"""Evaluate hybrid retrieval against the live knowledge base (phase 09).

Embeds each question via aipi, runs the same hybrid search the chat API
uses (cosine top-N + FTS top-N, RRF-fused), and prints the top-5 documents
with their cosine / fts / fused scores plus the honesty-gate verdict:

    uv run python -m scripts.eval_retrieval "How did I install gitlab?"
    uv run python -m scripts.eval_retrieval --from-file questions.txt

Requires ``AIPI_KEY`` in the environment (same convention as
``scripts/llm_probe.py``) and an imported knowledge base
(``python -m scripts.import_docs``). Exit code 0 when all questions were
scored (deflections are a normal result — the verdict column shows them).
"""
from __future__ import annotations

import argparse
import asyncio
import os
import sys

from dotenv import load_dotenv

load_dotenv()


def build_parser() -> argparse.ArgumentParser:
    p = argparse.ArgumentParser(
        prog="python -m scripts.eval_retrieval",
        description="Rank hybrid retrieval results for one or more questions.",
    )
    p.add_argument(
        "questions",
        nargs="*",
        metavar="QUESTION",
        help="one or more questions to evaluate",
    )
    p.add_argument(
        "--from-file",
        type=str,
        default=None,
        metavar="PATH",
        help="read questions from a file (one per line, blanks/# skipped)",
    )
    p.add_argument(
        "--top",
        type=int,
        default=5,
        help="documents to print per question (default: 5)",
    )
    return p


def read_questions(args: argparse.Namespace) -> list[str]:
    questions = list(args.questions)
    if args.from_file:
        with open(args.from_file, encoding="utf-8") as f:
            questions.extend(
                line.strip() for line in f if line.strip() and not line.lstrip().startswith("#")
            )
    return questions


async def _embed_all(llm, questions: list[str]) -> list[list[float]]:
    return await llm.embed(questions)


def main(argv: list[str] | None = None) -> int:
    args = build_parser().parse_args(argv)
    api_key = os.environ.get("BOR_LLM_API_KEY") or os.environ.get("AIPI_KEY", "")
    if not api_key or api_key == "not-needed":
        print(
            "eval_retrieval: AIPI_KEY is required in the environment "
            "(same convention as scripts/llm_probe.py).",
            file=sys.stderr,
        )
        return 1
    questions = read_questions(args)
    if not questions:
        print("eval_retrieval: no questions given (positional or --from-file).", file=sys.stderr)
        return 1

    from app.config import get_settings
    from app.db import SessionLocal, db_available
    from app.rag.llm import LLMClient
    from app.rag.retriever import RetrievedChunk, retrieve

    settings = get_settings()
    if not db_available():
        print("eval_retrieval: Postgres is down — run `podman compose up -d db`.", file=sys.stderr)
        return 1

    llm = LLMClient(settings)
    vectors = asyncio.run(_embed_all(llm, questions))

    print(
        f"eval: threshold={settings.relevance_threshold} "
        f"vector_candidates={settings.hybrid_vector_candidates} "
        f"lexical_candidates={settings.hybrid_lexical_candidates} rrf_k={settings.rrf_k}"
    )
    with SessionLocal() as db:
        for question, vec in zip(questions, vectors, strict=True):
            chunks = retrieve(db, question, vec)
            best_cosine = max((c.cosine for c in chunks), default=0.0)
            fts_hits = sum(1 for c in chunks if c.fts_hit)
            verdict = (
                "LOW (deflect)"
                if best_cosine < settings.relevance_threshold and fts_hits == 0
                else "HIGH (answer)"
            )
            print(f"\nquestion: {question!r}")
            print(f"  gate: best_cosine={best_cosine:.4f} fts_hits={fts_hits} -> {verdict}")
            # Best chunk per document, in fused rank order.
            best_by_doc: dict[str, RetrievedChunk] = {}
            for c in chunks:
                key = f"{c.document.source}/{c.document.path}"
                if key not in best_by_doc:
                    best_by_doc[key] = c
            for i, c in enumerate(list(best_by_doc.values())[: args.top], start=1):
                print(
                    f"  {i}. {c.document.source}/{c.document.path}  "
                    f"cosine={c.cosine:.4f} fts={int(c.fts_hit)} fused={c.score:.5f}  "
                    f"({c.document.title})"
                )
    return 0


if __name__ == "__main__":
    sys.exit(main())