<?php
declare(strict_types=1);

include_once __DIR__ . '/libs/vendor/autoload.php'; // TCPDF via Composer

class Abrechnung extends IPSModule
{
    public function Create()
    {
        parent::Create();

        // Eigenschaften
        $this->RegisterPropertyString('Users', '[]');
        $this->RegisterPropertyString('PowerMeters', '[]');
        $this->RegisterPropertyString('WaterMeters', '[]');
        $this->RegisterPropertyString('Tariffs', '[]');

        // Variablen
        $this->RegisterVariableInteger('FromDate', 'Startdatum', '~UnixTimestamp', 1);
        $this->RegisterVariableInteger('ToDate', 'Enddatum', '~UnixTimestamp', 2);
        $this->RegisterVariableString('LastResult', 'Letzte Abrechnung', '', 3);
        $this->EnableAction('FromDate');
        $this->EnableAction('ToDate');

        // Abrechnungs-Button
        $this->RegisterScript('StartBilling', 'Abrechnung starten', "<?php IPS_RequestAction(" . $this->InstanceID . ", 'StartBilling', ''); ?>");

        // 🧾 Media-Objekt für PDF-Ergebnis
        $this->RegisterMediaDocument('InvoicePDF', 'Letzte Rechnung', 'pdf');
    }

    public function ApplyChanges()
    {
        parent::ApplyChanges();
        IPS_LogMessage('Abrechnung', 'Modul geladen');
    }

    private function RegisterMediaDocument($Ident, $Name, $Extension, $Position = 0)
    {
        $mid = @IPS_GetObjectIDByIdent($Ident, $this->InstanceID);
        if ($mid === false) {
            $mid = IPS_CreateMedia(5); // 5 = Document
            IPS_SetParent($mid, $this->InstanceID);
            IPS_SetIdent($mid, $Ident);
            IPS_SetName($mid, $Name);
            IPS_SetPosition($mid, $Position);
            IPS_SetMediaFile($mid, 'media/' . $mid . '.' . $Extension, false);
        }
    }

    public function RequestAction($Ident, $Value)
    {
        IPS_LogMessage('Abrechnung', "RequestAction: $Ident");

        switch ($Ident) {
            case 'FromDate':
            case 'ToDate':
                SetValue($this->GetIDForIdent($Ident), $Value);
                break;

            case 'StartBilling':
                IPS_LogMessage('Abrechnung', 'Starte Abrechnung...');
                try {
                    $pdfContent = $this->GenerateInvoices();
                    if (!$pdfContent) {
                        echo "❌ Fehler bei der PDF-Erstellung";
                        return;
                    }

                    $mediaID = $this->GetIDForIdent('InvoicePDF');
                    IPS_SetMediaContent($mediaID, base64_encode($pdfContent));
                    SetValue($this->GetIDForIdent('LastResult'), 'Abrechnung vom ' . date('d.m.Y H:i'));
                    IPS_LogMessage('Abrechnung', '✅ Abrechnung erfolgreich erstellt');
                    echo "✅ PDF erfolgreich erstellt.";
                } catch (Throwable $e) {
                    IPS_LogMessage('Abrechnung', '💥 Fehler: ' . $e->getMessage());
                    echo "❌ Ausnahmefehler: " . $e->getMessage();
                }
                break;
        }
    }

    // ====================== PDF-Erstellung ======================

    public function GenerateInvoices()
    {
        $from = GetValue($this->GetIDForIdent('FromDate'));
        $to   = GetValue($this->GetIDForIdent('ToDate'));

        $users   = json_decode($this->ReadPropertyString('Users'), true);
        $power   = json_decode($this->ReadPropertyString('PowerMeters'), true);
        $water   = json_decode($this->ReadPropertyString('WaterMeters'), true);
        $tariffs = json_decode($this->ReadPropertyString('Tariffs'), true);

        if (!class_exists('TCPDF')) {
            IPS_LogMessage('Abrechnung', '❌ TCPDF nicht gefunden');
            return false;
        }

