/*
 * @file host_api_test.cpp
 * @brief Host API unit tests: service registration, event bus, config store,
 *        alloc/free, logging, init/shutdown lifecycle.
 * Host API 单元测试：服务注册、事件总线、配置存储、alloc/free、日志、init/shutdown 生命周期。
 * Copyright (c) 2026 dstalk contributors. GPLv3.
 */

#include <cstdarg>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <string>

// 引入 ServiceRegistry 实现做纯单元测试 / Include ServiceRegistry impl for pure unit tests
#include "service_registry.hpp"

#include "dstalk/dstalk_host.h"

// ---- 轻量断言 ----
static int g_failures = 0;
// Lightweight assertion helper: increments g_failures counter on failure
#define TCHECK(cond, msg) do {                            \
    if (cond) {                                           \
        std::cout << "[OK] " << (msg) << "\n";            \
    } else {                                              \
        std::cerr << "[FAIL] " << (msg) << "\n";          \
        g_failures++;                                     \
    }                                                     \
} while (0)


// Helper: creates a temporary config.toml pointing to a non-existent plugin dir,
// so dstalk_init loads no external plugins during tests.
// 辅助函数：创建临时 config.toml 指向不存在的插件目录，使 dstalk_init 在测试时不加载任何外部插件。
static std::string make_temp_config(const std::string& tag) {
    auto dir = std::filesystem::temp_directory_path() / ("dstalk-host-api-" + tag);
    std::filesystem::create_directories(dir);
    auto config_path = dir / "config.toml";
    {
        std::ofstream c(config_path);
        // 指向不存在的插件目录，避免加载任何 .dll / Point to nonexistent plugin dir, avoid loading any .dll
        c << "plugin_dir = \"__no_such_plugins_dir__\"\n";
    }
    return config_path.string();
}

// Host API 单元测试：覆盖注册/查询重复、版本不匹配、双重 init 防护、alloc/free 边界、日志级别、shutdown 后查询。
// Host API unit tests: covers register/query duplicates, version mismatch,
// double-init guard, alloc/free edge cases, logging levels, and post-shutdown query.
int main()
{
    std::cout << "=== dstalk host_api unit tests ===\n\n";

    // ====================================================================
    // Test 1: register_service 重复注册 同名+同版本 → 应返回 -2
    // Test 1: register_service duplicate same-name+same-version -> should return -2
    // ====================================================================
    {
        dstalk::ServiceRegistry reg;
        void* dummy_vtable = reinterpret_cast<void*>(0x1);
        int r1 = reg.register_service("echo", 1, dummy_vtable);
        TCHECK(r1 == 0, "register_service(\"echo\",1) first call returns 0");

        int r2 = reg.register_service("echo", 1, dummy_vtable);
        TCHECK(r2 == -2,
               "register_service(\"echo\",1) duplicate same-version returns -2");
    }

    // ====================================================================
    // Test 2: register_service 同名+不同版本 → 应返回 -2
    //         名称已占用，与版本无关
    // Test 2: register_service same-name+different-version -> should return -2
    //         Name already taken, regardless of version
    // ====================================================================
    {
        dstalk::ServiceRegistry reg;
        void* dummy_vtable = reinterpret_cast<void*>(0x1);
        int r1 = reg.register_service("calc", 1, dummy_vtable);
        TCHECK(r1 == 0, "register_service(\"calc\",1) first call returns 0");

        int r2 = reg.register_service("calc", 99, dummy_vtable);
        TCHECK(r2 == -2,
               "register_service(\"calc\",99) diff-version duplicate returns -2");
    }

    // ====================================================================
    // Test 3: query_service 不存在的 name → nullptr
    // Test 3: query_service nonexistent name -> nullptr
    // ====================================================================
    {
        dstalk::ServiceRegistry reg;
        void* q = reg.query_service("ghost_service", 1);
        TCHECK(q == nullptr, "query_service(\"ghost_service\",1) returns nullptr");
    }

