"""Measure host fast-path vs subprocess rc-jav.py for cached single-ID search.

Step 11 of the console-consolidation roadmap asks: does the host's
`handle_cached_search_fast` actually save meaningful latency vs just
shelling out to `rc-jav.py --search ID --format json --quick`? If yes,
under what conditions (idle Python vs Python actively scanning)?

This script runs both paths N times against a set of query IDs and
reports min / median / mean / p95 / max in milliseconds.

Usage:
    python benchmarks/host-fast-path.py [--queries Q1 Q2 ...] [--iterations N]

To measure (b) Python-actively-scanning, kick off a `rc-jav.py --scan` in
another terminal, then run this script while the scan runs.

The fast-path implementation is replicated inline here (not imported
from the host module) so the benchmark is self-contained.
"""
from __future__ import annotations

import argparse
import json
import statistics
import subprocess
import sys
import time
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
if str(ROOT) not in sys.path:
    sys.path.insert(0, str(ROOT))

from rcjav.cache import load_cache  # noqa: E402
from rcjav.ids import current_rules_signature, normalize_id  # noqa: E402


DEFAULT_QUERIES = ["SSIS-001", "ABP-100", "FC2-1841460", "MIDD-500", "IBW-902"]
DEFAULT_ITERATIONS = 20


def fast_path_search(cache: dict, query: str) -> int:
    """Replicates handle_cached_search_fast minus the response shape.

    Returns hit count. Walks every remote's files[] looking for jav_id
    matching the normalized query (exact or `<id>#partN`).
    """
    norm = normalize_id(query)
    if not norm:
        return 0
    hits = 0
    for remote, entry in (cache.get("remotes") or {}).items():
        files = entry.get("files") or []
        for item in files:
            jid = item.get("jav_id", "")
            if jid == norm or (isinstance(jid, str) and jid.startswith(norm + "#part")):
                hits += 1
    return hits


def time_fast_path(query: str, iterations: int) -> list[float]:
    sig = current_rules_signature()
    cache = load_cache(sig)
    out: list[float] = []
    for _ in range(iterations):
        t0 = time.perf_counter()
        fast_path_search(cache, query)
        out.append((time.perf_counter() - t0) * 1000)
    return out


def time_subprocess(query: str, iterations: int) -> list[float]:
    cmd = [
        sys.executable,
        str(ROOT / "rc-jav.py"),
        "--search", query,
        "--cache",        # force cache mode (no rclone)
        "--format", "json",
        "--basic", "--no-color",
    ]
    out: list[float] = []
    for _ in range(iterations):
        t0 = time.perf_counter()
        proc = subprocess.run(cmd, capture_output=True, text=True, encoding="utf-8", errors="replace")
        out.append((time.perf_counter() - t0) * 1000)
        if proc.returncode not in (0, 1):  # 1 = no hits, still valid
            sys.stderr.write(f"subprocess returned {proc.returncode}; stderr={proc.stderr[:200]!r}\n")
    return out


def percentile(values: list[float], p: float) -> float:
    if not values:
        return 0.0
    s = sorted(values)
    k = (len(s) - 1) * p
    f = int(k)
    c = min(f + 1, len(s) - 1)
    return s[f] + (s[c] - s[f]) * (k - f)


def summarize(label: str, values: list[float]) -> None:
    if not values:
        print(f"  {label}: (no data)")
        return
    print(f"  {label}:")
    print(f"    n={len(values)}  min={min(values):.2f}ms  median={statistics.median(values):.2f}ms  "
          f"mean={statistics.mean(values):.2f}ms  p95={percentile(values, 0.95):.2f}ms  max={max(values):.2f}ms")


def main() -> int:
    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument("--queries", nargs="+", default=DEFAULT_QUERIES,
                    help=f"JAV IDs to search (default: {DEFAULT_QUERIES})")
    ap.add_argument("--iterations", type=int, default=DEFAULT_ITERATIONS,
                    help=f"Iterations per query per path (default: {DEFAULT_ITERATIONS})")
    args = ap.parse_args()

    print(f"Host fast-path vs subprocess rc-jav.py benchmark")
    print(f"queries: {args.queries}")
    print(f"iterations per path: {args.iterations}")
    print(f"cache: {ROOT / 'cache.json'}")
    print()

    all_fast: list[float] = []
    all_sub: list[float] = []
    for q in args.queries:
        print(f"[{q}]")
        fast = time_fast_path(q, args.iterations)
        summarize("fast-path (in-process dict walk)", fast)
        sub = time_subprocess(q, args.iterations)
        summarize("subprocess rc-jav.py --search --cache", sub)
        all_fast.extend(fast)
        all_sub.extend(sub)
        if fast and sub:
            speedup = statistics.median(sub) / max(statistics.median(fast), 0.001)
            print(f"  speedup (median sub / median fast): {speedup:.1f}x")
        print()

    print("=== aggregate ===")
    summarize("fast-path total", all_fast)
    summarize("subprocess total", all_sub)
    if all_fast and all_sub:
        med_speedup = statistics.median(all_sub) / max(statistics.median(all_fast), 0.001)
        p95_speedup = percentile(all_sub, 0.95) / max(percentile(all_fast, 0.95), 0.001)
        print(f"  median speedup: {med_speedup:.1f}x")
        print(f"  p95 speedup:    {p95_speedup:.1f}x")
    return 0


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