import 'package:flutter/material.dart';
import 'package:mobile_scanner/mobile_scanner.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_database/firebase_database.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:intl/intl.dart';

class ScanQrScreen extends StatefulWidget {
  const ScanQrScreen({super.key});

  @override
  State<ScanQrScreen> createState() => _ScanQrScreenState();
}

class _ScanQrScreenState extends State<ScanQrScreen> {
  static const Color primaryColor = Color(0xFFA5CC36);

  final TextEditingController nominalController = TextEditingController();

  bool loading = false;
  bool isScanned = false;
  String? qrData;

  String rupiah(int value) {
    return NumberFormat.currency(
      locale: 'id_ID',
      symbol: 'Rp ',
      decimalDigits: 0,
    ).format(value);
  }

  void addNumber(String number) {
    setState(() {
      nominalController.text += number;
    });
  }

  void backspace() {
    setState(() {
      if (nominalController.text.isNotEmpty) {
        nominalController.text = nominalController.text.substring(
          0,
          nominalController.text.length - 1,
        );
      }
    });
  }

  void clearNominal() {
    setState(() {
      nominalController.clear();
    });
  }

  void showError(String pesan) {
    showDialog(
      context: context,
      builder: (_) => Dialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(25)),
        child: Padding(
          padding: const EdgeInsets.all(25),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Container(
                width: 90,
                height: 90,
                decoration: const BoxDecoration(
                  color: Colors.red,
                  shape: BoxShape.circle,
                ),
                child: const Icon(Icons.close, size: 60, color: Colors.white),
              ),
              const SizedBox(height: 20),
              const Text(
                "Pembayaran Gagal",
                style: TextStyle(fontSize: 22, fontWeight: FontWeight.bold),
              ),
              const SizedBox(height: 10),
              Text(pesan, textAlign: TextAlign.center),
              const SizedBox(height: 20),
              SizedBox(
                width: double.infinity,
                child: ElevatedButton(
                  onPressed: () => Navigator.pop(context),
                  child: const Text("OK"),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  void showSuccess(int nominal, int saldoBaru) {
    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (_) => Dialog(
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(30)),
        child: Padding(
          padding: const EdgeInsets.all(25),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              TweenAnimationBuilder(
                duration: const Duration(milliseconds: 700),
                tween: Tween(begin: 0.0, end: 1.0),
                builder: (context, value, child) {
                  return Transform.scale(
                    scale: value,
                    child: Container(
                      width: 100,
                      height: 100,
                      decoration: const BoxDecoration(
                        color: Color(0xFFA5CC36),
                        shape: BoxShape.circle,
                      ),
                      child: const Icon(
                        Icons.check,
                        size: 65,
                        color: Colors.black,
                      ),
                    ),
                  );
                },
              ),
              const SizedBox(height: 20),
              const Text(
                "Pembayaran Berhasil",
                style: TextStyle(fontSize: 24, fontWeight: FontWeight.bold),
              ),
              const SizedBox(height: 10),

              Text("Nominal pembayaran", textAlign: TextAlign.center),

              const SizedBox(height: 5),

              Text(
                rupiah(nominal),
                style: const TextStyle(
                  fontWeight: FontWeight.bold,
                  fontSize: 20,
                ),
              ),

              const SizedBox(height: 10),

              Text(
                "Sisa saldo : ${rupiah(saldoBaru)}",
                textAlign: TextAlign.center,
              ),

              const SizedBox(height: 25),

              SizedBox(
                width: double.infinity,
                child: ElevatedButton(
                  style: ElevatedButton.styleFrom(
                    backgroundColor: primaryColor,
                    foregroundColor: Colors.black,
                  ),
                  onPressed: () {
                    Navigator.pop(context);
                    Navigator.pop(context);
                  },
                  child: const Text("SELESAI"),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }

