// collections_health_widget.dart

import 'package:flutter/material.dart';

// --- MAIN WIDGET FILE ---
class CollectionsHealthWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    // Derived Metrics from the JSON Analysis:
    const double totalDue = 34190.0;
    const double totalCollected = 5000.0;
    const double totalValue = totalDue + totalCollected;
    // Calculate Pending Percentage for Gauge
    final double pendingPercentage =
        totalValue > 0 ? totalDue / totalValue : 0.0;

    // 1. MAIN CARD CONTAINER (White Theme)
    return Container(
      decoration: BoxDecoration(
        // Main card background color: WHITE
        color: Colors.white,
        borderRadius: BorderRadius.circular(5),
        boxShadow: [
          BoxShadow(
            // Lighter shadow for white background
            color: Colors.black.withOpacity(0.1),
            blurRadius: 10,
            offset: const Offset(0, 5),
          ),
        ],
      ),
      padding: const EdgeInsets.all(16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisSize: MainAxisSize.min,
        children: <Widget>[
          // 1. HEADER
          _buildHeader(),
          const SizedBox(height: 20),
          // 2. MAIN CONTENT ROW (Layout)
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: <Widget>[
              // Left Section: Gauge Chart, Due Amount, & Timelines
              Expanded(
                flex: 5,
                child: _buildLeftChartSection(
                  totalDue: totalDue,
                  pendingPercentage: pendingPercentage,
                ),
              ),
              const SizedBox(width: 16),
              // Right Section: Metric Cards
              Expanded(
                flex: 4,
                child: _buildRightMetricsSection(
                  totalCollected: totalCollected,
                ),
              ),
            ],
          ),
          const SizedBox(height: 20),
          // 3. NEW: AGING ANALYSIS SECTION
          _buildAgingAnalysis(),
        ],
      ),
    );
  }

  // --- HELPER METHOD 1: HEADER ---
  Widget _buildHeader() {
    return Row(
      children: const <Widget>[
        Text(
          'Collections Health Overview',
          style: TextStyle(
            // Text color: Dark for contrast on white background
            color: Colors.black87,
            fontSize: 18,
            fontWeight: FontWeight.bold,
          ),
        ),
      ],
    );
  }

  // --- HELPER METHOD 2: LEFT SECTION (CHARTS) ---
  Widget _buildLeftChartSection({
    required double totalDue,
    required double pendingPercentage,
  }) {
    // Format the percentage for display
    String pendingPercentStr = (pendingPercentage * 100).toStringAsFixed(0);
    // Use the derived totalCollected for a better context
    const double totalCollected = 5000.0;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        // Top: Gauge Chart and Due Amount
        Row(
          children: <Widget>[
            // Use White-Theme Gauge Placeholder with calculated percentage
            _GaugeChartPlaceholder(
                backgroundColor: Colors.white,
                pendingPercentage: pendingPercentage),
            const SizedBox(width: 12),
          ],
        ),

        const SizedBox(height: 20),
        Row(
          children: [
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  Text(
                    '₹${totalDue.toStringAsFixed(0)} DUE',
                    style: const TextStyle(
                      // Text color: Dark for contrast
                      color: Colors.black87,
                      fontSize: 22,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                  const SizedBox(height: 4),
                  Text(
                    '• Pending ($pendingPercentStr%) • ₹${totalCollected.toStringAsFixed(0)} Collected',
                    // Sub-text color: Lighter dark color
                    style: const TextStyle(color: Colors.black54, fontSize: 12),
                  ),
                ],
              ),
            ),
          ],
        ),
        const SizedBox(height: 20),
        // Bottom: Timeline Charts (Trend Analysis)
        Row(
          children: <Widget>[
            // Expected Collections Timeline (Bar Chart Placeholder)
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  const Text('Expected Collections Trend',
                      // Text color: Dark for contrast
                      style: TextStyle(color: Colors.black87, fontSize: 12)),
                  const SizedBox(height: 8),
                  _TimelineChartPlaceholder(
                      isBar: true,
                      barColor: const Color(0xFF2196F3)), // Blue Bar Chart
                  const Text('Week 16 Nov 2025',
                      style: TextStyle(color: Colors.black54, fontSize: 10)),
                ],
              ),
            ),
            const SizedBox(width: 10),
            // Collection Rate Trend (Area Chart Placeholder for Analysis)
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: <Widget>[
                  const Text('Collection Rate Trend',
                      // Text color: Dark for contrast
                      style: TextStyle(color: Colors.black87, fontSize: 12)),
                  const SizedBox(height: 8),
                  _TimelineChartPlaceholder(
                      isBar: false,
                      areaColor:
                          const Color(0xFF4CAF50)), // Green Area Chart (Rate)
                  const Text('Week 14 Nov 2025',
                      style: TextStyle(color: Colors.black54, fontSize: 10)),
                ],
              ),
            ),
          ],
        ),
      ],
    );
  }

