legal-ai/mcp-server/src/legal_mcp/services/claims_extractor.py

"""חילוץ טענות מכתבי טענות (ערר, תשובה) באמצעות Claude Code session.

שתי גישות:
1. extract_claims_with_ai — חילוץ עם Claude Code headless (לכתבי טענות קלט)
2. extract_claims_from_block — חילוץ regex (מבלוק ז של החלטות סופיות)
"""

from __future__ import annotations

import asyncio
import logging
import re
from uuid import UUID

from legal_mcp import config
from legal_mcp.config import parse_llm_json
from legal_mcp.services import db, claude_session

logger = logging.getLogger(__name__)

# Each chunk targets ~12K chars (≈3K tokens of Hebrew). Smaller than the
# previous 25K because:
#   • A single ``claude -p`` call on a 25K-char Hebrew prompt with cold
#     cache routinely hit ~150-180s. 12K chunks finish in ~60-90s.
#   • Per-chunk retry costs less when chunks are smaller.
#   • Parallel chunks benefit more — see CHUNK_CONCURRENCY.
CHUNK_TARGET_CHARS = 12000

# How many chunks to send to Claude in parallel. Each subprocess holds
# ~300 MB RSS plus its own MCP stack; concurrency=3 keeps the box usable.
CHUNK_CONCURRENCY = 3

# How many retry attempts per failed chunk before giving up on it.
CHUNK_RETRY_ATTEMPTS = 1


EXTRACT_CLAIMS_PROMPT = """אתה מנתח מסמכים משפטיים בתחום תכנון ובניה. תפקידך לחלץ טענות מכתב טענות.

## כללים חשובים:
1. **נאמנות למקור** — כל טענה חייבת לשקף את מה שנכתב, לא לפרש או להוסיף.
2. **טענה = טיעון מובחן אחד** — אם פסקה מכילה 2 טיעונים שונים, פצל לשתי טענות.
3. **כל טענה חייבת להיות מובנת בפני עצמה** — גם בלי הקשר המסמך המלא.
4. **שמור על לשון הגוף שלישי** — גם אם המקור בגוף ראשון.

## סוג הצד (party_role):
- appellant — עורר/ת (מי שמגיש את הערר)
- respondent — משיב/ה (הצד שכנגד, לא הוועדה)
- committee — ועדה מקומית
- permit_applicant — מבקש/ת היתר

## פלט:
החזר JSON array בלבד — ללא markdown, ללא הסברים, רק JSON:
[{"party_role": "appellant", "claim_text": "הטענה בגוף שלישי", "topic": "נושא"}]

חשוב:
- claim_text קצר — עד 150 מילים לכל טענה
- קבץ טענות דומות לטענה אחת
- אם אין טענות החזר []
"""


# Section markers we treat as natural chunk boundaries when present.
# Hebrew legal briefs almost always use numbered sections like "10." or
# letter-section headings (".א", ".ב"). Splitting between sections keeps
# every chunk a self-contained argumentative unit.
_SECTION_BOUNDARY_RE = re.compile(
    r"\n\s*("
    r"\d+\.\s+\S"             # numbered section: "10. טענות"
    r"|[א-ת]\.\s+\S"          # Hebrew letter section: "א. רקע"
    r"|##\s+\S"               # markdown heading
    r"|פרק\s+\S"              # "פרק" headings
    r")"
)


def _split_by_sections(text: str, target: int = CHUNK_TARGET_CHARS) -> list[str]:
    """Split a long document into roughly ``target``-sized chunks at section
    boundaries. Falls back to paragraph breaks, then to hard splits if a
    section happens to be larger than ``target`` on its own.
    """
    if len(text) <= target:
        return [text]

    boundaries = [m.start() for m in _SECTION_BOUNDARY_RE.finditer(text)]
    boundaries = [0, *boundaries, len(text)]

    chunks: list[str] = []
    start = 0
    for cut in boundaries[1:]:
        # Greedy: keep adding sections to the current chunk until adding
        # the next one would push past ``target``.
        if cut - start < target:
            continue
        end = cut
        if end - start > target * 1.5:
            # Section group exceeds 1.5× target — fall back to paragraph
            # break inside it to avoid one chunk being far too big.
            soft = text.rfind("\n\n", start, start + target)
            if soft > start + target // 2:
                end = soft
        chunks.append(text[start:end].strip())
        start = end
    if start < len(text):
        chunks.append(text[start:].strip())

    # Hard splits for any chunk that is still too large (rare, but
    # documents without any section markers can fall through).
    final: list[str] = []
    for c in chunks:
        if len(c) <= target * 1.5:
            final.append(c)
            continue
        for i in range(0, len(c), target):
            final.append(c[i:i + target])
    return [c for c in final if c.strip()]


async def _extract_chunk(
    chunk: str,
    chunk_index: int,
    chunk_total: int,
    context: str,
) -> tuple[int, list[dict] | None]:
    """Run extraction on one chunk with retry. Returns ``(chunk_index, claims_or_None)``.

