Create app.py

app.py

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+"""
+Python Code Evaluator — SE-Group1
+COS60011 Technology Design Project
+"""
+
+# ---------------------------------------------------------------------------
+# IMPORTS (all at top)
+# ---------------------------------------------------------------------------
+import os
+import re
+import ast
+import time
+from collections import deque
+from dotenv import load_dotenv
+import gradio as gr
+from google import genai
+
+load_dotenv()
+
+
+# ---------------------------------------------------------------------------
+# MODULE 3 — Pre-processing Module
+# ---------------------------------------------------------------------------
+def build_prompt(description: str, code: str) -> str:
+    prompt = f"""<start_of_turn>user
+### ROLE
+You are an expert Python code reviewer. Your sole task is to determine whether the
+provided Python code correctly implements the behaviour described in the user's
+requirements description.
+### CONTEXT
+Developers sometimes write code that does not fully satisfy the requirements they
+were given. You will analyse the semantic relationship between a natural-language
+description and a Python code snippet, then produce a structured evaluation report.
+### INPUT DATA
+**Requirements Description:**
+{description.strip()}
+**Python Code:**
+```python
+{code.strip()}
+```
+### TASK
+1. Read the requirements description carefully.
+2. Analyse the Python code line by line.
+3. Determine whether the code fulfils ALL requirements stated in the description.
+4. Estimate an accuracy percentage (0–100) reflecting how completely the code
+   matches the description.
+5. List any specific requirements that are missing or incorrectly implemented.
+### CONSTRAINTS
+- Do NOT execute the code.
+- Base your evaluation solely on static code analysis and logical reasoning.
+- Keep feedback concise, clear, and actionable.
+- Your response MUST follow the output format exactly.
+### OUTPUT FORMAT
+Respond only with the following structure — no extra text before or after:
+RESULT: <PASS or FAIL>
+ACCURACY: <integer 0-100>%
+SUMMARY: <one sentence overall assessment>
+ISSUES:
+- <issue 1, or "None" if code fully matches the description>
+- <issue 2>
+...
+<end_of_turn>
+<start_of_turn>model
+"""
+    return prompt
+
+
+# ---------------------------------------------------------------------------
+# MODULE 4 — Generation Module
+# ---------------------------------------------------------------------------
+MODEL_ID       = "gemma-4-31b-it"
+GOOGLE_API_KEY = os.environ.get("GOOGLE_API_KEY")
+
+def generate_response(prompt: str) -> str:
+    if not GOOGLE_API_KEY:
+        return (
+            "⚠️ Error: API Key not found! "
+            "Please configure GOOGLE_API_KEY in Settings → Variables and secrets."
+        )
+    try:
+        client   = genai.Client(api_key=GOOGLE_API_KEY)
+        response = client.models.generate_content(model=MODEL_ID, contents=prompt)
+        return response.text
+    except Exception as e:
+        return f"❌ An error occurred during generation: {str(e)}"
+
+
+# ---------------------------------------------------------------------------
+# MODULE 5 — Output Module
+# ---------------------------------------------------------------------------
+def parse_output(raw: str) -> dict:
+    if "<start_of_turn>model" in raw:
+        raw = raw.split("<start_of_turn>model")[-1]
+
+    result_match   = re.search(r"RESULT:\s*(PASS|FAIL)", raw, re.IGNORECASE)
+    accuracy_match = re.search(r"ACCURACY:\s*(\d{1,3})%?", raw, re.IGNORECASE)
+    summary_match  = re.search(r"SUMMARY:\s*(.+)", raw, re.IGNORECASE)
+    issues_match   = re.search(r"ISSUES:\s*([\s\S]+)", raw, re.IGNORECASE)
+
+    result   = result_match.group(1).upper()  if result_match   else "UNKNOWN"
+    accuracy = int(accuracy_match.group(1))   if accuracy_match else -1
+    summary  = summary_match.group(1).strip() if summary_match  else "Could not extract summary."
+
+    if issues_match:
+        raw_issues = issues_match.group(1).strip()
+        issues = [
+            line.lstrip("-•* ").strip()
+            for line in raw_issues.splitlines()
+            if line.strip() and line.strip() not in ("-", "•")
+        ]
+    else:
+        issues = ["Could not extract issues from model response."]
