from datetime import datetime
from enum import Enum
from typing import ClassVar, List, Optional
from sqlmodel import (
    JSON,
    BigInteger,
    Column,
    Field,
    ForeignKey,
    Integer,
    Relationship,
    SQLModel,
    Text,
)

from gpustack.mixins import BaseModelMixin
from gpustack.schemas.common import ListParams, PaginatedList
from gpustack.schemas.links import (
    ModelInstanceDraftModelFileLink,
    ModelInstanceModelFileLink,
)
from gpustack.schemas.models import ModelSource, ModelInstance


class ModelFileStateEnum(str, Enum):
    ERROR = "error"
    DOWNLOADING = "downloading"
    READY = "ready"


class ModelFileBase(SQLModel, ModelSource):
    local_dir: Optional[str] = None
    worker_id: Optional[int] = None
    cleanup_on_delete: Optional[bool] = None

    size: Optional[int] = Field(sa_column=Column(BigInteger), default=None)
    download_progress: Optional[float] = None
    resolved_paths: List[str] = Field(sa_column=Column(JSON), default=[])
    state: ModelFileStateEnum = ModelFileStateEnum.DOWNLOADING
    state_message: Optional[str] = Field(
        default=None, sa_column=Column(Text, nullable=True)
    )


class ModelFile(ModelFileBase, BaseModelMixin, table=True):
    __tablename__ = 'model_files'
    id: Optional[int] = Field(default=None, primary_key=True)

    # Unique index of the model source
    source_index: Optional[str] = Field(index=True, unique=True, default=None)

    # Tenant scope. Server-derived from worker→cluster on creation; not
    # exposed on the create payload to avoid clients smuggling overrides.
    cluster_id: Optional[int] = Field(default=None)
    owner_principal_id: Optional[int] = Field(
        default=None,
        sa_column=Column(Integer, ForeignKey("principals.id"), nullable=True),
    )

    instances: list[ModelInstance] = Relationship(
        sa_relationship_kwargs={"lazy": "noload"},
        back_populates="model_files",
        link_model=ModelInstanceModelFileLink,
    )

    draft_instances: list[ModelInstance] = Relationship(
        back_populates="draft_model_files",
        link_model=ModelInstanceDraftModelFileLink,
        sa_relationship_kwargs={"lazy": "noload"},
    )


class ModelFileListParams(ListParams):
    sortable_fields: ClassVar[List[str]] = [
        "source",
        "worker_id",
        "state",
        "resolved_paths",
        "created_at",
        "updated_at",
    ]


class ModelFileCreate(ModelFileBase):
    pass


class ModelFileUpdate(ModelFileBase):
    pass


class ModelFilePublic(
    ModelFileBase,
):
    id: int
    created_at: datetime
    updated_at: datetime


ModelFilesPublic = PaginatedList[ModelFilePublic]