pdf-quiz-generator/backend/app/services/extraction_modes.py
Daniel 2a0dd56f95 Add ai_answer extraction + broader ai_decide sampling + flashcard title edit
ai_decide now samples 4 points across the section (start, 1/3, 2/3, end)
instead of just the first 30 + last 20 pages. This gives accurate strategy
detection on large documents where the answer format might be deeper in.

New ai_answer extraction mode:
- Extracts questions from Q&A-format PDFs that have no answer key
- AI picks the correct option from each question's choices
- Generates explanation using document context + medical knowledge
- Useful for PDFs like practice tests where answers were never included
- Available manually and as an ai_decide strategy

Flashcard decks can now be renamed:
- PATCH /flashcards/{deck_id} updates title
- Inline edit on FlashcardsPage with responsive layout (input full-width,
  buttons wrap under it so Cancel never overflows the card)
- Title truncates with ellipsis when not editing

Note: generate mode (textbook -> MCQs) is unchanged per user request.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-04-19 20:17:49 +02:00

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"""Additional extraction modes that run alongside (not replacing) the standard extractor.
Modes
-----
questions_only Extract Q+options with no answers. User fills answers later via QuizEditPage.
two_step Separate answer key section (PREP 2013): Phase 1 = questions, Phase 2 = key, Phase 3 = match.
regex AI generates a regex pattern for the document's answer format, then we apply it.
ai_decide AI samples the document and picks standard / two_step / questions_only.
generate AI reads plain text/study material and creates MCQ questions from scratch.
"""
from __future__ import annotations
import json
import logging
import re
from app.services import ai_service, vector_service
logger = logging.getLogger(__name__)
def _normalize(text: str) -> str:
return (text.replace("Pref erred", "Preferred").replace("Pre ferred", "Preferred")
.replace("Prefer red", "Preferred").replace("ltem", "Item").replace("ltcm", "Item"))
# ─── QUESTIONS ONLY ──────────────────────────────────────────────────────────
QUESTIONS_ONLY_PROMPT = """Extract every question from this PREP exam content.
Do NOT look for correct answers — we only need the question text and answer options.
Return ONLY JSON:
{{"questions": [
{{
"item_number": "<digits only, or null>",
"question_text": "<full vignette + stem>",
"question_type": "mcq",
"options": ["<A>", "<B>", "<C>", "<D>", "<E>"],
"has_figure": false,
"page_reference": {page_ref}
}}
]}}
Rules:
- A new question starts with "Item NNN" or "ltem NNN".
- Extract ALL questions even if no answer is visible.
- Do NOT include answer explanations or "Preferred Response:" content as questions.
- has_figure: true ONLY if the question references an image, figure, radiograph, photo, ECG, or chart essential to answering. false for decorative/branding images.
- Return ONLY JSON — no markdown, no preamble.
Content (pages {page_info}):
{content}"""
def extract_questions_only(content: str, page_info: str, page_ref: int | None,
model_id: str | None, api_key: str | None) -> list[dict]:
"""Extract questions + options with correct_answer = PENDING (to be filled by admin)."""
content = ai_service._truncate_content(content)
prompt = QUESTIONS_ONLY_PROMPT.format(
content=content, page_info=page_info,
page_ref=page_ref if page_ref else "null",
)
for attempt in range(3):
try:
text = ai_service._call_model(prompt, model_id, api_key).strip()
if text.startswith("```"):
text = text.split("\n", 1)[1] if "\n" in text else text[3:]
if text.endswith("```"):
text = text[:-3]
text = text.strip()
data = json.loads(text)
qs = data.get("questions", data) if isinstance(data, dict) else data
result = []
for q in qs:
if not q.get("question_text"):
continue
result.append({
"item_number": str(q.get("item_number") or "").strip().lstrip("0") or None,
"question_text": q["question_text"],
"question_type": q.get("question_type", "mcq"),
"options": q.get("options"),
"correct_answer": "PENDING", # placeholder — admin fills via QuizEditPage
"explanation": "",
"page_reference": q.get("page_reference"),
})
if result:
return result
raise ValueError("No questions found")
except Exception as e:
logger.warning(f"questions_only attempt {attempt + 1}: {e}")
raise RuntimeError("questions_only extraction failed after 3 attempts")
# ─── AI-ANSWERED (no inline/back answers — AI deduces correct answer) ───────
AI_ANSWER_PROMPT = """Pick the correct answer for each question below using medical knowledge and any supporting context from the provided document excerpt.
