import React, { useState, useMemo, useEffect } from 'react';
import {
  LineChart, Line, XAxis, YAxis, CartesianGrid, Tooltip, Legend, ResponsiveContainer
} from 'recharts';
import { SalesRecord, PivotRow, YearlyData, TimeSeriesData, ComparisonTimeSeriesPoint } from '../types';
import { pivotSalesData, generateCSV, aggregateForTimeSeries, aggregateForComparisonTimeSeries } from '../services/dataProcessor';
import MultiSelectDropdown from './MultiSelectDropdown';
import { DownloadIcon, FunnelIcon, CloseIcon, ChartIcon } from './Icons';

interface DataGridProps {
  data: SalesRecord[];
}

type SortConfig = {
  key: keyof PivotRow | string | null; // string for dynamic year sorting
  direction: 'asc' | 'desc';
};

type ConditionalFilter = {
    id: string;
    metric: string;
    operator: 'gt' | 'lt';
    value: number;
}

const ROWS_PER_PAGE = 50;
const MONTH_NAMES = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
const CHART_COLORS = ['#6366f1', '#ec4899', '#10b981', '#f59e0b', '#8b5cf6', '#0ea5e9'];

// Available grouping dimensions
const DIMENSION_OPTIONS = [
  { label: 'Product Line', value: 'line' },
  { label: 'Customer', value: 'customer' },
  { label: 'SKU', value: 'sku' },
  { label: 'Title', value: 'title' }, 
  { label: 'ASIN', value: 'asin' },
];

// Tooltip for single-period view with Week-over-Week comparison
const WoWTooltip = ({ active, payload, label, data }: any) => {
    if (active && payload && payload.length && data) {
        const currentIndex = data.findIndex((d: any) => d.name === label);
        const prevData = currentIndex > 0 ? data[currentIndex - 1] : null;

        return (
             <div className="bg-slate-900 border border-border p-3 rounded shadow-xl text-sm max-w-xs z-50">
                <p className="font-bold text-slate-100 mb-2 border-b border-slate-700 pb-1">{label}</p>
                {payload.map((p: any) => {
                    let wowEl = null;
                    if (prevData) {
                        const prevValue = prevData[p.dataKey];
                        const currentValue = p.value;
                        if (prevValue != null && prevValue > 0) {
                            const pct = ((currentValue - prevValue) / prevValue) * 100;
                            wowEl = (
                                <span className={`text-xs ml-2 font-bold ${pct >= 0 ? 'text-emerald-400' : 'text-red-400'}`}>
                                    {pct >= 0 ? '▲' : '▼'} {Math.abs(pct).toFixed(1)}%
                                </span>
                            );
                        }
                    }

                    return (
                        <div key={p.name} className="flex justify-between items-center gap-2 mb-1">
                             <span style={{ color: p.color }}>{p.name}:</span>
                             <div className="flex items-center">
                                <span className="font-mono font-semibold text-slate-200">
                                    {p.dataKey === 'sellOut'
                                    ? `€${Number(p.value).toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0})}`
                                    : `${Number(p.value).toLocaleString()} u`}
                                </span>
                                {wowEl}
                             </div>
                        </div>
                    );
                })}
            </div>
        );
    }
    return null;
}

// Tooltip for multi-year comparison view
const ComparisonTooltip = ({ active, payload, label }: any) => {
    if (active && payload && payload.length) {
        
        interface YearData {
            sellOut?: number;
            units?: number;
            color?: string;
        }

        const dataByYear: { [year: string]: YearData } = {};

        payload.forEach((p: any) => {
            const nameParts = p.name.split(' ');
            if (nameParts.length < 2) return;
            
            const year = nameParts[nameParts.length - 1];
            const metric = nameParts.slice(0, nameParts.length - 1).join(' ');

            if (!dataByYear[year]) {
                dataByYear[year] = {};
            }
            // Use the color from the Sell Out line for consistency for that year block
            if (metric.toLowerCase().includes('so')) {
                dataByYear[year].sellOut = p.value;
                dataByYear[year].color = p.stroke || p.color;
            } else if (metric.toLowerCase().includes('units')) {
                dataByYear[year].units = p.value;
                 if(!dataByYear[year].color) { // fallback color from units line
                    dataByYear[year].color = p.stroke || p.color;
                 }
            }
        });

        const sortedYears = Object.keys(dataByYear).sort((a, b) => parseInt(b) - parseInt(a));

