import importlib
import inspect
import logging
from abc import ABC
from graphlib import TopologicalSorter
from typing import Optional, List, Any, Dict, Set, Iterable, Union
from typing import Type, TypeVar, cast

from overrides import EnforceOverrides
from overrides import override
from typing_extensions import Literal
import platform


in_pydantic_v2 = False
try:
    from pydantic import BaseSettings
except ImportError:
    in_pydantic_v2 = True
    from pydantic.v1 import BaseSettings
    from pydantic.v1 import validator

if not in_pydantic_v2:
    from pydantic import validator  # type: ignore # noqa

# The thin client will have a flag to control which implementations to use
is_thin_client = False
try:
    from chromadb.is_thin_client import is_thin_client  # type: ignore
except ImportError:
    is_thin_client = False

logger = logging.getLogger(__name__)

LEGACY_ERROR = """\033[91mYou are using a deprecated configuration of Chroma.

\033[94mIf you do not have data you wish to migrate, you only need to change how you construct
your Chroma client. Please see the "New Clients" section of https://docs.trychroma.com/deployment/migration.
________________________________________________________________________________________________

If you do have data you wish to migrate, we have a migration tool you can use in order to
migrate your data to the new Chroma architecture.
Please `pip install chroma-migrate` and run `chroma-migrate` to migrate your data and then
change how you construct your Chroma client.

See https://docs.trychroma.com/deployment/migration for more information or join our discord at https://discord.gg/8g5FESbj for help!\033[0m"""

_legacy_config_keys = {
    "chroma_db_impl",
}

_legacy_config_values = {
    "duckdb",
    "duckdb+parquet",
    "clickhouse",
    "local",
    "rest",
    "chromadb.db.duckdb.DuckDB",
    "chromadb.db.duckdb.PersistentDuckDB",
    "chromadb.db.clickhouse.Clickhouse",
    "chromadb.api.local.LocalAPI",
}


# Map specific abstract types to the setting which specifies which
# concrete implementation to use.
# Please keep these sorted. We're civilized people.
_abstract_type_keys: Dict[str, str] = {
    # TODO: Don't use concrete types here to avoid circular deps. Strings are
    #       fine for right here!
    # NOTE: this is to support legacy api construction. Use ServerAPI instead
    "chromadb.api.API": "chroma_api_impl",
    "chromadb.api.ServerAPI": "chroma_api_impl",
    "chromadb.api.async_api.AsyncServerAPI": "chroma_api_impl",
    "chromadb.auth.ClientAuthProvider": "chroma_client_auth_provider",
    "chromadb.auth.ServerAuthenticationProvider": "chroma_server_authn_provider",
    "chromadb.auth.ServerAuthorizationProvider": "chroma_server_authz_provider",
    "chromadb.db.system.SysDB": "chroma_sysdb_impl",
    "chromadb.ingest.Consumer": "chroma_consumer_impl",
    "chromadb.ingest.Producer": "chroma_producer_impl",
    "chromadb.quota.QuotaProvider": "chroma_quota_provider_impl",
    "chromadb.rate_limit.RateLimitEnforcer": "chroma_rate_limit_enforcer_impl",
    "chromadb.segment.SegmentManager": "chroma_segment_manager_impl",
    "chromadb.segment.distributed.SegmentDirectory": "chroma_segment_directory_impl",
    "chromadb.segment.distributed.MemberlistProvider": "chroma_memberlist_provider_impl",
    "chromadb.telemetry.product.ProductTelemetryClient": "chroma_product_telemetry_impl",
}

DEFAULT_TENANT = "default_tenant"
DEFAULT_DATABASE = "default_database"


class Settings(BaseSettings):  # type: ignore
    # ==============
    # Generic config
    # ==============

    environment: str = ""

    # Can be "chromadb.api.segment.SegmentAPI" or "chromadb.api.fastapi.FastAPI"
    chroma_api_impl: str = "chromadb.api.segment.SegmentAPI"

