from django.utils import timezone
from django.contrib.contenttypes.models import ContentType
from .models import Document, DocumentVersion, DocumentLink

def create_document_and_link(*, tenant, patient, encounter=None, doc_type:str, title:str,
                             body_markdown:str="", body_json=None, links=None, author=None, sign=False):
    doc = Document.objects.create(
        tenant=tenant, patient=patient, encounter=encounter,
        doc_type=doc_type, title=title, body_markdown=body_markdown, body_json=body_json or {},
        authored_by=author, status="final" if sign else "draft",
        signed_at=timezone.now() if sign else None, signed_by=author if sign else None
    )
    DocumentVersion.objects.create(
        document=doc, version=1, snapshot_markdown=body_markdown, snapshot_json=body_json or {}, changed_by=author
    )
    for ln in links or []:
        ct = ContentType.objects.get(app_label=ln["app_label"], model=ln["model"].lower())
        DocumentLink.objects.create(document=doc, content_type=ct, object_id=str(ln["pk"]), role=ln.get("role","context"))
    return doc

def sign_document(doc: Document, user):
    doc.status = "final"; doc.signed_at = timezone.now(); doc.signed_by = user
    doc.save(update_fields=["status","signed_at","signed_by"])
    return doc

def amend_document(doc: Document, user, *, new_markdown:str="", new_json=None):
    next_version = (doc.versions.first().version + 1) if doc.versions.exists() else 2
    DocumentVersion.objects.create(
        document=doc, version=next_version, snapshot_markdown=new_markdown, snapshot_json=new_json or {}, changed_by=user
    )
    doc.body_markdown, doc.body_json, doc.is_amendment = new_markdown, (new_json or {}), True
    doc.save(update_fields=["body_markdown","body_json","updated_at","is_amendment"])
    return doc