Add Python backend for SVG rendering, connect frontend to backend, and UI/usability improvements

backend/app.py

@@ -0,0 +1,63 @@
+from __future__ import annotations
+
+import io
+from typing import Any
+
+from flask import Flask, jsonify, request
+from openpyxl import load_workbook
+
+app = Flask(__name__)
+
+
+def _extract_columns_from_xlsx(file_bytes: bytes, sheet_index: int) -> list[str]:
+    workbook = load_workbook(io.BytesIO(file_bytes), read_only=True, data_only=True)
+    sheets = workbook.worksheets
+    if not sheets:
+        return []
+    index = min(max(sheet_index, 0), len(sheets) - 1)
+    first_row = next(sheets[index].iter_rows(min_row=1, max_row=1, values_only=True), ())
+    return [str(cell).strip() for cell in first_row if isinstance(cell, str) and cell.strip()]
+
+
+@app.post('/api/render-plot')
+def render_plot() -> Any:
+    payload = request.get_json(silent=True) or {}
+    config = payload.get('config')
+    if not isinstance(config, dict):
+        return jsonify({'message': 'Missing config payload.'}), 400
+
+    svg = """<svg xmlns='http://www.w3.org/2000/svg' width='1200' height='675' viewBox='0 0 1200 675'>
+  <rect x='0' y='0' width='1200' height='675' fill='#f8fafc' />
+  <text x='40' y='64' font-size='32' font-family='Arial, sans-serif' fill='#111827'>Backend SVG placeholder</text>
+  <text x='40' y='104' font-size='18' font-family='Arial, sans-serif' fill='#334155'>Implement plotting logic inside backend/app.py render_plot().</text>
+  <text x='40' y='138' font-size='15' font-family='monospace' fill='#475569'>Received config keys: %s</text>
+</svg>""" % ', '.join(sorted(config.keys()))
+
+    return jsonify({'svg': svg})
+
+
+@app.post('/api/import-database')
+def import_database() -> Any:
+    if request.is_json:
+        payload = request.get_json(silent=True) or {}
+        teable_url = payload.get('teable_url')
+        api_key = payload.get('API_Key')
+        if not teable_url or not api_key:
+            return jsonify({'success': False, 'message': 'Missing teable_url or API_Key.'}), 400
+        return jsonify({'success': True, 'columns': []})
+
+    upload = request.files.get('file')
+    if upload is None:
+        return jsonify({'success': False, 'message': 'Missing uploaded file.'}), 400
+
+    try:
+        sheet_index = int(request.form.get('import_sheet', '0'))
+    except ValueError:
+        sheet_index = 0
+
+    columns = _extract_columns_from_xlsx(upload.read(), sheet_index)
+    return jsonify({'success': True, 'columns': columns})
+
+
+if __name__ == '__main__':
+    app.run(host='0.0.0.0', port=8000, debug=True)

backend/requirements.txt

@@ -0,0 +1,2 @@
+flask==3.1.1
+openpyxl==3.1.5

package.json

@@ -7,7 +7,8 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "backend": "python3 backend/app.py"
   },
   "dependencies": {
     "plotly.js-dist-min": "^3.5.0",