"""Pydantic schemas for file storage operations"""
from pydantic import BaseModel, Field, field_validator, field_serializer, ConfigDict
from typing import Optional, List
from datetime import datetime
from enum import Enum


class FileType(str, Enum):
    """File type enumeration"""
    IMAGE = "image"
    DOCUMENT = "document"
    LOG = "log"


class FileUploadResponse(BaseModel):
    """Response after successful file upload"""
    file_id: str
    message_id: Optional[str] = None  # Associated chat message ID
    filename: str
    file_type: FileType
    file_size: int
    mime_type: str
    download_url: str  # Presigned URL
    thumbnail_url: Optional[str] = None  # Thumbnail URL for images
    uploaded_at: datetime
    uploader_id: str

    model_config = ConfigDict(from_attributes=True)

    @field_serializer("uploaded_at")
    def serialize_datetime(self, dt: datetime) -> str:
        """Serialize datetime with 'Z' suffix to indicate UTC"""
        return dt.isoformat() + "Z"


class FileMetadata(BaseModel):
    """File metadata response"""
    file_id: str
    message_id: Optional[str] = None  # Associated chat message ID
    room_id: str
    filename: str
    file_type: FileType
    mime_type: str
    file_size: int
    minio_bucket: str
    minio_object_path: str
    uploaded_at: datetime
    uploader_id: str
    deleted_at: Optional[datetime] = None
    download_url: Optional[str] = None  # Presigned URL (only when requested)
    thumbnail_url: Optional[str] = None  # Thumbnail URL for images

    model_config = ConfigDict(from_attributes=True)

    @field_validator("file_size")
    @classmethod
    def validate_file_size(cls, v):
        """Validate file size is positive"""
        if v <= 0:
            raise ValueError("File size must be positive")
        return v

    @field_serializer("uploaded_at", "deleted_at")
    def serialize_datetime(self, dt: Optional[datetime]) -> Optional[str]:
        """Serialize datetime with 'Z' suffix to indicate UTC"""
        if dt is None:
            return None
        return dt.isoformat() + "Z"


class FileListResponse(BaseModel):
    """Paginated file list response"""
    files: List[FileMetadata]
    total: int
    limit: int
    offset: int
    has_more: bool

    model_config = ConfigDict(from_attributes=True)


class FileUploadParams(BaseModel):
    """Parameters for file upload (optional description)"""
    description: Optional[str] = Field(None, max_length=500)

    model_config = ConfigDict(from_attributes=True)