Add HTML5 authoring diff preview

services/api-server/src/api_server/html5.py

@@ -371,6 +371,25 @@ def render_html5_authoring_preview(project_id: str, preview: object | None, erro
             <button type="submit">Preview</button>
           </form>
           {render_html5_authoring_preview_result(project_id)}
+          <form
+            class="authoring-preview-form"
+            data-html5-authoring-diff-form
+            method="post"
+            action="/html5/projects/{quote(project_id)}/authoring/semantic-diff-preview"
+            hx-post="/html5/projects/{quote(project_id)}/authoring/semantic-diff-preview"
+            hx-target="[data-html5-authoring-diff-result]"
+            hx-swap="outerHTML"
+          >
+            <input name="routine_name" placeholder="routine_name" />
+            <input name="source_path" placeholder="source_path" />
+            <input name="task_id" placeholder="task_id" />
+            <input name="session_id" placeholder="session_id" />
+            <input name="user_id" placeholder="user_id" />
+            <textarea name="original_text" placeholder="Original BSL"></textarea>
+            <textarea name="proposed_text" placeholder="Proposed BSL"></textarea>
+            <button type="submit">Diff preview</button>
+          </form>
+          {render_html5_authoring_diff_result(project_id)}
         </div>
         """
     return render_html5_authoring_preview_result(project_id, preview, error)
@@ -411,6 +430,41 @@ def render_html5_authoring_preview_result(project_id: str, preview: object | Non
     """
 
 
+def render_html5_authoring_diff_result(project_id: str, preview: object | None = None, error: str | None = None) -> str:
+    if preview is None and error is None:
+        return '<div class="authoring-diff-result" data-html5-authoring-diff-result></div>'
+    if error:
+        return f"""
+        <div class="authoring-diff-result" data-html5-authoring-diff-result>
+          <div class="panel-title">Diff preview</div>
+          <p class="muted padded">{escape(error)}</p>
+        </div>
+        """
+    changed = bool(getattr(preview, "changed", False))
+    added = getattr(preview, "added_lines", 0)
+    removed = getattr(preview, "removed_lines", 0)
+    target = getattr(preview, "target", None)
+    target_name = getattr(target, "qualified_name", None) or getattr(target, "name", None) or "target unavailable"
+    checks = getattr(preview, "checks", []) or []
+    diff = getattr(preview, "semantic_diff", []) or []
+    version_preview = getattr(preview, "version_preview", None)
+    next_version_id = str(getattr(version_preview, "next_version_id", ""))
+    check_rows = "".join(_authoring_check_item(check) for check in checks[:8])
+    diff_rows = "".join(_authoring_diff_item(line) for line in diff[:12]) or '<p class="muted padded">Diff пустой</p>'
+    return f"""
+    <div class="authoring-diff-result" data-html5-authoring-diff-result data-html5-project-id="{escape(project_id)}">
+      <div class="panel-title">Diff preview · {'changed' if changed else 'unchanged'}</div>
+      <article class="authoring-change">
+        <strong>{escape(str(target_name))}</strong>
+        <span>+{escape(str(added))} / -{escape(str(removed))}</span>
+        <small>{escape(next_version_id or "version preview unavailable")}</small>
+      </article>
+      <div class="check-list">{check_rows}</div>
+      <div class="diff-list">{diff_rows}</div>
+    </div>
+    """
+
+
 def render_html5_authoring_change_detail(project_id: str, preview: object | None) -> str:
     if preview is None:
         return f"""

services/api-server/src/api_server/main.py

@@ -38,6 +38,7 @@ from pydantic import BaseModel, Field
 from api_server.html5 import (
     render_html5_authoring_changes,
     render_html5_authoring_change_detail,
+    render_html5_authoring_diff_result,
     render_html5_authoring_preview_result,
     render_html5_authoring_rollback_result,
     render_html5_editor,
@@ -1794,6 +1795,26 @@ async def html5_project_authoring_completion_preview(project_id: str, request: R
     return Response(html, media_type="text/html; charset=utf-8")
 
 
+@app.post("/html5/projects/{project_id}/authoring/semantic-diff-preview")
+async def html5_project_authoring_semantic_diff_preview(project_id: str, request: Request) -> Response:
+    form = await _html5_form_data(request)
+    payload = AuthoringSemanticDiffPreviewRequest(
+        routine_name=_form_value(form, "routine_name"),
+        source_path=_form_value(form, "source_path"),
+        original_text=_form_value(form, "original_text") or "",
+        proposed_text=_form_value(form, "proposed_text") or "",
+        task_id=_form_value(form, "task_id"),
+        session_id=_form_value(form, "session_id"),
+        user_id=_form_value(form, "user_id"),
+    )
+    try:
+        preview = _authoring_semantic_diff_preview(project_id, payload)
+        html = render_html5_authoring_diff_result(project_id, preview)
+    except HTTPException as error:
+        html = render_html5_authoring_diff_result(project_id, error=str(error.detail))
+    return Response(html, media_type="text/html; charset=utf-8")
+
+
 @app.get("/html5/projects/{project_id}/setup")
 async def html5_project_setup(project_id: str) -> Response:
     setup = _project_setup_response(project_id)

services/api-server/tests/test_api.py

@@ -115,6 +115,8 @@ def test_html5_server_rendered_project_editor(tmp_path: Path):
     assert "data-html5-authoring-preview" in editor.text
     assert "data-html5-authoring-preview-form" in editor.text
     assert f'hx-post="/html5/projects/{project_id}/authoring/completion-preview"' in editor.text
+    assert "data-html5-authoring-diff-form" in editor.text
+    assert f'hx-post="/html5/projects/{project_id}/authoring/semantic-diff-preview"' in editor.text
     assert "data-html5-authoring-changes" in editor.text
     assert f'hx-get="/html5/projects/{project_id}/authoring/changes"' in editor.text
     assert 'hx-get="/html5/projects/' in editor.text
@@ -2296,6 +2298,30 @@ def test_authoring_context_and_completion_preview(tmp_path: Path):
     assert "ADD" in html5_preview.text
     assert "<html" not in html5_preview.text
 
+    html5_diff_preview = client.post(
+        f"/html5/projects/{project_id}/authoring/semantic-diff-preview",
+        data={
+            "routine_name": "Проведение",
+            "source_path": str(module),
+            "original_text": source_text,
+            "proposed_text": source_text.replace(
+                "    Сумма = 0;",
+                "    Сумма = 0;\n    Если Отказ Тогда\n        Возврат;\n    КонецЕсли;",
+            ),
+            "task_id": "task.authoring",
+            "session_id": "session.authoring",
+            "user_id": "dev.ivan",
+        },
+    )
+    assert html5_diff_preview.status_code == 200
+    assert "text/html" in html5_diff_preview.headers["content-type"]
+    assert "data-html5-authoring-diff-result" in html5_diff_preview.text
+    assert "Diff preview" in html5_diff_preview.text
+    assert "Если Отказ Тогда" in html5_diff_preview.text
+    assert "task-session" in html5_diff_preview.text
+    assert "BLOCKED" in html5_diff_preview.text
+    assert "<html" not in html5_diff_preview.text
+
     diff_preview = client.post(
         f"/projects/{project_id}/authoring/semantic-diff-preview",
         json={