from datetime import datetime
from typing import Optional
from uuid import UUID
from pydantic import BaseModel, field_validator, Field

from app.api.admin_routes.knowledge_base.data_source.models import (
    KBDataSource,
    KBDataSourceCreate,
)
from app.api.admin_routes.models import (
    EmbeddingModelDescriptor,
    LLMDescriptor,
    UserDescriptor,
)
from app.exceptions import KBNoVectorIndexConfigured
from app.models import KgIndexStatus
from app.models.knowledge_base import IndexMethod, GeneralChunkingConfig, ChunkingConfig


class KnowledgeBaseCreate(BaseModel):
    name: str
    description: Optional[str] = None
    index_methods: list[IndexMethod] = Field(
        default_factory=lambda: [IndexMethod.VECTOR]
    )
    llm_id: Optional[int] = None
    embedding_model_id: Optional[int] = None
    chunking_config: ChunkingConfig = Field(default_factory=GeneralChunkingConfig)
    data_sources: list[KBDataSourceCreate] = Field(default_factory=list)

    @field_validator("name")
    def name_must_not_be_blank(cls, v: str) -> str:
        if not v.strip():
            raise ValueError("Please provide a name for the knowledge base")
        return v

    @field_validator("index_methods")
    def index_methods_must_has_vector(cls, v: list[IndexMethod]) -> list[IndexMethod]:
        # Notice: For now, knowledge base must be configured vector index method,
        # we will remove this limit in the feature.
        if IndexMethod.VECTOR not in v:
            raise KBNoVectorIndexConfigured()
        return v


class KnowledgeBaseUpdate(BaseModel):
    name: Optional[str] = None
    description: Optional[str] = None
    chunking_config: Optional[ChunkingConfig] = None


class KnowledgeBaseDetail(BaseModel):
    """
    Represents a detailed view of a knowledge base.
    """

    id: int
    name: str
    description: Optional[str] = None
    documents_total: int
    data_sources_total: int
    # Notice: By default, SQLModel will not serialize list type relationships.
    # https://github.com/fastapi/sqlmodel/issues/37#issuecomment-2093607242
    data_sources: list[KBDataSource]
    chunking_config: Optional[ChunkingConfig] = None
    index_methods: list[IndexMethod]
    llm_id: int | None = None
    llm: LLMDescriptor | None = None
    embedding_model_id: int | None = None
    embedding_model: EmbeddingModelDescriptor | None = None
    creator: UserDescriptor | None = None
    created_at: datetime | None = None
    updated_at: datetime | None = None


class KnowledgeBaseItem(BaseModel):
    """
    Represents a simplified view of a knowledge base for list display purposes.
    """

    id: int
    name: str
    description: Optional[str] = None
    documents_total: int
    data_sources_total: int
    index_methods: list[IndexMethod]
    creator: UserDescriptor | None = None
    created_at: datetime
    updated_at: datetime


class VectorIndexError(BaseModel):
    document_id: int
    document_name: str
    source_uri: str
    error: str | None = None


class KGIndexError(BaseModel):
    document_id: int
    document_name: str
    source_uri: str
    chunk_id: UUID
    error: str | None = None


class ChunkItem(BaseModel):
    id: UUID
    document_id: int
    hash: str
    text: str
    meta: Optional[dict | list]
    embedding: Optional[list[float]]
    relations: Optional[dict | list]
    source_uri: Optional[str]
    index_status: Optional[KgIndexStatus]
    index_result: Optional[str]
    created_at: Optional[datetime]
    updated_at: Optional[datetime]


class RetrievalRequest(BaseModel):
    query: str
    chat_engine: str = "default"
    top_k: Optional[int] = 5