Return ONLY JSON:
{{"answers": [
{{
"item_number": "<matches input>",
"correct_answer": "<exact text of one of the given options>",
"explanation": "<1-3 sentence explanation; cite the document if relevant, otherwise general medical reasoning>"
}}
]}}
Rules:
- correct_answer must be the EXACT text of one of the options (not "A", "B", etc.)
- Prefer wording and reasoning supported by the Document context — fall back to general medical knowledge only when the document doesn't address it
- Keep explanations focused on why the answer is correct and briefly why others are wrong
Document context (pages {page_info}):
{content}
Questions (JSON list):
{questions_json}"""
def ai_answer_questions(questions: list[dict], content: str, page_info: str,
model_id: str | None, api_key: str | None) -> list[dict]:
"""For questions extracted without answers, use AI to determine correct answer
and explanation, using the document content as supporting context.
Mutates and returns the questions list."""
if not questions:
return questions
# Strip-down representation to keep the prompt small
qs_for_prompt = [
{
"item_number": str(q.get("item_number") or "").strip() or None,
"question_text": q.get("question_text", ""),
"options": q.get("options") or [],
}
for q in questions
]
content = ai_service._truncate_content(content)
prompt = AI_ANSWER_PROMPT.format(
page_info=page_info,
content=content,
questions_json=json.dumps(qs_for_prompt, ensure_ascii=False),
)
for attempt in range(3):
try:
text = ai_service._call_model(prompt, model_id, api_key).strip()
if text.startswith("```"):
text = text.split("\n", 1)[1] if "\n" in text else text[3:]
if text.endswith("```"):
text = text[:-3]
text = text.strip()
data = json.loads(text)
answers = data.get("answers", data) if isinstance(data, dict) else data
# Match by item_number or by question_text fallback
by_item = {}
for a in answers:
item = str(a.get("item_number") or "").strip()
if item:
by_item[item] = a
for q in questions:
key = str(q.get("item_number") or "").strip()
ans = by_item.get(key)
if not ans:
# fallback: positional match if all numbers missing
continue
correct_text = (ans.get("correct_answer") or "").strip()
if correct_text:
# Find best-matching option text (case-insensitive contains)
opts = q.get("options") or []
matched = None
for opt in opts:
if opt.strip().lower() == correct_text.lower():
matched = opt
break
if not matched:
for opt in opts:
if correct_text.lower() in opt.lower() or opt.lower() in correct_text.lower():
matched = opt
break
q["correct_answer"] = matched or correct_text
q["explanation"] = (ans.get("explanation") or "").strip()
return questions
except Exception as e:
logger.warning(f"ai_answer attempt {attempt + 1}: {e}")
# If all attempts fail, return questions as-is (PENDING)
return questions
# ─── TWO-STEP (SEPARATE ANSWER KEY) ─────────────────────────────────────────
def extract_two_step(
document_id: int,
section_start: int,
section_end: int,
model_id: str | None,
api_key: str | None,
push_step, # callable(step, message) to report progress
chunk_pages: int = 50,
) -> tuple[list[dict], list[str]]:
"""
Two-phase extraction for PDFs with questions in the first half
and a separate answer key section (e.g. PREP 2013 "Preferred Response:").
Returns (valid_questions, skipped_list).
Raises ValueError if answer section not found or no questions matched.
"""
total = section_end - section_start + 1
min_answer_start = section_start + max(20, int(total * 0.20))
# Scan for answer key boundary
push_step("ai", "Two-step mode: scanning for answer key section…")
answer_section_start = None
for scan_p in range(min_answer_start, section_end, 10):
raw = vector_service.get_pages_text(document_id=document_id, start_page=scan_p,
end_page=min(scan_p + 9, section_end))
if raw and ("Preferred Response:" in _normalize(raw) or
"preferred response:" in raw.lower()):
answer_section_start = max(section_start, scan_p - 5)
break
if not answer_section_start:
raise ValueError(
"Two-step mode: could not find a separate answer key section "
"(no 'Preferred Response:' found after the first 20% of pages). "
"Try 'Standard' mode instead."
