// lib/screens/order_home_screen.dart

import "package:flutter/material.dart";
import "../services/api.dart";

class OrderHomeScreen extends StatefulWidget {
  // OPTIONAL so routes that call `const OrderHomeScreen()` compile.
  final int? businessId;
  final int? servicePointId;
  final int? userId;

  const OrderHomeScreen({
    super.key,
    this.businessId,
    this.servicePointId,
    this.userId,
  });

  @override
  State<OrderHomeScreen> createState() => _OrderHomeScreenState();
}

class _OrderHomeScreenState extends State<OrderHomeScreen> {
  bool _busy = false;
  String? _error;

  int? _businessId;
  int? _servicePointId;
  int? _userId;

  int? _orderId;

  int? _asIntNullable(dynamic v) {
    if (v == null) return null;
    if (v is int) return v;
    if (v is double) return v.toInt();
    if (v is String) {
      final s = v.trim();
      if (s.isEmpty) return null;
      return int.tryParse(s);
    }
    return null;
  }

  void _loadIdsFromWidgetAndRoute() {
    int? b = widget.businessId;
    int? sp = widget.servicePointId;
    int? u = widget.userId;

    // If not provided via constructor, attempt to read from route arguments.
    final args = ModalRoute.of(context)?.settings.arguments;

    if ((b == null || sp == null || u == null) && args is Map) {
      // Prefer exact key spellings that match labels.
      b ??= _asIntNullable(args["BusinessID"]);
      sp ??= _asIntNullable(args["ServicePointID"]);
      u ??= _asIntNullable(args["UserID"]);

      // Fallback keys (common Flutter style)
      b ??= _asIntNullable(args["businessId"]);
      sp ??= _asIntNullable(args["servicePointId"]);
      u ??= _asIntNullable(args["userId"]);
    }

    // Normalize "0" to null (so we don't show misleading zeros).
    if (b == 0) b = null;
    if (sp == 0) sp = null;
    if (u == 0) u = null;

    final changed = (b != _businessId) || (sp != _servicePointId) || (u != _userId);
    if (changed) {
      setState(() {
        _businessId = b;
        _servicePointId = sp;
        _userId = u;
      });
    }
  }

  @override
  void initState() {
    super.initState();
    // cannot read ModalRoute here reliably; do it in didChangeDependencies.
    _businessId = widget.businessId == 0 ? null : widget.businessId;
    _servicePointId = widget.servicePointId == 0 ? null : widget.servicePointId;
    _userId = widget.userId == 0 ? null : widget.userId;
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _loadIdsFromWidgetAndRoute();
  }

  @override
  void didUpdateWidget(covariant OrderHomeScreen oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.businessId != widget.businessId ||
        oldWidget.servicePointId != widget.servicePointId ||
        oldWidget.userId != widget.userId) {
      _loadIdsFromWidgetAndRoute();
    }
  }

  Future<void> _run(Future<void> Function() fn) async {
    if (_busy) return;
    setState(() {
      _busy = true;
      _error = null;
    });
    try {
      await fn();
    } catch (e) {
      setState(() => _error = e.toString());
    } finally {
      if (mounted) setState(() => _busy = false);
    }
  }

  bool get _hasAllIds => _businessId != null && _servicePointId != null && _userId != null;

  Future<void> _createOrLoadCart() async {
    if (!_hasAllIds) {
      setState(() {
        _error = "Missing IDs. BusinessID / ServicePointID / UserID were not provided to this screen.";
      });
      return;
    }

    await _run(() async {
      final cartData = await Api.getOrCreateCart(
        userId: _userId!,
        businessId: _businessId!,
        servicePointId: _servicePointId!,
        orderTypeId: 1, // MVP default: dine-in
      );

      final oid = _asIntNullable(cartData is Map ? cartData["OrderID"] : null);
      setState(() => _orderId = oid);
    });
  }

  Future<void> _refreshCart() async {
    if (_orderId == null) return;
    await _run(() async {
      await Api.getCart(orderId: _orderId!);
    });
  }

  Future<void> _addDemoItem(int itemId) async {
    if (_orderId == null) {
      setState(() => _error = "No cart yet. Tap 'Create/Load Cart' first.");
      return;
    }

    await _run(() async {
      await Api.setLineItem(
        orderId: _orderId!,
        parentOrderLineItemId: 0,
        itemId: itemId,
        qty: 1,
        selectedChildItemIds: const <int>[],
      );
    });
  }

  Future<void> _submit() async {
    if (_orderId == null) {
      setState(() => _error = "No cart yet.");
      return;
    }

    await _run(() async {
      await Api.submitOrder(orderId: _orderId!);
    });
  }

  Widget _idRow(String label, int? value) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 6),
      child: Row(
        children: [
          SizedBox(
            width: 120,
            child: Text(label, style: const TextStyle(fontWeight: FontWeight.w600)),
          ),
          Expanded(
            child: Text(
              value == null ? "(missing)" : value.toString(),
              textAlign: TextAlign.right,
            ),
          ),
        ],
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final orderId = _orderId;

    return Scaffold(
      appBar: AppBar(title: const Text("Order (Compile-Only MVP)")),
      body: ListView(
        padding: const EdgeInsets.all(16),
        children: [
          const Text(
            "This screen exists only to compile cleanly against\n"
            "Api.dart.\n"
            "No menu, no models, no polish.",
          ),
          const SizedBox(height: 16),

          Card(
            child: Padding(
              padding: const EdgeInsets.all(12),
              child: Column(
                children: [
                  _idRow("BusinessID", _businessId),
                  _idRow("ServicePointID", _servicePointId),
                  _idRow("UserID", _userId),
                ],
              ),
            ),
          ),

          const SizedBox(height: 16),

          Row(
            children: [
              Expanded(
                child: ElevatedButton(
                  onPressed: _busy ? null : _createOrLoadCart,
                  child: const Text("Create/Load Cart"),
                ),
              ),
              const SizedBox(width: 12),
              Expanded(
                child: OutlinedButton(
                  onPressed: (_busy || orderId == null) ? null : _refreshCart,
                  child: const Text("Refresh Cart"),
                ),
              ),
            ],
          ),

          const SizedBox(height: 16),

          Card(
            child: Padding(
              padding: const EdgeInsets.all(12),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text("Cart OrderID: ${orderId ?? "(none)"}"),
                  const SizedBox(height: 10),
                  Wrap(
                    spacing: 10,
                    runSpacing: 10,
                    children: [
                      ElevatedButton(
                        onPressed: _busy ? null : () => _addDemoItem(101),
                        child: const Text("Add Demo Item 101"),
                      ),
                      ElevatedButton(
                        onPressed: _busy ? null : () => _addDemoItem(102),
                        child: const Text("Add Demo Item 102"),
                      ),
                      ElevatedButton(
                        onPressed: _busy ? null : () => _addDemoItem(103),
                        child: const Text("Add Demo Item 103"),
                      ),
                    ],
                  ),
                  const SizedBox(height: 12),
                  ElevatedButton(
                    onPressed: (_busy || orderId == null) ? null : _submit,
                    child: const Text("Submit Order"),
                  ),
                ],
              ),
            ),
          ),

          const SizedBox(height: 16),

          if (_busy) ...[
            const Center(child: CircularProgressIndicator()),
            const SizedBox(height: 16),
          ],

          if (_error != null)
            Card(
              child: Padding(
                padding: const EdgeInsets.all(12),
                child: Text(_error!),
              ),
            ),
        ],
      ),
    );
  }
}