changes

app/services/template_service.py

@@ -0,0 +1,147 @@
+"""
+Template service helpers extracted from API layer for document template and version operations.
+
+These functions centralize database lookups, validation, storage interactions, and
+preview/download resolution so that API endpoints remain thin.
+"""
+from __future__ import annotations
+
+from typing import Optional, List, Tuple, Dict, Any
+import os
+import hashlib
+
+from fastapi import HTTPException, status
+from sqlalchemy.orm import Session
+
+from app.models.templates import DocumentTemplate, DocumentTemplateVersion, TemplateKeyword
+from app.services.storage import get_default_storage
+from app.services.template_merge import extract_tokens_from_bytes, build_context, resolve_tokens, render_docx
+
+
+def get_template_or_404(db: Session, template_id: int) -> DocumentTemplate:
+    tpl = db.query(DocumentTemplate).filter(DocumentTemplate.id == template_id).first()
+    if not tpl:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Template not found")
+    return tpl
+
+
+def list_template_versions(db: Session, template_id: int) -> List[DocumentTemplateVersion]:
+    _ = get_template_or_404(db, template_id)
+    return (
+        db.query(DocumentTemplateVersion)
+        .filter(DocumentTemplateVersion.template_id == template_id)
+        .order_by(DocumentTemplateVersion.created_at.desc())
+        .all()
+    )
+
+
+def add_template_version(
+    db: Session,
+    *,
+    template_id: int,
+    semantic_version: str,
+    changelog: Optional[str],
+    approve: bool,
+    content: bytes,
+    filename_hint: str,
+    content_type: Optional[str],
+    created_by: Optional[str],
+) -> DocumentTemplateVersion:
+    tpl = get_template_or_404(db, template_id)
+    if not content:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="No file uploaded")
+
+    sha256 = hashlib.sha256(content).hexdigest()
+    storage = get_default_storage()
+    storage_path = storage.save_bytes(content=content, filename_hint=filename_hint or "template.bin", subdir="templates")
+
+    version = DocumentTemplateVersion(
+        template_id=template_id,
+        semantic_version=semantic_version,
+        storage_path=storage_path,
+        mime_type=content_type,
+        size=len(content),
+        checksum=sha256,
+        changelog=changelog,
+        created_by=created_by,
+        is_approved=bool(approve),
+    )
+    db.add(version)
+    db.flush()
+    if approve:
+        tpl.current_version_id = version.id
+    db.commit()
+    return version
+
+
+def resolve_template_preview(
+    db: Session,
+    *,
+    template_id: int,
+    version_id: Optional[int],
+    context: Dict[str, Any],
+) -> Tuple[Dict[str, Any], List[str], bytes, str]:
+    tpl = get_template_or_404(db, template_id)
+    resolved_version_id = version_id or tpl.current_version_id
+    if not resolved_version_id:
+        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Template has no versions")
+
+    ver = (
+        db.query(DocumentTemplateVersion)
+        .filter(DocumentTemplateVersion.id == resolved_version_id)
+        .first()
+    )
+    if not ver:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Version not found")
+
+    storage = get_default_storage()
+    content = storage.open_bytes(ver.storage_path)
+    tokens = extract_tokens_from_bytes(content)
+    built_context = build_context(context or {}, "template", str(template_id))
+    resolved, unresolved = resolve_tokens(db, tokens, built_context)
+
+    output_bytes = content
+    output_mime = ver.mime_type
+    if ver.mime_type == "application/vnd.openxmlformats-officedocument.wordprocessingml.document":
+        output_bytes = render_docx(content, resolved)
+        output_mime = ver.mime_type
+
+    return resolved, unresolved, output_bytes, output_mime
+
+
+def get_download_payload(
+    db: Session,
+    *,
+    template_id: int,
+    version_id: Optional[int],
+) -> Tuple[bytes, str, str]:
+    tpl = get_template_or_404(db, template_id)
+    resolved_version_id = version_id or tpl.current_version_id
+    if not resolved_version_id:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Template has no approved version")
+
+    ver = (
+        db.query(DocumentTemplateVersion)
+        .filter(
+            DocumentTemplateVersion.id == resolved_version_id,
+            DocumentTemplateVersion.template_id == tpl.id,
+        )
+        .first()
+    )
+    if not ver:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Version not found")
+
+    storage = get_default_storage()
+    try:
+        content = storage.open_bytes(ver.storage_path)
+    except Exception:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Stored file not found")
+
+    base = os.path.basename(ver.storage_path)
+    if "_" in base:
+        original_name = base.split("_", 1)[1]
+    else:
+        original_name = base
+    return content, ver.mime_type, original_name
+
+