  // --- HELPER METHOD 3: RIGHT SECTION (METRICS) ---
  Widget _buildRightMetricsSection({
    required double totalCollected,
  }) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.spaceBetween,
      children: <Widget>[
        // Metric Card 1: Top Client (From Invoice 1)
        _buildMetricCard(
          title: 'Top Client Balance',
          value: 'Peninsula Land Limited',
          subValue: '₹34,190',
          valueColor: const Color(0xFFF44336), // Red (Pending/Due)
          isDetailed: true,
        ),
        const SizedBox(height: 10),
        // Metric Card 2 (NEW): Total Collected (From Invoice 2)
        _buildMetricCard(
          title: 'Total Collected (YTD)',
          value: '₹${totalCollected.toStringAsFixed(0)}',
          subValue: 'Collected',
          valueColor: const Color(0xFF4CAF50), // Green (Positive Value)
          isDetailed: false,
        ),
        const SizedBox(height: 10),
        // Metric Card 3: Days Sales Outstanding (DSO) (Analytical Placeholder)
        _buildMetricCard(
          title: 'Days Sales Outstanding (DSO)',
          value: '45 Days',
          subValue: '↑ 5 Days',
          valueColor: const Color(0xFFFF9800), // Orange (Needs improvement)
          isDetailed: false,
        ),
        const SizedBox(height: 10),
        // Metric Card 4: Last Metric Card in the image (Repeating rate for layout)
        _buildMetricCard(
          title: 'Bad Debt Ratio',
          value: '0.8%',
          subValue: '↓ 0.2%',
          valueColor: const Color(0xFF4CAF50), // Green (Positive Change)
          isDetailed: false,
        ),
      ],
    );
  }

  // --- HELPER METHOD 4: METRIC CARD WIDGET (Unchanged) ---
  Widget _buildMetricCard({
    required String title,
    required String value,
    required String subValue,
    required Color valueColor,
    required bool isDetailed,
  }) {
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 8),
      decoration: BoxDecoration(
        // Light grey background for card separation on white theme
        color: const Color(0xFFF5F5F5),
        borderRadius: BorderRadius.circular(5),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: <Widget>[
          Text(
            title,
            // Title text color: Soft dark grey
            style: const TextStyle(color: Colors.black54, fontSize: 10),
          ),
          const SizedBox(height: 2),
          // Conditional rendering for the detailed vs simple card structure
          if (isDetailed) ...[
            Text(
              value, // Client Name
              style: const TextStyle(
                // Value text color: Dark
                color: Colors.black87,
                fontSize: 12,
                fontWeight: FontWeight.w600,
              ),
            ),
            Text(
              subValue, // Due Amount
              style: TextStyle(
                // Color remains dynamic (Red/Green/etc.)
                color: valueColor,
                fontSize: 16,
                fontWeight: FontWeight.bold,
              ),
            ),
          ] else
            Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: <Widget>[
                Text(
                  value,
                  style: const TextStyle(
                    // Value text color: Dark
                    color: Colors.black87,
                    fontSize: 14,
                    fontWeight: FontWeight.w600,
                  ),
                ),
                Text(
                  subValue,
                  style: TextStyle(
                    // Color remains dynamic (Red/Green/etc.)
                    color: valueColor,
                    fontSize: 14,
                    fontWeight: FontWeight.w600,
                  ),
                ),
              ],
            ),
        ],
      ),
    );
  }

  // --- NEW HELPER METHOD: AGING ANALYSIS ---
  // --- NEW HELPER METHOD: AGING ANALYSIS (MODIFIED) ---
  Widget _buildAgingAnalysis() {
    // Hardcoded data based on the JSON analysis
    const double due0to20Days = 0.0;
    const double due20to45Days = 34190.0;
    const double due45to90Days = 0.0;
    const double dueOver90Days = 0.0;

    final double totalOutstanding =
        due0to20Days + due20to45Days + due45to90Days + dueOver90Days;

    // Define buckets with their risk color
    final List<AgingBucketData> buckets = [
      AgingBucketData('0-20 Days', due0to20Days,
          const Color(0xFF4CAF50)), // Green (Low Risk)
      AgingBucketData('20-45 Days', due20to45Days,
          const Color(0xFFFF9800)), // Orange (Medium Risk)
      AgingBucketData('45-90 Days', due45to90Days,
          const Color(0xFFF44336).withOpacity(0.7)), // Light Red (High Risk)
      AgingBucketData('> 90 Days', dueOver90Days,
          const Color(0xFFF44336)), // Dark Red (Very High Risk)
    ];