)
push_step("ai", f"Answer key section starts around page {answer_section_start}.")
q_end = answer_section_start - 1
q_chunks = []
p = section_start
while p <= q_end:
end = min(p + chunk_pages - 1, q_end)
q_chunks.append((p, end))
p = end + 1
n = len(q_chunks)
# Phase 1 — questions
raw_questions: list[dict] = []
for i, (sp, ep) in enumerate(q_chunks, 1):
push_step("ai", f"Phase 1 Chunk {i}/{n}: pages {sp}{ep} (questions)…")
chunk = vector_service.get_pages_text(document_id=document_id, start_page=sp, end_page=ep)
if not chunk:
continue
try:
qs = ai_service.extract_questions_no_answers(
_normalize(chunk), page_info=f"{sp}-{ep}", page_ref=sp,
model_id=model_id, api_key=api_key,
)
raw_questions.extend(qs)
push_step("ai", f" Pages {sp}{ep}: {len(qs)} questions. Total: {len(raw_questions)}.")
except Exception as e:
push_step("ai", f" Pages {sp}{ep} failed: {e}. Continuing…")
# Phase 2 — answer key
push_step("ai", f"Phase 2 Answer key from pages {answer_section_start}{section_end}")
answer_key: dict = {}
for ans_start in range(answer_section_start, section_end + 1, chunk_pages):
ans_end = min(ans_start + chunk_pages - 1, section_end)
ans_content = vector_service.get_pages_text(document_id=document_id,
start_page=ans_start, end_page=ans_end)
if not ans_content:
continue
chunk_key = ai_service.extract_answer_key(
_normalize(ans_content), page_info=f"{ans_start}-{ans_end}",
model_id=model_id, api_key=api_key,
)
answer_key.update(chunk_key)
push_step("ai", f" Answer pages {ans_start}{ans_end}: +{len(chunk_key)}. Total: {len(answer_key)}.")
push_step("ai", f"Answer key complete: {len(answer_key)} items.")
# Phase 3 — match
push_step("ai", "Phase 3 Matching questions to answers…")
valid: list[dict] = []
skipped: list[str] = []
for q in raw_questions:
item = q.get("item_number")
letter = answer_key.get(item) if item else None
if not letter:
skipped.append(q.get("question_text", "")[:120])
continue
options = q.get("options") or []
idx = ord(letter.upper()) - ord("A")
if 0 <= idx < len(options):
q["correct_answer"] = options[idx]
valid.append(q)
else:
skipped.append(q.get("question_text", "")[:120])
push_step("ai", f"Matching: {len(valid)} matched, {len(skipped)} unmatched.")
return valid, skipped
# ─── REGEX MODE ──────────────────────────────────────────────────────────────
REGEX_ANALYSIS_PROMPT = """Look at this PREP exam PDF content and identify the pattern used to mark correct answers.
Describe:
1. The exact text pattern before the correct answer letter (e.g. "Correct Answer:" or "Preferred Response:")
2. Whether answers appear right after each question (inline) or in a separate section at the back
3. A Python regex pattern that would match: the answer indicator + whitespace + the letter (A-E)
Return ONLY JSON:
{{"indicator": "<text before letter>",
"placement": "inline" | "end_of_doc",
"regex": "<python regex with one capture group for the letter>",
"notes": "<any relevant observation>"}}
Sample content (first 30 pages):
{content}"""
def extract_with_regex(
document_id: int,
section_start: int,
section_end: int,
model_id: str | None,
api_key: str | None,
push_step,
chunk_pages: int = 50,
) -> tuple[list[dict], list[str]]:
"""AI analyses format, generates regex for answer extraction, then applies it."""
