//////////////////////////////////////////////////////
//
// SaherElm IT Center MQL5 Indicator
// ---------------------------------------------
// Name: XVLM
// Description: Volume Trend Indicator ...
//
//
// Maintainer:
// ------------
// Hadi Khazaee Asl (hadi_khazaee_asl@yahoo.com)
//
//////////////////////////////////////////////////////
//
// Global Properties ...
#property copyright "Copyright 2023, SaherElm IT Center"
#property link "https://saherelm.ir"
#property version "1.00"
#property description "SaherElm XVLM Indicator"
#property strict

//
// Imports ...
#include <Math/Stat/Normal.mqh>

//
// Definitions ...

//
#define ShortName "XVLM"

//
// Inputs ...

//
input int length = 14; // Length

//
// Buffers ...

//
#property indicator_chart_window

//
#property indicator_buffers 2
#property indicator_plots 0

///
#define volumeBufferIndex 0
double volumeBuffer[];

//
#define volumeColorBufferIndex 1
double volumeColorBuffer[];

//
#property indicator_label1 "XVLM"
#property indicator_type1 DRAW_COLOR_HISTOGRAM
#property indicator_color1 clrLime, clrRed

//
#define bullishColorIndex 0
#define bearishColorIndex 1

//
// Variables ...

//
int maxLength;

//
double volumes[];
double distances[];

//
// Event Handlers ...

//
// Initialization ...
int OnInit()
{
    //
    // Validate Inputs ...
    if (!ValidateInputs())
    {
        return INIT_PARAMETERS_INCORRECT;
    }

    //
    // because in some cases we may have more than one input for
    // calculation and we must prevent any calculation
    // untill we pass the biggest input length, here we get max Input length
    // and then wait until pass it ...
    maxLength = ExtractMaxLengthOfInputs();

    //
    ArrayResize(volumes, maxLength, 0);
    ArrayResize(distances, maxLength, 0);

    //
    // Define Index Buffers ...
    DefineBuffers();

    //
    // Set Indicator ShortName ...
    SetIndicatorName();

    //
    // Init Succeed ...
    return INIT_SUCCEEDED;
}

//
// DeInitialization ...
void OnDeinit(const int reason)
{
    //
    // REASON_PROGRAM 0 The EA has stopped working calling the ExpertRemove() function
    // REASON_REMOVE 1 Program removed from a chart
    // REASON_RECOMPILE 2 Program recompiled
    // REASON_CHARTCHANGE 3 A symbol or a chart period is changed
    // REASON_CHARTCLOSE 4 Chart closed
    // REASON_PARAMETERS 5 Inputs changed by a user
    // REASON_ACCOUNT 6 Another account has been activated or reconnection to the trade server has occurred due to changes in the account settings
    // REASON_TEMPLATE 7 Another chart template applied
    // REASON_INITFAILED 8 The OnInit() handler returned a non-zero value
    // REASON_CLOSE 9 Terminal closed

    //
    // Here we can handle De Initialization Reasons ...
}

//
// Calculating what we want ...
int OnCalculate(
    const int rates_total,     // Total Bars on Chart ...
    const int prev_calculated, // Total Calculated Bars on Charts ...
    const datetime &time[],    // History of Open Time ...
    const double &open[],      // History of Open Price ...
    const double &high[],      // History of High Price ...
    const double &low[],       // History of Low Price ...
    const double &close[],     // History of Close Price ...
    const long &tick_volume[], // History of Tick Volumes on Bar ...
    const long &volume[],      // History of Trade Volumes ...
    const int &spread[]        // History of Spread Price ...
)
{
    //
    static int i = maxLength * 2;
    for (i; i < rates_total; i++)
    {
        //
        for (int x = 0; x < length; x++)
        {
            //
            volumes[x] = (double)tick_volume[i - x];
            distances[x] =
                (close[i - x] > open[i - x])
                    ? high[i - x] - low[i - x]
                    : low[i - x] - high[i - x];
        }

        //
        double iValue = MathMean(volumes) * MathMean(distances);

        //
        volumeBuffer[i] = iValue;
        volumeColorBuffer[i] = iValue > 0
                                   ? bullishColorIndex
                                   : bearishColorIndex;
    }

    //
    i = rates_total - 1;

    //
    return rates_total;
}

//
// Custom Functions ...

//
// Validate Input Args for Initialization ...
bool ValidateInputs()
{
    //
    bool result = false;

    //
    // Validate Args ...
    result =
        //
        length >= 2
        //
        ;

    //
    return result;
}

//
// Retrieve all Exists Input Max Length ...
// use for Start Of Drawing ...
int ExtractMaxLengthOfInputs()
{
    //
    int result = 0;

    //
    result = length;

    //
    return result;
}

//
// Set Indicator Short Name and also we can define Buffers Labels ...
void SetIndicatorName()
{
    IndicatorSetString(INDICATOR_SHORTNAME, ShortName);
}

//
// Define Indexes and Styles ...
void DefineBuffers()
{
    //
    SetIndexBuffer(volumeBufferIndex, volumeBuffer, INDICATOR_CALCULATIONS);
    SetIndexBuffer(volumeColorBufferIndex, volumeColorBuffer, INDICATOR_CALCULATIONS);
}