from typing import Dict, Any, List, Optional, Literal
from enum import Enum
from datetime import datetime
from pydantic import BaseModel, Field, field_validator
import uuid


class EntityType(str, Enum):
    USER = "user"
    DEVELOPER = "developer"


class QueryReturnType(str, Enum):
    CHUNKS = "chunks"
    DOCUMENTS = "documents"


class Document(BaseModel):
    """Represents a document stored in MongoDB documents collection"""
    external_id: str = Field(default_factory=lambda: str(uuid.uuid4()))
    content_type: str
    filename: Optional[str] = None
    metadata: Dict[str, Any] = Field(default_factory=dict)
    storage_info: Dict[str, str] = Field(default_factory=dict)  # s3_bucket, s3_key
    system_metadata: Dict[str, Any] = Field(
        default_factory=lambda: {
            "created_at": datetime.utcnow(),
            "updated_at": datetime.utcnow(),
            "version": 1
        }
    )
    access_control: Dict[str, Any] = Field(
        default_factory=lambda: {
            "owner": None,
            "readers": set(),
            "writers": set(),
            "admins": set()
        }
    )
    chunk_ids: List[str] = Field(default_factory=list)


class DocumentChunk(BaseModel):
    """Represents a chunk stored in VectorStore"""
    document_id: str  # external_id of parent document
    # TODO: This might be suboptimal due to storage size. consider moving to separate store. 
    content: str
    embedding: List[float]
    chunk_number: int
    version: int = 1


class ChunkResult(BaseModel):
    """Query result at chunk level"""
    content: str
    score: float
    document_id: str  # external_id
    chunk_number: int
    metadata: Dict[str, Any]
    content_type: str
    filename: Optional[str] = None
    download_url: Optional[str] = None


class DocumentContent(BaseModel):
    """Represents either a URL or content string"""
    type: Literal["url", "string"] 
    value: str
    filename: Optional[str] = Field(None, description="Filename when type is url")

    @field_validator('filename')
    def filename_only_for_url(cls, v, values):
        if values.get('type') == 'string' and v is not None:
            raise ValueError('filename can only be set when type is url')
        if values.get('type') == 'url' and v is None:
            raise ValueError('filename is required when type is url')
        return v


class DocumentResult(BaseModel):
    """Query result at document level"""
    score: float        # Highest chunk score
    document_id: str    # external_id
    metadata: Dict[str, Any]
    content: DocumentContent