        return (
            <div className="bg-slate-900/90 backdrop-blur-sm border border-border p-3 rounded-lg shadow-xl text-sm w-56 z-50">
                <p className="font-bold text-slate-100 mb-2 border-b border-slate-700 pb-1">{label}</p>
                {sortedYears.map((year, index) => {
                    const yearData = dataByYear[year];
                    const prevYear = sortedYears[index + 1];
                    const prevYearData = prevYear ? dataByYear[prevYear] : null;

                    let sellOutGrowthEl = null;
                    if (prevYearData && prevYearData.sellOut != null && prevYearData.sellOut !== 0 && yearData.sellOut != null) {
                        const pct = ((yearData.sellOut - prevYearData.sellOut) / prevYearData.sellOut) * 100;
                        sellOutGrowthEl = (
                            <span className={`text-xs ml-2 font-bold ${pct >= 0 ? 'text-emerald-400' : 'text-red-400'}`}>
                                {pct >= 0 ? '▲' : '▼'} {Math.abs(pct).toFixed(1)}%
                            </span>
                        );
                    }

                    let unitsGrowthEl = null;
                    if (prevYearData && prevYearData.units != null && prevYearData.units !== 0 && yearData.units != null) {
                        const pct = ((yearData.units - prevYearData.units) / prevYearData.units) * 100;
                        unitsGrowthEl = (
                            <span className={`text-xs ml-2 font-bold ${pct >= 0 ? 'text-emerald-400' : 'text-red-400'}`}>
                                {pct >= 0 ? '▲' : '▼'} {Math.abs(pct).toFixed(1)}%
                            </span>
                        );
                    }
                    
                    return (
                        <div key={year} className="mt-2">
                            <p className="font-bold text-slate-200 text-base">{year}</p>
                            
                            {yearData.sellOut != null && (
                                <div className="flex justify-between items-center gap-2 pl-1 mt-1">
                                    <span className="font-medium" style={{ color: yearData.color }}>Sell Out:</span>
                                    <div className="flex items-center">
                                        <span className="font-mono font-semibold" style={{ color: yearData.color }}>
                                            €{Number(yearData.sellOut).toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 0})}
                                        </span>
                                        {sellOutGrowthEl}
                                    </div>
                                </div>
                            )}

                            {yearData.units != null && (
                                <div className="flex justify-between items-center gap-2 pl-1 mt-1">
                                    <span className="font-medium" style={{ color: yearData.color }}>Units:</span>
                                    <div className="flex items-center">
                                        <span className="font-mono font-semibold" style={{ color: yearData.color }}>
                                            {Number(yearData.units).toLocaleString()} u
                                        </span>
                                        {unitsGrowthEl}
                                    </div>
                                </div>
                            )}
                        </div>
                    );
                })}
            </div>
        );
    }
    return null;
};

// Reusable Expandable Card for the Chart
const ExpandableChartCard: React.FC<{ title: string; children: React.ReactNode; className?: string }> = ({ title, children, className }) => {
  const [isExpanded, setIsExpanded] = useState(false);

  const toggleExpand = () => setIsExpanded(!isExpanded);
  
  if (isExpanded) {
    return (
      <div className="fixed inset-0 z-[80] bg-slate-950 px-6 pb-6 pt-16 flex flex-col animate-fade-in overflow-hidden">
        <div className="flex justify-between items-center mb-4 border-b border-slate-800 pb-4 shrink-0">
          <h3 className="text-xl font-bold text-slate-100 uppercase tracking-wide">{title}</h3>
           <button 
                onClick={toggleExpand}
                className="p-2 bg-red-600/90 hover:bg-red-500 border border-red-400 rounded-full text-white transition-all shadow-2xl hover:scale-110 flex items-center gap-2 group"
                title="Exit Fullscreen"
            >
                <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={2.5} stroke="currentColor" className="w-5 h-5"><path strokeLinecap="round" strokeLinejoin="round" d="M6 18 18 6M6 6l12 12" /></svg>
            </button>
        </div>
        <div className="flex-1 overflow-auto bg-slate-900 rounded-xl p-6 border border-border custom-scrollbar">
          {children}
        </div>
      </div>
    );
  }

