"""
Build script for Cython extensions.

Usage:
    python scripts/build_cython.py build_ext --inplace
    
Or via make:
    make build-cython
"""

import os
import subprocess
import sys
from pathlib import Path


def get_pcre2_config():
    include_dirs = []
    library_dirs = []
    libraries = ["pcre2-8"]
    
    try:
        cflags = subprocess.check_output(
            ["pkg-config", "--cflags", "libpcre2-8"],
            stderr=subprocess.DEVNULL
        ).decode().strip()
        libs = subprocess.check_output(
            ["pkg-config", "--libs", "libpcre2-8"],
            stderr=subprocess.DEVNULL
        ).decode().strip()
        
        for flag in cflags.split():
            if flag.startswith("-I"):
                include_dirs.append(flag[2:])
        
        for flag in libs.split():
            if flag.startswith("-L"):
                library_dirs.append(flag[2:])
            elif flag.startswith("-l"):
                lib = flag[2:]
                if lib not in libraries:
                    libraries.append(lib)
        
        return include_dirs, library_dirs, libraries
    except (subprocess.CalledProcessError, FileNotFoundError):
        pass
    
    try:
        cflags = subprocess.check_output(
            ["pcre2-config", "--cflags"],
            stderr=subprocess.DEVNULL
        ).decode().strip()
        libs = subprocess.check_output(
            ["pcre2-config", "--libs8"],
            stderr=subprocess.DEVNULL
        ).decode().strip()
        
        for flag in cflags.split():
            if flag.startswith("-I"):
                include_dirs.append(flag[2:])
        
        for flag in libs.split():
            if flag.startswith("-L"):
                library_dirs.append(flag[2:])
            elif flag.startswith("-l"):
                lib = flag[2:]
                if lib not in libraries:
                    libraries.append(lib)
        
        return include_dirs, library_dirs, libraries
    except (subprocess.CalledProcessError, FileNotFoundError):
        pass
    
    # Fallback: try common paths
    common_paths = [
        "/opt/homebrew",  # macOS ARM
        "/usr/local",     # macOS Intel / Linux
        "/usr",           # Linux
    ]
    
    for base in common_paths:
        include_path = Path(base) / "include"
        lib_path = Path(base) / "lib"
        if (include_path / "pcre2.h").exists():
            include_dirs.append(str(include_path))
            library_dirs.append(str(lib_path))
            break
    
    return include_dirs, library_dirs, libraries


def build_extensions():
    try:
        from Cython.Build import cythonize
    except ImportError:
        print("Cython not installed. Skipping Cython build.")
        print("Install with: pip install cython")
        return False
    
    try:
        from setuptools import Extension
        from setuptools.dist import Distribution
        from setuptools.command.build_ext import build_ext
    except ImportError:
        print("setuptools not installed. Skipping Cython build.")
        print("Install with: pip install setuptools")
        return False
    
    pcre2_include, pcre2_libdir, pcre2_libs = get_pcre2_config()
    
    if not pcre2_include:
        print("WARNING: PCRE2 not found. Routing module may not compile.")
        print("Install PCRE2: brew install pcre2 (macOS) or apt install libpcre2-dev (Linux)")
    else:
        print(f"Found PCRE2: includes={pcre2_include}, libs={pcre2_libdir}")
    
    extensions = [
        Extension(
            "pyserve._path_matcher",
            sources=["pyserve/_path_matcher.pyx"],
            extra_compile_args=["-O3", "-ffast-math"],
            define_macros=[("NPY_NO_DEPRECATED_API", "NPY_1_7_API_VERSION")],
        ),
        Extension(
            "pyserve._routing",
            sources=["pyserve/_routing.pyx"],
            include_dirs=pcre2_include,
            library_dirs=pcre2_libdir,
            libraries=pcre2_libs,
            extra_compile_args=["-O3", "-ffast-math"],
            define_macros=[
                ("NPY_NO_DEPRECATED_API", "NPY_1_7_API_VERSION"),
                ("PCRE2_CODE_UNIT_WIDTH", "8"),
            ],
        ),
    ]
    
    ext_modules = cythonize(
        extensions,
        compiler_directives={
            "language_level": "3",
            "boundscheck": False,
            "wraparound": False,
            "cdivision": True,
            "embedsignature": True,
        },
        annotate=True,
    )
    
    dist = Distribution({"ext_modules": ext_modules})
    dist.package_dir = {"": "."}
    
    cmd = build_ext(dist)
    cmd.ensure_finalized()
    cmd.inplace = True
    cmd.run()
    
    print("\nCython extensions built successfully!")
    ext_suffix = ".pyd" if sys.platform == "win32" else ".so"
    print(f"   - pyserve/_path_matcher{ext_suffix}")
    print(f"   - pyserve/_routing{ext_suffix}")
    
    return True


if __name__ == "__main__":
    project_root = Path(__file__).parent.parent
    os.chdir(project_root)
    
    success = build_extensions()
    sys.exit(0 if success else 1)