Fix cheat sheet editor and saved-sheet state issues

README.md

@@ -35,7 +35,7 @@ A full-stack web application for generating LaTeX-based cheat sheets. Users sele
 | Frontend | React 18 + Vite |
 | Backend | Django 6 + Django REST Framework |
 | LaTeX Engine | Tectonic |
-| Database | SQLite (dev) / MariaDB (prod) |
+| Database | SQLite (dev) / PostgreSQL (Docker/prod) |
 | Container | Docker Compose |
 
 ## Project Structure
@@ -141,7 +141,7 @@ The frontend will be available at `http://localhost:5173/`.
 docker compose up --build
 ```
 
-This builds and starts the Django backend, React frontend, and MariaDB database.
+This builds and starts the Django backend, React frontend, and PostgreSQL database.
 
 ## Running Tests
 

backend/api/models.py

@@ -31,6 +31,44 @@ class CheatSheet(models.Model):
 
     def __str__(self):
         return self.title
+
+    def _build_practice_problems_section(self):
+        problems = list(self.problems.all())
+        if not problems:
+            return ""
+
+        section_lines = ["\\section*{Practice Problems}"]
+        for problem in problems:
+            section_lines.append(
+                f"\\textbf{{Problem {problem.order}:}} {problem.question_latex}"
+            )
+            if problem.answer_latex:
+                section_lines.append(f"\\textbf{{Answer:}} {problem.answer_latex}")
+            section_lines.append("")
+
+        return "\n".join(section_lines).rstrip()
+
+    def _inject_practice_problems_into_document(self, content):
+        practice_problems = self._build_practice_problems_section()
+        if not practice_problems:
+            return content
+
+        end_document = r"\end{document}"
+        end_multicols = r"\end{multicols}"
+
+        insert_before = end_document
+        if end_multicols in content and content.rfind(end_multicols) < content.rfind(end_document):
+            insert_before = end_multicols
+
+        insert_index = content.rfind(insert_before)
+        if insert_index == -1:
+            return content
+
+        return (
+            f"{content[:insert_index].rstrip()}\n\n"
+            f"{practice_problems}\n"
+            f"{content[insert_index:]}"
+        )
 
     def build_full_latex(self):
         """
@@ -40,21 +78,22 @@ def build_full_latex(self):
         """
         content = self.latex_content or ""
 
-        # If it's already a complete document, return as-is
-        if r"\begin{document}" in content:
-            return content
+        # If it's already a complete document, keep its layout and inject problems if needed
+        if r"\begin{document}" in content and r"\end{document}" in content:
+            return self._inject_practice_problems_into_document(content)
 
         # Build document header
+        document_class = "extarticle" if self.font_size in {"8pt", "9pt"} else "article"
         header = [
-            "\\documentclass{article}",
+            f"\\documentclass{{{document_class}}}",
             "\\usepackage[utf8]{inputenc}",
             "\\usepackage{amsmath, amssymb}",
             f"\\usepackage[a4paper, margin={self.margins}]{{geometry}}",
         ]
 
         # Add font size if specified
         if self.font_size and self.font_size != "10pt":
-            header[0] = f"\\documentclass[{self.font_size}]{{article}}"
+            header[0] = f"\\documentclass[{self.font_size}]{{{document_class}}}"
 
         # Add multicolumn support if needed
         if self.columns > 1:
@@ -75,15 +114,9 @@ def build_full_latex(self):
         # Add main content
         document_parts.append(content)
 
-        # Add practice problems if they exist
-        problems = self.problems.all()
-        if problems:
-            document_parts.append("\\section*{Practice Problems}")
-            for problem in problems:
