#include <clang/Frontend/ASTUnit.h>
#include <clang/Tooling/Tooling.h>

#include <catch2/catch_test_macros.hpp>
#include <memory>
#include <string>

#include "fold/detect/weak_crypto.hpp"
#include "fold/report/finding.hpp"

namespace {

std::unique_ptr<clang::ASTUnit> parse(const std::string& code) {
    return clang::tooling::buildASTFromCodeWithArgs(code, {"-std=c++20"}, "input.cpp");
}

} // namespace

TEST_CASE("weak-crypto: CommonCrypto MD5 is flagged", "[weak-crypto][commoncrypto]") {
    auto unit = parse(R"(
        extern "C" unsigned char *CC_MD5(const void *, unsigned long, unsigned char *);
        int caller(const void *p, unsigned char *out) {
            return CC_MD5(p, 4, out) != nullptr;
        }
    )");
    REQUIRE(unit);
    auto findings = fold::detectWeakCryptoInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].kind == fold::FindingKind::WeakCrypto);
    REQUIRE(findings[0].message.find("MD5") != std::string::npos);
}

TEST_CASE("weak-crypto: AES ECB EVP helper is flagged", "[weak-crypto][ecb]") {
    auto unit = parse(R"(
        extern "C" const void *EVP_aes_256_ecb();
        const void *caller() { return EVP_aes_256_ecb(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectWeakCryptoInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].message.find("ECB") != std::string::npos);
}

TEST_CASE("weak-crypto: weak digest string lookup is flagged", "[weak-crypto][string-lookup]") {
    auto unit = parse(R"(
        extern "C" const void *EVP_get_digestbyname(const char *);
        const void *caller() { return EVP_get_digestbyname("sha1"); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectWeakCryptoInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].message.find("SHA-1") != std::string::npos);
    REQUIRE(findings[0].message.find("EVP_get_digestbyname") != std::string::npos);
}

TEST_CASE("weak-crypto: strong digest string lookup is not flagged",
          "[weak-crypto][string-lookup][negative]") {
    auto unit = parse(R"(
        extern "C" const void *EVP_get_digestbyname(const char *);
        const void *caller() { return EVP_get_digestbyname("sha256"); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectWeakCryptoInContext(unit->getASTContext());
    REQUIRE(findings.empty());
}