#!/usr/bin/env python3
"""
API-level performance test script for search stack services.

Default scenarios (aligned with docs/搜索API对接指南.md):
- backend_search      POST /search/
- backend_suggest     GET  /search/suggestions
- embed_text          POST /embed/text
- translate           POST /translate
- rerank              POST /rerank

Examples:
  python scripts/perf_api_benchmark.py --scenario backend_search --duration 30 --concurrency 20 --tenant-id 162
  python scripts/perf_api_benchmark.py --scenario backend_suggest --duration 30 --concurrency 50 --tenant-id 162
  python scripts/perf_api_benchmark.py --scenario all --duration 60 --concurrency 80 --tenant-id 162
  python scripts/perf_api_benchmark.py --scenario all --cases-file scripts/perf_cases.json.example --output perf_result.json
"""

from __future__ import annotations

import argparse
import asyncio
import json
import math
import statistics
import time
from dataclasses import dataclass
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

import httpx


@dataclass
class RequestTemplate:
    method: str
    path: str
    params: Optional[Dict[str, Any]] = None
    json_body: Optional[Any] = None
    headers: Optional[Dict[str, str]] = None


@dataclass
class Scenario:
    name: str
    templates: List[RequestTemplate]
    timeout_sec: float


@dataclass
class RequestResult:
    ok: bool
    status_code: int
    latency_ms: float
    error: str = ""


def _is_finite_number(v: Any) -> bool:
    if isinstance(v, bool):
        return False
    if isinstance(v, (int, float)):
        return math.isfinite(float(v))
    return False


def validate_response_payload(
    scenario_name: str,
    tpl: RequestTemplate,
    payload: Any,
) -> Tuple[bool, str]:
    """
    Lightweight payload validation for correctness-aware perf tests.
    Currently strict for embed_text to catch NaN/null vector regressions.
    """
    if scenario_name != "embed_text":
        return True, ""

    expected_len = len(tpl.json_body) if isinstance(tpl.json_body, list) else None
    if not isinstance(payload, list):
        return False, "invalid_payload_non_list"
    if expected_len is not None and len(payload) != expected_len:
        return False, "invalid_payload_length"
    if len(payload) == 0:
        return False, "invalid_payload_empty"

    for i, vec in enumerate(payload):
        if not isinstance(vec, list) or len(vec) == 0:
            return False, f"invalid_vector_{i}_shape"
        for x in vec:
            if not _is_finite_number(x):
                return False, f"invalid_vector_{i}_non_finite"
    return True, ""


def percentile(sorted_values: List[float], p: float) -> float:
    if not sorted_values:
        return 0.0
    if p <= 0:
        return sorted_values[0]
    if p >= 100:
        return sorted_values[-1]
    rank = (len(sorted_values) - 1) * (p / 100.0)
    low = int(math.floor(rank))
    high = int(math.ceil(rank))
    if low == high:
        return sorted_values[low]
    weight = rank - low
    return sorted_values[low] * (1.0 - weight) + sorted_values[high] * weight


def make_default_templates(tenant_id: str) -> Dict[str, List[RequestTemplate]]:
    return {
        "backend_search": [
            RequestTemplate(
                method="POST",
                path="/search/",
                headers={"X-Tenant-ID": tenant_id},
                json_body={"query": "wireless mouse", "size": 10, "language": "en"},
            ),
            RequestTemplate(
                method="POST",
                path="/search/",
                headers={"X-Tenant-ID": tenant_id},
                json_body={"query": "芭比娃娃", "size": 10, "language": "zh"},
            ),
            RequestTemplate(
                method="POST",
                path="/search/",
                headers={"X-Tenant-ID": tenant_id},
                json_body={"query": "f", "size": 10, "language": "en"},
            ),
        ],
        "backend_suggest": [
            RequestTemplate(
                method="GET",
                path="/search/suggestions",
                headers={"X-Tenant-ID": tenant_id},
                params={"q": "f", "size": 10, "language": "en"},
            ),
            RequestTemplate(
                method="GET",
                path="/search/suggestions",
                headers={"X-Tenant-ID": tenant_id},
                params={"q": "玩", "size": 10, "language": "zh"},
            ),
            RequestTemplate(
                method="GET",
                path="/search/suggestions",
                headers={"X-Tenant-ID": tenant_id},
                params={"q": "shi", "size": 10, "language": "en"},
            ),
        ],
        "embed_text": [
            RequestTemplate(
                method="POST",
                path="/embed/text",
                json_body=["wireless mouse", "gaming keyboard", "barbie doll"],
            )
        ],
        "translate": [
            RequestTemplate(
                method="POST",
                path="/translate",
                json_body={"text": "商品名称", "target_lang": "en", "source_lang": "zh", "model": "qwen"},
            ),
            RequestTemplate(
                method="POST",
                path="/translate",
                json_body={"text": "Product title", "target_lang": "zh", "model": "qwen"},
            ),
        ],
        "rerank": [
            RequestTemplate(
                method="POST",
                path="/rerank",
                json_body={
                    "query": "wireless mouse",
                    "docs": [
                        "Wireless ergonomic mouse with rechargeable battery",
                        "USB-C cable 1m",
                        "Gaming mouse 26000 DPI",
                    ],
                    "normalize": True,
                },
            )
        ],
    }