+
+    return {
+        "result":   result,
+        "accuracy": accuracy,
+        "summary":  summary,
+        "issues":   issues,
+        "raw":      raw.strip(),
+    }
+
+
+def format_for_display(parsed: dict) -> tuple[str, str, str]:
+    emoji   = "✅" if parsed["result"] == "PASS" else ("❌" if parsed["result"] == "FAIL" else "⚠️")
+    verdict = f"{emoji}  {parsed['result']}"
+    acc_str = f"{parsed['accuracy']}%" if parsed["accuracy"] >= 0 else "N/A"
+    metrics = f"Accuracy: {acc_str}\n\nSummary: {parsed['summary']}"
+    issues_text = "\n".join(f"• {issue}" for issue in parsed["issues"])
+    return verdict, metrics, issues_text
+
+
+# ---------------------------------------------------------------------------
+# MODULE 2 — Validation & Flow Management Module
+# ---------------------------------------------------------------------------
+MIN_DESCRIPTION_CHARS = 20
+MAX_DESCRIPTION_CHARS = 3000
+MIN_CODE_CHARS        = 10
+MAX_CODE_CHARS        = 8000
+MAX_CODE_LINES        = 300
+
+FORBIDDEN_PATTERNS = [
+    r"ignore (all |previous |above )?instructions",
+    r"disregard (all |previous |above )?instructions",
+    r"you are now",
+    r"act as (a |an )?",
+    r"<\s*(script|iframe|object|embed)",
+    r"system\s*prompt",
+    r"jailbreak",
+]
+
+PYTHON_KEYWORDS = {
+    "def", "class", "import", "from", "return", "if", "else", "elif",
+    "for", "while", "try", "except", "with", "lambda", "yield", "pass",
+    "raise", "assert", "in", "not", "and", "or", "True", "False", "None",
+    "print", "len", "range", "self",
+}
+
+class RateLimiter:
+    def __init__(self, max_calls: int = 5, window_seconds: int = 60):
+        self.max_calls      = max_calls
+        self.window_seconds = window_seconds
+        self._timestamps: deque = deque()
+
+    def is_allowed(self) -> tuple[bool, str]:
+        now = time.time()
+        while self._timestamps and now - self._timestamps[0] > self.window_seconds:
+            self._timestamps.popleft()
+        if len(self._timestamps) >= self.max_calls:
+            wait = int(self.window_seconds - (now - self._timestamps[0])) + 1
+            return False, (
+                f"⏳ Rate limit reached — {self.max_calls} requests in "
+                f"{self.window_seconds}s. Please wait ~{wait}s and try again."
+            )
+        self._timestamps.append(now)
+        return True, ""
+
+_rate_limiter = RateLimiter(max_calls=5, window_seconds=60)
+
+def _check_forbidden(text: str) -> str | None:
+    lower = text.lower()
+    for pattern in FORBIDDEN_PATTERNS:
+        if re.search(pattern, lower):
+            return (
+                "Input contains disallowed content. "
+                "Please remove prompt-injection or HTML patterns and try again."
+            )
+    return None
+
+def _looks_like_python(code: str) -> tuple[bool, str]:
+    tokens = set(re.findall(r"[A-Za-z_]\w*", code))
+    if not tokens.intersection(PYTHON_KEYWORDS):
+        return False, (
+            "🐍 The code doesn't appear to be Python — no recognisable Python "
+            "keywords found (e.g. def, class, import, return). "
+            "Please submit Python code only."
+        )
+    try:
+        ast.parse(code)
+    except SyntaxError as exc:
+        line_hint = f" (line {exc.lineno})" if exc.lineno else ""
+        return False, (
+            f"🐍 Python syntax error{line_hint}: {exc.msg}. "
+            "Please fix the syntax error before evaluating."
+        )
+    return True, ""
+
+def validate_inputs(description: str, code: str) -> list[str]:
+    errors: list[str] = []
+
+    if not description or not description.strip():
+        errors.append("📋 Requirements description is required.")
+    if not code or not code.strip():
+        errors.append("🐍 Python code is required.")
+    if errors:
+        return errors
+
+    desc, code_ = description.strip(), code.strip()
+
+    if len(desc) < MIN_DESCRIPTION_CHARS:
+        errors.append(f"📋 Description too short ({len(desc)} chars) — minimum is {MIN_DESCRIPTION_CHARS} characters.")
+    if len(code_) < MIN_CODE_CHARS:
+        errors.append(f"🐍 Code too short ({len(code_)} chars) — minimum is {MIN_CODE_CHARS} characters.")
