#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Script:    scripts/import_markdown.py
Version:   0.7.1 (2025-09-06)
Autor:     mindnet / Architektur Datenimporte & Sync

Kurzbeschreibung
---------------
Importiert Markdown-Notizen aus einem Obsidian-ähnlichen Vault in Qdrant:
- Validiert Frontmatter / Note-Payload (gegen note.schema.json).
- Chunking + Embeddings.
- Leitet Edges direkt beim Import aus [[Wikilinks]] ab:
  - 'references' (Note→Note)
  - 'references_at' (Chunk→Note)
  - 'backlink' (Note←Note) (symmetrisch zu 'references')
- Idempotente Upserts (deterministische IDs über qdrant_points).

Neu in 0.7.1
------------
- Korrekte Änderungsdetektion via SHA-256 über die **komplette Datei** (Frontmatter+Body):
  - Feld: payload.hash_fulltext
  - Vergleicht neuen Hash gegen bestehenden Hash in Qdrant.
  - Nur bei Änderung → Verarbeitung/Upsert; sonst "skip".
- `--purge-before-upsert` wird **nur** ausgeführt, wenn sich die Note **wirklich geändert** hat.
- Robuste Qdrant-Scroll-Kompatibilität (2- oder 3-Tupel Rückgaben).

Aufrufbeispiele
---------------
Dry-Run (nur prüfen, nichts schreiben):
    python3 -m scripts.import_markdown --vault ./vault

Nur eine spezifische Note:
    python3 -m scripts.import_markdown --vault ./vault --note-id 20250821-foo

Apply (schreiben) mit Purge (nur geänderte Noten werden bereinigt + neu geschrieben):
    python3 -m scripts.import_markdown --vault ./vault --apply --purge-before-upsert

Parameter
---------
--vault PATH                 : Pflicht. Root-Verzeichnis des Vaults.
--apply                      : Wenn gesetzt, werden Upserts durchgeführt (sonst Dry-Run).
--purge-before-upsert        : Vor Upsert alte Chunks/Edges der **geänderten** Note löschen.
--note-id ID                 : Optional, verarbeitet nur diese eine Note.

Umgebungsvariablen (.env)
-------------------------
QDRANT_URL, QDRANT_API_KEY, COLLECTION_PREFIX, VECTOR_DIM
Defaults: url=http://127.0.0.1:6333, prefix=mindnet, dim=384

Kompatibilität
--------------
- Bestehende Kernmodule werden weiterverwendet:
  app.core.parser              (read_markdown, normalize_frontmatter, validate_required_frontmatter)
  app.core.validate_note       (validate_note_payload)
  app.core.chunker             (assemble_chunks)
  app.core.chunk_payload       (make_chunk_payloads)
  app.core.embed               (embed_texts)
  app.core.qdrant              (QdrantConfig, ensure_collections, get_client, collection_names)
  app.core.qdrant_points       (points_for_note, points_for_chunks, points_for_edges, upsert_batch)
  app.core.derive_edges        (build_note_index, derive_wikilink_edges)

Hinweise
--------
- Bitte im aktivierten venv laufen lassen:  source .venv/bin/activate
"""

from __future__ import annotations
import argparse
import glob
import hashlib
import json
import os
import sys
from typing import List, Dict, Tuple, Optional

from dotenv import load_dotenv
from qdrant_client.http import models as rest
from qdrant_client import QdrantClient

# Kern-Bausteine (aus eurem Projekt)
from app.core.parser import (
    read_markdown,
    normalize_frontmatter,
    validate_required_frontmatter,
)
from app.core.validate_note import validate_note_payload
from app.core.chunker import assemble_chunks
from app.core.chunk_payload import make_chunk_payloads
from app.core.embed import embed_texts
from app.core.qdrant import QdrantConfig, ensure_collections, get_client, collection_names
from app.core.qdrant_points import (
    points_for_note,
    points_for_chunks,
    points_for_edges,
    upsert_batch,
)
from app.core.derive_edges import build_note_index, derive_wikilink_edges