def load_cases_from_file(path: Path, tenant_id: str) -> Dict[str, List[RequestTemplate]]:
    data = json.loads(path.read_text(encoding="utf-8"))
    out: Dict[str, List[RequestTemplate]] = {}
    for scenario_name, requests_data in (data.get("scenarios") or {}).items():
        templates: List[RequestTemplate] = []
        for item in requests_data:
            headers = dict(item.get("headers") or {})
            if "X-Tenant-ID" in headers and str(headers["X-Tenant-ID"]).strip() == "${tenant_id}":
                headers["X-Tenant-ID"] = tenant_id
            templates.append(
                RequestTemplate(
                    method=str(item.get("method", "GET")).upper(),
                    path=str(item.get("path", "")).strip(),
                    params=item.get("params"),
                    json_body=item.get("json"),
                    headers=headers or None,
                )
            )
        if templates:
            out[scenario_name] = templates
    return out


def build_scenarios(args: argparse.Namespace) -> Dict[str, Scenario]:
    defaults = make_default_templates(args.tenant_id)
    if args.cases_file:
        custom = load_cases_from_file(Path(args.cases_file), tenant_id=args.tenant_id)
        defaults.update(custom)

    scenario_base = {
        "backend_search": args.backend_base,
        "backend_suggest": args.backend_base,
        "embed_text": args.embedding_base,
        "translate": args.translator_base,
        "rerank": args.reranker_base,
    }

    scenarios: Dict[str, Scenario] = {}
    for name, templates in defaults.items():
        if name not in scenario_base:
            continue
        base = scenario_base[name].rstrip("/")
        rewritten: List[RequestTemplate] = []
        for t in templates:
            path = t.path if t.path.startswith("/") else f"/{t.path}"
            rewritten.append(
                RequestTemplate(
                    method=t.method,
                    path=f"{base}{path}",
                    params=t.params,
                    json_body=t.json_body,
                    headers=t.headers,
                )
            )
        scenarios[name] = Scenario(name=name, templates=rewritten, timeout_sec=args.timeout)
    return scenarios


async def run_single_scenario(
    scenario: Scenario,
    duration_sec: int,
    concurrency: int,
    max_requests: int,
    max_errors: int,
) -> Dict[str, Any]:
    latencies: List[float] = []
    status_counter: Dict[int, int] = {}
    err_counter: Dict[str, int] = {}
    total_requests = 0
    success_requests = 0
    stop_flag = False
    lock = asyncio.Lock()
    start = time.perf_counter()

    timeout = httpx.Timeout(timeout=scenario.timeout_sec)
    limits = httpx.Limits(max_connections=max(concurrency * 2, 20), max_keepalive_connections=max(concurrency, 10))

    async def worker(worker_id: int, client: httpx.AsyncClient) -> None:
        nonlocal total_requests, success_requests, stop_flag
        idx = worker_id % len(scenario.templates)

        while not stop_flag:
            elapsed = time.perf_counter() - start
            if duration_sec > 0 and elapsed >= duration_sec:
                break

            async with lock:
                if max_requests > 0 and total_requests >= max_requests:
                    stop_flag = True
                    break
                total_requests += 1

