#include "gtest/gtest.h"
#include "alert_manager.hpp"
#include <vector>
#include <string>

// Mock time function for deterministic testing
uint32_t mock_timestamp = 1640995200; // 2022-01-01 00:00:00 UTC

// Mock function to replace std::time
uint32_t get_mock_timestamp() {
    return mock_timestamp;
}

// Override the global function in alert_manager.cpp
extern "C" uint32_t std_time() {
    return get_mock_timestamp();
}

// Test fixture for AlertManager
class AlertManagerTest : public ::testing::Test {
protected:
    AlertManager alert_manager;

    void SetUp() override {
        mock_timestamp = 1640995200;
        alert_manager.initialize();
    }

    void advance_time(uint32_t seconds) {
        mock_timestamp += seconds;
    }
};

// Test case: AlertManager 构造函数初始化默认阈值
TEST_F(AlertManagerTest, testAlertManagerInitialization) {
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().first, 100.0f);
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().second, -50.0f);
    EXPECT_TRUE(alert_manager.getActiveAlerts().empty());
    EXPECT_TRUE(alert_manager.getAlertHistory(10).empty());
}

// Test case: AlertManager 析构函数无副作用
TEST_F(AlertManagerTest, testAlertManagerDestructor) {
    // No specific assertion needed as destructor has no logic
    // Just ensure it compiles and runs without crash
    EXPECT_TRUE(true);
}

// Test case: initialize 输出初始化信息
TEST_F(AlertManagerTest, testInitializeOutput) {
    // Capture output using a mock stream
    std::ostringstream buffer;
    std::streambuf* orig_cout = std::cout.rdbuf();
    std::cout.rdbuf(buffer.rdbuf());

    alert_manager.initialize();

    std::cout.rdbuf(orig_cout);

    EXPECT_NE(buffer.str().find("预警管理器初始化完成。"), std::string::npos);
    EXPECT_NE(buffer.str().find("默认预警阈值：上限=100米，下限=-50米"), std::string::npos);
}

// Test case: checkAltitudeAlert 正常高度不触发预警
TEST_F(AlertManagerTest, testCheckAltitudeAlertNormalHeight) {
    alert_manager.checkAltitudeAlert(50.0f, mock_timestamp);
    EXPECT_TRUE(alert_manager.getActiveAlerts().empty());
}

// Test case: checkAltitudeAlert 触发上限预警
TEST_F(AlertManagerTest, testCheckAltitudeAlertUpperThreshold) {
    alert_manager.checkAltitudeAlert(101.0f, mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 1);
    EXPECT_EQ(active_alerts[0].type, AlertType::ALTITUDE_UPPER);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
    EXPECT_EQ(active_alerts[0].trigger_time, mock_timestamp);
}

// Test case: checkAltitudeAlert 触发下限预警
TEST_F(AlertManagerTest, testCheckAltitudeAlertLowerThreshold) {
    alert_manager.checkAltitudeAlert(-51.0f, mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 1);
    EXPECT_EQ(active_alerts[0].type, AlertType::ALTITUDE_LOWER);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
}

// Test case: checkAltitudeAlert 高度恢复后解除预警
TEST_F(AlertManagerTest, testCheckAltitudeAlertResolution) {
    alert_manager.checkAltitudeAlert(101.0f, mock_timestamp); // Trigger upper
    advance_time(10);
    alert_manager.checkAltitudeAlert(99.0f, mock_timestamp); // Resolve
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
}

// Test case: setAltitudeThresholds 合法输入更新阈值
TEST_F(AlertManagerTest, testSetAltitudeThresholdsValidInput) {
    alert_manager.setAltitudeThresholds(150.0f, -80.0f);
    auto thresholds = alert_manager.getAltitudeThresholds();
    EXPECT_FLOAT_EQ(thresholds.first, 150.0f);
    EXPECT_FLOAT_EQ(thresholds.second, -80.0f);
}

// Test case: setAltitudeThresholds 非法输入（上界 <= 下界）
TEST_F(AlertManagerTest, testSetAltitudeThresholdsInvalidInput) {
    std::ostringstream buffer;
    std::streambuf* orig_cerr = std::cerr.rdbuf();
    std::cerr.rdbuf(buffer.rdbuf());

    alert_manager.setAltitudeThresholds(50.0f, 100.0f);

    std::cerr.rdbuf(orig_cerr);
    EXPECT_NE(buffer.str().find("错误：上限阈值必须大于下限阈值。"), std::string::npos);
}