    @validator("chroma_server_nofile", pre=True, always=True, allow_reuse=True)
    def empty_str_to_none(cls, v: str) -> Optional[str]:
        if type(v) is str and v.strip() == "":
            return None
        return v

    chroma_server_nofile: Optional[int] = None
    # the number of maximum threads to handle synchronous tasks in the FastAPI server
    chroma_server_thread_pool_size: int = 40

    # ==================
    # Client-mode config
    # ==================

    tenant_id: str = "default"
    topic_namespace: str = "default"

    chroma_server_host: Optional[str] = None
    chroma_server_headers: Optional[Dict[str, str]] = None
    chroma_server_http_port: Optional[int] = None
    chroma_server_ssl_enabled: Optional[bool] = False

    chroma_server_ssl_verify: Optional[Union[bool, str]] = None
    chroma_server_api_default_path: Optional[str] = "/api/v1"
    # eg ["http://localhost:3000"]
    chroma_server_cors_allow_origins: List[str] = []

    # ==================
    # Server config
    # ==================

    is_persistent: bool = False
    persist_directory: str = "./chroma"

    chroma_memory_limit_bytes: int = 0
    chroma_segment_cache_policy: Optional[str] = None

    allow_reset: bool = False

    # ===========================
    # {Client, Server} auth{n, z}
    # ===========================

    # The header to use for the token. Defaults to "Authorization".
    chroma_auth_token_transport_header: Optional[str] = None

    # ================
    # Client auth{n,z}
    # ================

    # The provider for client auth. See chromadb/auth/__init__.py
    chroma_client_auth_provider: Optional[str] = None
    # If needed by the provider (e.g. BasicAuthClientProvider),
    # the credentials to use.
    chroma_client_auth_credentials: Optional[str] = None

    # ================
    # Server auth{n,z}
    # ================

    chroma_server_auth_ignore_paths: Dict[str, List[str]] = {
        "/api/v1": ["GET"],
        "/api/v1/heartbeat": ["GET"],
        "/api/v1/version": ["GET"],
    }
    # Overwrite singleton tenant and database access from the auth provider
    # if applicable. See chromadb/server/fastapi/__init__.py's
    # authenticate_and_authorize_or_raise method.
    chroma_overwrite_singleton_tenant_database_access_from_auth: bool = False

    # ============
    # Server authn
    # ============

    chroma_server_authn_provider: Optional[str] = None
    # Only one of the below may be specified.
    chroma_server_authn_credentials: Optional[str] = None
    chroma_server_authn_credentials_file: Optional[str] = None

    # ============
    # Server authz
    # ============

    chroma_server_authz_provider: Optional[str] = None
    # Only one of the below may be specified.
    chroma_server_authz_config: Optional[str] = None
    chroma_server_authz_config_file: Optional[str] = None

    # =========
    # Telemetry
    # =========

    chroma_product_telemetry_impl: str = "chromadb.telemetry.product.posthog.Posthog"
    # Required for backwards compatibility
    chroma_telemetry_impl: str = chroma_product_telemetry_impl

    anonymized_telemetry: bool = True

    chroma_otel_collection_endpoint: Optional[str] = ""
    chroma_otel_service_name: Optional[str] = "chromadb"
    chroma_otel_collection_headers: Dict[str, str] = {}
    chroma_otel_granularity: Optional[str] = None

    # ==========
    # Migrations
    # ==========

    migrations: Literal["none", "validate", "apply"] = "apply"
    # you cannot change the hash_algorithm after migrations have already
    # been applied once this is intended to be a first-time setup configuration
    migrations_hash_algorithm: Literal["md5", "sha256"] = "md5"

