#!/usr/bin/env python3
"""ASME clause-KB backlinks: resolve clause-id mentions in each clause doc -> clause_links.
dst resolved to the clause doc of the same parent (top-level code); sub-code mention -> anchor;
unresolved (cross-standard / material spec not split) -> dangling (dst_doc_id NULL).
Idempotent per parent. Usage: python3 asme_backlinks_persist.py <parent_id> [--commit]
"""
import asyncio, os, re, sys

MENTION_RE = re.compile(r'(?<![A-Za-z0-9])([A-Z]{1,4}-\d+(?:\.\d+)*[A-Za-z]?)(?![A-Za-z0-9])')
def top(code): return re.match(r'^[A-Z]{1,4}-\d+', code).group(0)

async def main():
    parent = int(sys.argv[1]); commit = '--commit' in sys.argv
    import asyncpg
    conn = await asyncpg.connect(os.environ['DATABASE_URL'].replace('+asyncpg', ''))
    docs = await conn.fetch("SELECT id, clause_code, md_content FROM documents "
                            "WHERE parent_id=$1 AND doc_kind='clause' ORDER BY clause_order", parent)
    code2id = {d['clause_code']: d['id'] for d in docs}
    edges = []          # (src_id, dst_code, dst_doc_id, anchor, ctx, char_off)
    resolved = dangling = 0
    for d in docs:
        body = d['md_content']; src_top = d['clause_code']
        seen = set()
        for m in MENTION_RE.finditer(body):
            code = m.group(1); t = top(code)
            if t == src_top: continue                 # self-reference
            if (d['id'], code) in seen: continue      # dedup per (src,dst_code)
            seen.add((d['id'], code))
            dst_id = code2id.get(t)                    # resolve to same-parent clause doc
            anchor = code.lower().replace('.', '-') if code != t else None
            off = m.start()
            ctx = re.sub(r'\s+', ' ', body[max(0, off-50):off+50]).strip()
            edges.append((d['id'], code, dst_id, anchor, ctx, off))
            if dst_id: resolved += 1
            else: dangling += 1
    print(f"parent={parent} clause_docs={len(docs)} edges={len(edges)} resolved={resolved} dangling={dangling}")
    # top referenced clauses
    from collections import Counter
    tgt = Counter(top(e[1]) for e in edges if e[2])
    print("most-referenced:", tgt.most_common(8))
    if not commit:
        print("DRY-RUN. pass --commit to persist."); await conn.close(); return
    async with conn.transaction():
        ids = [d['id'] for d in docs]
        await conn.execute("DELETE FROM clause_links WHERE src_doc_id = ANY($1::bigint[])", ids)
        await conn.executemany(
            "INSERT INTO clause_links(src_doc_id,dst_code,dst_doc_id,anchor,ctx,char_off) "
            "VALUES ($1,$2,$3,$4,$5,$6)", edges)
        n = await conn.fetchval("SELECT count(*) FROM clause_links WHERE src_doc_id = ANY($1::bigint[])", ids)
        print(f"COMMITTED: {n} clause_links for parent {parent}")
    await conn.close()

asyncio.run(main())