            tpl = scenario.templates[idx % len(scenario.templates)]
            idx += 1

            t0 = time.perf_counter()
            ok = False
            status = 0
            err = ""
            try:
                resp = await client.request(
                    method=tpl.method,
                    url=tpl.path,
                    params=tpl.params,
                    json=tpl.json_body,
                    headers=tpl.headers,
                )
                status = int(resp.status_code)
                ok = 200 <= status < 300
                if ok:
                    try:
                        payload = resp.json()
                    except Exception:
                        ok = False
                        err = "invalid_json_response"
                    else:
                        valid, reason = validate_response_payload(
                            scenario_name=scenario.name,
                            tpl=tpl,
                            payload=payload,
                        )
                        if not valid:
                            ok = False
                            err = reason or "invalid_payload"
                if not ok and not err:
                    err = f"http_{status}"
            except Exception as e:
                err = type(e).__name__
            t1 = time.perf_counter()
            cost_ms = (t1 - t0) * 1000.0

            async with lock:
                latencies.append(cost_ms)
                if status:
                    status_counter[status] = status_counter.get(status, 0) + 1
                if ok:
                    success_requests += 1
                else:
                    err_counter[err or "unknown"] = err_counter.get(err or "unknown", 0) + 1
                    total_err = sum(err_counter.values())
                    if max_errors > 0 and total_err >= max_errors:
                        stop_flag = True

    async with httpx.AsyncClient(timeout=timeout, limits=limits) as client:
        tasks = [asyncio.create_task(worker(i, client)) for i in range(concurrency)]
        await asyncio.gather(*tasks)

    elapsed = max(time.perf_counter() - start, 1e-9)
    lat_sorted = sorted(latencies)

    result = {
        "scenario": scenario.name,
        "duration_sec": round(elapsed, 3),
        "total_requests": total_requests,
        "success_requests": success_requests,
        "failed_requests": max(total_requests - success_requests, 0),
        "success_rate": round((success_requests / total_requests) * 100.0, 2) if total_requests else 0.0,
        "throughput_rps": round(total_requests / elapsed, 2),
        "latency_ms": {
            "avg": round(statistics.mean(lat_sorted), 2) if lat_sorted else 0.0,
            "p50": round(percentile(lat_sorted, 50), 2),
            "p90": round(percentile(lat_sorted, 90), 2),
            "p95": round(percentile(lat_sorted, 95), 2),
            "p99": round(percentile(lat_sorted, 99), 2),
            "max": round(max(lat_sorted), 2) if lat_sorted else 0.0,
        },
        "status_codes": dict(sorted(status_counter.items(), key=lambda x: x[0])),
        "errors": dict(sorted(err_counter.items(), key=lambda x: x[0])),
    }
    return result


def format_summary(result: Dict[str, Any]) -> str:
    lines = []
    lines.append(f"\\n=== Scenario: {result['scenario']} ===")
    lines.append(
        "requests={total_requests} success={success_requests} fail={failed_requests} "
        "success_rate={success_rate}% rps={throughput_rps}".format(**result)
    )
    lat = result["latency_ms"]
    lines.append(
        f"latency(ms): avg={lat['avg']} p50={lat['p50']} p90={lat['p90']} p95={lat['p95']} p99={lat['p99']} max={lat['max']}"
    )
    lines.append(f"status_codes: {result['status_codes']}")
    if result["errors"]:
        lines.append(f"errors: {result['errors']}")
    return "\\n".join(lines)


def aggregate_results(results: List[Dict[str, Any]]) -> Dict[str, Any]:
    if not results:
        return {}
    total_requests = sum(x["total_requests"] for x in results)
    success_requests = sum(x["success_requests"] for x in results)
    failed_requests = sum(x["failed_requests"] for x in results)
    total_duration = sum(x["duration_sec"] for x in results)
    weighted_avg_latency = 0.0
    if total_requests > 0:
        weighted_avg_latency = sum(x["latency_ms"]["avg"] * x["total_requests"] for x in results) / total_requests

    return {
        "scenario": "ALL",
        "total_requests": total_requests,
        "success_requests": success_requests,
        "failed_requests": failed_requests,
        "success_rate": round((success_requests / total_requests) * 100.0, 2) if total_requests else 0.0,
        "aggregate_rps": round(total_requests / max(total_duration, 1e-9), 2),
        "weighted_avg_latency_ms": round(weighted_avg_latency, 2),
    }