// Test case: triggerSensorFailure 触发传感器故障预警
TEST_F(AlertManagerTest, testTriggerSensorFailure) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 1);
    EXPECT_EQ(active_alerts[0].type, AlertType::SENSOR_FAILURE);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
    EXPECT_EQ(active_alerts[0].trigger_time, mock_timestamp);
}

// Test case: triggerLowBattery 触发低电量预警
TEST_F(AlertManagerTest, testTriggerLowBattery) {
    alert_manager.triggerLowBattery(mock_timestamp, 15.5f);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 1);
    EXPECT_EQ(active_alerts[0].type, AlertType::LOW_BATTERY);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
    EXPECT_EQ(active_alerts[0].trigger_time, mock_timestamp);
    EXPECT_NE(active_alerts[0].description.find("低电量警告：当前电量15.5%"), std::string::npos);
}

// Test case: triggerCommunicationError 触发通信错误预警
TEST_F(AlertManagerTest, testTriggerCommunicationError) {
    alert_manager.triggerCommunicationError(mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 1);
    EXPECT_EQ(active_alerts[0].type, AlertType::COMMUNICATION_ERROR);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
    EXPECT_EQ(active_alerts[0].trigger_time, mock_timestamp);
}

// Test case: acknowledgeAllAlerts 确认所有活动预警
TEST_F(AlertManagerTest, testAcknowledgeAllAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    alert_manager.acknowledgeAllAlerts(mock_timestamp + 2);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
    EXPECT_EQ(alert_manager.getActiveAlerts().size(), 0);
}

// Test case: acknowledgeAlert 确认指定类型预警
TEST_F(AlertManagerTest, testAcknowledgeAlert) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.acknowledgeAlert(AlertType::SENSOR_FAILURE, mock_timestamp + 1);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
}

// Test case: resetAlert 重置指定类型预警
TEST_F(AlertManagerTest, testResetAlert) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.resetAlert(AlertType::SENSOR_FAILURE);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
}

// Test case: resetAllAlerts 重置所有预警
TEST_F(AlertManagerTest, testResetAllAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    alert_manager.resetAllAlerts();
    EXPECT_TRUE(alert_manager.getActiveAlerts().empty());
}

// Test case: hasActiveAlerts 检查是否存在活动预警
TEST_F(AlertManagerTest, testHasActiveAlerts) {
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());
}

// Test case: hasUnacknowledgedAlerts 检查是否存在未确认预警
TEST_F(AlertManagerTest, testHasUnacknowledgedAlerts) {
    EXPECT_FALSE(alert_manager.hasUnacknowledgedAlerts());
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasUnacknowledgedAlerts());
    alert_manager.acknowledgeAlert(AlertType::SENSOR_FAILURE, mock_timestamp + 1);
    EXPECT_FALSE(alert_manager.hasUnacknowledgedAlerts());
}

// Test case: getActiveAlerts 获取活动预警列表
TEST_F(AlertManagerTest, testGetActiveAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    auto alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(alerts.size(), 1);
    EXPECT_EQ(alerts[0].type, AlertType::SENSOR_FAILURE);
}

// Test case: getAlertHistory 获取最近历史记录
TEST_F(AlertManagerTest, testGetAlertHistory) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    auto history = alert_manager.getAlertHistory(1);
    EXPECT_EQ(history.size(), 1);
    EXPECT_EQ(history[0].type, AlertType::LOW_BATTERY);
}

// Test case: getStatusDescription 生成系统状态描述
TEST_F(AlertManagerTest, testGetStatusDescription) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    std::string status_desc = alert_manager.getStatusDescription();
    EXPECT_NE(status_desc.find("系统状态：有1个活动预警"), std::string::npos);
    EXPECT_NE(status_desc.find("传感器故障"), std::string::npos);
}

// Test case: clearHistory 清空历史记录
TEST_F(AlertManagerTest, testClearHistory) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.clearHistory();
    EXPECT_TRUE(alert_manager.getAlertHistory(10).empty());
}

// Test case: addToHistory 添加历史记录并限制数量
TEST_F(AlertManagerTest, testAddToHistoryLimit) {
    const size_t MAX_HISTORY = 5;
    for (int i = 0; i < MAX_HISTORY + 1; ++i) {
        alert_manager.triggerSensorFailure(mock_timestamp + i);
    }
    auto history = alert_manager.getAlertHistory(MAX_HISTORY);
    EXPECT_EQ(history.size(), MAX_HISTORY);
    EXPECT_EQ(history[0].trigger_time, mock_timestamp + 1);
    EXPECT_EQ(history[MAX_HISTORY - 1].trigger_time, mock_timestamp + MAX_HISTORY);
}