    None means the chunk failed both the initial call and every retry
    (caller can use this to mark the result as partial).
    """
    chunk_label = f" (חלק {chunk_index + 1}/{chunk_total})" if chunk_total > 1 else ""
    prompt = (
        f"{EXTRACT_CLAIMS_PROMPT}\n\n"
        f"{context}{chunk_label}\n\n"
        f"--- תחילת מסמך ---\n{chunk}\n--- סוף מסמך ---"
    )
    last_err: Exception | None = None
    for attempt in range(CHUNK_RETRY_ATTEMPTS + 1):
        try:
            claims = await claude_session.query_json(prompt, tools="")  # no tool_use → no error_max_turns
        except Exception as e:
            last_err = e
            logger.warning(
                "extract_claims chunk %d/%d attempt %d raised: %s",
                chunk_index + 1, chunk_total, attempt + 1, e,
            )
            continue
        if isinstance(claims, list):
            return chunk_index, claims
        logger.warning(
            "extract_claims chunk %d/%d attempt %d returned non-list (%s)",
            chunk_index + 1, chunk_total, attempt + 1, type(claims).__name__,
        )
    logger.error(
        "extract_claims chunk %d/%d failed after %d attempts: %s",
        chunk_index + 1, chunk_total, CHUNK_RETRY_ATTEMPTS + 1, last_err,
    )
    return chunk_index, None


async def extract_claims_with_ai(
    text: str,
    doc_type: str = "appeal",
    party_hint: str = "",
) -> list[dict]:
    """חילוץ טענות מכתב טענות באמצעות Claude.

    Splits ``text`` at section boundaries, runs every chunk through
    Claude in parallel (bounded by ``CHUNK_CONCURRENCY``), retries each
    failed chunk once, and merges the results in original document order.
    Failed chunks are logged but don't block the overall extraction —
    we return what we got and surface the gap via the logs.

    Args:
        text: טקסט המסמך
        doc_type: סוג המסמך (appeal/response)
        party_hint: רמז לזהות הצד (אם ידוע)

    Returns:
        רשימת טענות עם party_role, claim_text, topic, claim_index.
    """
    context = f"סוג המסמך: {doc_type}"
    if party_hint:
        context += f"\nהצד המגיש: {party_hint}"

    chunks = _split_by_sections(text)
    if len(chunks) > 1:
        logger.info(
            "extract_claims: split %d chars into %d chunks (target=%d, concurrency=%d)",
            len(text), len(chunks), CHUNK_TARGET_CHARS, CHUNK_CONCURRENCY,
        )

    sem = asyncio.Semaphore(CHUNK_CONCURRENCY)

    async def _bounded(idx: int, c: str) -> tuple[int, list[dict] | None]:
        async with sem:
            return await _extract_chunk(c, idx, len(chunks), context)

    results = await asyncio.gather(*[_bounded(i, c) for i, c in enumerate(chunks)])

    # Merge in original order. Skip chunks that failed entirely.
    failed = [i for i, r in results if r is None]
    if failed:
        logger.warning(
            "extract_claims: %d/%d chunks failed (indices=%s) — returning partial result",
            len(failed), len(chunks), failed,
        )
    merged: list[dict] = []
    for idx, claims in sorted(results, key=lambda x: x[0]):
        if not claims:
            continue
        merged.extend(claims)

    # Add claim_index and drop entries missing required fields.
    cleaned: list[dict] = []
    for i, claim in enumerate(merged):
        if not isinstance(claim, dict):
            continue
        if "party_role" not in claim or "claim_text" not in claim:
            continue
        claim["claim_index"] = i
        cleaned.append(claim)
    return cleaned


def _infer_claim_type(doc_type: str, source_name: str) -> str:
    """Determine claim_type from document type and title.