  return (
    <div className={`bg-surface border-b border-border group relative transition-all duration-300 ${className}`}>
        <div className="p-4 flex justify-between items-start">
            <h3 className="text-sm font-semibold text-slate-400 uppercase tracking-wide">{title}</h3>
            <button 
                onClick={toggleExpand}
                className="opacity-0 group-hover:opacity-100 text-slate-500 hover:text-primary transition-opacity"
                title="Expand to Fullscreen"
            >
                <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={1.5} stroke="currentColor" className="w-5 h-5"><path strokeLinecap="round" strokeLinejoin="round" d="M3.75 3.75v4.5m0-4.5h4.5m-4.5 0L9 9M3.75 20.25v-4.5m0 4.5h4.5m-4.5 0L9 15M20.25 3.75h-4.5m4.5 0v4.5m0-4.5L15 9m5.25 11.25h-4.5m4.5 0v-4.5m0 4.5L15 15" /></svg>
            </button>
        </div>
        <div className="cursor-pointer px-4 pb-4" onClick={toggleExpand}>
            {children}
        </div>
    </div>
  );
};


const DataGrid: React.FC<DataGridProps> = ({ data }) => {
  const [currentPage, setCurrentPage] = useState(1);
  const [sortConfig, setSortConfig] = useState<SortConfig>({ key: null, direction: 'desc' });
  const [showChart, setShowChart] = useState(true);
  const [visibleMetrics, setVisibleMetrics] = useState<('sellOut' | 'units')[]>(['sellOut', 'units']);
  
  // State for dynamic grouping
  const [selectedDimensions, setSelectedDimensions] = useState<string[]>(['line', 'customer', 'sku', 'title']);

  // State for Advanced Filtering
  const [showFilterBuilder, setShowFilterBuilder] = useState(false);
  const [rowFilters, setRowFilters] = useState<ConditionalFilter[]>([]);
  // Temp state for new filter inputs
  const [newFilterMetric, setNewFilterMetric] = useState<string>('');
  const [newFilterOperator, setNewFilterOperator] = useState<'gt' | 'lt'>('gt');
  const [newFilterValue, setNewFilterValue] = useState<string>('');

  // Effective dimensions for rendering
  const effectiveDimensions = useMemo(() => 
      selectedDimensions.length > 0 ? selectedDimensions : ['customer'], 
  [selectedDimensions]);

  // Transform flat data into Pivot structure
  const { rows: pivotRows, years } = useMemo(() => {
    return pivotSalesData(data, effectiveDimensions);
  }, [data, effectiveDimensions]);
  
  // Data for the time series chart, supporting single and multi-year comparison
  const { chartData, uniqueYears, isComparisonView, chartTitle } = useMemo(() => {
      const yearsInView = Array.from(new Set(data.map(d => d.year.toString()))).sort((a, b) => parseInt(b) - parseInt(a));
      const isMultiYear = yearsInView.length > 1;

      if (isMultiYear) {
          return {
              chartData: aggregateForComparisonTimeSeries(data),
              uniqueYears: yearsInView,
              isComparisonView: true,
              chartTitle: `Weekly Sales Comparison: ${yearsInView.join(' vs ')}`
          };
      } else {
          return {
              chartData: aggregateForTimeSeries(data),
              uniqueYears: yearsInView,
              isComparisonView: false,
              chartTitle: `Weekly Sales Evolution ${yearsInView[0] || ''}`
          };
      }
  }, [data]);

  // Filter Options based on available data
  const metricOptions = useMemo(() => {
      const options = [];
      // Totals
      years.forEach(y => {
          options.push({ label: `Total Sell Out ${y} (€)`, value: `total_sellOut_${y}` });
          options.push({ label: `Total Units ${y}`, value: `total_units_${y}` });
      });
      // Growth (Latest vs Previous)
      if (years.length >= 2) {
          options.push({ label: `Growth % Sell Out (${years[0]} vs ${years[1]})`, value: 'growth_sellOut' });
          options.push({ label: `Growth % Units (${years[0]} vs ${years[1]})`, value: 'growth_units' });
      }
      return options;
  }, [years]);

  // Default sorting
  const effectiveSortKey = sortConfig.key || (years.length > 0 ? `total_${years[0]}` : null);

  // Apply Advanced Row Filters THEN Sort
  const processedRows = useMemo(() => {
    let result = pivotRows;

    // 1. Filter
    if (rowFilters.length > 0) {
        const latestYear = years[0];
        const prevYear = years[1]; 

        result = result.filter(row => {
            return rowFilters.every(filter => {
                let rowValue = 0;