# Sample first 30 pages for analysis
push_step("ai", "Regex mode: analysing document format…")
sample = vector_service.get_pages_text(document_id=document_id,
start_page=section_start,
end_page=min(section_start + 29, section_end))
if not sample:
raise ValueError("No content found for format analysis")
prompt = REGEX_ANALYSIS_PROMPT.format(content=_normalize(sample)[:60000])
analysis_text = ai_service._call_model(prompt, model_id, api_key).strip()
if analysis_text.startswith("```"):
analysis_text = analysis_text.split("\n", 1)[1] if "\n" in analysis_text else analysis_text[3:]
if analysis_text.endswith("```"): analysis_text = analysis_text[:-3]
analysis = json.loads(analysis_text.strip())
regex_pattern = analysis.get("regex", r"(?:Correct Answer|Preferred Response)\s*[:\.]?\s*([A-E])")
placement = analysis.get("placement", "inline")
push_step("ai", f"Format detected: {placement} answers. Indicator: {analysis.get('indicator','?')!r}. Regex: {regex_pattern!r}")
# Extract questions using standard no-answer prompt
push_step("ai", "Extracting questions…")
q_end = section_end
if placement == "end_of_doc":
# Try to find boundary
for scan_p in range(section_start + 20, section_end, 10):
raw = vector_service.get_pages_text(document_id=document_id, start_page=scan_p,
end_page=min(scan_p + 9, section_end))
if raw:
norm = _normalize(raw)
try:
if re.search(regex_pattern, norm, re.IGNORECASE):
q_end = max(section_start, scan_p - 5)
break
except re.error:
break
raw_questions: list[dict] = []
q_chunks = []
p = section_start
while p <= q_end:
q_chunks.append((p, min(p + chunk_pages - 1, q_end)))
p += chunk_pages
for i, (sp, ep) in enumerate(q_chunks, 1):
push_step("ai", f"Questions chunk {i}/{len(q_chunks)}: pages {sp}{ep}")
chunk = vector_service.get_pages_text(document_id=document_id, start_page=sp, end_page=ep)
if not chunk:
continue
try:
qs = ai_service.extract_questions_no_answers(
_normalize(chunk), page_info=f"{sp}-{ep}", page_ref=sp,
model_id=model_id, api_key=api_key,
)
raw_questions.extend(qs)
except Exception as e:
push_step("ai", f" Chunk {i} failed: {e}")
push_step("ai", f"{len(raw_questions)} questions extracted. Applying regex to full document for answers…")
# Apply regex to full document to find item→letter mapping
answer_map: dict = {}
for ans_start in range(section_start, section_end + 1, chunk_pages):
ans_end = min(ans_start + chunk_pages - 1, section_end)
ans_content = vector_service.get_pages_text(document_id=document_id,
start_page=ans_start, end_page=ans_end)
if not ans_content:
continue
norm = _normalize(ans_content)
# Find Item NNN + answer pattern
combined = r"Item\s+(\d+)[\s\S]{0,300}?" + regex_pattern
try:
for m in re.finditer(combined, norm, re.IGNORECASE):
item_num = m.group(1).lstrip("0") or m.group(1)
letter = m.group(2).upper() if len(m.groups()) > 1 else ""
if letter:
answer_map[item_num] = letter
except re.error:
pass
push_step("ai", f"Regex found {len(answer_map)} item→answer mappings.")
# Match
valid: list[dict] = []
skipped: list[str] = []
for q in raw_questions:
item = q.get("item_number")
letter = answer_map.get(item) if item else None
if not letter:
skipped.append(q.get("question_text", "")[:120])
continue
options = q.get("options") or []
idx = ord(letter.upper()) - ord("A")
if 0 <= idx < len(options):
q["correct_answer"] = options[idx]
valid.append(q)
else:
skipped.append(q.get("question_text", "")[:120])
push_step("ai", f"Matched {len(valid)}, skipped {len(skipped)}.")
return valid, skipped
# ─── AI DECIDES ──────────────────────────────────────────────────────────────
AI_DECIDE_PROMPT = """You are analysing a medical study PDF to determine the best extraction strategy.
Section spans pages {start_page}-{end_page} ({total_pages} pages total).