+    if len(desc) > MAX_DESCRIPTION_CHARS:
+        errors.append(f"📋 Description too long ({len(desc):,} chars) — max is {MAX_DESCRIPTION_CHARS:,} characters.")
+    if len(code_) > MAX_CODE_CHARS:
+        errors.append(f"🐍 Code too long ({len(code_):,} chars) — max is {MAX_CODE_CHARS:,} characters.")
+    if len(code_.splitlines()) > MAX_CODE_LINES:
+        errors.append(f"🐍 Code has too many lines ({len(code_.splitlines())}) — max is {MAX_CODE_LINES} lines.")
+
+    if err := _check_forbidden(desc):
+        errors.append(f"📋 {err}")
+    if err := _check_forbidden(code_):
+        errors.append(f"🐍 {err}")
+
+    if not errors:
+        is_python, py_error = _looks_like_python(code_)
+        if not is_python:
+            errors.append(py_error)
+
+    if not errors:
+        allowed, rate_msg = _rate_limiter.is_allowed()
+        if not allowed:
+            errors.append(rate_msg)
+
+    return errors
+
+def validate_and_evaluate(description: str, code: str):
+    errors = validate_inputs(description, code)
+    if errors:
+        return "", "", "", "\n".join(f"{i+1}. {e}" for i, e in enumerate(errors))
+
+    if not GOOGLE_API_KEY:
+        return "", "", "", "❌ GOOGLE_API_KEY secret not set in Space Settings."
+
+    prompt = build_prompt(description, code)
+    try:
+        raw_output = generate_response(prompt)
+    except Exception as exc:
+        return "", "", "", f"❌ Model error: {exc}"
+
+    parsed = parse_output(raw_output)
+    verdict, metrics, issues = format_for_display(parsed)
+    return verdict, metrics, issues, ""
+
+
+# ---------------------------------------------------------------------------
+# MODULE 1 — UI Module
+# ---------------------------------------------------------------------------
+CUSTOM_CSS = """
+@import url('https://fonts.googleapis.com/css2?family=Space+Mono:wght@400;700&family=DM+Sans:ital,wght@0,300;0,400;0,500;0,600;1,400&display=swap');
+*, *::before, *::after { box-sizing: border-box; }
+body, .gradio-container {
+    font-family: 'DM Sans', sans-serif !important;
+    background: #0D0F14 !important;
+    color: #E8EAF0 !important;
+}
+.gradio-container {
+    max-width: 1140px !important;
+    margin: 0 auto !important;
+    padding: 32px 24px !important;
+}
+.eval-header {
+    display: flex;
+    align-items: center;
+    gap: 16px;
+    padding: 0 0 28px;
+    border-bottom: 1px solid #2E3140;
+    margin-bottom: 28px;
+}
+.eval-header .logo {
+    width: 44px; height: 44px;
+    border-radius: 10px;
+    background: linear-gradient(135deg, #534AB7 0%, #1D9E75 100%);
+    display: flex; align-items: center; justify-content: center;
+    flex-shrink: 0;
+    font-size: 22px; line-height: 1;
+}
+.eval-header h1 {
+    font-size: 20px !important;
+    font-weight: 600 !important;
+    letter-spacing: -0.3px !important;
+    color: #E8EAF0 !important;
+    margin: 0 !important;
+}
+.eval-header .model-badge {
+    margin-left: auto;
+    font-family: 'Space Mono', monospace;
+    font-size: 10px;
+    background: #1E2028;
+    border: 1px solid #3A3E52;
+    color: #6A6E80;
+    padding: 4px 10px;
+    border-radius: 4px;
+    letter-spacing: 1.5px;
+    white-space: nowrap;
+}
+.gradio-textbox textarea,
+.gradio-code textarea,
+.gradio-textbox input {
+    background: #161820 !important;
+    border: 1px solid #2E3140 !important;
+    border-radius: 10px !important;
+    color: #E8EAF0 !important;
+    font-family: 'DM Sans', sans-serif !important;
+    font-size: 13.5px !important;
+    line-height: 1.7 !important;
+    padding: 14px 16px !important;
+    transition: border-color 0.15s !important;
+    resize: vertical !important;
+}
+.gradio-textbox textarea:focus,
+.gradio-code textarea:focus {
+    border-color: #534AB7 !important;
+    outline: none !important;
+    box-shadow: 0 0 0 3px rgba(83, 74, 183, 0.15) !important;
+}
+.gradio-textbox textarea::placeholder {
+    color: #4A4E60 !important;
+}
+#code-input textarea {
+    font-family: 'Space Mono', monospace !important;
+    font-size: 12.5px !important;
+    line-height: 1.65 !important;
+}
+.gradio-textbox label span,
+.gradio-code label span {
+    font-family: 'DM Sans', sans-serif !important;
