from django.db import transaction
from django.shortcuts import get_object_or_404
from rest_framework.exceptions import ValidationError, PermissionDenied

from apps.clients.models import Client
from apps.projects.models import Project, ProjectMembership
from apps.workspaces.models import WorkspaceMembership


@transaction.atomic
def create_project(user, workspace, name, client=None, description="", color=""):
    """
    Creates a new project and automatically assigns the creator 
    as an active MANAGER of that project.
    """
    workspace_member = WorkspaceMembership.objects.filter(
        workspace=workspace,
        user=user,
        is_active=True,
        is_deleted=False
    ).first()
    
    if not workspace_member:
        raise PermissionDenied("You do not have access to this workspace.")

    if Project.objects.filter(workspace=workspace, name=name, is_deleted=False).exists():
        raise ValidationError({"name": "A project with this name already exists in the workspace."})

    project = Project.objects.create(
        workspace=workspace,
        name=name,
        client=client,
        description=description,
        color=color,
        created_by=user,
        updated_by=user,
    )

    ProjectMembership.objects.create(
        project=project,
        user=user,
        role=ProjectMembership.Role.MANAGER,
        is_active=True
    )

    return project


def update_project(project, **kwargs):
    """
    Updates specific fields of an existing project.
    """
    update_fields = []
    
    # Optional manual uniqueness check if name is being updated
    if "name" in kwargs and kwargs["name"] != project.name:
        if Project.objects.filter(workspace=project.workspace, name=kwargs["name"], is_deleted=False).exists():
            raise ValidationError({"name": "A project with this name already exists in the workspace."})

    client_id = kwargs.pop("client")
    client = get_object_or_404(Client, id=client_id, is_deleted=False) if client_id else None
    kwargs["client"] = client

    for field, value in kwargs.items():
        if hasattr(project, field) and getattr(project, field) != value:
            setattr(project, field, value)
            update_fields.append(field)
            
    if update_fields:
        update_fields.append("updated_at")
        project.save(update_fields=update_fields)
        
    return project


def toggle_project_archive(project) -> Project:
    """
    Archives or unarchives a project.
    """
    project.is_archived = not project.is_archived
    project.save(update_fields=["is_archived", "updated_at"])
    return project