from pydantic import BaseModel, Field
from typing import Optional
from datetime import datetime

class MigrationBase(BaseModel):
    version: str = Field(..., description="Migration version identifier", index=True)
    description: Optional[str] = Field(None, description="Migration description")
    applied: bool = Field(False, description="Whether the migration has been applied")
    script_path: str = Field(..., description="Path to the migration script file")
    checksum: Optional[str] = Field(None, description="Migration file checksum")
    execution_time: Optional[datetime] = Field(None, description="When the migration was executed")

class MigrationCreate(MigrationBase):
    class Config:
        schema_extra = {
            "example": {
                "version": "v1.0.0",
                "description": "Initial schema migration",
                "applied": False,
                "script_path": "/migrations/v1_0_0_initial.sql",
                "checksum": "a1b2c3d4e5f6",
                "execution_time": "2023-01-01T00:00:00"
            }
        }

class Migration(MigrationBase):
    class Config:
        orm_mode = True
        schema_extra = {
            "example": {
                "version": "v1.0.0",
                "description": "Initial schema migration",
                "applied": True,
                "script_path": "/migrations/v1_0_0_initial.sql",
                "checksum": "a1b2c3d4e5f6",
                "execution_time": "2023-01-01T00:00:00"
            }
        }