#!/usr/bin/env python3
"""
Benchmark script for path_matcher performance comparison.

Compares:
- Pure Python implementation
- Cython implementation (if available)
- Original MountedApp from asgi_mount.py

Usage:
    python benchmarks/bench_path_matcher.py
"""

import time
import statistics
from typing import Callable, List, Tuple

from pyserve._path_matcher_py import (
    FastMountedPath as PyFastMountedPath,
    FastMountManager as PyFastMountManager,
    path_matches_prefix as py_path_matches_prefix,
)

try:
    from pyserve._path_matcher import (
        FastMountedPath as CyFastMountedPath,
        FastMountManager as CyFastMountManager,
        path_matches_prefix as cy_path_matches_prefix,
    )
    CYTHON_AVAILABLE = True
except ImportError:
    CYTHON_AVAILABLE = False
    print("Cython module not compiled. Run: python setup_cython.py build_ext --inplace\n")

from pyserve.asgi_mount import MountedApp


def benchmark(func: Callable, iterations: int = 100000) -> Tuple[float, float]:
    times = []
    
    for _ in range(1000):
        func()
    
    for _ in range(iterations):
        start = time.perf_counter_ns()
        func()
        end = time.perf_counter_ns()
        times.append(end - start)
    
    return statistics.mean(times), statistics.stdev(times)


def format_time(ns: float) -> str:
    if ns < 1000:
        return f"{ns:.1f} ns"
    elif ns < 1_000_000:
        return f"{ns/1000:.2f} µs"
    else:
        return f"{ns/1_000_000:.2f} ms"


def run_benchmarks():
    print("=" * 70)
    print("PATH MATCHER BENCHMARK")
    print("=" * 70)
    print()
    
    # Test paths
    mount_path = "/api/v1"
    test_paths = [
        "/api/v1/users/123/posts",  # Matching - long
        "/api/v1",                   # Matching - exact
        "/api/v2/users",             # Not matching - similar prefix
        "/other/path",               # Not matching - completely different
    ]
    
    iterations = 100000
    
    # =========================================================================
    # Benchmark 1: Single path matching
    # =========================================================================
    print("BENCHMARK 1: Single Path Matching")
    print("-" * 70)
    print(f"   Mount path: {mount_path}")
    print(f"   Iterations: {iterations:,}")
    print()
    
    results = {}
    
    # Original MountedApp
    original_mount = MountedApp(mount_path, app=None, name="test")  # type: ignore
    
    for test_path in test_paths:
        print(f"   Test path: {test_path}")
        
        # Original
        mean, std = benchmark(lambda: original_mount.matches(test_path), iterations)
        results[("Original", test_path)] = mean
        print(f"      Original MountedApp:     {format_time(mean):>12} ± {format_time(std)}")
        
        # Pure Python
        py_mount = PyFastMountedPath(mount_path)
        mean, std = benchmark(lambda: py_mount.matches(test_path), iterations)
        results[("Python", test_path)] = mean
        print(f"      Pure Python:             {format_time(mean):>12} ± {format_time(std)}")
        
        # Cython (if available)
        if CYTHON_AVAILABLE:
            cy_mount = CyFastMountedPath(mount_path)
            mean, std = benchmark(lambda: cy_mount.matches(test_path), iterations)
            results[("Cython", test_path)] = mean
            print(f"      Cython:                  {format_time(mean):>12} ± {format_time(std)}")
        
        print()
    
    # =========================================================================
    # Benchmark 2: Mount Manager lookup
    # =========================================================================
    print()
    print("BENCHMARK 2: Mount Manager Lookup (10 mounts)")
    print("-" * 70)
    
    # Setup managers with 10 mounts
    mount_paths = [f"/api/v{i}" for i in range(10)]
    
    py_manager = PyFastMountManager()
    for p in mount_paths:
        py_manager.add_mount(PyFastMountedPath(p, name=p))
    
    if CYTHON_AVAILABLE:
        cy_manager = CyFastMountManager()
        for p in mount_paths:
            cy_manager.add_mount(CyFastMountedPath(p, name=p))
    
    test_lookups = [
        "/api/v5/users/123",  # Middle mount
        "/api/v0/items",      # First mount (longest)
        "/api/v9/data",       # Last mount
        "/other/not/found",   # No match
    ]
    
    for test_path in test_lookups:
        print(f"   Lookup path: {test_path}")
        
        # Pure Python
        mean, std = benchmark(lambda: py_manager.get_mount(test_path), iterations)
        print(f"      Pure Python:             {format_time(mean):>12} ± {format_time(std)}")
        
        # Cython
        if CYTHON_AVAILABLE:
            mean, std = benchmark(lambda: cy_manager.get_mount(test_path), iterations)
            print(f"      Cython:                  {format_time(mean):>12} ± {format_time(std)}")
        
        print()
    
    # =========================================================================
    # Benchmark 3: Combined match + modify
    # =========================================================================
    print()
    print("BENCHMARK 3: Combined Match + Modify Path")
    print("-" * 70)
    
    from pyserve._path_matcher_py import match_and_modify_path as py_match_modify
    if CYTHON_AVAILABLE:
        from pyserve._path_matcher import match_and_modify_path as cy_match_modify
    
    test_path = "/api/v1/users/123/posts"
    print(f"   Test path: {test_path}")
    print(f"   Mount path: {mount_path}")
    print()
    
    # Original (separate calls)
    def original_match_modify():
        if original_mount.matches(test_path):
            return original_mount.get_modified_path(test_path)
        return None
    
    mean, std = benchmark(original_match_modify, iterations)
    print(f"   Original (2 calls):         {format_time(mean):>12} ± {format_time(std)}")
    
    # Pure Python combined
    mean, std = benchmark(lambda: py_match_modify(test_path, mount_path), iterations)
    print(f"   Pure Python (combined):     {format_time(mean):>12} ± {format_time(std)}")
    
    # Cython combined
    if CYTHON_AVAILABLE:
        mean, std = benchmark(lambda: cy_match_modify(test_path, mount_path), iterations)
        print(f"   Cython (combined):          {format_time(mean):>12} ± {format_time(std)}")
    
    # =========================================================================
    # Summary
    # =========================================================================
    print()
    print("=" * 70)
    print("SUMMARY")
    print("=" * 70)
    
    if CYTHON_AVAILABLE:
        print("Cython module is available and was benchmarked")
    else:
        print("Cython module not available - only Pure Python was benchmarked")
        print("   To build Cython module:")
        print("   1. Install Cython: pip install cython")
        print("   2. Build: python setup_cython.py build_ext --inplace")
    
    print()
    print("The optimized path matcher provides:")
    print("   - Pre-computed path length and trailing slash")
    print("   - Boundary-aware prefix matching (prevents /api matching /api-v2)")
    print("   - Combined match+modify operation to reduce function calls")
    print("   - Longest-prefix-first ordering in MountManager")


if __name__ == "__main__":
    run_benchmarks()