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

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

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

// Override the global time function in AlertManager
namespace {
    uint32_t mock_time() { return 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 constructor initializes thresholds and clears lists
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: Destructor does not require explicit cleanup
TEST_F(AlertManagerTest, testAlertManagerDestructor) {
    // No assertion needed as destructor is empty
    // This ensures no memory leaks or crashes
}

// Test case: initialize outputs correct messages
TEST_F(AlertManagerTest, testInitializeOutput) {
    // We cannot directly capture stdout in gtest without external tools,
    // but we can verify that initialization logic runs without crash.
    // The actual output is tested via integration.
    EXPECT_NO_FATAL_FAILURE(alert_manager.initialize());
}

// Test case: checkAltitudeAlert triggers upper threshold alert
TEST_F(AlertManagerTest, testCheckAltitudeAlertUpperThreshold) {
    float altitude = 101.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    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 resolves upper threshold when altitude normalizes
TEST_F(AlertManagerTest, testCheckAltitudeAlertResolveUpper) {
    float altitude = 101.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    altitude = 99.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp + 1);
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
}

// Test case: checkAltitudeAlert triggers lower threshold alert
TEST_F(AlertManagerTest, testCheckAltitudeAlertLowerThreshold) {
    float altitude = -51.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    EXPECT_EQ(active_alerts[0].type, AlertType::ALTITUDE_LOWER);
    EXPECT_EQ(active_alerts[0].status, AlertStatus::ACTIVE);
}

// Test case: checkAltitudeAlert resolves lower threshold when altitude normalizes
TEST_F(AlertManagerTest, testCheckAltitudeAlertResolveLower) {
    float altitude = -51.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    altitude = -49.0f;
    alert_manager.checkAltitudeAlert(altitude, mock_timestamp + 1);
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
}

// Test case: setAltitudeThresholds validates input
TEST_F(AlertManagerTest, testSetAltitudeThresholdsInvalidInput) {
    EXPECT_NO_FATAL_FAILURE(alert_manager.setAltitudeThresholds(50.0f, 100.0f));
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().first, 100.0f);
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().second, -50.0f);
}

// Test case: setAltitudeThresholds updates valid thresholds
TEST_F(AlertManagerTest, testSetAltitudeThresholdsValidInput) {
    alert_manager.setAltitudeThresholds(200.0f, -100.0f);
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().first, 200.0f);
    EXPECT_FLOAT_EQ(alert_manager.getAltitudeThresholds().second, -100.0f);
}

// Test case: triggerSensorFailure creates correct alert
TEST_F(AlertManagerTest, testTriggerSensorFailure) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    EXPECT_EQ(active_alerts[0].type, AlertType::SENSOR_FAILURE);
    EXPECT_EQ(active_alerts[0].description, "传感器故障");
}

// Test case: triggerLowBattery creates correct alert with battery level
TEST_F(AlertManagerTest, testTriggerLowBattery) {
    alert_manager.triggerLowBattery(mock_timestamp, 15.5f);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    EXPECT_EQ(active_alerts[0].type, AlertType::LOW_BATTERY);
    EXPECT_EQ(active_alerts[0].description, "低电量警告：当前电量15.5%");
}

// Test case: triggerCommunicationError creates correct alert
TEST_F(AlertManagerTest, testTriggerCommunicationError) {
    alert_manager.triggerCommunicationError(mock_timestamp);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    EXPECT_EQ(active_alerts[0].type, AlertType::COMMUNICATION_ERROR);
    EXPECT_EQ(active_alerts[0].description, "通信错误");
}

// Test case: acknowledgeAllAlerts marks all active alerts as acknowledged
TEST_F(AlertManagerTest, testAcknowledgeAllAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    alert_manager.acknowledgeAllAlerts(mock_timestamp + 2);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
    EXPECT_FALSE(alert_manager.hasUnacknowledgedAlerts());
}

// Test case: acknowledgeAlert acknowledges specific alert
TEST_F(AlertManagerTest, testAcknowledgeAlert) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    alert_manager.acknowledgeAlert(AlertType::SENSOR_FAILURE, mock_timestamp + 1);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
}

// Test case: resetAlert removes specified alert
TEST_F(AlertManagerTest, testResetAlert) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    alert_manager.resetAlert(AlertType::SENSOR_FAILURE);
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
}

// Test case: resetAllAlerts clears all alerts
TEST_F(AlertManagerTest, testResetAllAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());

    alert_manager.resetAllAlerts();
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
}

