// Matrix row C7 — deprecated-API detector. Flags call sites whose
// target decl is marked `[[deprecated]]`, `__attribute__((deprecated))`,
// or `__attribute__((availability(...,deprecated=...)))`. Uses
// clang::Decl::isDeprecated under the hood.

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

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

#include "fold/detect/deprecated_api.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("deprecated-api: [[deprecated]] call site is flagged",
          "[deprecated-api][cxx-attribute]") {
    auto unit = parse(R"(
        [[deprecated]] int legacy();
        int caller() { return legacy(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].kind == fold::FindingKind::DeprecatedApi);
}

TEST_CASE("deprecated-api: __attribute__((deprecated)) call site is flagged",
          "[deprecated-api][gnu-attribute]") {
    auto unit = parse(R"(
        __attribute__((deprecated)) int legacy();
        int caller() { return legacy(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].kind == fold::FindingKind::DeprecatedApi);
}

TEST_CASE("deprecated-api: deprecation message is carried into the finding",
          "[deprecated-api][message]") {
    auto unit = parse(R"(
        [[deprecated("use modern_api() instead")]] int legacy();
        int caller() { return legacy(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
    REQUIRE(findings[0].message.find("use modern_api() instead") != std::string::npos);
}

TEST_CASE("deprecated-api: non-deprecated calls do not fire", "[deprecated-api][negative]") {
    auto unit = parse(R"(
        int modern();
        int caller() { return modern(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.empty());
}

TEST_CASE("deprecated-api: declaration alone is not flagged (only call sites)",
          "[deprecated-api][decl-only]") {
    // A deprecated declaration without any call sites should produce
    // zero findings — the detector flags USE, not definition.
    auto unit = parse(R"(
        [[deprecated]] int legacy();
        // no caller
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.empty());
}

TEST_CASE("deprecated-api: multiple call sites produce multiple findings",
          "[deprecated-api][repeat]") {
    auto unit = parse(R"(
        [[deprecated]] int legacy();
        int caller() { return legacy() + legacy(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.size() == 2);
}

TEST_CASE("deprecated-api: deprecated method on a class is flagged", "[deprecated-api][method]") {
    auto unit = parse(R"(
        struct S {
            [[deprecated]] int legacy();
            int modern();
        };
        int caller(S* s) { return s->legacy() + s->modern(); }
    )");
    REQUIRE(unit);
    auto findings = fold::detectDeprecatedApiInContext(unit->getASTContext());
    REQUIRE(findings.size() == 1);
}