from sqlalchemy.orm import Session
from typing import List, Optional
from fastapi import HTTPException
from app.models.project import Project
from app.models.specialty import Specialty
from app.models.contractor import Contractor
from app.schemas.project import ProjectCreate

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

    def get_projects(self, skip: int = 0, limit: int = 100) -> List[Project]:
        return self._db.query(Project).offset(skip).limit(limit).all()

    def get_project(self, project_id: int) -> Project:
        db_project = self._db.query(Project).filter(Project.id == project_id).first()
        if db_project is None:
            raise HTTPException(status_code=404, detail="Project not found")
        return db_project

    def create_project(self, project: ProjectCreate) -> Project:
        db_project = self._db.query(Project).filter(Project.code == project.code).first()
        if db_project:
            raise HTTPException(status_code=400, detail="Project code already exists")
        
        project_data = project.model_dump(exclude={'specialty_ids', 'contractor_ids'})
        db_project = Project(**project_data)
        
        # Handle Parent Project
        if project.parent_id:
            parent = self.get_project(project.parent_id)
            if not parent:
                raise HTTPException(status_code=404, detail="Parent project not found")

        # Handle Specialties
        if project.specialty_ids:
            specialties = self._db.query(Specialty).filter(Specialty.id.in_(project.specialty_ids)).all()
            db_project.specialties = specialties
            
        # Handle Contractors
        if project.contractor_ids:
            contractors = self._db.query(Contractor).filter(Contractor.id.in_(project.contractor_ids)).all()
            db_project.contractors = contractors

        self._db.add(db_project)
        self._db.commit()
        self._db.refresh(db_project)
        return db_project

    def update_project(self, project_id: int, project: ProjectCreate) -> Project:
        db_project = self.get_project(project_id)
        
        # Update simple fields
        for key, value in project.model_dump(exclude={'specialty_ids', 'contractor_ids'}).items():
            setattr(db_project, key, value)
        
        # Handle Parent Project
        if project.parent_id is not None:
            if project.parent_id != 0:
                self.get_project(project.parent_id)
                db_project.parent_id = project.parent_id
            else:
                db_project.parent_id = None
        
        # Update Specialties
        if project.specialty_ids is not None:
            specialties = self._db.query(Specialty).filter(Specialty.id.in_(project.specialty_ids)).all()
            db_project.specialties = specialties
            
        # Update Contractors
        if project.contractor_ids is not None:
            contractors = self._db.query(Contractor).filter(Contractor.id.in_(project.contractor_ids)).all()
            db_project.contractors = contractors

        self._db.commit()
        self._db.refresh(db_project)
        return db_project

    def delete_project(self, project_id: int):
        db_project = self.get_project(project_id)
        self._db.delete(db_project)
        self._db.commit()
        return None