<?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);
            IPS_LogMessage('Abrechnung', 'Media-Datei erstellt: media/' . $mid . '.' . $Extension);
        }
    }

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 === false) {
                    IPS_LogMessage('Abrechnung', '❌ GenerateInvoices() lieferte false zurück');
                    echo "❌ Fehler bei der PDF-Erstellung (GenerateInvoices)";
                    return;
                }
                if ($pdfContent === null) {
                    IPS_LogMessage('Abrechnung', '❌ GenerateInvoices() gab null zurück');
                    echo "❌ Fehler bei der PDF-Erstellung (leer)";
                    return;
                }
                if (strlen($pdfContent) < 100) {
                    IPS_LogMessage('Abrechnung', '❌ PDF-Inhalt zu kurz: ' . strlen($pdfContent));
                    echo "❌ Fehler bei der PDF-Erstellung (leeres PDF)";
                    return;
                }

                $mediaID = $this->GetIDForIdent('InvoicePDF');
                if (!$mediaID) {
                    IPS_LogMessage('Abrechnung', '❌ Media-ID nicht gefunden');
                    echo "❌ Kein Media-Objekt vorhanden";
                    return;
                }

                IPS_SetMediaContent($mediaID, base64_encode($pdfContent));
                SetValue($this->GetIDForIdent('LastResult'), 'Abrechnung vom ' . date('d.m.Y H:i'));
                IPS_LogMessage('Abrechnung', '✅ Abrechnung erfolgreich gespeichert (' . strlen($pdfContent) . ' Bytes)');
                echo "✅ PDF erfolgreich erstellt.";

            } catch (Throwable $e) {
                IPS_LogMessage('Abrechnung', '💥 Exception in StartBilling: ' . $e->getMessage());
                echo "❌ Ausnahmefehler: " . $e->getMessage();
            }
            break;
    }
}


    // ====================== PDF-Logik ======================

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

        if ($from >= $to) {
            IPS_LogMessage('Abrechnung', '❌ Ungültiger Zeitraum');
            return false;
        }

        $users   = json_decode($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 (empty($users)) {
            IPS_LogMessage('Abrechnung', 'Keine Benutzer vorhanden');
            return false;
        }

        $pdf = new TCPDF('P', 'mm', 'A4', true, 'UTF-8', false);
        $pdf->SetCreator('IPSymcon Abrechnung');
        $pdf->SetAuthor('Abrechnung Modul');
        $pdf->SetTitle('Zählerabrechnung');
        $pdf->SetMargins(15, 15, 15);
        $pdf->SetAutoPageBreak(true, 20);
        $pdf->SetFont('dejavusans', '', 10);

        foreach ($users as $user) {
            $pdf->AddPage();
            $pdf->writeHTML("<h2>Rechnung für {$user['name']}</h2>");
            $pdf->writeHTML("<p>{$user['address']}<br>{$user['city']}</p>");
            $pdf->Ln(4);

            $pdf->writeHTML("<table border='1' cellpadding='5'>
                <tr style='background-color:#e0e0e0;'>
                    <th>Zähler</th>
                    <th>Typ</th>
                    <th>Start</th>
                    <th>Ende</th>
                    <th>Verbrauch</th>
                    <th>Tarif (Rp)</th>
                    <th>Kosten (CHF)</th>
                </tr>");

            $total = 0.0;

            // Stromzähler
            foreach ($power as $m) {
                if ($m['user_id'] != $user['id']) continue;
                $total += $this->AddMeterToPDF($pdf, $m, $tariffs, $from, $to, 'Strombezug');
            }

            // Wasserzähler
            foreach ($water as $m) {
                if ($m['user_id'] != $user['id']) continue;
                $type = $m['meter_type'] ?? 'Warmwasser';
                $total += $this->AddMeterToPDF($pdf, $m, $tariffs, $from, $to, $type);
            }

            $pdf->writeHTML("</table>");
            $pdf->Ln(5);
            $pdf->writeHTML("<h3>Gesamtsumme: " . number_format($total, 2) . " CHF</h3>");
        }

        IPS_LogMessage('Abrechnung', 'PDF-Daten fertiggestellt');
        return $pdf->Output('Abrechnung.pdf', 'S');
    }

    private function AddMeterToPDF($pdf, $meter, $tariffs, $from, $to, $type)
    {
        $start = $this->GetValueAt($meter['var_consumption'], $from);
        $end   = $this->GetValueAt($meter['var_consumption'], $to);
        if ($start === null || $end === null) return 0;

        $diff  = max(0, $end - $start);
        $tariffRp = $this->GetTariff($tariffs, $type, $from, $to);
        $cost  = ($tariffRp / 100) * $diff;

        $pdf->writeHTML("
            <tr>
                <td>{$meter['name']}</td>
                <td>$type</td>
                <td>$start</td>
                <td>$end</td>
                <td>$diff</td>
                <td>$tariffRp</td>
                <td>" . number_format($cost, 2) . "</td>
            </tr>", false, false, false, false, '');

        return $cost;
    }

    private function GetTariff(array $tariffs, string $type, int $from, int $to): float
    {
        foreach ($tariffs as $t) {
            $start = strtotime($t['start']);
            $end   = strtotime($t['end']);
            if ($from >= $start && $to <= $end && strtolower($t['unit_type']) == strtolower($type)) {
                return floatval($t['price']);
            }
        }
        // Kein passender Tarif gefunden
        return 0.0;
    }

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

        $values = @AC_GetLoggedValues($archiveID, $varId, $timestamp - 3600, $timestamp + 3600, 1);
        if ($values && count($values) > 0) {
            return floatval($values[0]['Value']);
        }
        return floatval(GetValue($varId));
    }
}