#!/usr/bin/env python3
"""Reindex all technique pages into LightRAG for entity/relationship extraction.

Connects to PostgreSQL, extracts formatted text from each technique page
(with creator and key moment data), and submits to the LightRAG API.

Supports resume (skips already-processed file_sources) and dry-run mode.

Usage:
    # Dry run — format and preview without submitting
    python3 /app/scripts/reindex_lightrag.py --dry-run --limit 3

    # Submit first 2 pages
    python3 /app/scripts/reindex_lightrag.py --limit 2

    # Full reindex
    python3 /app/scripts/reindex_lightrag.py
"""

import argparse
import json
import logging
import os
import sys
import time
from typing import Any

import httpx
from sqlalchemy import create_engine
from sqlalchemy.orm import Session, joinedload, sessionmaker

# Resolve imports whether run from /app/ (Docker) or backend/ (local)
_script_dir = os.path.dirname(os.path.abspath(os.path.realpath(__file__)))
_backend_dir = os.path.dirname(_script_dir)
sys.path.insert(0, _backend_dir)

from models import Creator, KeyMoment, TechniquePage  # noqa: E402

logger = logging.getLogger("reindex_lightrag")


# ── Database ─────────────────────────────────────────────────────────────────


def get_sync_engine(db_url: str):
    """Create a sync SQLAlchemy engine, converting async URL if needed."""
    url = db_url.replace("postgresql+asyncpg://", "postgresql+psycopg2://")
    return create_engine(url, pool_pre_ping=True)


def load_technique_pages(session: Session, limit: int | None = None) -> list[TechniquePage]:
    """Load all technique pages with creator and key moments eagerly."""
    query = (
        session.query(TechniquePage)
        .options(
            joinedload(TechniquePage.creator),
            joinedload(TechniquePage.key_moments),
        )
        .order_by(TechniquePage.title)
    )
    if limit:
        query = query.limit(limit)
    return query.all()


# ── Text formatting ──────────────────────────────────────────────────────────


def _format_v1_sections(body_sections: dict) -> str:
    """Format v1 body_sections (flat dict: heading → content)."""
    parts = []
    for heading, content in body_sections.items():
        parts.append(f"## {heading}")
        if isinstance(content, str):
            parts.append(content)
        elif isinstance(content, list):
            parts.append("\n".join(str(item) for item in content))
        parts.append("")
    return "\n".join(parts)


def _format_v2_sections(body_sections: list[dict]) -> str:
    """Format v2 body_sections (list of {heading, content, subsections})."""
    parts = []
    for section in body_sections:
        heading = section.get("heading", "")
        content = section.get("content", "")
        if heading:
            parts.append(f"## {heading}")
        if content:
            parts.append(content)
        # Flatten subsections
        for sub in section.get("subsections", []):
            sub_heading = sub.get("heading", "")
            sub_content = sub.get("content", "")
            if sub_heading:
                parts.append(f"### {sub_heading}")
            if sub_content:
                parts.append(sub_content)
        parts.append("")
    return "\n".join(parts)


def format_technique_page(page: TechniquePage) -> str:
    """Convert a TechniquePage + relations into a rich text document for LightRAG."""
    lines = []

    # Header metadata
    lines.append(f"Technique: {page.title}")
    if page.creator:
        lines.append(f"Creator: {page.creator.name}")
    lines.append(f"Category: {page.topic_category or 'Uncategorized'}")
    if page.topic_tags:
        lines.append(f"Tags: {', '.join(page.topic_tags)}")
    if page.plugins:
        lines.append(f"Plugins: {', '.join(page.plugins)}")
    lines.append("")

    # Summary
    if page.summary:
        lines.append(f"Summary: {page.summary}")
        lines.append("")

    # Body sections — handle both formats
    if page.body_sections:
        fmt = getattr(page, "body_sections_format", "v1") or "v1"
        if fmt == "v2" and isinstance(page.body_sections, list):
            lines.append(_format_v2_sections(page.body_sections))
        elif isinstance(page.body_sections, dict):
            lines.append(_format_v1_sections(page.body_sections))
        elif isinstance(page.body_sections, list):
            # v1 tag but list data — treat as v2
            lines.append(_format_v2_sections(page.body_sections))
        else:
            lines.append(str(page.body_sections))

    # Key moments from source videos
    if page.key_moments:
        lines.append("Key Moments from Source Videos:")
        for km in page.key_moments:
            lines.append(f"- {km.title}: {km.summary}")
        lines.append("")

    return "\n".join(lines).strip()


def file_source_for_page(page: TechniquePage) -> str:
    """Deterministic file_source identifier for a technique page."""
    return f"technique:{page.slug}"


# ── LightRAG API ─────────────────────────────────────────────────────────────


def get_processed_sources(lightrag_url: str) -> set[str]:
    """Fetch all file_paths from LightRAG documents for resume support."""
    url = f"{lightrag_url}/documents"
    try:
        resp = httpx.get(url, timeout=30)
        resp.raise_for_status()
        data = resp.json()
    except httpx.HTTPError as e:
        logger.warning("Failed to fetch existing documents for resume: %s", e)
        return set()

    sources = set()
    statuses = data.get("statuses", {})
    for status_group in statuses.values():
        for doc in status_group:
            fp = doc.get("file_path")
            if fp:
                sources.add(fp)
    return sources