Samples from several points across the section so you can see the overall structure:
[BEGIN — pages {start_page}-{s1_end}]
{sample_start}
[MIDDLE — pages {s2_start}-{s2_end}]
{sample_middle_1}
[MIDDLE — pages {s3_start}-{s3_end}]
{sample_middle_2}
[END — pages {s4_start}-{end_page}]
{sample_end}
Based on these samples taken from across the document, which extraction strategy should be used?
1. standard — "Correct Answer: X" or "Preferred Response: X" appears right after each question
2. two_step — questions come first (no answers inline), then a separate answer key section at the back
3. ai_answer — document has Q&A format but NO answers anywhere; AI will pick the correct option and write an explanation
Return ONLY JSON:
{{"strategy": "standard" | "two_step" | "ai_answer",
"reasoning": "<one sentence>"}}"""
# ─── GENERATE FROM TEXT ──────────────────────────────────────────────────────
GENERATE_PROMPT = """You are a pediatric medical education expert. Read the text below and generate {n} high-quality multiple-choice questions to test comprehension.
Rules:
- The CORRECT answer must be directly supported by the text — do not invent facts
- Create 3 plausible but incorrect distractors using your medical knowledge
- Questions should test understanding of concepts, not just exact word recall
- Prefer clinical application questions over pure recall when the content allows
- Include a 1-2 sentence explanation that cites the key concept from the text
- Spread questions across different parts of the text, not just the first section
- Each option should be a complete, standalone phrase (not "A", "B" labels)
Return ONLY valid JSON (no markdown, no preamble):
{{"questions": [
{{
"question_text": "<clear clinical or conceptual question>",
"question_type": "mcq",
"options": ["<correct answer text>", "<distractor B>", "<distractor C>", "<distractor D>"],
"correct_answer": "<exact text of the correct option>",
"explanation": "<1-2 sentence explanation>",
"page_reference": {page_ref}
}}
]}}
Text (pages {page_info}):
{content}"""
QUESTIONS_PER_CHUNK = 8 # target questions per ~50-page chunk
def generate_from_text(content: str, page_info: str, page_ref: int | None,
model_id: str | None, api_key: str | None,
n: int = QUESTIONS_PER_CHUNK) -> list[dict]:
"""Generate MCQ questions from plain text — correct answers from the document,
distractors from AI medical knowledge."""
content = ai_service._truncate_content(content)
prompt = GENERATE_PROMPT.format(
content=content,
page_info=page_info,
page_ref=page_ref if page_ref is not None else "null",
n=n,
)
for attempt in range(3):
try:
text = ai_service._call_model(prompt, model_id, api_key).strip()
if text.startswith("```"):
text = text.split("\n", 1)[1] if "\n" in text else text[3:]
if text.endswith("```"):
text = text[:-3]
text = text.strip()
data = json.loads(text)
qs = data.get("questions", data) if isinstance(data, dict) else data
result = []
for q in qs:
if not q.get("question_text") or not q.get("correct_answer"):
continue
options = q.get("options") or []
correct = q["correct_answer"]
# Validate correct_answer is among options
if options and correct not in options:
# Try to find closest match
matches = [o for o in options if correct.lower() in o.lower() or o.lower() in correct.lower()]
if matches:
correct = matches[0]
else:
continue # skip malformed question
result.append({
"question_text": q["question_text"],
"question_type": q.get("question_type", "mcq"),
"options": options,
"correct_answer": correct,
"explanation": q.get("explanation", ""),
"page_reference": q.get("page_reference"),
"item_number": None,
})
if result:
return result
raise ValueError("No valid questions generated")
except Exception as e:
logger.warning(f"generate_from_text attempt {attempt + 1}: {e}")
raise RuntimeError("generate_from_text failed after 3 attempts")
# ─── AI DECIDES ──────────────────────────────────────────────────────────────
def ai_decide_strategy(
document_id: int,
section_start: int,
section_end: int,
model_id: str | None,
api_key: str | None,
) -> str:
"""AI samples across the section (start, two middle points, end) to decide extraction strategy.
