#include <gtest/gtest.h>
#include <gmock/gmock.h>
#include <vector>
#include <string>
#include <stdexcept>

// 假设的数据结构
struct RackListResponse {
    std::string rack_id;
    std::string rack_name;
    int unit_count;
};

// 服务接口
class Service {
public:
    virtual ~Service() = default;
    virtual std::vector<RackListResponse> list_racks() = 0;
};

// 全局服务指针（模拟原 Python 代码中的 service 模块）
Service* g_service = nullptr;

// 被测函数：对应原 Python 中的 list_racks()
std::vector<RackListResponse> list_racks() {
    return g_service->list_racks();
}

// Mock 服务类
class MockService : public Service {
public:
    MOCK_METHOD(std::vector<RackListResponse>, list_racks, (), (override));
};

// 测试夹具
class ListRacksTest : public ::testing::Test {
protected:
    void SetUp() override {
        mock_service = new MockService();
        g_service = mock_service;
    }

    void TearDown() override {
        delete mock_service;
        g_service = nullptr;
    }

    MockService* mock_service;
};

// 正常输入测试：返回非空机架列表
TEST_F(ListRacksTest, testListRacksNormal) {
    std::vector<RackListResponse> expected = {
        {"rack-1", "机架A", 5},
        {"rack-2", "机架B", 3}
    };

    EXPECT_CALL(*mock_service, list_racks())
        .WillOnce(::testing::Return(expected));

    auto result = list_racks();
    ASSERT_EQ(result.size(), 2);
    EXPECT_EQ(result[0].rack_id, "rack-1");
    EXPECT_EQ(result[0].rack_name, "机架A");
    EXPECT_EQ(result[0].unit_count, 5);
    EXPECT_EQ(result[1].rack_id, "rack-2");
    EXPECT_EQ(result[1].rack_name, "机架B");
    EXPECT_EQ(result[1].unit_count, 3);
}

// 边界值测试：返回空列表
TEST_F(ListRacksTest, testListRacksEmpty) {
    std::vector<RackListResponse> empty;

    EXPECT_CALL(*mock_service, list_racks())
        .WillOnce(::testing::Return(empty));

    auto result = list_racks();
    EXPECT_TRUE(result.empty());
}

// 异常输入测试：服务抛出异常
TEST_F(ListRacksTest, testListRacksServiceThrows) {
    EXPECT_CALL(*mock_service, list_racks())
        .WillOnce(::testing::Throw(std::runtime_error("database error")));

    EXPECT_THROW(list_racks(), std::runtime_error);
}