import os
import shutil
import uuid
import datetime
from sqlalchemy.orm import Session
from typing import Optional
from fastapi import HTTPException, UploadFile
from app.models.non_conformity import NonConformity
from app.models.evidence import Evidence
from app.schemas.non_conformity import NonConformityUpdate

UPLOAD_DIR = "uploads"

class GuestService:
    def __init__(self, db: Session):
        self._db = db

    def get_nc_by_hash(self, access_hash: str) -> NonConformity:
        db_nc = self._db.query(NonConformity).filter(NonConformity.access_hash == access_hash).first()
        if not db_nc:
            raise HTTPException(status_code=404, detail="Non-Conformity not found or invalid link")
        return db_nc

    def update_guest_nc(self, access_hash: str, nc_update: NonConformityUpdate) -> NonConformity:
        db_nc = self.get_nc_by_hash(access_hash)
        
        if nc_update.guest_actions is not None:
            db_nc.guest_actions = nc_update.guest_actions
            
        if nc_update.closure_description is not None:
            db_nc.closure_description = nc_update.closure_description
            
        if nc_update.status is not None:
            db_nc.status = nc_update.status
            
        self._db.commit()
        self._db.refresh(db_nc)
        return db_nc

    def upload_guest_evidence(
        self,
        access_hash: str,
        file: UploadFile,
        description: Optional[str] = None
    ) -> Evidence:
        db_nc = self.get_nc_by_hash(access_hash)

        # Generate unique filename
        file_ext = os.path.splitext(file.filename)[1]
        unique_filename = f"guest_nc_{uuid.uuid4()}{file_ext}"
        file_path = os.path.join(UPLOAD_DIR, unique_filename)

        # Save file
        if not os.path.exists(UPLOAD_DIR):
            os.makedirs(UPLOAD_DIR)
            
        with open(file_path, "wb") as buffer:
            shutil.copyfileobj(file.file, buffer)

        # Save to database
        db_evidence = Evidence(
            non_conformity_id=db_nc.id,
            file_path=file_path,
            media_type=file.content_type,
            description=description,
            captured_at=datetime.datetime.utcnow()
        )
        self._db.add(db_evidence)
        self._db.commit()
        self._db.refresh(db_evidence)
        
        return db_evidence