Untitled

public static function fetchExchangeMarketCap(Exchange $exchange)
    {
        $response = [];
        $companyIds = self::getTotalCompaniesInExchange($exchange);

        $companyCount = count($companyIds['all_companies']);

        $exchangeCorpCount = count($companyIds['exchange_companies']);
        
        // Chart Start Date
        $date1YAgo = Carbon::now()->subDays(366)->format('Y-m-d');

        // Chart 1: exchange
        $response['exchangeMarketCap'] = $exchange->exchangeMarketCaps()
            ->where('current_date', '>', $date1YAgo)
            ->orderBy('current_date')->get();

        // Chart 2: exchange Fetch the average market cap per day for all companies on Eucaps platform
        $rawAvgAllCorpMarketCap = MarketCap::query()
            ->whereIn('company_id', $companyIds['all_companies'])
            ->selectRaw('DATE(market_caps.current_date) as date, ROUND(AVG(market_cap), 6) as average_market_cap, count(*) as total')
            ->where('current_date', '>', $date1YAgo)
            ->groupBy('current_date')
            ->orderBy('current_date')
            ->get();

        // Sanitizing Raw Chart Data For Better stability
        function chartNormalizer($rawAvgAllCorpMarketCap, $companyCount)
        {
            $capPercentage = 20; //100 => no_cap
            $companyCap = intval($companyCount - ($companyCount * ($capPercentage / 100.0)));
            $normalizedChartData = []; //main data object

            $avgMarketCaps = $rawAvgAllCorpMarketCap->pluck('average_market_cap')->toArray();

            // Calculate mean and variance
            $mean = array_sum($avgMarketCaps) / count($avgMarketCaps);
            $variance = array_sum(array_map(function ($value) use ($mean) {
                return pow($value - $mean, 2);
            }, $avgMarketCaps)) / count($avgMarketCaps);

            //Standard Deviation
            $stdDev = sqrt($variance);

            // Set a threshold for anomaly detection (e.g., z-score > 2 or < -2)
            $threshold = 2; // reference: normal distribution chart

            foreach ($rawAvgAllCorpMarketCap as $dayItem) {

                $value = $dayItem->average_market_cap ?? null;
                $zScore = ($value - $mean) / $stdDev;

                //Triggers if item is within normalizing threshold & avg_based_on_companies not an out-liner
                if (!(abs($zScore) > $threshold) && ($dayItem->total > $companyCap)) {
                    $normalizedChartData[] = $dayItem;
                }
            }

            return $normalizedChartData;
        }

        // $response['averageAllCompaniesMarketCap'] = $rawAvgAllCorpMarketCap;
        $response['averageAllCompaniesMarketCap'] = chartNormalizer($rawAvgAllCorpMarketCap, $companyCount);

        // Chart 3: Fetch the average market cap per day for companies under the exchange
        $rawAvgExchangeCorpMarketCap = MarketCap::query()
            ->whereIn('company_id', $companyIds['exchange_companies'])
            ->selectRaw('DATE(market_caps.current_date) as date, ROUND(AVG(market_cap), 6) as average_market_cap, count(*) as total')
            ->where('current_date', '>', $date1YAgo)
            ->groupBy('current_date')
            ->orderBy('current_date')
            ->get();

        // $response['averageExchangeCompaniesMarketCap'] = $rawAvgExchangeCorpMarketCap;
        $response['averageExchangeCompaniesMarketCap'] = chartNormalizer($rawAvgExchangeCorpMarketCap, $exchangeCorpCount);

        return $response;
    }