// Test case: hasActiveAlerts returns true if any alert is active
TEST_F(AlertManagerTest, testHasActiveAlertsTrue) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasActiveAlerts());
}

// Test case: hasActiveAlerts returns false if no alert is active
TEST_F(AlertManagerTest, testHasActiveAlertsFalse) {
    EXPECT_FALSE(alert_manager.hasActiveAlerts());
}

// Test case: hasUnacknowledgedAlerts returns true if any active alert exists
TEST_F(AlertManagerTest, testHasUnacknowledgedAlertsTrue) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    EXPECT_TRUE(alert_manager.hasUnacknowledgedAlerts());
}

// Test case: hasUnacknowledgedAlerts returns false after acknowledgment
TEST_F(AlertManagerTest, testHasUnacknowledgedAlertsFalseAfterAck) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.acknowledgeAllAlerts(mock_timestamp + 1);
    EXPECT_FALSE(alert_manager.hasUnacknowledgedAlerts());
}

// Test case: getActiveAlerts returns correct list of active alerts
TEST_F(AlertManagerTest, testGetActiveAlerts) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_EQ(active_alerts.size(), 2);
    EXPECT_EQ(active_alerts[0].type, AlertType::SENSOR_FAILURE);
    EXPECT_EQ(active_alerts[1].type, AlertType::LOW_BATTERY);
}

// Test case: getAlertHistory returns recent entries
TEST_F(AlertManagerTest, testGetAlertHistory) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.triggerLowBattery(mock_timestamp + 1, 10.0f);
    alert_manager.triggerCommunicationError(mock_timestamp + 2);

    auto history = alert_manager.getAlertHistory(2);
    EXPECT_EQ(history.size(), 2);
    EXPECT_EQ(history[0].type, AlertType::LOW_BATTERY);
    EXPECT_EQ(history[1].type, AlertType::COMMUNICATION_ERROR);
}

// Test case: getStatusDescription generates correct string for active alerts
TEST_F(AlertManagerTest, testGetStatusDescriptionWithActiveAlerts) {
    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: getStatusDescription returns normal state when no alerts
TEST_F(AlertManagerTest, testGetStatusDescriptionNormalState) {
    std::string status_desc = alert_manager.getStatusDescription();
    EXPECT_EQ(status_desc, "系统状态：正常");
}

// Test case: clearHistory clears all history
TEST_F(AlertManagerTest, testClearHistory) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.clearHistory();
    EXPECT_TRUE(alert_manager.getAlertHistory(10).empty());
}

// Test case: addToHistory limits history size
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].type, AlertType::SENSOR_FAILURE);
}

// Test case: triggerAlert creates new alert and adds to history
TEST_F(AlertManagerTest, testTriggerAlert) {
    alert_manager.triggerAlert(AlertType::ALTITUDE_UPPER, mock_timestamp, "Test alert");
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_FALSE(active_alerts.empty());
    EXPECT_EQ(active_alerts[0].description, "Test alert");
}

// Test case: updateAlertStatus changes status correctly
TEST_F(AlertManagerTest, testUpdateAlertStatus) {
    alert_manager.triggerSensorFailure(mock_timestamp);
    alert_manager.updateAlertStatus(AlertType::SENSOR_FAILURE, AlertStatus::ACKNOWLEDGED, mock_timestamp + 1);
    auto active_alerts = alert_manager.getActiveAlerts();
    EXPECT_TRUE(active_alerts.empty());
}

// Test case: getAlertTypeName returns correct string
TEST_F(AlertManagerTest, testGetAlertTypeName) {
    EXPECT_EQ(alert_manager.getAlertTypeName(AlertType::ALTITUDE_UPPER), "高度上限预警");
    EXPECT_EQ(alert_manager.getAlertTypeName(AlertType::NONE), "无");
    EXPECT_EQ(alert_manager.getAlertTypeName(static_cast<AlertType>(99)), "未知预警");
}

// Test case: getAlertStatusName returns correct string
TEST_F(AlertManagerTest, testGetAlertStatusName) {
    EXPECT_EQ(alert_manager.getAlertStatusName(AlertStatus::ACTIVE), "预警中");
    EXPECT_EQ(alert_manager.getAlertStatusName(AlertStatus::RESOLVED), "已解决");
    EXPECT_EQ(alert_manager.getAlertStatusName(static_cast<AlertStatus>(99)), "未知状态");
}