  Future<void> prosesPembayaran() async {
    final nominal = int.tryParse(nominalController.text) ?? 0;

    if (qrData == null) {
      showError("QR belum dipindai");
      return;
    }

    if (nominal < 1000) {
      showError("Minimal pembayaran Rp1.000");
      return;
    }

    setState(() => loading = true);

    try {
      final uid = FirebaseAuth.instance.currentUser!.uid;

      final firestoreUser = await FirebaseFirestore.instance
          .collection("users")
          .doc(uid)
          .get();

      final rfid = firestoreUser.data()?["rfid_uid"]?.toString();

      if (rfid == null || rfid.isEmpty) {
        throw Exception("RFID user tidak ditemukan");
      }

      final userRef = FirebaseDatabase.instance.ref("users/$rfid");

      final snapshot = await userRef.get();

      final data = Map<String, dynamic>.from(snapshot.value as Map);

      final saldo = (data["saldo"] ?? 0) as int;

      if (saldo < nominal) {
        showError("Saldo tidak mencukupi");
        return;
      }

      final saldoBaru = saldo - nominal;

      await userRef.update({"saldo": saldoBaru});

      await userRef.child("history").push().set({
        "type": "Pembayaran QRIS",
        "nilai": nominal,
        "waktu": DateTime.now().toIso8601String(),
        "saldo_sebelum": saldo,
        "saldo_sesudah": saldoBaru,
        "qr_data": qrData,
      });

      if (mounted) {
        showSuccess(nominal, saldoBaru);
      }
    } catch (e) {
      showError(e.toString());
    } finally {
      if (mounted) {
        setState(() => loading = false);
      }
    }
  }

  Widget buildKeypad() {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        for (var row in [
          ["1", "2", "3"],
          ["4", "5", "6"],
          ["7", "8", "9"],
          ["C", "0", "⌫"],
        ])
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 4),
            child: Row(
              children: row.map((e) {
                return Expanded(
                  child: Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 5),
                    child: SizedBox(
                      height: 60,
                      child: ElevatedButton(
                        onPressed: () {
                          if (e == "C") {
                            clearNominal();
                          } else if (e == "⌫") {
                            backspace();
                          } else {
                            addNumber(e);
                          }
                        },
                        child: Text(e),
                      ),
                    ),
                  ),
                );
              }).toList(),
            ),
          ),
      ],
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: const Color(0xFF0B1600),
      appBar: AppBar(
        title: const Text("Scan QRIS"),
        backgroundColor: primaryColor,
      ),
      body: qrData == null
          ? Stack(
              children: [
                MobileScanner(
                  onDetect: (capture) {
                    if (isScanned) return;

                    final code = capture.barcodes.first.rawValue;

                    if (code != null) {
                      setState(() {
                        isScanned = true;
                        qrData = code;
                      });
                    }
                  },
                ),
                Center(
                  child: Container(
                    width: 260,
                    height: 260,
                    decoration: BoxDecoration(
                      border: Border.all(color: primaryColor, width: 4),
                      borderRadius: BorderRadius.circular(20),
                    ),
                  ),
                ),
              ],
            )
          : Padding(
              padding: const EdgeInsets.all(20),
              child: Column(
                children: [
                  const Text(
                    "QRIS Berhasil Dipindai",
                    style: TextStyle(
                      color: Colors.white,
                      fontSize: 22,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                  const SizedBox(height: 20),
                  Container(
                    width: double.infinity,
                    padding: const EdgeInsets.all(15),
                    decoration: BoxDecoration(
                      color: const Color(0xFF1A1A1A),
                      borderRadius: BorderRadius.circular(12),
                    ),
                    child: Text(
                      nominalController.text.isEmpty
                          ? "Rp 0"
                          : "Rp ${nominalController.text}",
                      style: const TextStyle(
                        color: Colors.white,
                        fontSize: 28,
                        fontWeight: FontWeight.bold,
                      ),
                    ),
                  ),
                  const SizedBox(height: 20),
                  Expanded(child: buildKeypad()),
                  SizedBox(
                    width: double.infinity,
                    height: 55,
                    child: ElevatedButton(
                      style: ElevatedButton.styleFrom(
                        backgroundColor: primaryColor,
                        foregroundColor: Colors.black,
                      ),
                      onPressed: loading ? null : prosesPembayaran,
                      child: loading
                          ? const CircularProgressIndicator()
                          : const Text("Bayar"),
                    ),
                  ),
                ],
              ),
            ),
    );
  }
}