelExporterConfig = Field(default_factory=OTelExporterConfig)
    dump_body: TraceDumpBodyConfig = Field(default_factory=TraceDumpBodyConfig)

    model_config = {"extra": "forbid"}


class TempUploadConfig(BaseModel):
    """Temporary upload configuration."""

    default_mode: Literal["local", "shared"] = "local"
    shared_max_size_bytes: int = 512 * 1024 * 1024
    shared_prefix: str = "viking://upload"

    model_config = {"extra": "forbid"}


class ToolOutputExternalizationConfig(BaseModel):
    """External storage controls for oversized tool outputs."""

    enabled: bool = True
    threshold_chars: int = 20_000
    preview_chars: int = 2_000
    assistant_turn_inline_budget_chars: int = 100_000
    assistant_turn_preview_budget_chars: int = 10_000
    min_preview_chars: int = 1_000
    aggregate_selection_strategy: Literal["largest_first"] = "largest_first"
    failure_mode: Literal["reject", "preserve_raw", "preview_only"] = "preserve_raw"

    model_config = {"extra": "forbid"}


class ServerConfig(BaseModel):
    host: str = "127.0.0.1"
    port: int = 1933
    workers: int = 1
    # Seconds an idle HTTP keep-alive connection is kept open before the server
    # closes it. Defaults to 5 to match uvicorn's built-in default and preserve
    # the existing service behavior. Raise it above the idle-connection lifetime
    # of any upstream client or load balancer that reuses connections (e.g. the
    # serverless VKE forwarder keeps idle connections for up to 60s via
    # WithMaxIdleConnDuration(1*time.Minute)); otherwise the server may close
    # connections the client still believes are reusable, causing sporadic
    # connection-reset / EOF errors.
    timeout_keep_alive: int = 5
    auth_mode: Optional[str] = None  # If None, auto-detect based on root_api_key
    root_api_key: Optional[str] = None
    # OIDC/LDAP authentication configuration
    oidc: Optional[OIDCConfig] = None
    ldap: Optional[LDAPConfig] = None
    profile_enabled: bool = False
    cors_origins: List[str] = Field(default_factory=lambda: ["*"])
    with_bot: bool = False  # Enable Bot API proxy to Vikingbot
    bot_api_url: str = "http://localhost:18790"  # Vikingbot OpenAPIChannel URL (default port)
    encryption_enabled: bool = False  # Whether file-level AES encryption is enabled
    api_key_hashing_enabled: bool = False  # Whether API key Argon2id hashing is enabled (default: false, rely on file encryption)
    # When true, poll the shared key store and reload the in-memory index on change so
    # read replicas pick up writer-side user add/rotate/remove. Default off (single writer).
    api_key_watch_enabled: bool = False
    # Poll interval; each check only stats registry files and reads fully on change.
    api_key_watch_interval_seconds: float = 30.0
    observability: ObservabilityConfig = Field(default_factory=ObservabilityConfig)
    usage_reporter: UsageReporterConfig = Field(default_factory=UsageReporterConfig)
    # Public-facing base URL emitted in MCP-issued upload instructions. See
    # ``openviking.server.mcp_endpoint._resolve_public_base_url`` for the full
    # resolution chain: env var > this field > X-Forwarded-Host/Proto > Host header
    # > listen-address fallback. Set this (or the env var) when the server runs
    # behind a reverse proxy that does not forward X-Forwarded-* headers.
    public_base_url: Optional[str] = None
    upload_signed_ttl_seconds: int = 600
    temp_upload: TempUploadConfig = Field(default_factory=TempUploadConfig)
    user_config_defaults: UserConfig = Field(default_factory=UserConfig)
    agent_evolution: AgentEvolutionConfig = Field(default_factory=AgentEvolutionConfig)
    tool_output_externalization: ToolOutputExternalizationConfig = Field(
        default_factory=ToolOutputExternalizationConfig
    )

    model_config = {"extra": "forbid"}

    def get_effective_auth_mode(self) -> str:
        """Get effective auth mode, auto-detecting if not explicitly set.

