#!/usr/bin/env python3
"""kb/index - build the 2dph brain from markdown + factual leafs.

  bin/kb/index [--corpus DIR] [--rebuild] [--limit N]
  bin/kb/index --json                 # emit stats as JSON

Reads every .md under the corpus (default: repo root docs, skills, READMEs)
as `info` leafs, embeds them with model2vec (potion-multilingual-128M), and
writes them into var/kb.lbug with FTS + HNSW indexes. `facts` leafs come
from bin/facts/extract (docker x compose x ssh-config pairing).

--rebuild drops the database file and indexes from scratch. Without it a run
is idempotent (MERGE by (source,text) id).
"""
from __future__ import annotations

import json
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parents[2]
sys.path.insert(0, str(ROOT / "bin" / "tools"))

from kblib import (  # noqa: E402
    connect, create_fts_and_vector, init_schema, upsert_leaf,
    open_readonly, stats,
)
from mdleaves import read_markdown, to_all, walk_markdown  # noqa: E402

CORPUS_DEFAULTS = ["README.md", "PLAN.md", "AGENTS.md", "docs", "skills"]


def load_corpus(root: Path) -> list[dict]:
    files: list[Path] = []
    for entry in CORPUS_DEFAULTS:
        p = root / entry
        if p.is_file():
            files.append(p)
        elif p.is_dir():
            files.extend(walk_markdown(p))
    leafs: list[dict] = []
    for path in files:
        try:
            leafs.extend(to_all(read_markdown(path), path, repo="eSlider/2dph"))
        except OSError as e:
            print(f"kb/index: skip {path}: {e}", file=sys.stderr)
    return leafs


def load_corpus_glob(source: str) -> list[dict]:
    """Add arbitrary markdown dirs/files as corpus roots (repo=dirname)."""
    root = Path(source)
    if not root.exists():
        print(f"kb/index: skip missing corpus {source}", file=sys.stderr)
        return []
    files = [root] if root.is_file() else walk_markdown(root)
    repo = root.name if root.is_dir() else root.parent.name
    leafs: list[dict] = []
    for path in files:
        try:
            leafs.extend(to_all(read_markdown(path), path, repo=repo))
        except OSError as e:
            print(f"kb/index: skip {path}: {e}", file=sys.stderr)
    # yaml seeds (knowledge-mesh, workspace catalogs) as plain info leafs
    if root.is_dir():
        for path in sorted(root.rglob("*.y*ml")):
            try:
                leafs.append({
                    "source": str(path), "repo": repo, "heading": path.stem,
                    "text": path.read_text(encoding="utf-8", errors="replace")[:20000],
                    "type": "seed", "status": "current", "related": "",
                })
            except OSError:
                continue
    return leafs


def index_leafs(conn, leafs: list[dict], embed_fn, limit: int) -> tuple[int, int]:
    count = 0
    for lf in leafs[:limit] if limit else leafs:
        query = f"{lf['heading']}\n\n{lf['text']}"
        emb = embed_fn(lf["text"]) if lf["text"] else None
        upsert_leaf(conn, text=query, root="info", confidence="confirmed",
                    source=lf["source"], source_rev="working-tree",
                    how="kb/index", loc=lf["source"], type_=lf.get("type", "reference"),
                    embedding=emb)
        count += 1
    return count, len(leafs)


def embedder():
    from model2vec import StaticModel
    model = StaticModel.from_pretrained("minishlab/potion-multilingual-128M")
    return lambda text: model.encode([text])[0].astype(float).tolist()


def main(argv: list[str]) -> int:
    import argparse
    p = argparse.ArgumentParser(description="build the 2dph brain index")
    p.add_argument("--corpus", action="append", help="extra markdown dir/file to index (may repeat)")
    p.add_argument("--rebuild", action="store_true", help="fresh db + indexes")
    p.add_argument("--limit", type=int, default=0, help="max leafs to embed")
    p.add_argument("--json", action="store_true")
    a = p.parse_args(argv)

    from kblib import DB_PATH, VAR
    VAR.mkdir(exist_ok=True)
    if a.rebuild and DB_PATH.exists():
        DB_PATH.unlink()

    leafs = load_corpus(ROOT)
    if a.corpus:
        for source in a.corpus:
            leafs.extend(load_corpus_glob(source))

    db, conn = connect(DB_PATH, read_only=False)
    init_schema(conn)

    if not (a.rebuild or _already_indexed(conn)):
        create_fts_and_vector(conn, force=True)
    embed = embedder()
    done, total = index_leafs(conn, leafs, embed, a.limit)
    create_fts_and_vector(conn, force=(done > 0 or a.rebuild))
    s = stats(conn)
    conn.close()
    db.close()

    result = {"indexed": done, "corpus_total": total, **{k: v for k, v in s.items() if k in ("total", "by_root")}}
    print(json.dumps(result, indent=2) if a.json else f"indexed {done}/{total} leafs; db total {s['total']}")
    return 0


def _already_indexed(conn) -> bool:
    try:
        return conn.execute("MATCH (l:Leaf) RETURN count(*)").get_all()[0][0] > 0
    except Exception:
        return False


if __name__ == "__main__":
    sys.exit(main(sys.argv[1:]))