Flashlight

#pragma strict

public var flashlight          : Light;           // The flashlight GameObject (must have Light component)
public var switchOn            : AudioClip;       // Switch on  sound
public var switchOff           : AudioClip;       // Switch off sound
public var isOn                : boolean = false; // Is the light on?
public var alpha               : float;           // Flashlight color
public var charge              : float;           // Battery charge speed
public var curPower            : float;           // Current battery power
public var maxPower            : float;           // Maximum battery power
public var flickerTime         : float;           // Flashlight flicker threshold (percent until flashlight flickers)
public var flickerDuration     : float;           // Time between each flicker

private var _isBatteryFull     : boolean;         // Is the battery fully charged?
private var _defaultIntensity  : float;           // Reference to the flashlight intensity

/// <summary> Turn off/on the flashlight (When a key is pressed). </summary>
public function UseFlashlight()
{
    // Toggle flashlight? (Pressed "F" key)
    if ( Input.GetKeyDown( KeyCode.F ) )
    {
        ToggleFlashlight();

        Debug.Log( "Flashlight On: " + isOn );
    }

    // Is flashlight on?
    if ( isOn == true )
    {
        // Use a function to drain /decrease the battery power over time
        DrainBattery ();
    }
    // Battery full?
    else if ( _isBatteryFull == false )
    {
        // Use a function to charge/increase the battery power over time
        ChargeBattery();
    }
}

/// <summary> Drain the flashlight battery (While in use). </summary>
public function DrainBattery()
{
    _isBatteryFull = false;

    // Battery active?
    if ( curPower > 0.0 )
    {
        Debug.Log( "Battery in use..." );

        curPower -= Time.deltaTime * charge;

        Debug.Log( "Battery power: " + curPower );

        // Flicker?
        if ( curPower < maxPower / flickerTime )
        {
            FlickerFlashlight();
        }
    }
    else
    {
        // Once the battery is dead, automatically toggle the light off
        ToggleFlashlight();
    }
}

/// <summary> Charge the flashlight battery. </summary>
public function ChargeBattery()
{
    // Charged?
    if ( curPower >= maxPower )
    {
        curPower       = maxPower;
        _isBatteryFull = true;
        return;
    }

    Debug.Log( "Charging battery..." );

    // Flicker?
    if ( curPower < maxPower / flickerTime )
    {
        // Fade the color back to white if within flickerTime threshold
        FadeFlashlight();
    }
    else
    {
        // Once the flashlight passes the flickerTime threshold, its color will reset to full
        SetFlashlight( 1.0 );
    }

    curPower += Time.deltaTime * ( charge / 2 );

    Debug.Log( "Battery power: " + curPower   );
}

/// <summary> Turn on the flashlight. </summary>
public function FlashlightOn()
{
    isOn               = true;
    flashlight.enabled = isOn;
}

/// <summary> Turn off the flashlight. </summary>
public function FlashlightOff()
{
    isOn               = false;
    flashlight.enabled =  isOn;
}

/// <summary> Toggle the flashlight (Turn on-and-off). </summary>
public function ToggleFlashlight()
{
    // If isOn is true, it will be flipped to false and vice-versa.
    isOn               = !isOn;

    // Set the flashlight to your flag.
    flashlight.enabled =  isOn;
}

/// <summary> Fade the flashlight color. </summary>
public function FadeFlashlight()
{
    alpha            = curPower / maxPower;
    flashlight.color = Color( alpha, alpha, alpha, alpha );
}

/// <summary> Set the flashlight color. </summary>
public function SetFlashlight( value : float )
{
    alpha            = value;
    flashlight.color = Color( alpha, alpha, alpha, alpha );
}

/// <summary> Flicker the flashlight. </summary>
public function FlickerFlashlight()
{
    FadeFlashlight();

    var phi       : float = Time.time / flickerDuration;
    var amplitude : float = Mathf.Cos( phi ) * 0.5 + _defaultIntensity;
    flashlight.intensity  = amplitude + Random.Range( 0.1, 1.0 );
}

function Start()
{
    // In my opinion, it is better to use a public variable and drag the flashlight
    // inside the slot in the inspector so as to avoid searching for the gameobject.

    // In case you forget to do that, here we check to see
    // if there is a light and search for it if necessary.
    if ( flashlight == null )
    {
        Debug.LogWarning( "There is no flashlight GameObject attached to this component! Searching scene now..." );

        // OPTION 1 - Using Find/FindWithTag
        // GameObject.FindWithTag is less expensive to use than
        // GameObject.Find but its use is not recommended every frame.
        flashlight = GameObject.FindWithTag( "Flashlight" ).GetComponent( Light );

        // OPTION 2 - Better choice
        // Instead of searching for the GameObject, this script should
        // be attached to the actual flashlight scene object. Then you
        // can reference this GameObject if the flashlight is null
        flashlight = GetComponent( Light );
    }

    flashlight.enabled = isOn;
    _defaultIntensity  = flashlight.intensity;
    curPower           = maxPower;
}

function Update()
{
    UseFlashlight();
}