#!/usr/bin/env python3
"""
Generate a single GoogleTest binary from lightweight per-source test stubs.
Run from repo root: python3 tests/gtest/generate_gtests.py
"""
import os
from pathlib import Path
ROOT = Path(__file__).resolve().parents[2]
SRC_DIR = ROOT / 'Z' / 'src'
OUT_DIR = ROOT / 'tests' / 'gtest' / 'Z'
OUT_DIR.mkdir(parents=True, exist_ok=True)

TEMPLATE = '''#include <gtest/gtest.h>\n{includes}\n\nTEST({test_suite}, smoke) {{\n    // TODO: replace with meaningful unit tests for {rel_cpp}\n    ASSERT_TRUE(true);\n}}\n'''

sources = []
for cpp in sorted(SRC_DIR.rglob('*.cpp')):
    rel = cpp.relative_to(SRC_DIR)
    name = str(rel).replace(os.sep, '__')
    out_cpp = OUT_DIR / (name + '_test.cpp')
    # try to include corresponding header if exists
    header = cpp.with_suffix('.h')
    includes = ''
    if header.exists():
        includes = f'#include "{header.relative_to(ROOT)}"'
    else:
        includes = '// no corresponding header to include'
    content = TEMPLATE.format(includes=includes, test_suite=name.replace('.', '_'), rel_cpp=str(rel))
    out_cpp.write_text(content)
    sources.append(str(Path('tests/gtest/Z') / (name + '_test.cpp')))

# Write CMakeLists for gtests
cmake = ROOT / 'tests' / 'gtest' / 'CMakeLists.txt'
cmake.write_text('''
cmake_minimum_required(VERSION 3.21)
project(GTests LANGUAGES CXX)

include(FetchContent)
FetchContent_Declare(
  googletest
  URL https://github.com/google/googletest/archive/refs/tags/release-1.14.0.tar.gz
)
FetchContent_MakeAvailable(googletest)

# Collect generated test sources
file(GLOB GTEST_SRCS "${CMAKE_SOURCE_DIR}/Z/*_test.cpp")
add_executable(gtests_all ${GTEST_SRCS})
target_compile_features(gtests_all PRIVATE cxx_std_20)
target_include_directories(gtests_all PRIVATE ${CMAKE_SOURCE_DIR}/../../)
# link to gtest
target_link_libraries(gtests_all PRIVATE GTest::gtest_main)

include(GoogleTest)
gtest_discover_tests(gtests_all)
''')

print(f"Wrote {len(sources)} test stubs to {OUT_DIR}")
print("Run: cmake -S . -B build && cmake --build build -- -j5 && ctest --test-dir build -j5")