        $pdf = new TCPDF('P', 'mm', 'A4', true, 'UTF-8', false);
        $pdf->SetCreator('IPSymcon Abrechnung');
        $pdf->SetMargins(15, 15, 15);
        $pdf->SetAutoPageBreak(true, 20);
        $pdf->SetFont('dejavusans', '', 9);

        foreach ($users as $user) {
            $this->BuildUserInvoice($pdf, $user, $power, $water, $tariffs, $from, $to);
        }

        return $pdf->Output('Abrechnung.pdf', 'S');
    }

    private function BuildUserInvoice($pdf, array $user, array $power, array $water, array $tariffs, int $from, int $to)
    {
        $pdf->AddPage();

        $html = "
        <h2>Rechnung für {$user['name']}</h2>
        <p>{$user['address']}<br>{$user['city']}</p>
        <p><strong>Zeitraum:</strong> " . date('d.m.Y', $from) . " – " . date('d.m.Y', $to) . "</p><br>";

        // ⚡ Stromkosten
        $html .= "<h3>⚡ Stromkosten</h3>";
        $powerResult = $this->CalculatePowerCosts($power, $tariffs, $user['id'], $from, $to);
        $html .= $powerResult['html'];
        $totalPower = $powerResult['sum'];

        // 💧 Nebenkosten
        $html .= "<h3>💧 Nebenkosten (Wasser/Wärme)</h3>";
        $additionalResult = $this->CalculateAdditionalCosts($water, $tariffs, $user['id'], $from, $to);
        $html .= $additionalResult['html'];
        $totalAdditional = $additionalResult['sum'];

        $grandTotal = $totalPower + $totalAdditional;
        $html .= "<h3 style='text-align:right;'>Gesamttotal: <strong>" . number_format($grandTotal, 2) . " CHF</strong></h3>";

        $pdf->writeHTML($html, true, false, true, false, '');
    }

    // ====================== Stromkosten ======================

    private function CalculatePowerCosts(array $powerMeters, array $tariffs, int $userId, int $from, int $to): array
    {
        $html = "<table border='1' cellspacing='0' cellpadding='3' width='100%' style='font-size:8px;'>
        <tr style='background-color:#f0f0f0;'>
            <th>Zähler</th><th>Typ</th><th>Start</th><th>Ende</th>
            <th>Zähler Start</th><th>Zähler Ende</th><th>Verbrauch</th><th>Tarif (Rp)</th><th>Kosten (CHF)</th>
        </tr>";

        $total = 0.0;
        foreach ($powerMeters as $m) {
            if ($m['user_id'] != $userId) continue;
            $cost = $this->AddMeterToPDFRow($m, $tariffs, $from, $to, 'Strombezug');
            $html .= $cost['row'];
            $total += $cost['value'];
        }

        $html .= "<tr style='background-color:#f9f9f9; font-weight:bold;'>
            <td colspan='8' align='right'>Total Stromkosten:</td>
            <td align='right'>" . number_format($total, 2) . "</td>
        </tr></table><br>";

        return ['html' => $html, 'sum' => $total];
    }

    // ====================== Nebenkosten ======================

    private function CalculateAdditionalCosts(array $waterMeters, array $tariffs, int $userId, int $from, int $to): array
    {
        $html = "<table border='1' cellspacing='0' cellpadding='3' width='100%' style='font-size:8px;'>
        <tr style='background-color:#f0f0f0;'>
            <th>Zähler</th><th>Typ</th><th>Start</th><th>Ende</th>
            <th>Zähler Start</th><th>Zähler Ende</th><th>Verbrauch</th><th>Tarif (Rp)</th><th>Kosten (CHF)</th>
        </tr>";

        $total = 0.0;
        foreach ($waterMeters as $m) {
            if ($m['user_id'] != $userId) continue;
            $type = $m['meter_type'] ?? 'Warmwasser';
            $cost = $this->AddMeterToPDFRow($m, $tariffs, $from, $to, $type);
            $html .= $cost['row'];
            $total += $cost['value'];
        }

        $html .= "<tr style='background-color:#f9f9f9; font-weight:bold;'>
            <td colspan='8' align='right'>Total Nebenkosten:</td>
            <td align='right'>" . number_format($total, 2) . "</td>
        </tr></table><br>";

        return ['html' => $html, 'sum' => $total];
    }

    // ====================== Kernberechnung ======================

    private function AddMeterToPDFRow($meter, $tariffs, $from, $to, $type)
    {
        $rows = '';
        $totalCost = 0.0;
        $varId = $meter['var_consumption'];

        if (!IPS_VariableExists($varId)) return ['row' => '', 'value' => 0];

        date_default_timezone_set('Europe/Zurich');