def submit_document(lightrag_url: str, text: str, file_source: str) -> dict[str, Any] | None:
    """Submit a text document to LightRAG. Returns response dict or None on error."""
    url = f"{lightrag_url}/documents/text"
    payload = {"text": text, "file_source": file_source}
    try:
        resp = httpx.post(url, json=payload, timeout=60)
        resp.raise_for_status()
        return resp.json()
    except httpx.HTTPError as e:
        logger.error("Failed to submit document %s: %s", file_source, e)
        return None


def wait_for_pipeline(lightrag_url: str, timeout: int = 600) -> bool:
    """Poll pipeline_status until busy=false. Returns True if finished, False on timeout."""
    url = f"{lightrag_url}/documents/pipeline_status"
    start = time.monotonic()
    while time.monotonic() - start < timeout:
        try:
            resp = httpx.get(url, timeout=10)
            resp.raise_for_status()
            data = resp.json()
            if not data.get("busy", False):
                return True
            msg = data.get("latest_message", "")
            if msg:
                logger.debug("  Pipeline: %s", msg)
        except httpx.HTTPError as e:
            logger.warning("  Pipeline status check failed: %s", e)
        time.sleep(10)
    logger.warning("Pipeline did not finish within %ds timeout", timeout)
    return False


# ── Main ─────────────────────────────────────────────────────────────────────


def main():
    parser = argparse.ArgumentParser(
        description="Reindex technique pages into LightRAG"
    )
    parser.add_argument(
        "--lightrag-url",
        default=os.environ.get("LIGHTRAG_URL", "http://chrysopedia-lightrag:9621"),
        help="LightRAG API base URL (default: http://chrysopedia-lightrag:9621)",
    )
    parser.add_argument(
        "--db-url",
        default=os.environ.get(
            "DATABASE_URL",
            "postgresql+asyncpg://chrysopedia:changeme@chrysopedia-db:5432/chrysopedia",
        ),
        help="Database URL (async or sync format accepted)",
    )
    parser.add_argument(
        "--dry-run",
        action="store_true",
        help="Format and preview pages without submitting to LightRAG",
    )
    parser.add_argument(
        "--limit",
        type=int,
        default=None,
        help="Process only the first N pages (for testing)",
    )
    parser.add_argument(
        "--verbose", "-v",
        action="store_true",
        help="Enable debug logging",
    )
    args = parser.parse_args()

    logging.basicConfig(
        level=logging.DEBUG if args.verbose else logging.INFO,
        format="%(asctime)s %(levelname)s %(message)s",
        datefmt="%H:%M:%S",
    )

    # Connect to PostgreSQL
    logger.info("Connecting to PostgreSQL...")
    try:
        engine = get_sync_engine(args.db_url)
        SessionLocal = sessionmaker(bind=engine)
        session = SessionLocal()
    except Exception as e:
        logger.error("Failed to connect to PostgreSQL: %s", e)
        sys.exit(1)

    # Load technique pages
    pages = load_technique_pages(session, limit=args.limit)
    total = len(pages)
    logger.info("Loaded %d technique page(s)", total)

    if total == 0:
        logger.info("No pages to process.")
        session.close()
        return

    # Resume support — get already-processed sources
    processed_sources: set[str] = set()
    if not args.dry_run:
        logger.info("Checking LightRAG for already-processed documents...")
        processed_sources = get_processed_sources(args.lightrag_url)
        logger.info("Found %d existing document(s) in LightRAG", len(processed_sources))

    # Process pages
    submitted = 0
    skipped = 0
    errors = 0
    total_chars = 0

    for i, page in enumerate(pages, 1):
        slug = page.slug
        source = file_source_for_page(page)
        text = format_technique_page(page)
        total_chars += len(text)

        if args.dry_run:
            if i == 1:
                print("=" * 80)
                print(f"PREVIEW: {page.title} ({source})")
                print("=" * 80)
                print(text)
                print("=" * 80)
            logger.info("[%d/%d] Formatted: %s (%d chars)", i, total, slug, len(text))
            continue

        # Resume — skip already-processed
        if source in processed_sources:
            logger.info("[%d/%d] Skipped (already processed): %s", i, total, slug)
            skipped += 1
            continue

        # Submit
        logger.info("[%d/%d] Submitting: %s (%d chars)", i, total, slug, len(text))
        result = submit_document(args.lightrag_url, text, source)
        if result is None:
            errors += 1
            continue

        status = result.get("status", "unknown")
        if status == "duplicated":
            logger.info("[%d/%d] Duplicated (already in LightRAG): %s", i, total, slug)
            skipped += 1
            continue

        if status not in ("success", "partial_success"):
            logger.error("[%d/%d] Unexpected status '%s' for %s: %s",
                         i, total, status, slug, result.get("message", ""))
            errors += 1
            continue

        submitted += 1
        logger.info("[%d/%d] Submitted: %s (track_id=%s)", i, total, slug,
                     result.get("track_id", "?"))

        # Wait for pipeline to finish before submitting next
        logger.info("[%d/%d] Waiting for pipeline to process %s...", i, total, slug)
        finished = wait_for_pipeline(args.lightrag_url)
        if finished:
            logger.info("[%d/%d] Processed: %s", i, total, slug)
        else:
            logger.warning("[%d/%d] Pipeline timeout for %s — continuing anyway", i, total, slug)

    session.close()

    # Summary
    print()
    print(f"{'DRY RUN ' if args.dry_run else ''}Summary:")
    print(f"  Total pages: {total}")
    print(f"  Total chars: {total_chars:,}")
    if not args.dry_run:
        print(f"  Submitted:   {submitted}")
        print(f"  Skipped:     {skipped}")
        print(f"  Errors:      {errors}")


if __name__ == "__main__":
    main()