"""Configuration comparison: run e2e eval across multiple pipeline settings.

Usage (from the rag-qa/ directory):
    python -m evaluation.compare path/to/doc.pdf [more.pdf ...]
"""

import logging
import sys
from pathlib import Path

from ingestion.embedder import Embedder
from ingestion.pipeline import IngestionPipeline
from retrieval.index import VectorIndex
from generation.generator import Generator
from evaluation.eval_e2e import PLACEHOLDER_TEST_CASES, evaluate_e2e

logger = logging.getLogger(__name__)

_DEFAULT_CONFIGURATIONS = [
    {"label": "baseline (no rerank)", "chunk_size": 500,  "overlap": 50,  "use_reranking": False},
    {"label": "with reranking",        "chunk_size": 500,  "overlap": 50,  "use_reranking": True},
    {"label": "larger chunks + rerank","chunk_size": 1000, "overlap": 100, "use_reranking": True},
]


def compare_configurations(
    pdf_paths: list[str | Path],
    test_cases: list[dict] | None = None,
    configurations: list[dict] | None = None,
    rate_limit_delay: float = 1.5,
) -> list[dict]:
    """Re-ingest PDFs under multiple configurations and compare end-to-end metrics.

    Each configuration dict supports:
        label         (str)  — display name (auto-generated if omitted)
        chunk_size    (int)  — default 500
        overlap       (int)  — default 50
        use_reranking (bool) — default True

    Args:
        pdf_paths:         PDFs to ingest for each configuration.
        test_cases:        Labelled queries (defaults to PLACEHOLDER_TEST_CASES).
        configurations:    List of config dicts (defaults to three standard presets).
        rate_limit_delay:  Seconds between Gemini judge calls.

    Returns:
        List of result dicts with label and aggregate metric values. Also prints
        a formatted comparison table.
    """
    if test_cases is None:
        test_cases = PLACEHOLDER_TEST_CASES
    if configurations is None:
        configurations = _DEFAULT_CONFIGURATIONS

    pdf_paths = [Path(p) for p in pdf_paths]
    missing = [p for p in pdf_paths if not p.exists()]
    if missing:
        raise FileNotFoundError(f"PDF(s) not found: {missing}")

    print("Loading embedder and generator (shared across all configurations)...")
    embedder = Embedder()
    generator = Generator()

    rows: list[dict] = []

    for idx, cfg in enumerate(configurations, start=1):
        label = cfg.get("label") or f"config-{idx}"
        chunk_size = int(cfg.get("chunk_size", 500))
        overlap = int(cfg.get("overlap", 50))
        use_reranking = bool(cfg.get("use_reranking", True))

        print(f"\n[{idx}/{len(configurations)}] {label}  "
              f"(chunk={chunk_size}, overlap={overlap}, rerank={use_reranking})")

        index = VectorIndex(dimension=embedder.dimension)
        pipeline = IngestionPipeline(
            embedder=embedder, index=index,
            strategy="recursive_character",
            chunk_size=chunk_size, overlap=overlap,
        )
        for p in pdf_paths:
            r = pipeline.ingest_pdf(p)
            if r.error:
                logger.warning("  Skipped %s: %s", p.name, r.error)
            else:
                print(f"  {p.name}: {r.chunks} chunks")

        metrics = evaluate_e2e(
            test_cases, embedder, index, generator,
            rate_limit_delay=rate_limit_delay, use_reranking=use_reranking,
        )
        print(f"  → {metrics}")

        rows.append({
            "label": label,
            "chunk_size": chunk_size,
            "overlap": overlap,
            "use_reranking": use_reranking,
            "hit_rate":     metrics.retrieval_hit_rate,
            "faithfulness": metrics.avg_faithfulness,
            "relevance":    metrics.avg_relevance,
            "keyword_cov":  metrics.avg_keyword_coverage,
            "composite":    metrics.avg_composite,
        })

    _print_table(rows)
    return rows


def _print_table(rows: list[dict]) -> None:
    L, H, F, R, K, C = 28, 7, 8, 8, 10, 10
    total = L + H + F + R + K + C
    div = "-" * total

    print(f"\n{'Configuration Comparison':^{total}}")
    print(div)
    print(
        "Configuration".ljust(L) + "Hit".ljust(H) + "Faith.".ljust(F)
        + "Relev.".ljust(R) + "Keywords".ljust(K) + "Composite".ljust(C)
    )
    print(div)
    for row in rows:
        label = (row["label"][:L - 2] + "…") if len(row["label"]) > L - 1 else row["label"]
        print(
            label.ljust(L)
            + f"{row['hit_rate']:.2f}".ljust(H)
            + f"{row['faithfulness']:.2f}".ljust(F)
            + f"{row['relevance']:.2f}".ljust(R)
            + f"{row['keyword_cov']:.2f}".ljust(K)
            + f"{row['composite']:.2f}".ljust(C)
        )
    print(div)
    best = max(rows, key=lambda r: r["composite"])
    print(f"\nBest by composite score: {best['label']} ({best['composite']:.2f})")


if __name__ == "__main__":
    logging.basicConfig(level=logging.INFO, format="%(levelname)s | %(name)s | %(message)s")

    if len(sys.argv) < 2:
        print("Usage: python -m evaluation.compare <path/to/doc.pdf> [more.pdf ...]")
        sys.exit(0)

    compare_configurations([Path(p) for p in sys.argv[1:]])