+    font-size: 13px !important;
+    font-weight: 700 !important;
+    color: #E8EAF0 !important;
+    text-transform: uppercase !important;
+    letter-spacing: 0.8px !important;
+}
+#eval-btn {
+    background: #534AB7 !important;
+    border: none !important;
+    color: #fff !important;
+    font-family: 'DM Sans', sans-serif !important;
+    font-size: 14px !important;
+    font-weight: 500 !important;
+    padding: 12px 32px !important;
+    border-radius: 8px !important;
+    cursor: pointer !important;
+    transition: background 0.15s, transform 0.1s !important;
+    letter-spacing: -0.1px !important;
+}
+#eval-btn:hover { background: #7F77DD !important; transform: translateY(-1px) !important; }
+#eval-btn:active { transform: translateY(0) !important; }
+#clear-btn {
+    background: transparent !important;
+    border: 1px solid #3A3E52 !important;
+    color: #9DA0B0 !important;
+    font-family: 'DM Sans', sans-serif !important;
+    font-size: 13px !important;
+    padding: 12px 20px !important;
+    border-radius: 8px !important;
+    cursor: pointer !important;
+    transition: border-color 0.15s, color 0.15s !important;
+}
+#clear-btn:hover { border-color: #7F77DD !important; color: #E8EAF0 !important; }
+.results-heading {
+    font-size: 11px !important;
+    font-weight: 500 !important;
+    color: #6A6E80 !important;
+    text-transform: uppercase !important;
+    letter-spacing: 1px !important;
+    padding: 0 0 16px !important;
+    border-bottom: 1px solid #2E3140 !important;
+    margin-bottom: 20px !important;
+}
+#verdict-out textarea {
+    background: #161820 !important; border: 1px solid #2E3140 !important;
+    border-radius: 10px !important; font-family: 'Space Mono', monospace !important;
+    font-size: 26px !important; font-weight: 700 !important;
+    text-align: center !important; padding: 20px !important;
+    color: #E8EAF0 !important; cursor: default !important;
+}
+#accuracy-out textarea {
+    background: #161820 !important; border: 1px solid #2E3140 !important;
+    border-radius: 10px !important; font-family: 'Space Mono', monospace !important;
+    font-size: 26px !important; font-weight: 700 !important;
+    text-align: center !important; padding: 20px !important;
+    color: #E8EAF0 !important; cursor: default !important;
+}
+#summary-out textarea {
+    background: #161820 !important; border: 1px solid #2E3140 !important;
+    border-radius: 10px !important; font-family: 'DM Sans', sans-serif !important;
+    font-size: 13.5px !important; line-height: 1.7 !important;
+    padding: 16px !important; color: #C0C3D0 !important; cursor: default !important;
+}
+#issues-out textarea {
+    background: #161820 !important; border: 1px solid #2E3140 !important;
+    border-radius: 10px !important; font-family: 'DM Sans', sans-serif !important;
+    font-size: 13.5px !important; line-height: 1.8 !important;
+    padding: 16px !important; color: #C0C3D0 !important;
+    cursor: default !important; min-height: 120px !important;
+}
+#error-out textarea {
+    background: #1A0E0E !important; border: 1px solid #5a2020 !important;
+    border-radius: 10px !important; font-family: 'DM Sans', sans-serif !important;
+    font-size: 13.5px !important; padding: 14px 16px !important;
+    color: #F0997B !important; cursor: default !important;
+}
+.divider { height: 1px; background: #2E3140; margin: 20px 0; }
+footer { display: none !important; }
+::-webkit-scrollbar { width: 6px; height: 6px; }
+::-webkit-scrollbar-track { background: transparent; }
+::-webkit-scrollbar-thumb { background: #3A3E52; border-radius: 3px; }
+::-webkit-scrollbar-thumb:hover { background: #534AB7; }
+"""
+
+HEADER_HTML = """
+<div class="eval-header">
+  <div class="logo">🔍</div>
+  <div><h1>Python Code Evaluator</h1></div>
+  <div class="model-badge">GEMMA-4 · 31B-IT</div>
+</div>
+"""
+
+RESULTS_HEADING_HTML = """
+<div class="divider"></div>
+<div class="results-heading">⬡ &nbsp; Evaluation Results</div>
+"""
+
+INPUT_HINT_HTML = """
+<div style="font-size:12px;color:#4A4E60;margin-top:-4px;padding-bottom:4px;">
+  Tip — paste your description and code above, then click
+  <strong style="color:#7F77DD">Evaluate</strong>.