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        const Text(
          'Outstanding Collections Aging Analysis',
          style: TextStyle(
            color: Colors.black87,
            fontSize: 14,
            fontWeight: FontWeight.bold,
          ),
        ),
        const SizedBox(height: 10),

        // NEW: STACKED BAR VISUALIZATION
        _AgingStackedBar(
          buckets: buckets,
          totalOutstanding: totalOutstanding,
        ),

        const SizedBox(height: 15),

        // NEW: LEGEND/BUCKET DETAILS (Replaces the old _buildAgingBucket layout)
        Wrap(
          spacing: 12,
          runSpacing: 8,
          children: buckets
              .map((bucket) => _buildAgingLegendItem(
                  bucket.title, bucket.amount, bucket.color))
              .toList(),
        ),
      ],
    );
  }

// Keep the old _buildAgingBucket helper and rename it to a legend item
// This is more efficient than recreating the logic
  Widget _buildAgingLegendItem(String title, double amount, Color color) {
    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Container(
          width: 10,
          height: 10,
          decoration: BoxDecoration(
            color: color,
            shape: BoxShape.circle,
          ),
        ),
        const SizedBox(width: 6),
        Text(
          '${title}: ₹${amount.toStringAsFixed(0)}',
          style: const TextStyle(color: Colors.black87, fontSize: 12),
        ),
      ],
    );
  }
}

// --- CUSTOM PAINTERS / PLACEHOLDERS (Modified to accept percentage) ---

// Placeholder for the Semi-Circle Gauge Chart
class _GaugeChartPlaceholder extends StatelessWidget {
  final Color backgroundColor;
  final double pendingPercentage;

  const _GaugeChartPlaceholder(
      {required this.backgroundColor, required this.pendingPercentage});

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 120,
      height: 80,
      child: Stack(
        children: [
          // BACKGROUND GAUGE
          CustomPaint(
            size: const Size(120, 70),
            // Pass the pending percentage to the painter
            painter: _SemiCirclePainter(
                canvasColor: backgroundColor,
                pendingPercentage: pendingPercentage),
          ),

          // CENTER CIRCLE
          Positioned(
            bottom: 0,
            left: 30,
            child: Container(
              height: 60,
              width: 60,
              decoration: BoxDecoration(
                // Center circle background is the same as the main card background (white)
                color: backgroundColor,
                shape: BoxShape.circle,
                border: Border.all(color: Colors.black.withOpacity(0.1)),
              ),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: const [
                  // Icon color: Dark
                  Icon(Icons.work, color: Colors.black87, size: 20),
                  SizedBox(height: 2),
                  Text(
                    'RISK LEVEL',
                    // Text color: Soft dark grey
                    style: TextStyle(color: Colors.black54, fontSize: 8),
                  ),
                ],
              ),
            ),
          ),
        ],
      ),
    );
  }
}

// Painter for the semi-circular gauge chart visualization (Simplified)
class _SemiCirclePainter extends CustomPainter {
  final Color canvasColor;
  final double pendingPercentage;

  _SemiCirclePainter(
      {required this.canvasColor, required this.pendingPercentage});

  @override
  void paint(Canvas canvas, Size size) {
    final rect = Rect.fromCircle(
        center: Offset(size.width / 2, size.height), radius: size.width / 2);

    // Radians for a semi-circle
    const double totalArc = 3.14159;
    // Calculate the sweep angles
    final double pendingSweepAngle = totalArc * pendingPercentage;
    final double collectedSweepAngle = totalArc * (1.0 - pendingPercentage);

    // Background Arc (Full semi-circle)
    final backgroundPaint = Paint()
      // Background arc is a soft grey on a white theme
      ..color = Colors.black.withOpacity(0.1)
      ..style = PaintingStyle.stroke
      ..strokeWidth = 10;
    canvas.drawArc(rect, totalArc, totalArc, false,
        backgroundPaint); // Start at 180 deg (Pi)

    // Pending Arc (Red/Orange segment)
    final pendingPaint = Paint()
      ..color = const Color(0xFFF44336) // Red
      ..style = PaintingStyle.stroke
      ..strokeWidth = 10
      ..shader = const LinearGradient(colors: [
        Color(0xFFFF9800), // Orange
        Color(0xFFF44336), // Red
      ]).createShader(rect);
    // Start angle: 3.14 (180 deg)
    canvas.drawArc(rect, totalArc, pendingSweepAngle, false, pendingPaint);

    // Collected Arc (Green segment)
    final collectedPaint = Paint()
      ..color = const Color(0xFF4CAF50) // Green
      ..style = PaintingStyle.stroke
      ..strokeWidth = 10;
    // Start angle: 3.14 + pendingSweepAngle
    canvas.drawArc(rect, totalArc + pendingSweepAngle, collectedSweepAngle,
        false, collectedPaint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
}