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Interface-level load test for search and related microservices")
    parser.add_argument(
        "--scenario",
        type=str,
        default="all",
        help="Scenario: backend_search | backend_suggest | embed_text | translate | rerank | all",
    )
    parser.add_argument("--tenant-id", type=str, default="162", help="Tenant ID for backend search/suggest")
    parser.add_argument("--duration", type=int, default=30, help="Duration seconds per scenario; <=0 means no duration cap")
    parser.add_argument("--concurrency", type=int, default=20, help="Concurrent workers per scenario")
    parser.add_argument("--max-requests", type=int, default=0, help="Stop after N requests per scenario (0 means unlimited)")
    parser.add_argument("--timeout", type=float, default=10.0, help="Request timeout seconds")
    parser.add_argument("--max-errors", type=int, default=0, help="Stop scenario when accumulated errors reach this value")

    parser.add_argument("--backend-base", type=str, default="http://127.0.0.1:6002", help="Base URL for backend search API")
    parser.add_argument("--embedding-base", type=str, default="http://127.0.0.1:6005", help="Base URL for embedding service")
    parser.add_argument("--translator-base", type=str, default="http://127.0.0.1:6006", help="Base URL for translation service")
    parser.add_argument("--reranker-base", type=str, default="http://127.0.0.1:6007", help="Base URL for reranker service")

    parser.add_argument("--cases-file", type=str, default="", help="Optional JSON file to override/add request templates")
    parser.add_argument("--output", type=str, default="", help="Optional output JSON path")
    parser.add_argument("--pause", type=float, default=0.0, help="Pause seconds between scenarios in all mode")
    return parser.parse_args()


async def main_async() -> int:
    args = parse_args()
    scenarios = build_scenarios(args)

    all_names = ["backend_search", "backend_suggest", "embed_text", "translate", "rerank"]
    if args.scenario == "all":
        run_names = [x for x in all_names if x in scenarios]
    else:
        if args.scenario not in scenarios:
            print(f"Unknown scenario: {args.scenario}")
            print(f"Available: {', '.join(sorted(scenarios.keys()))}")
            return 2
        run_names = [args.scenario]

    if not run_names:
        print("No scenarios to run.")
        return 2

    print("Load test config:")
    print(f"  scenario={args.scenario}")
    print(f"  tenant_id={args.tenant_id}")
    print(f"  duration={args.duration}s")
    print(f"  concurrency={args.concurrency}")
    print(f"  max_requests={args.max_requests}")
    print(f"  timeout={args.timeout}s")
    print(f"  max_errors={args.max_errors}")
    print(f"  backend_base={args.backend_base}")
    print(f"  embedding_base={args.embedding_base}")
    print(f"  translator_base={args.translator_base}")
    print(f"  reranker_base={args.reranker_base}")

    results: List[Dict[str, Any]] = []
    for i, name in enumerate(run_names, start=1):
        scenario = scenarios[name]
        print(f"\\n[{i}/{len(run_names)}] running {name} ...")
        result = await run_single_scenario(
            scenario=scenario,
            duration_sec=args.duration,
            concurrency=args.concurrency,
            max_requests=args.max_requests,
            max_errors=args.max_errors,
        )
        print(format_summary(result))
        results.append(result)

        if args.pause > 0 and i < len(run_names):
            await asyncio.sleep(args.pause)

    final = {
        "timestamp": time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()),
        "config": {
            "scenario": args.scenario,
            "tenant_id": args.tenant_id,
            "duration_sec": args.duration,
            "concurrency": args.concurrency,
            "max_requests": args.max_requests,
            "timeout_sec": args.timeout,
            "max_errors": args.max_errors,
            "backend_base": args.backend_base,
            "embedding_base": args.embedding_base,
            "translator_base": args.translator_base,
            "reranker_base": args.reranker_base,
            "cases_file": args.cases_file or None,
        },
        "results": results,
        "overall": aggregate_results(results),
    }

    print("\\n=== Overall ===")
    print(json.dumps(final["overall"], ensure_ascii=False, indent=2))

    if args.output:
        out_path = Path(args.output)
        out_path.parent.mkdir(parents=True, exist_ok=True)
        out_path.write_text(json.dumps(final, ensure_ascii=False, indent=2), encoding="utf-8")
        print(f"Saved JSON report: {out_path}")

    return 0


def main() -> int:
    try:
        return asyncio.run(main_async())
    except KeyboardInterrupt:
        print("Interrupted by user")
        return 130


if __name__ == "__main__":
    raise SystemExit(main())