+</div>
+"""
+
+def build_ui(evaluate_fn):
+
+    def _split_metrics(metrics_str: str):
+        acc, summary = "", ""
+        if not metrics_str:
+            return acc, summary
+        for line in metrics_str.splitlines():
+            if line.startswith("Accuracy:"):
+                acc = line.replace("Accuracy:", "").strip()
+            elif line.startswith("Summary:"):
+                summary = line.replace("Summary:", "").strip()
+        return acc, summary
+
+    def _ui_evaluate(description: str, code: str):
+        verdict, metrics, issues, error = evaluate_fn(description, code)
+        accuracy, summary = _split_metrics(metrics)
+        if "PASS" in verdict.upper():
+            verdict_display = "✅  PASS"
+        elif "FAIL" in verdict.upper():
+            verdict_display = "❌  FAIL"
+        else:
+            verdict_display = verdict or ""
+        return verdict_display, accuracy, summary, issues, error
+
+    with gr.Blocks(css=CUSTOM_CSS, title="Python Code Evaluator") as demo:
+
+        gr.HTML(HEADER_HTML)
+
+        with gr.Row(equal_height=True):
+            description_input = gr.Textbox(
+                label="Requirements Description",
+                placeholder=(
+                    "Describe what the Python code is supposed to do…\n\n"
+                    "Example: Write a function that accepts a list of integers "
+                    "and returns the sum of all even numbers."
+                ),
+                lines=10, max_lines=20, elem_id="desc-input",
+            )
+            code_input = gr.Textbox(
+                label="Python Code",
+                placeholder="# Paste your Python code here…\n\ndef example(data):\n    pass\n",
+                lines=10, max_lines=30, elem_id="code-input",
+            )
+
+        gr.HTML(INPUT_HINT_HTML)
+
+        with gr.Row():
+            eval_btn  = gr.Button("Evaluate", variant="primary",  elem_id="eval-btn",  scale=0)
+            clear_btn = gr.Button("Clear",    variant="secondary", elem_id="clear-btn", scale=0)
+
+        gr.HTML(RESULTS_HEADING_HTML)
+
+        with gr.Row(equal_height=True):
+            verdict_out  = gr.Textbox(label="Verdict",   interactive=False, elem_id="verdict-out",  scale=1)
+            accuracy_out = gr.Textbox(label="Accuracy",  interactive=False, elem_id="accuracy-out", scale=1)
+            summary_out  = gr.Textbox(label="Summary",   interactive=False, elem_id="summary-out",  scale=2, lines=3)
+
+        issues_out = gr.Textbox(label="Issues Detected", interactive=False, lines=5,  elem_id="issues-out")
+        error_out  = gr.Textbox(label="Status / Errors", interactive=False, visible=True, elem_id="error-out")
+
+        gr.HTML("""
+        <div style="text-align:right;font-size:11px;color:#4A4E60;margin-top:8px;">
+          Press <kbd style="background:#1E2028;border:1px solid #3A3E52;border-radius:4px;
+          padding:2px 6px;font-family:'Space Mono',monospace;font-size:10px;color:#9DA0B0;">
+          Ctrl+Enter</kbd> to evaluate
+        </div>
+        """)
+
+        outputs = [verdict_out, accuracy_out, summary_out, issues_out, error_out]
+        eval_btn.click(fn=_ui_evaluate, inputs=[description_input, code_input], outputs=outputs)
+        description_input.submit(fn=_ui_evaluate, inputs=[description_input, code_input], outputs=outputs)
+        code_input.submit(fn=_ui_evaluate, inputs=[description_input, code_input], outputs=outputs)
+
+        def _clear():
+            return "", "", "", "", "", ""
+
+        clear_btn.click(
+            fn=_clear, inputs=[],
+            outputs=[description_input, code_input,
+                     verdict_out, accuracy_out, summary_out, issues_out],
+        )
+
+    return demo
+
+
+# ---------------------------------------------------------------------------
+# ENTRY POINT
+# ---------------------------------------------------------------------------
+if __name__ == "__main__":
+    app = build_ui(validate_and_evaluate)
+    app.launch(server_name="0.0.0.0", server_port=7860, share=False, show_error=True)