app/projects/services/approval_service.py

from __future__ import annotations
from app.projects.repositories.approval_repository import ApprovalRepository
from app.projects.repositories.editor_repository import ProjectEditorRepository
from app.projects.models.collaboration import ApprovalWorkflow, ApprovalRequest, ReviewComment

class ApprovalService:
    def __init__(self, repository: ApprovalRepository, editor_repository: ProjectEditorRepository) -> None:
        self.repository = repository
        self.editor_repository = editor_repository

    async def create_workflow(self, workspace_id: str, project_id: str, name: str) -> ApprovalWorkflow:
        return await self.repository.create_workflow(workspace_id, project_id, name)

    async def create_request(self, workspace_id: str, workflow_id: str, project_id: str, user_id: str) -> ApprovalRequest:
        state = await self.editor_repository.get_state(workspace_id, project_id)
        return await self.repository.create_request(workspace_id, workflow_id, project_id, user_id, state.revision)

    async def approve_request(self, request_id: str, actor_user_id: str) -> ApprovalRequest:
        request = await self.repository.get_request(request_id)
        if request.created_by == actor_user_id:
             raise Exception("Separation of duties: Cannot approve your own submission.")
        
        # Verify revision hasn't changed
        state = await self.editor_repository.get_state(request.workspace_id, request.project_id)
        if state.revision != request.editor_revision:
            raise Exception("Content has changed since request; approval is stale.")

        return await self.repository.update_request_status(request_id, "approved")

    async def reject_request(self, request_id: str, actor_user_id: str) -> ApprovalRequest:
        return await self.repository.update_request_status(request_id, "rejected")

    async def add_comment(self, request_id: str, user_id: str, workspace_id: str, content: str) -> ReviewComment:
        return await self.repository.add_review_comment(request_id, user_id, workspace_id, content)

    async def list_requests(self, workflow_id: str) -> list[ApprovalRequest]:
        return await self.repository.list_requests(workflow_id)