For large documents this gives a much better view than just start+end."""
total = max(1, section_end - section_start + 1)
sample_size = min(15, max(6, total // 15)) # 6-15 pages per sample
# Evenly spaced sample windows across the section
s1_start = section_start
s1_end = min(section_start + sample_size - 1, section_end)
s2_start = min(section_start + total // 3, section_end - sample_size + 1)
s2_end = min(s2_start + sample_size - 1, section_end)
s3_start = min(section_start + (2 * total) // 3, section_end - sample_size + 1)
s3_end = min(s3_start + sample_size - 1, section_end)
s4_start = max(section_start, section_end - sample_size + 1)
s4_end = section_end
def _page_text(a, b):
return _normalize(vector_service.get_pages_text(document_id=document_id, start_page=a, end_page=b) or "")
sample_start = _page_text(s1_start, s1_end)[:12000]
sample_middle_1 = _page_text(s2_start, s2_end)[:12000]
sample_middle_2 = _page_text(s3_start, s3_end)[:12000]
sample_end = _page_text(s4_start, s4_end)[:12000]
prompt = AI_DECIDE_PROMPT.format(
start_page=section_start, end_page=section_end, total_pages=total,
s1_end=s1_end, s2_start=s2_start, s2_end=s2_end,
s3_start=s3_start, s3_end=s3_end, s4_start=s4_start,
sample_start=sample_start,
sample_middle_1=sample_middle_1,
sample_middle_2=sample_middle_2,
sample_end=sample_end,
)
try:
text = ai_service._call_model(prompt, model_id, api_key).strip()
if text.startswith("```"):
text = text.split("\n", 1)[1] if "\n" in text else text[3:]
if text.endswith("```"): text = text[:-3]
result = json.loads(text.strip())
strategy = result.get("strategy", "standard")
reasoning = result.get("reasoning", "")
logger.info(f"AI decided: {strategy}{reasoning}")
return strategy, reasoning
except Exception as e:
logger.warning(f"ai_decide failed: {e}, falling back to standard")
return "standard", "Fallback to standard due to analysis error"
# ─── FLASHCARD GENERATION ────────────────────────────────────────────────────
FLASHCARD_PROMPT = """You are a pediatric medical education expert. Read the text below and create {n} high-quality flashcards for studying.
Each flashcard has a FRONT (question, term, or concept prompt) and a BACK (answer, definition, or explanation).
Rules:
- Mix question-style fronts ("What is the most common cause of...") and term-style fronts ("Hyperbilirubinemia")
- FRONT should be concise — one sentence or a few words
- BACK should be complete but not verbose — 1-3 sentences with the key facts
- Focus on high-yield facts: diagnostic criteria, treatment protocols, age-specific norms, pathophysiology
- Do NOT repeat the same concept in multiple cards
- Spread cards across different parts of the text
- Each card must be directly supported by the text — do not invent facts
Return ONLY valid JSON (no markdown, no preamble):
{{"cards": [
{{
"front": "<question or term>",
"back": "<answer or definition>",
"page_reference": {page_ref}
}}
]}}
Text (pages {page_info}):
{content}"""
FLASHCARDS_PER_CHUNK = 15
def generate_flashcards(content: str, page_info: str, page_ref: int | None,
model_id: str | None, api_key: str | None,
n: int = FLASHCARDS_PER_CHUNK) -> list[dict]:
"""Generate flashcards from text content using AI."""
content = ai_service._truncate_content(content)
prompt = FLASHCARD_PROMPT.format(
content=content, page_info=page_info,
page_ref=page_ref if page_ref else "null",
n=n,
)
for attempt in range(3):
try:
text = ai_service._call_model(prompt, model_id, api_key).strip()
if text.startswith("```"):
text = text.split("\n", 1)[1] if "\n" in text else text[3:]
if text.endswith("```"):
text = text[:-3]
text = text.strip()
data = json.loads(text)
cards = data.get("cards", data) if isinstance(data, dict) else data
result = []
for c in cards:
if not c.get("front") or not c.get("back"):
continue
result.append({
"front": c["front"].strip(),
"back": c["back"].strip(),
"page_reference": c.get("page_reference"),
})
return result
except (json.JSONDecodeError, KeyError) as e:
logger.warning(f"Flashcard generation attempt {attempt + 1} failed: {e}")
continue
return []