        - If root_api_key is configured (non-empty) and auth_mode is None: api_key
        - If root_api_key is not configured and auth_mode is None: dev
        """
        auth_mode_text = str(self.auth_mode).strip() if self.auth_mode is not None else ""
        if auth_mode_text:
            return auth_mode_text

        if self.root_api_key is not None and str(self.root_api_key).strip():
            return AuthMode.API_KEY.value
        return AuthMode.DEV.value


def map_bind_host_to_loopback(host: str) -> str:
    """Map a server *bind* host to a client-connectable *loopback* host.

    ``server.host`` configures the address the server binds/listens on. A
    wildcard bind address such as ``0.0.0.0`` (or IPv6 ``::``) is valid to
    listen on but is *not* a destination a client can connect to. Clients that
    derive a connect URL from the configured host (the bot proxy, the bot's
    own config loader, ``doctor``) must translate the wildcard to loopback:

    - ``"0.0.0.0"``, ``""``, ``"*"``   -> ``"127.0.0.1"``
    - ``"::"``, ``"::0"``, ``"[::]"``  -> ``"[::1]"``
    - bare IPv6 literals (e.g. ``"::1"``) are bracketed for URL syntax
    - everything else passes through unchanged
    """
    host = str(host or "").strip()
    if host in ("0.0.0.0", "", "*"):
        return "127.0.0.1"
    if host in ("::", "::0", "[::]"):
        return "[::1]"
    if ":" in host and not (host.startswith("[") and host.endswith("]")):
        return f"[{host}]"
    return host


def get_server_url_from_server_data(server_data: object) -> str:
    """Return the loopback URL clients use for the configured OpenViking server."""
    if isinstance(server_data, dict):
        host_value = server_data.get("host")
        port_value = server_data.get("port")
    else:
        host_value = getattr(server_data, "host", None)
        port_value = getattr(server_data, "port", None)
    host = map_bind_host_to_loopback(str(host_value or "127.0.0.1"))
    port = str(port_value or "1933").strip()
    return f"http://{host}:{port}"


def load_server_config(config_path: Optional[str] = None) -> ServerConfig:
    """Load server configuration from ov.conf.

    Reads the ``server`` section of ov.conf and also ensures the full
    ov.conf is loaded into the OpenVikingConfigSingleton so that model
    and storage settings are available.

    Resolution chain:
      1. Explicit ``config_path`` (from --config)
      2. OPENVIKING_CONFIG_FILE environment variable
      3. ~/.openviking/ov.conf

    Args:
        config_path: Explicit path to ov.conf.

    Returns:
        ServerConfig instance with defaults for missing fields.

    Raises:
        FileNotFoundError: If no config file is found.
    """
    path = resolve_config_path(config_path, OPENVIKING_CONFIG_ENV, DEFAULT_OV_CONF)
    if path is None:
        default_path_user = DEFAULT_CONFIG_DIR / DEFAULT_OV_CONF
        default_path_system = SYSTEM_CONFIG_DIR / DEFAULT_OV_CONF
        raise FileNotFoundError(
            f"OpenViking configuration file not found.\n"
            f"Please create {default_path_user} or {default_path_system}, or set {OPENVIKING_CONFIG_ENV}.\n"
            f"See: https://openviking.ai/docs"
        )

    data = load_json_config(path)
    server_data = data.get("server", {})
    if server_data is None:
        server_data = {}
    if not isinstance(server_data, dict):
        raise ValueError("Invalid server config: 'server' section must be an object")

    # Convert auth_mode string — built-in enums are converted to their string
    # value; custom modes are kept as-is for plugin extensibility.
    if "auth_mode" in server_data and isinstance(server_data["auth_mode"], str):
        try:
            server_data["auth_mode"] = AuthMode(server_data["auth_mode"]).value
        except ValueError:
            # Custom auth mode — keep as string for plugin registration
            pass

    # Get encryption enabled from config data directly (for test compatibility)
    encryption_enabled = data.get("encryption", {}).get("enabled", False)
    # Get API key hashing enabled from config data directly (under encryption namespace)
    # Default: false - rely on file-level encryption for API key protection
    api_key_hashing_enabled = (
        data.get("encryption", {}).get("api_key_hashing", {}).get("enabled", False)
    )