# -------------------------------------------------
# Hilfsfunktionen
# -------------------------------------------------

def iter_md(root: str) -> List[str]:
    patterns = ["**/*.md", "*.md"]
    out: List[str] = []
    for p in patterns:
        out.extend(glob.glob(os.path.join(root, p), recursive=True))
    # de-dupe + sort
    return sorted(list(dict.fromkeys(out)))


def file_sha256(path: str) -> str:
    """SHA256 über die **Rohdatei** (Frontmatter + Body)."""
    h = hashlib.sha256()
    with open(path, "rb") as f:
        for chunk in iter(lambda: f.read(8192), b""):
            h.update(chunk)
    return h.hexdigest()


def qdrant_scroll(client: QdrantClient, **kwargs) -> Tuple[List, Optional[str]]:
    """
    Wrapper, der sowohl (points, next_offset) als auch (points, next_page, _) Signaturen abdeckt.
    """
    res = client.scroll(**kwargs)
    if isinstance(res, tuple):
        if len(res) == 2:
            return res[0], res[1]
        if len(res) >= 3:
            return res[0], res[1]
    return res, None


def fetch_existing_note_hash(client: QdrantClient, prefix: str, note_id: str) -> Optional[str]:
    """Liest hash_fulltext aus mindnet_notes.payload für eine Note."""
    notes_col, _, _ = collection_names(prefix)
    f = rest.Filter(must=[rest.FieldCondition(key="note_id", match=rest.MatchValue(value=note_id))])
    pts, _ = qdrant_scroll(
        client,
        collection_name=notes_col,
        scroll_filter=f,
        with_payload=True,
        with_vectors=False,
        limit=1
    )
    if not pts:
        return None
    pl = getattr(pts[0], "payload", {}) or {}
    return pl.get("hash_fulltext")


def make_note_stub(abs_path: str, vault_root: str) -> Dict:
    """Minimaler Stub (id/title/path) für build_note_index."""
    parsed = read_markdown(abs_path)
    fm = normalize_frontmatter(parsed.frontmatter or {})
    if "id" not in fm or not fm["id"]:
        raise ValueError(f"Missing id in frontmatter: {abs_path}")
    rel = os.path.relpath(abs_path, vault_root)
    return {"note_id": fm["id"], "title": fm.get("title"), "path": rel}


def build_vault_index(vault_root: str) -> tuple[Dict, Dict, Dict]:
    """Index für robuste Wikilink-Auflösung über alle Noten im Vault."""
    stubs = []
    for p in iter_md(vault_root):
        try:
            stubs.append(make_note_stub(p, vault_root))
        except Exception:
            continue
    return build_note_index(stubs)


def purge_for_note(client: QdrantClient, prefix: str, note_id: str, chunk_ids: List[str]) -> None:
    """
    Selektives Purge der alten Daten für **diese** Note:
    - löscht Chunks (payload.note_id == note_id)
    - löscht Edges, deren source_id == note_id ODER in chunk_ids
    Notes selbst werden nicht gelöscht (Upsert reicht).
    """
    notes_col, chunks_col, edges_col = collection_names(prefix)

    # Chunks löschen
    f_chunks = rest.Filter(must=[rest.FieldCondition(key="note_id", match=rest.MatchValue(value=note_id))])
    client.delete(collection_name=chunks_col, points_selector=f_chunks, wait=True)

    # Edges löschen (OR über source_id Werte)
    should_conds = [rest.FieldCondition(key="source_id", match=rest.MatchValue(value=note_id))]
    for cid in chunk_ids:
        should_conds.append(rest.FieldCondition(key="source_id", match=rest.MatchValue(value=cid)))
    if should_conds:
        f_edges = rest.Filter(should=should_conds)
        client.delete(collection_name=edges_col, points_selector=f_edges, wait=True)