    # ==================
    # Distributed Chroma
    # ==================

    chroma_segment_directory_impl: str = "chromadb.segment.impl.distributed.segment_directory.RendezvousHashSegmentDirectory"
    chroma_memberlist_provider_impl: str = "chromadb.segment.impl.distributed.segment_directory.CustomResourceMemberlistProvider"
    worker_memberlist_name: str = "query-service-memberlist"

    chroma_coordinator_host = "localhost"
    # TODO this is the sysdb port. Should probably rename it.
    chroma_server_grpc_port: Optional[int] = None
    chroma_sysdb_impl: str = "chromadb.db.impl.sqlite.SqliteDB"

    chroma_producer_impl: str = "chromadb.db.impl.sqlite.SqliteDB"
    chroma_consumer_impl: str = "chromadb.db.impl.sqlite.SqliteDB"

    chroma_segment_manager_impl: str = (
        "chromadb.segment.impl.manager.local.LocalSegmentManager"
    )

    chroma_logservice_host = "localhost"
    chroma_logservice_port = 50052

    chroma_quota_provider_impl: Optional[str] = None
    chroma_rate_limiting_provider_impl: Optional[str] = None

    chroma_rate_limit_enforcer_impl: str = (
        "chromadb.rate_limit.simple_rate_limit.SimpleRateLimitEnforcer"
    )

    # ==========
    # gRPC service config
    # ==========
    chroma_logservice_request_timeout_seconds: int = 3
    chroma_sysdb_request_timeout_seconds: int = 3
    chroma_query_request_timeout_seconds: int = 60

    # ======
    # Legacy
    # ======

    chroma_db_impl: Optional[str] = None
    chroma_collection_assignment_policy_impl: str = (
        "chromadb.ingest.impl.simple_policy.SimpleAssignmentPolicy"
    )

    # =======
    # Methods
    # =======

    def require(self, key: str) -> Any:
        """Return the value of a required config key, or raise an exception if it is not
        set"""
        val = self[key]
        if val is None:
            raise ValueError(f"Missing required config value '{key}'")
        return val

    def __getitem__(self, key: str) -> Any:
        val = getattr(self, key)
        # Error on legacy config values
        if isinstance(val, str) and val in _legacy_config_values:
            raise ValueError(LEGACY_ERROR)
        return val

    class Config:
        env_file = ".env"
        env_file_encoding = "utf-8"


T = TypeVar("T", bound="Component")


class Component(ABC, EnforceOverrides):
    _dependencies: Set["Component"]
    _system: "System"
    _running: bool

    def __init__(self, system: "System"):
        self._dependencies = set()
        self._system = system
        self._running = False

    def require(self, type: Type[T]) -> T:
        """Get a Component instance of the given type, and register as a dependency of
        that instance."""
        inst = self._system.instance(type)
        self._dependencies.add(inst)
        return inst

    def dependencies(self) -> Set["Component"]:
        """Return the full set of components this component depends on."""
        return self._dependencies

    def stop(self) -> None:
        """Idempotently stop this component's execution and free all associated
        resources."""
        logger.debug(f"Stopping component {self.__class__.__name__}")
        self._running = False

    def start(self) -> None:
        """Idempotently start this component's execution"""
        logger.debug(f"Starting component {self.__class__.__name__}")
        self._running = True

    def reset_state(self) -> None:
        """Reset this component's state to its initial blank state. Only intended to be
        called from tests."""
        logger.debug(f"Resetting component {self.__class__.__name__}")


class System(Component):
    settings: Settings
    _instances: Dict[Type[Component], Component]

    def __init__(self, settings: Settings):
        if is_thin_client:
            # The thin client is a system with only the API component
            if settings["chroma_api_impl"] not in [
                "chromadb.api.fastapi.FastAPI",
                "chromadb.api.async_fastapi.AsyncFastAPI",
            ]:
                raise RuntimeError(
                    "Chroma is running in http-only client mode, and can only be run with 'chromadb.api.fastapi.FastAPI' or 'chromadb.api.async_fastapi.AsyncFastAPI' as the chroma_api_impl. \
            see https://docs.trychroma.com/guides#using-the-python-http-only-client for more information."
                )
        # Validate settings don't contain any legacy config values
        for key in _legacy_config_keys:
            if settings[key] is not None:
                raise ValueError(LEGACY_ERROR)

        if (
            settings["chroma_segment_cache_policy"] is not None
            and settings["chroma_segment_cache_policy"] != "LRU"
        ):
            logger.error(
                "Failed to set chroma_segment_cache_policy: Only LRU is available."
            )
            if settings["chroma_memory_limit_bytes"] == 0:
                logger.error(
                    "Failed to set chroma_segment_cache_policy: chroma_memory_limit_bytes is require."
                )

