<?php
declare(strict_types=1);

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

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

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

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

    public function ApplyChanges()
    {
        parent::ApplyChanges();
    }

    // UI-Eingaben (Visualisierung)
    public function RequestAction($Ident, $Value)
    {
        switch ($Ident) {
            case 'FromDate':
                SetValue($this->GetIDForIdent('FromDate'), $Value);
                break;
            case 'ToDate':
                SetValue($this->GetIDForIdent('ToDate'), $Value);
                break;
            case 'StartBilling':
                $pdfPath = $this->GenerateInvoices();
                if ($pdfPath) {
                    SetValue($this->GetIDForIdent('LastResult'), basename($pdfPath));
                    echo "✅ Abrechnung erstellt: " . basename($pdfPath);
                } else {
                    echo "❌ Fehler bei der PDF-Erstellung";
                }
                break;
        }
    }

    // Hauptfunktion: PDF generieren
    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);

        // TCPDF laden
        if (!class_exists('TCPDF')) {
            $lib = IPS_GetKernelDir() . 'libs/tcpdf/tcpdf.php';
            if (!file_exists($lib)) {
                IPS_LogMessage('Abrechnung', 'TCPDF fehlt in /libs/tcpdf/');
                return false;
            }
            require_once $lib;
        }

        $pdf = new TCPDF();
        $pdf->SetCreator('IPSymcon Abrechnung');
        $pdf->SetAuthor('Abrechnung Modul');
        $pdf->SetTitle('Zählerabrechnung');
        $pdf->SetMargins(15, 15, 15);
        $pdf->SetAutoPageBreak(true, 20);

        foreach ($users as $user) {
            $pdf->AddPage();
            $pdf->SetFont('helvetica', 'B', 14);
            $pdf->Cell(0, 10, 'Rechnung für ' . $user['name'], 0, 1);
            $pdf->SetFont('helvetica', '', 10);
            $pdf->Cell(0, 6, $user['address'] . ' - ' . $user['city'], 0, 1);
            $pdf->Ln(5);

            // Alle Zähler des Benutzers
            $userMeters = array_merge(
                array_filter($power, fn($m) => $m['user_id'] == $user['id']),
                array_filter($water, fn($m) => $m['user_id'] == $user['id'])
            );

            $total = 0.0;
            $pdf->SetFont('helvetica', 'B', 11);
            $pdf->Cell(60, 8, 'Zähler', 1);
            $pdf->Cell(35, 8, 'Start', 1);
            $pdf->Cell(35, 8, 'Ende', 1);
            $pdf->Cell(25, 8, 'Verbrauch', 1);
            $pdf->Cell(25, 8, 'Kosten', 1);
            $pdf->Ln();

            $pdf->SetFont('helvetica', '', 9);
            foreach ($userMeters as $m) {
                $start = $this->GetValueAt($m['var_consumption'], $from);
                $end = $this->GetValueAt($m['var_consumption'], $to);
                if ($start === null || $end === null) continue;

                $diff = max(0, $end - $start);
                $price = $this->GetTariffForMeter($tariffs, $from, $to, $m);
                $cost = $diff * $price;
                $total += $cost;

                $pdf->Cell(60, 7, $m['name'], 1);
                $pdf->Cell(35, 7, number_format($start, 2), 1);
                $pdf->Cell(35, 7, number_format($end, 2), 1);
                $pdf->Cell(25, 7, number_format($diff, 2), 1);
                $pdf->Cell(25, 7, number_format($cost, 2), 1);
                $pdf->Ln();
            }

            $pdf->Ln(4);
            $pdf->SetFont('helvetica', 'B', 11);
            $pdf->Cell(0, 8, 'Gesamtbetrag: ' . number_format($total, 2) . ' CHF', 0, 1, 'R');
        }

        $dir = IPS_GetKernelDir() . 'media/Abrechnung';
        if (!is_dir($dir)) mkdir($dir, 0777, true);
        $filename = 'Abrechnung_' . date('Ymd_His', $from) . '.pdf';
        $path = $dir . '/' . $filename;
        $pdf->Output($path, 'F');

        return $path;
    }

    private function GetValueAt(int $varId, int $timestamp)
    {
        if (!AC_GetLoggedValues(0, 0, 0, 0)) return GetValue($varId); // Fallback
        $archiveID = @IPS_GetInstanceListByModuleID('{43192F0B-135B-4CE7-A0A7-1475603F3060}')[0];
        if (!$archiveID) return GetValue($varId);
        $values = AC_GetLoggedValues($archiveID, $varId, $timestamp - 3600, $timestamp + 3600, 1);
        if (count($values) > 0) return floatval($values[0]['Value']);
        return GetValue($varId);
    }

    private function GetTariffForMeter(array $tariffs, int $from, int $to, array $meter): float
    {
        $type = $meter['meter_type'] ?? 'Wärme';
        $tariff = 0.0;
        foreach ($tariffs as $t) {
            $start = strtotime($t['start']);
            $end = strtotime($t['end']);
            if ($from >= $start && $to <= $end && $t['unit_type'] == $type) {
                $tariff = floatval($t['price']) / 100.0; // Rp → CHF
            }
        }
        return $tariff;
    }
}