# -------------------------------------------------
# Main
# -------------------------------------------------

def main():
    ap = argparse.ArgumentParser()
    ap.add_argument("--vault", required=True, help="Pfad zum Vault-Root")
    ap.add_argument("--apply", action="store_true", help="Schreibt in Qdrant (sonst Dry-Run)")
    ap.add_argument(
        "--purge-before-upsert",
        action="store_true",
        help="Vor Upsert alte Chunks/Edges **nur für geänderte** Noten löschen.",
    )
    ap.add_argument("--note-id", help="Optional: nur diese Note verarbeiten")
    args = ap.parse_args()

    load_dotenv()
    cfg = QdrantConfig(
        url=os.getenv("QDRANT_URL", "http://127.0.0.1:6333"),
        api_key=os.getenv("QDRANT_API_KEY", None),
        prefix=os.getenv("COLLECTION_PREFIX", "mindnet"),
        dim=int(os.getenv("VECTOR_DIM", "384")),
    )
    client = get_client(cfg)
    ensure_collections(client, cfg.prefix, cfg.dim)

    vault_root = os.path.abspath(args.vault)
    files = iter_md(vault_root)
    if not files:
        print("Keine Markdown-Dateien gefunden.", file=sys.stderr)
        sys.exit(2)

    # Index einmal bauen (für Linkauflösung bei geänderten Noten)
    note_index = build_vault_index(vault_root)

    processed = 0
    for abs_path in files:
        parsed = read_markdown(abs_path)
        fm = normalize_frontmatter(parsed.frontmatter or {})
        try:
            validate_required_frontmatter(fm)
        except Exception:
            # unvollständige Note überspringen
            continue
        if args.note_id and fm.get("id") != args.note_id:
            continue

        processed += 1

        # Änderungsdetektion (Datei-Hash vs. Qdrant)
        new_hash = file_sha256(abs_path)
        old_hash = fetch_existing_note_hash(client, cfg.prefix, fm["id"])
        changed = (old_hash != new_hash)

        decision = "skip"
        if changed:
            decision = "apply" if args.apply else "dry-run"

        # Bei "skip" kein teures Chunking/Embedding/Edges nötig
        if not changed:
            print(json.dumps({
                "note_id": fm["id"],
                "title": fm.get("title"),
                "changed": False,
                "decision": "skip",
                "path": os.path.relpath(abs_path, vault_root),
            }, ensure_ascii=False))
            continue

        # --- Ab hier: Nur für geänderte Noten ---

        # Note-Payload erzeugen
        from app.core.note_payload import make_note_payload  # lazy import
        note_pl = make_note_payload(parsed, vault_root=vault_root)
        # Hash im Payload mitschreiben (Schema erlaubt hash_fulltext)
        note_pl["hash_fulltext"] = new_hash
        validate_note_payload(note_pl)

        # Chunking & Payloads
        chunks = assemble_chunks(fm["id"], parsed.body, fm.get("type", "concept"))
        chunk_pls = make_chunk_payloads(fm, note_pl["path"], chunks)

        # Embeddings
        texts = [c.get("text") or c.get("content") or "" for c in chunk_pls]
        vectors = embed_texts(texts)

        # Edges ableiten (Note-/Chunk-Level)
        edges = derive_wikilink_edges(note_pl, chunk_pls, note_index)

        # Purge (nur wenn apply + Option gesetzt)
        if args.apply and args.purge_before_upsert:
            # Chunk-IDs bestimmen (für Edge-Purge by source_id)
            chunk_ids = []
            for i, ch in enumerate(chunk_pls, start=1):
                cid = ch.get("chunk_id") or ch.get("id") or f"{fm['id']}#{i}"
                ch["chunk_id"] = cid  # sicherstellen
                chunk_ids.append(cid)
            purge_for_note(client, cfg.prefix, fm["id"], chunk_ids)

        # Upserts (nur Apply)
        if args.apply:
            notes_col, note_pts = points_for_note(cfg.prefix, note_pl, note_vec=None, dim=cfg.dim)
            upsert_batch(client, notes_col, note_pts)

            chunks_col, chunk_pts = points_for_chunks(cfg.prefix, chunk_pls, vectors)
            upsert_batch(client, chunks_col, chunk_pts)

            edges_col, edge_pts = points_for_edges(cfg.prefix, edges)
            upsert_batch(client, edges_col, edge_pts)

        # Logging geänderte Note
        print(json.dumps({
            "note_id": fm["id"],
            "title": fm.get("title"),
            "chunks": len(chunk_pls),
            "edges": len(edges),
            "changed": True,
            "decision": decision,
            "path": note_pl["path"],
        }, ensure_ascii=False))

    print(f"Done. Processed notes: {processed}")


if __name__ == "__main__":
    main()