    # BREAKING CHANGE: Previously, encryption.enabled=true implicitly enabled API key Argon2id hashing.
    # Now, you must explicitly configure encryption.api_key_hashing.enabled=true to enable hashing.
    # When encryption.enabled=true but api_key_hashing.enabled=false (default),
    # API keys will be stored in plaintext within AES-GCM encrypted files.
    if encryption_enabled and not api_key_hashing_enabled:
        logger.info(
            "API key hashing is disabled while file encryption is enabled. "
            "Previously, encryption.enabled=true implicitly enabled API key Argon2id hashing. "
            "Now, API keys will be stored in plaintext within AES-GCM encrypted files. "
            "To maintain the previous behavior, set encryption.api_key_hashing.enabled=true. "
            "See documentation for more details."
        )

    try:
        config = ServerConfig.model_validate(server_data)
    except ValidationError as e:
        raise ValueError(
            f"Invalid server config in {path}:\n"
            f"{format_validation_error(root_model=ServerConfig, error=e, path_prefix='server')}"
        ) from e

    return config.model_copy(
        update={
            "encryption_enabled": encryption_enabled,
            "api_key_hashing_enabled": api_key_hashing_enabled,
        }
    )


_LOCALHOST_HOSTS = {"127.0.0.1", "localhost", "::1"}


def _is_localhost(host: str) -> bool:
    """Return True if *host* resolves to a loopback address."""
    return host in _LOCALHOST_HOSTS


def load_bot_gateway_token(config_path: Optional[str] = None) -> str:
    """Load bot gateway token from ov.conf bot.gateway.token."""
    path = resolve_config_path(config_path, OPENVIKING_CONFIG_ENV, DEFAULT_OV_CONF)
    if path is None:
        return ""

    data = load_json_config(path)
    bot_config = data.get("bot", {})
    if not isinstance(bot_config, dict):
        return ""
    gateway_config = bot_config.get("gateway", {})
    if not isinstance(gateway_config, dict):
        return ""
    return gateway_config.get("token", "") or ""


def validate_server_config(config: ServerConfig) -> None:
    """Validate server config for safe startup.

    Validation is delegated to the auth plugin registered for the effective
    auth_mode. Built-in plugins (dev, api_key, trusted) preserve the original
    validation behaviour.

    If auth_mode is not explicitly configured:
    - If root_api_key is configured (non-empty): auto-select api_key mode
    - If root_api_key is not configured: auto-select dev mode

    Raises:
        SystemExit: If the configuration is unsafe.
    """
    # Check for empty root_api_key
    if config.root_api_key == "":
        logger.error(
            "Invalid server.root_api_key: empty string is not allowed. "
            "Either set a non-empty root_api_key or remove the setting entirely."
        )
        sys.exit(1)

    effective_auth_mode = config.get_effective_auth_mode()

    # Ensure built-in plugins are registered before validation.
    # If a non-built-in plugin has already claimed a built-in mode name,
    # log a security warning and forcefully override it.
    from openviking.server.auth.plugins import ApiKeyAuthPlugin, DevAuthPlugin, TrustedAuthPlugin

    registry = get_registry()
    _BUILTIN_PLUGINS = {
        "dev": DevAuthPlugin,
        "api_key": ApiKeyAuthPlugin,
        "trusted": TrustedAuthPlugin,
    }
    for mode, plugin_cls in _BUILTIN_PLUGINS.items():
        existing = registry.get(mode)
        if existing is None:
            registry.register(plugin_cls)
        elif existing is not plugin_cls:
            logger.warning(
                "SECURITY: Auth mode %r was registered by %s but is being "
                "overridden by the built-in %s.",
                mode,
                existing.__name__,
                plugin_cls.__name__,
            )
            registry._plugins[mode] = plugin_cls

    plugin_cls = registry.get(effective_auth_mode)
    if plugin_cls is None:
        logger.error(
            "Unknown auth_mode: %r. No auth plugin registered for this mode. Registered modes: %s.",
            effective_auth_mode,
            ", ".join(registry.list_modes()),
        )
        sys.exit(1)

    plugin_cls().validate_config(config)