    - 'claim' = from appeal documents (כתב ערר)
    - 'response' = from original response documents (כתב תשובה)
    - 'reply' = from supplementary responses (תגובה, השלמת טיעון)
    """
    name_lower = source_name.lower() if source_name else ""
    if doc_type == "appeal" or "כתב ערר" in name_lower:
        return "claim"
    if "כתב תשובה" in name_lower:
        return "response"
    if any(kw in name_lower for kw in ["תגובת", "השלמת טיעון", "תגובה"]):
        return "reply"
    if doc_type == "response":
        return "response"
    return "claim"


# ── Regex-based extraction (from existing decisions) ──────────────

PARTY_PATTERNS = [
    (r"טענות\s*העוררי[םן]|טענות\s*העורר\b|טענות\s*המבקש|טענות\s*המערער", "appellant"),
    (r"עמדת\s*הוועדה\s*המקומית|עמדת\s*המשיבה|טענות\s*המשיבה|תגובת\s*המשיבה|הוועדה\s*המקומית$", "committee"),
    (r"עמדת\s*המשיבי[םן]|עמדת\s*המשיב\b|טענות\s*המשיבי[םן]|טענות\s*המשיב\b", "respondent"),
    (r"מבקשי\s*ההיתר|עמדת\s*מבקש|עמדת\s*היזם|מגישי\s*התכנית", "permit_applicant"),
    (r"הבהרות\s*השמא|התייחסות\s*הצדדים", "appraiser"),
]


def _detect_party_role(line: str) -> str | None:
    for pattern, role in PARTY_PATTERNS:
        if re.search(pattern, line):
            return role
    return None


def extract_claims_from_block(text: str) -> list[dict]:
    """חילוץ טענות מבלוק ז של החלטה סופית (regex-based).

    Replicates the logic from scripts/extract-claims.py for use as a service.
    """
    lines = text.split("\n")
    claims = []
    current_role = "appellant"
    current_claim_lines: list[str] = []
    claim_index = 0

    for line in lines:
        stripped = line.strip()
        if not stripped:
            continue

        role = _detect_party_role(stripped) if len(stripped.split()) <= 8 else None
        if role:
            if current_claim_lines:
                claim_text = "\n".join(current_claim_lines).strip()
                if len(claim_text) > 30:
                    claims.append({
                        "party_role": current_role,
                        "claim_text": claim_text,
                        "claim_index": claim_index,
                    })
                    claim_index += 1
                current_claim_lines = []
            current_role = role
            continue

        # Numbered sub-header starts new claim
        if re.match(r"^\d+\.\s+\S.{3,40}$", stripped):
            if current_claim_lines:
                claim_text = "\n".join(current_claim_lines).strip()
                if len(claim_text) > 30:
                    claims.append({
                        "party_role": current_role,
                        "claim_text": claim_text,
                        "claim_index": claim_index,
                    })
                    claim_index += 1
            current_claim_lines = [stripped]
            continue

        # Each paragraph is a claim
        if current_claim_lines:
            claim_text = "\n".join(current_claim_lines).strip()
            if len(claim_text) > 30:
                claims.append({
                    "party_role": current_role,
                    "claim_text": claim_text,
                    "claim_index": claim_index,
                })
                claim_index += 1
        current_claim_lines = [stripped]

    # Last claim
    if current_claim_lines:
        claim_text = "\n".join(current_claim_lines).strip()
        if len(claim_text) > 30:
            claims.append({
                "party_role": current_role,
                "claim_text": claim_text,
                "claim_index": claim_index,
            })

    return claims


async def extract_and_store_claims(
    case_id: UUID,
    document_id: UUID,
    text: str,
    doc_type: str = "appeal",
    party_hint: str = "",
) -> dict:
    """חילוץ טענות ושמירה ב-DB.

    Args:
        case_id: מזהה התיק
        document_id: מזהה המסמך
        text: טקסט המסמך
        doc_type: סוג (appeal/response)
        party_hint: שם הצד המגיש

    Returns:
        סיכום: כמה טענות חולצו, לפי צד
    """
    doc = await db.get_document(document_id)
    source_name = doc["title"] if doc else str(document_id)

    claims = await extract_claims_with_ai(text, doc_type, party_hint)

    if not claims:
        return {"status": "no_claims", "total": 0, "source": source_name}

    # Determine claim_type from document type and title
    claim_type = _infer_claim_type(doc_type, source_name)
    for c in claims:
        c["claim_type"] = claim_type

    stored = await db.store_claims(case_id, claims, source_document=source_name)

    # Summarize by role
    role_counts: dict[str, int] = {}
    for c in claims:
        role = c["party_role"]
        role_counts[role] = role_counts.get(role, 0) + 1

    return {
        "status": "completed",
        "total": stored,
        "by_role": role_counts,
        "source": source_name,
    }