                if (filter.metric.startsWith('total_sellOut_')) {
                    const y = filter.metric.split('_')[2];
                    rowValue = row.totalsByYear[y]?.sellOut || 0;
                }
                else if (filter.metric.startsWith('total_units_')) {
                    const y = filter.metric.split('_')[2];
                    rowValue = row.totalsByYear[y]?.units || 0;
                }
                else if (filter.metric === 'growth_sellOut') {
                    if (!prevYear) return true; 
                    const curr = row.totalsByYear[latestYear]?.sellOut || 0;
                    const prev = row.totalsByYear[prevYear]?.sellOut || 0;
                    if (prev === 0) return curr > 0;
                    rowValue = ((curr - prev) / prev) * 100;
                }
                else if (filter.metric === 'growth_units') {
                    if (!prevYear) return true; 
                    const curr = row.totalsByYear[latestYear]?.units || 0;
                    const prev = row.totalsByYear[prevYear]?.units || 0;
                    if (prev === 0) return curr > 0;
                    rowValue = ((curr - prev) / prev) * 100;
                }

                if (filter.operator === 'gt') return rowValue > filter.value;
                if (filter.operator === 'lt') return rowValue < filter.value;
                return true;
            });
        });
    }

    // 2. Sort
    if (effectiveSortKey) {
        result = [...result].sort((a, b) => {
            let aVal: string | number = 0; 
            let bVal: string | number = 0;

            const sortKeyStr = String(effectiveSortKey);

            if (effectiveDimensions.includes(sortKeyStr)) {
                const key = sortKeyStr as keyof PivotRow;
                const valA = a[key];
                const valB = b[key];
                if (typeof valA === 'string' || typeof valA === 'number') {
                    aVal = valA;
                }
                if (typeof valB === 'string' || typeof valB === 'number') {
                    bVal = valB;
                }
            } else if (sortKeyStr.startsWith('total_')) {
                const year = sortKeyStr.split('_')[1];
                aVal = a.totalsByYear[year]?.sellOut || 0;
                bVal = b.totalsByYear[year]?.sellOut || 0;
            }

            if (typeof aVal === 'string' && typeof bVal === 'string') {
                return sortConfig.direction === 'asc' 
                  ? String(aVal).localeCompare(String(bVal)) 
                  : String(bVal).localeCompare(String(aVal));
            }

            if (aVal < bVal) return sortConfig.direction === 'asc' ? -1 : 1;
            if (aVal > bVal) return sortConfig.direction === 'asc' ? 1 : -1;
            return 0;
        });
    }

    return result;
  }, [pivotRows, rowFilters, effectiveSortKey, sortConfig, effectiveDimensions, years]);


  // Grand Totals (Calculated on Filtered Rows for context)
  const grandTotals = useMemo(() => {
    const accTotalsByYear: Record<string, YearlyData> = {};
    const accMonthsByYear: Record<number, Record<string, YearlyData>> = {}; 
    
    years.forEach(y => {
        accTotalsByYear[y] = { sellOut: 0, units: 0 };
    });
    for(let i=0; i<12; i++) {
        accMonthsByYear[i] = {};
        years.forEach(y => {
            accMonthsByYear[i][y] = { sellOut: 0, units: 0 };
        });
    }

    processedRows.forEach(row => {
        // Totals
        Object.entries(row.totalsByYear).forEach(([y, val]) => {
            const v = val as YearlyData;
            if (accTotalsByYear[y]) {
                accTotalsByYear[y].sellOut += v.sellOut;
                accTotalsByYear[y].units += v.units;
            }
        });
        
        // Months
        row.months.forEach((m, idx) => {
             Object.entries(m.byYear).forEach(([y, val]) => {
                 const v = val as YearlyData;
                 if (accMonthsByYear[idx][y]) {
                     accMonthsByYear[idx][y].sellOut += v.sellOut;
                     accMonthsByYear[idx][y].units += v.units;
                 }
             });
        });
    });
    
    return { totalsByYear: accTotalsByYear, months: accMonthsByYear };
  }, [processedRows, years]);

  // Pagination
  const totalPages = Math.ceil(processedRows.length / ROWS_PER_PAGE);
  const currentRows = useMemo(() => {
    const start = (currentPage - 1) * ROWS_PER_PAGE;
    return processedRows.slice(start, start + ROWS_PER_PAGE);
  }, [processedRows, currentPage]);

  // Handlers
  const requestSort = (key: string) => {
    let direction: 'asc' | 'desc' = 'desc';
    if (sortConfig.key === key && sortConfig.direction === 'desc') {
      direction = 'asc';
    }
    setSortConfig({ key, direction });
    setCurrentPage(1);
  };

  const handlePrev = () => setCurrentPage(p => Math.max(1, p - 1));
  const handleNext = () => setCurrentPage(p => Math.min(totalPages, p + 1));
  const handleExport = () => generateCSV(processedRows, effectiveDimensions, years);
  const getLabel = (val: string) => DIMENSION_OPTIONS.find(d => d.value === val)?.label || val;

  const toggleMetric = (metric: 'sellOut' | 'units') => {
      setVisibleMetrics(prev => 
          prev.includes(metric) 
              ? prev.filter(m => m !== metric)
              : [...prev, metric]
      );
  };