-                document_parts.append(f"\\textbf{{Problem {problem.order}:}} {problem.question_latex}")
-                if problem.answer_latex:
-                    document_parts.append(f"\\textbf{{Answer:}} {problem.answer_latex}")
-                document_parts.append("")  # Add spacing
+        practice_problems = self._build_practice_problems_section()
+        if practice_problems:
+            document_parts.append(practice_problems)
 
         # Close multicolumn environment if needed
         if self.columns > 1:

backend/api/tests.py

@@ -95,6 +95,50 @@ def test_build_full_latex_passthrough(self):
         )
         assert sheet.build_full_latex() == raw
 
+    def test_build_full_latex_passthrough_inserts_problems_before_document_end(self):
+        raw = "\\documentclass{article}\n\\begin{document}\nCustom\n\\end{document}"
+        sheet = CheatSheet.objects.create(
+            title="Raw With Problems",
+            latex_content=raw,
+        )
+        PracticeProblem.objects.create(
+            cheat_sheet=sheet,
+            question_latex="Show that $x^2 \\ge 0$.",
+            answer_latex="Because squares are nonnegative.",
+            order=1,
+        )
+
+        full = sheet.build_full_latex()
+
+        assert "Practice Problems" in full
+        assert "Show that $x^2 \\ge 0$." in full
+        assert full.index("Practice Problems") < full.index("\\end{document}")
+
+    def test_build_full_latex_passthrough_inserts_problems_before_end_multicols(self):
+        raw = (
+            "\\documentclass{article}\n"
+            "\\usepackage{multicol}\n"
+            "\\begin{document}\n"
+            "\\begin{multicols}{2}\n"
+            "Custom\n"
+            "\\end{multicols}\n"
+            "\\end{document}"
+        )
+        sheet = CheatSheet.objects.create(
+            title="Raw Multi",
+            latex_content=raw,
+        )
+        PracticeProblem.objects.create(
+            cheat_sheet=sheet,
+            question_latex="Integrate $x$.",
+            answer_latex="$x^2 / 2 + C$",
+            order=1,
+        )
+
+        full = sheet.build_full_latex()
+
+        assert full.index("Practice Problems") < full.index("\\end{multicols}")
+
     def test_build_full_latex_with_problems(self):
         sheet = CheatSheet.objects.create(
             title="With Problems",
@@ -111,6 +155,17 @@ def test_build_full_latex_with_problems(self):
         assert "What is $1+1$?" in full
         assert "$2$" in full
 
+    def test_build_full_latex_8pt_uses_extarticle(self):
+        sheet = CheatSheet.objects.create(
+            title="Small Font",
+            latex_content="Content",
+            font_size="8pt",
+        )
+
+        full = sheet.build_full_latex()
+
+        assert "\\documentclass[8pt]{extarticle}" in full
+
 
 # ── API Tests ────────────────────────────────────────────────────────
 

backend/requirements.txt

@@ -6,7 +6,7 @@ dj-database-url>=2.1
 psycopg2-binary>=2.9
 
 # Testing
-pytest>=8.0
+pytest>=9.0.3
 pytest-django>=4.8
 
 # Development (linting, security)

frontend/eslint.config.js

@@ -3,6 +3,9 @@ import reactPlugin from 'eslint-plugin-react';
 import reactHooksPlugin from 'eslint-plugin-react-hooks';
 
 export default [
+  {
+    ignores: ['dist/**', 'node_modules/**'],
+  },
   js.configs.recommended,
   {
     files: ['**/*.{js,jsx}'],
@@ -41,5 +44,13 @@ export default [
         version: 'detect'
       }
     }
+  },
+  {
+    files: ['vite.config.js'],
+    languageOptions: {
+      globals: {
+        process: 'readonly'
+      }
+    }
   }
 ];

frontend/package.json

@@ -26,6 +26,9 @@
     "eslint": "^9.0.0",
     "eslint-plugin-react": "^7.34.0",
     "eslint-plugin-react-hooks": "^5.0.0",
-    "vite": "^6.0.0"
+    "vite": "^6.4.2"
+  },
+  "overrides": {
+    "picomatch": "^4.0.4"
   }
 }