#!/usr/bin/env python3
import argparse
import json
import os
from pathlib import Path
from typing import List, Dict, Any

import requests


def chunk_text(text: str, max_chars: int = 1200, overlap: int = 200) -> List[str]:
    chunks: List[str] = []
    start = 0
    n = len(text)
    while start < n:
        end = min(start + max_chars, n)
        chunk = text[start:end].strip()
        if chunk:
            chunks.append(chunk)
        if end == n:
            break
        start = max(0, end - overlap)
    return chunks


def embed_texts_ollama(texts: List[str], model: str = "nomic-embed-text", host: str = "http://localhost:11434") -> List[List[float]]:
    url = f"{host}/api/embeddings"
    vectors: List[List[float]] = []
    for t in texts:
        resp = requests.post(url, json={"model": model, "prompt": t}, timeout=120)
        resp.raise_for_status()
        data = resp.json()
        vectors.append(data["embedding"])  # type: ignore[index]
    return vectors


def main() -> None:
    parser = argparse.ArgumentParser(description="Build simple vector index using Ollama embeddings")
    parser.add_argument("--text", default=None, help="Path to extracted .txt; default = first in data/")
    parser.add_argument("--model", default="nomic-embed-text", help="Ollama embedding model name")
    parser.add_argument("--host", default="http://localhost:11434", help="Ollama host")
    parser.add_argument("--out", default="data/index.jsonl", help="Output JSONL path")
    parser.add_argument("--max-chars", type=int, default=1200, help="Max characters per chunk")
    parser.add_argument("--overlap", type=int, default=200, help="Characters overlap between chunks")
    args = parser.parse_args()

    data_dir = Path("data")
    if args.text:
        text_path = Path(args.text)
    else:
        txts = sorted(data_dir.glob("*.txt"))
        if not txts:
            raise SystemExit("data/*.txt가 없습니다. 먼저 scripts/pdf_stats.py로 PDF를 추출하세요.")
        text_path = txts[0]

    text = text_path.read_text(encoding="utf-8")
    chunks = chunk_text(text, max_chars=args.max_chars, overlap=args.overlap)

    vectors = embed_texts_ollama(chunks, model=args.model, host=args.host)

    out_path = Path(args.out)
    out_path.parent.mkdir(parents=True, exist_ok=True)
    with out_path.open("w", encoding="utf-8") as f:
        for i, (chunk, vec) in enumerate(zip(chunks, vectors)):
            row: Dict[str, Any] = {
                "id": f"{text_path.stem}:{i}",
                "text": chunk,
                "vector": vec,
                "source": text_path.name,
            }
            f.write(json.dumps(row, ensure_ascii=False) + "\n")

    meta = {
        "source_text": str(text_path),
        "embedding_model": args.model,
        "host": args.host,
        "chunks": len(chunks),
        "index_path": str(out_path),
    }
    print(json.dumps(meta, ensure_ascii=False))


if __name__ == "__main__":
    main()