        $filteredTariffs = array_filter($tariffs, fn($t) =>
            strtolower(trim($t['unit_type'] ?? '')) === strtolower(trim($type))
        );

        if (empty($filteredTariffs)) return ['row' => '', 'value' => 0];

        foreach ($filteredTariffs as &$t) {
            $t['start_ts'] = $this->toUnixTs($t['start'], false);
            $t['end_ts']   = $this->toUnixTs($t['end'], true);
        }
        unset($t);
        usort($filteredTariffs, fn($a, $b) => ($a['start_ts'] ?? 0) <=> ($b['start_ts'] ?? 0));

        $currentStart = $from;
        while ($currentStart < $to) {
            $activeTariff = null;
            foreach ($filteredTariffs as $t) {
                if (($t['start_ts'] ?? 0) <= $currentStart && $currentStart <= ($t['end_ts'] ?? 0)) {
                    $activeTariff = $t;
                    break;
                }
            }

            if (!$activeTariff) {
                $activeTariff = ['start_ts' => $currentStart, 'end_ts' => $to, 'price' => 0.0];
            }

            $tariffEnd = intval($activeTariff['end_ts']);
            $tariffPrice = floatval($activeTariff['price']);

            $startValue = $this->GetValueAt($varId, $currentStart, true);
            $segmentEnd = ($tariffEnd < $to) ? $tariffEnd : $to;
            $endValue   = $this->GetValueAt($varId, $segmentEnd, true);

            if ($startValue === null || $endValue === null) break;

            $verbrauch = max(0, $endValue - $startValue);
            $kosten = round(($tariffPrice / 100) * $verbrauch, 2);
            $totalCost += $kosten;

            $rows .= "<tr>
                <td>{$meter['name']}</td>
                <td>{$type}</td>
                <td align='center'>" . date('d.m.Y', $currentStart) . "</td>
                <td align='center'>" . date('d.m.Y', $segmentEnd) . "</td>
                <td align='right'>" . number_format($startValue, 2) . "</td>
                <td align='right'>" . number_format($endValue, 2) . "</td>
                <td align='right'>" . number_format($verbrauch, 2) . "</td>
                <td align='right'>" . number_format($tariffPrice, 2) . "</td>
                <td align='right'>" . number_format($kosten, 2) . "</td>
            </tr>";

            if ($tariffEnd < $to) $currentStart = $tariffEnd + 1;
            else break;
        }

        if ($rows === '') return ['row' => '', 'value' => 0];

        return ['row' => $rows, 'value' => $totalCost];
    }

    // ====================== Hilfsfunktionen ======================

    private function GetValueAt(int $varId, int $timestamp, bool $nearestAfter = true)
    {
        $archiveID = @IPS_GetInstanceListByModuleID('{43192F0B-135B-4CE7-A0A7-1475603F3060}')[0];
        if (!$archiveID || !IPS_VariableExists($varId)) return null;

        $values = @AC_GetLoggedValues($archiveID, $varId, $timestamp - 30 * 86400, $timestamp + 30 * 86400, 0);
        if (empty($values)) return floatval(GetValue($varId));

        $closest = null;
        foreach ($values as $v) {
            if ($nearestAfter && $v['TimeStamp'] >= $timestamp) {
                $closest = $v['Value'];
                break;
            } elseif (!$nearestAfter && $v['TimeStamp'] <= $timestamp) {
                $closest = $v['Value'];
            }
        }

        return $closest ?? floatval(GetValue($varId));
    }

    private function toUnixTs($val, bool $endOfDay = false): ?int
    {
        if (is_int($val)) return $val;
        if (is_numeric($val)) return intval($val);

        if (is_string($val)) {
            $s = trim($val);
            if ($s !== '' && $s[0] === '{') {
                $obj = json_decode($s, true);
                if (isset($obj['year'], $obj['month'], $obj['day'])) {
                    $time = $endOfDay ? '23:59:59' : '00:00:00';
                    return strtotime(sprintf('%04d-%02d-%02d %s', $obj['year'], $obj['month'], $obj['day'], $time));
                }
            }
            $ts = strtotime($s);
            return $ts === false ? null : $ts;
        }
        return null;
    }
}