// Placeholder for the Bar/Area Charts (Unchanged)
class _TimelineChartPlaceholder extends StatelessWidget {
  final bool isBar;
  final Color? barColor;
  final Color? areaColor;

  const _TimelineChartPlaceholder(
      {required this.isBar, this.barColor, this.areaColor});

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 50,
      width: double.infinity,
      color: Colors.transparent, // Transparent container for visual space
      child: isBar
          ? _BarChartVisual(barColor: barColor!)
          : _AreaChartVisual(areaColor: areaColor!),
    );
  }
}

class _BarChartVisual extends StatelessWidget {
  final Color barColor;

  const _BarChartVisual({required this.barColor});

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.end,
      mainAxisAlignment: MainAxisAlignment.spaceEvenly,
      children: [
        _Bar(0.4, barColor),
        _Bar(0.7, barColor),
        _Bar(1.0, barColor),
        _Bar(0.6, barColor),
        _Bar(0.8, barColor),
      ],
    );
  }
}

class _Bar extends StatelessWidget {
  final double heightFactor;
  final Color color;

  const _Bar(this.heightFactor, this.color);

  @override
  Widget build(BuildContext context) {
    return Container(
      width: 8,
      height: 50 * heightFactor,
      decoration: BoxDecoration(
        color: color,
        borderRadius: BorderRadius.circular(5),
      ),
    );
  }
}

class _AreaChartVisual extends StatelessWidget {
  final Color areaColor;

  const _AreaChartVisual({required this.areaColor});

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: _AreaChartPainter(areaColor: areaColor),
      size: const Size(double.infinity, 50),
    );
  }
}

class _AreaChartPainter extends CustomPainter {
  final Color areaColor;

  _AreaChartPainter({required this.areaColor});

  @override
  void paint(Canvas canvas, Size size) {
    final points = [
      Offset(0, size.height * 0.5),
      Offset(size.width * 0.25, size.height * 0.8),
      Offset(size.width * 0.5, size.height * 0.3),
      Offset(size.width * 0.75, size.height * 0.9),
      Offset(size.width, size.height * 0.4),
    ];

    // Path for the area
    final path = Path()
      ..moveTo(points.first.dx, size.height)
      ..lineTo(points.first.dx, points.first.dy);
    for (int i = 1; i < points.length; i++) {
      path.lineTo(points[i].dx, points[i].dy);
    }
    path.lineTo(points.last.dx, size.height);
    path.close();

    // Paint for the gradient fill
    final areaPaint = Paint()
      ..shader = LinearGradient(
        begin: Alignment.topCenter,
        end: Alignment.bottomCenter,
        colors: [
          areaColor.withOpacity(0.5), // Lighter opacity on white theme
          areaColor.withOpacity(0.0), // Transparent
        ],
      ).createShader(Rect.fromLTWH(0, 0, size.width, size.height))
      ..style = PaintingStyle.fill;
    canvas.drawPath(path, areaPaint);

    // Paint for the line stroke
    final linePaint = Paint()
      ..color = areaColor
      ..strokeWidth = 2
      ..style = PaintingStyle.stroke;
    canvas.drawPath(Path()..addPolygon(points, false), linePaint);
  }

  @override
  bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
}

// --- NEW DATA MODEL ---
class AgingBucketData {
  final String title;
  final double amount;
  final Color color;

  AgingBucketData(this.title, this.amount, this.color);
}

// --- NEW HELPER WIDGET: STACKED BAR VISUAL ---
class _AgingStackedBar extends StatelessWidget {
  final List<AgingBucketData> buckets;
  final double totalOutstanding;

  const _AgingStackedBar({
    required this.buckets,
    required this.totalOutstanding,
  });

  @override
  Widget build(BuildContext context) {
    if (totalOutstanding == 0) {
      return Container(
        height: 16,
        decoration: BoxDecoration(
          color: Colors.grey[200],
          borderRadius: BorderRadius.circular(8),
        ),
        child: const Center(
          child: Text(
            'No Outstanding Collections',
            style: TextStyle(color: Colors.black54, fontSize: 10),
          ),
        ),
      );
    }

    // Build the segments for the Row
    final List<Widget> segments =
        buckets.where((b) => b.amount > 0).map((bucket) {
      final double flexValue = bucket.amount / totalOutstanding;
      return Expanded(
        flex: (flexValue * 100).toInt(), // Use a scaled integer for flex
        child: Container(
          height: 16,
          color: bucket.color,
        ),
      );
    }).toList();

    return ClipRRect(
      borderRadius: BorderRadius.circular(8),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.center,
        children: segments,
      ),
    );
  }
}