<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use App\Models\Invoice;
use App\Models\InvoiceItem;
use Mpdf\Mpdf;
use App\Models\InvoiceInstallment;
use Illuminate\Support\Facades\Log;


class AdminInvoiceController extends Controller
{
    // -------------------------------------------------------------
    // INVOICE LIST PAGE
    // -------------------------------------------------------------
    public function index()
    {
        $invoices = Invoice::with(['order.shipments'])->latest()->get();
        return view('admin.invoice', compact('invoices'));
    }

    // -------------------------------------------------------------
    // POPUP VIEW (AJAX)
    // -------------------------------------------------------------
   public function popup($id)
    {
        $invoice = Invoice::with(['items', 'order'])->findOrFail($id);

        // Find actual Shipment record
        $shipment = \App\Models\Shipment::whereHas('items', function ($q) use ($invoice) {
                $q->where('order_id', $invoice->order_id);
            })
            ->first();

        return view('admin.popup_invoice', compact('invoice', 'shipment'));
    }


    // -------------------------------------------------------------
    // EDIT INVOICE PAGE
    // -------------------------------------------------------------
    public function edit($id)
    {
        $invoice = Invoice::with(['order.shipments'])->findOrFail($id);

        $shipment = $invoice->order?->shipments?->first();

        return view('admin.invoice_edit', compact('invoice', 'shipment'));
    }

    // -------------------------------------------------------------
    // UPDATE INVOICE
    // -------------------------------------------------------------

public function update(Request $request, $id)
{
    Log::info("🟡 Invoice Update Request Received", [
        'invoice_id' => $id,
        'request'    => $request->all()
    ]);

    $invoice = Invoice::findOrFail($id);

    $data = $request->validate([
        'invoice_date'      => 'required|date',
        'due_date'          => 'required|date|after_or_equal:invoice_date',
        'final_amount'      => 'required|numeric|min:0',
        'tax_type'          => 'required|in:gst,igst',
        'tax_percent'       => 'required|numeric|min:0|max:28',
        'status'            => 'required|in:pending,paid,overdue',
        'notes'             => 'nullable|string',
    ]);

    Log::info("✅ Validated Invoice Update Data", $data);

    $finalAmount = floatval($data['final_amount']);
    $taxPercent  = floatval($data['tax_percent']);
    $taxAmount   = 0;

    if ($data['tax_type'] === 'gst') {
        Log::info("🟢 GST Selected", compact('taxPercent'));

        $data['cgst_percent'] = $taxPercent / 2;
        $data['sgst_percent'] = $taxPercent / 2;
        $data['igst_percent'] = 0;
    } else {
        Log::info("🔵 IGST Selected", compact('taxPercent'));

        $data['cgst_percent'] = 0;
        $data['sgst_percent'] = 0;
        $data['igst_percent'] = $taxPercent;
    }

    $taxAmount = ($finalAmount * $taxPercent) / 100;

    $data['gst_amount'] = $taxAmount;
    $data['final_amount_with_gst'] = $finalAmount + $taxAmount;

    // ✅ store original % for UI reference
    $data['gst_percent'] = $taxPercent;

    Log::info("📌 Final Calculated Invoice Values", [
        'invoice_id'             => $invoice->id,
        'final_amount'           => $finalAmount,
        'gst_amount'             => $data['gst_amount'],
        'final_amount_with_gst'  => $data['final_amount_with_gst'],
        'tax_type'               => $data['tax_type'],
        'cgst_percent'           => $data['cgst_percent'],
        'sgst_percent'           => $data['sgst_percent'],
        'igst_percent'           => $data['igst_percent'],
    ]);

    $invoice->update($data);

    Log::info("✅ Invoice Updated Successfully", [
        'invoice_id' => $invoice->id
    ]);

    // regenerate PDF
    $this->generateInvoicePDF($invoice);

    return redirect()
        ->route('admin.invoices.index')
        ->with('success', 'Invoice updated & PDF generated successfully.');
}


    // -------------------------------------------------------------
    // PDF GENERATION USING mPDF
    // -------------------------------------------------------------
    public function generateInvoicePDF($invoice)
    {
        // Load relationship including shipment
        $invoice->load(['items', 'order.shipments']);

        // Fetch shipment
        $shipment = $invoice->order?->shipments?->first();

        // PDF filename
        $fileName = 'invoice-' . $invoice->invoice_number . '.pdf';

        // Directory path
        $folder = public_path('invoices/');

        if (!file_exists($folder)) {
            mkdir($folder, 0777, true);
        }

        $filePath = $folder . $fileName;

        // Delete old file if exists
        if (file_exists($filePath)) {
            unlink($filePath);
        }

        // Create mPDF instance
        $mpdf = new Mpdf([
            'mode' => 'utf-8',
            'format' => 'A4',
            'default_font' => 'sans-serif',
        ]);

        // Load HTML view
        $html = view('admin.pdf.invoice', [
            'invoice' => $invoice,
            'shipment' => $shipment
        ])->render();

        // Write HTML to PDF
        $mpdf->WriteHTML($html);

        // Save PDF
        $mpdf->Output($filePath, 'F');

        // Update DB path
        $invoice->update([
            'pdf_path' => 'invoices/' . $fileName
        ]);
    }


public function storeInstallment(Request $request, $invoice_id)
{
    $request->validate([
        'installment_date' => 'required|date',
        'payment_method' => 'required|string',
        'reference_no' => 'nullable|string',
        'amount' => 'required|numeric|min:1',
    ]);

    $invoice = Invoice::findOrFail($invoice_id);

    $paidTotal = $invoice->installments()->sum('amount');
    $remaining = $invoice->final_amount - $paidTotal;

    if ($request->amount > $remaining) {
        return response()->json([
            'status' => 'error',
            'message' => 'Installment amount exceeds remaining balance.'
        ], 422);
    }

    $installment = InvoiceInstallment::create([
        'invoice_id' => $invoice_id,
        'installment_date' => $request->installment_date,
        'payment_method' => $request->payment_method,
        'reference_no' => $request->reference_no,
        'amount' => $request->amount,
    ]);

    // Update invoice status to paid if fully cleared
    $newPaid = $paidTotal + $request->amount;

    if ($newPaid >= $invoice->final_amount) {
        $invoice->update(['status' => 'paid']);
    }

    return response()->json([
        'status' => 'success',
        'message' => 'Installment added successfully.',
        'installment' => $installment,
        'totalPaid' => $newPaid,
        'remaining' => max(0, $invoice->final_amount - $newPaid),
        'isCompleted' => $newPaid >= $invoice->final_amount
    ]);
}

public function deleteInstallment($id)
{
    $installment = InvoiceInstallment::findOrFail($id);
    $invoice = $installment->invoice;

    // delete installment
    $installment->delete();

    // recalc totals
    $paidTotal = $invoice->installments()->sum('amount');
    $remaining = $invoice->final_amount - $paidTotal;

    // auto update invoice status
    if ($remaining > 0 && $invoice->status === "paid") {
        $invoice->update(['status' => 'pending']);
    }

    return response()->json([
        'status' => 'success',
        'message' => 'Installment deleted.',
        'totalPaid' => $paidTotal,
        'remaining' => $remaining,
        'isZero' => $paidTotal == 0
    ]);
}


}