    // ====================================================================
    // Test 4: query_service 错误版本号 → nullptr
    //         注册 v=1, 查询 min_version=2 → 不满足 → nullptr
    // Test 4: query_service wrong version -> nullptr
    //         Registered v=1, query min_version=2 -> unsatisfied -> nullptr
    // ====================================================================
    {
        dstalk::ServiceRegistry reg;
        void* dummy_vtable = reinterpret_cast<void*>(0x2);
        reg.register_service("solo", 1, dummy_vtable);

        void* q = reg.query_service("solo", 2);
        TCHECK(q == nullptr, "query_service(\"solo\",2) with only v1 available returns nullptr");

        // 确证以正确版本查询能拿到 / Confirm correct version query works
        void* q2 = reg.query_service("solo", 1);
        TCHECK(q2 == dummy_vtable, "query_service(\"solo\",1) with v1 available returns vtable");
    }

    // ====================================================================
    // Test 5: dstalk_init 多次调用 → 第二次应返回 -1 (幂等拒绝)
    // Test 5: dstalk_init multiple calls -> second should return -1 (idempotent guard)
    // ====================================================================
    {
        std::string cfg = make_temp_config("init-twice");
        int r1 = dstalk_init(cfg.c_str());
        TCHECK(r1 == 0, "dstalk_init first call returns 0");

        int r2 = dstalk_init(cfg.c_str());
        TCHECK(r2 == -1, "dstalk_init second call returns -1 (idempotent guard)");

        dstalk_shutdown();
    }

    // ====================================================================
    // Test 6: alloc(0) / free(nullptr) 行为
    //         malloc(0) 可返回 null 或合法指针; 两者都可 free
    //         free(nullptr) 是安全空操作
    // Test 6: alloc(0) / free(nullptr) behavior
    //         malloc(0) may return null or valid pointer; both are free-able
    //         free(nullptr) is a safe no-op
    // ====================================================================
    {
        void* p = dstalk_alloc(0);
        std::cout << "[OK] dstalk_alloc(0) returned " << p
                  << " (null or valid, both acceptable)\n";
        dstalk_free(p);
        std::cout << "[OK] dstalk_free(alloc(0)) did not crash\n";

        dstalk_free(nullptr);
        std::cout << "[OK] dstalk_free(nullptr) did not crash\n";
    }

    // ====================================================================
    // Test 7: log 各 level 不崩溃 (DEBUG / INFO / WARN / ERROR)
    // Test 7: log at each level no crash (DEBUG / INFO / WARN / ERROR)
    // ====================================================================
    {
        dstalk_log(DSTALK_LOG_DEBUG, "host_api_test: debug level message");
        std::cout << "[OK] dstalk_log(DEBUG) no crash\n";

        dstalk_log(DSTALK_LOG_INFO, "host_api_test: info level message");
        std::cout << "[OK] dstalk_log(INFO) no crash\n";

        dstalk_log(DSTALK_LOG_WARN, "host_api_test: warn level message");
        std::cout << "[OK] dstalk_log(WARN) no crash\n";

        dstalk_log(DSTALK_LOG_ERROR, "host_api_test: error level message");
        std::cout << "[OK] dstalk_log(ERROR) no crash\n";

        // 带格式参数 / With format args
        dstalk_log(DSTALK_LOG_INFO, "formatted: %s %d", "answer", 42);
        std::cout << "[OK] dstalk_log with format args no crash\n";
    }

    // ====================================================================
    // Test 8: dstalk_shutdown 后 query_service → nullptr
    //         g_service_registry 已被 delete 置空
    // Test 8: query_service after dstalk_shutdown -> nullptr
    //         g_service_registry has been deleted and nulled
    // ====================================================================
    {
        std::string cfg = make_temp_config("after-shutdown");
        dstalk_init(cfg.c_str());
        dstalk_shutdown();

        void* q = dstalk_service_query("any_service", 1);
        TCHECK(q == nullptr, "dstalk_service_query after shutdown returns nullptr");
    }

    // ====================================================================
    // 结果 / Result
    // ====================================================================
    std::cout << "\n";
    if (g_failures == 0) {
        std::cout << "=== All host_api tests passed ===\n";
        return 0;
    } else {
        std::cerr << "=== " << g_failures << " host_api test(s) FAILED ===\n";
        return 1;
    }
}