        # Apply the nofile limit if set
        if settings["chroma_server_nofile"] is not None:
            if platform.system() != "Windows":
                import resource

                curr_soft, curr_hard = resource.getrlimit(resource.RLIMIT_NOFILE)
                desired_soft = settings["chroma_server_nofile"]
                # Validate
                if desired_soft > curr_hard:
                    logging.warning(
                        f"chroma_server_nofile cannot be set to a value greater than the current hard limit of {curr_hard}. Keeping soft limit at {curr_soft}"
                    )
                # Apply
                elif desired_soft > curr_soft:
                    try:
                        resource.setrlimit(
                            resource.RLIMIT_NOFILE, (desired_soft, curr_hard)
                        )
                        logger.info(f"Set chroma_server_nofile to {desired_soft}")
                    except Exception as e:
                        logger.error(
                            f"Failed to set chroma_server_nofile to {desired_soft}: {e} nofile soft limit will remain at {curr_soft}"
                        )
                # Don't apply if reducing the limit
                elif desired_soft < curr_soft:
                    logger.warning(
                        f"chroma_server_nofile is set to {desired_soft}, but this is less than current soft limit of {curr_soft}. chroma_server_nofile will not be set."
                    )
            else:
                logger.warning(
                    "chroma_server_nofile is not supported on Windows. chroma_server_nofile will not be set."
                )

        self.settings = settings
        self._instances = {}
        super().__init__(self)

    def instance(self, type: Type[T]) -> T:
        """Return an instance of the component type specified. If the system is running,
        the component will be started as well."""

        if inspect.isabstract(type):
            type_fqn = get_fqn(type)
            if type_fqn not in _abstract_type_keys:
                raise ValueError(f"Cannot instantiate abstract type: {type}")
            key = _abstract_type_keys[type_fqn]
            fqn = self.settings.require(key)
            type = get_class(fqn, type)

        if type not in self._instances:
            impl = type(self)
            self._instances[type] = impl
            if self._running:
                impl.start()

        inst = self._instances[type]
        return cast(T, inst)

    def components(self) -> Iterable[Component]:
        """Return the full set of all components and their dependencies in dependency
        order."""
        sorter: TopologicalSorter[Component] = TopologicalSorter()
        for component in self._instances.values():
            sorter.add(component, *component.dependencies())

        return sorter.static_order()

    @override
    def start(self) -> None:
        super().start()
        for component in self.components():
            component.start()

    @override
    def stop(self) -> None:
        super().stop()
        for component in reversed(list(self.components())):
            component.stop()

    @override
    def reset_state(self) -> None:
        """Reset the state of this system and all constituents in reverse dependency order"""
        if not self.settings.allow_reset:
            raise ValueError(
                "Resetting is not allowed by this configuration (to enable it, set `allow_reset` to `True` in your Settings() or include `ALLOW_RESET=TRUE` in your environment variables)"
            )
        for component in reversed(list(self.components())):
            component.reset_state()


C = TypeVar("C")


def get_class(fqn: str, type: Type[C]) -> Type[C]:
    """Given a fully qualifed class name, import the module and return the class"""
    module_name, class_name = fqn.rsplit(".", 1)
    module = importlib.import_module(module_name)
    cls = getattr(module, class_name)
    return cast(Type[C], cls)


def get_fqn(cls: Type[object]) -> str:
    """Given a class, return its fully qualified name"""
    return f"{cls.__module__}.{cls.__name__}"