  // Filter Handlers
  const addFilter = () => {
      if (!newFilterMetric || !newFilterValue) return;
      setRowFilters(prev => [
          ...prev, 
          { 
              id: Date.now().toString(), 
              metric: newFilterMetric, 
              operator: newFilterOperator, 
              value: parseFloat(newFilterValue) 
          }
      ]);
      setNewFilterValue('');
      // Don't close builder to allow adding more
  };

  const removeFilter = (id: string) => {
      setRowFilters(prev => prev.filter(f => f.id !== id));
  };

  // Render Helpers
  const renderGrowth = (current: number, previous: number, size: 'sm' | 'xs' = 'xs') => {
    if (previous === 0) return null; 
    const pct = ((current - previous) / previous) * 100;
    const isPositive = pct >= 0;
    const textSize = size === 'sm' ? 'text-xs' : 'text-[10px]';
    
    return (
      <span className={`${textSize} font-bold ml-1.5 ${isPositive ? 'text-emerald-400' : 'text-rose-400'} bg-slate-800 border border-slate-700 px-1 rounded inline-block`}>
        {isPositive ? '↑' : '↓'}{Math.abs(pct).toFixed(0)}%
      </span>
    );
  };

  if (data.length === 0) return null;

  return (
    <div className="max-w-[100vw] mx-auto px-4 pb-24 h-screen flex flex-col">
      <div className="bg-surface border border-border rounded-xl shadow-lg flex flex-col flex-1">
        
        {/* Header Bar */}
        <div className="p-4 border-b border-border bg-slate-900 flex flex-col gap-4 shrink-0 rounded-t-xl z-50">
            <div className="flex flex-wrap gap-4 justify-between items-center">
                <div>
                    <h3 className="text-lg font-bold text-slate-100">Dynamic Pivot Table</h3>
                    <p className="text-xs text-slate-500">
                        Comparing {years.join(', ')} • {processedRows.length} Rows 
                        {rowFilters.length > 0 && <span className="text-indigo-400 ml-1">(Filtered)</span>}
                    </p>
                </div>
                
                <div className="flex items-center gap-4">
                    <div className="flex items-center gap-2">
                        <span className="text-sm text-slate-400 font-medium">Group By:</span>
                        <MultiSelectDropdown 
                            label="Variables"
                            selected={selectedDimensions}
                            options={DIMENSION_OPTIONS.map(d => d.value)}
                            onChange={setSelectedDimensions}
                            className="w-64"
                        />
                    </div>

                    <button 
                        onClick={() => setShowFilterBuilder(!showFilterBuilder)}
                        className={`flex items-center gap-2 px-3 py-2 rounded-lg text-sm font-medium transition-colors shadow-sm border
                            ${showFilterBuilder || rowFilters.length > 0 ? 'bg-indigo-900/50 border-indigo-500 text-indigo-300' : 'bg-slate-800 border-border text-slate-300 hover:text-white hover:bg-slate-700'}`}
                    >
                        <FunnelIcon /> 
                        {rowFilters.length > 0 ? `${rowFilters.length} Active` : 'Filter Rows'}
                    </button>

                     <button 
                        onClick={() => setShowChart(!showChart)}
                        className={`flex items-center gap-2 px-3 py-2 rounded-lg text-sm font-medium transition-colors shadow-sm border
                            ${showChart ? 'bg-indigo-900/50 border-indigo-500 text-indigo-300' : 'bg-slate-800 border-border text-slate-300 hover:text-white hover:bg-slate-700'}`}
                    >
                        <ChartIcon /> 
                        {showChart ? 'Hide Trend' : 'Show Trend'}
                    </button>

                    <button 
                        onClick={handleExport}
                        className="flex items-center gap-2 px-3 py-2 bg-indigo-600 hover:bg-indigo-700 text-white rounded-lg text-sm font-medium transition-colors shadow-sm"
                    >
                        <DownloadIcon /> Export CSV
                    </button>
                </div>
            </div>

            {/* Advanced Filter Builder Panel */}
            {(showFilterBuilder || rowFilters.length > 0) && (
                <div className="bg-slate-950/50 p-4 rounded-lg border border-border space-y-3 animate-fade-in">
                    
                    {/* Active Filters List */}
                    {rowFilters.length > 0 && (
                        <div className="flex flex-wrap gap-2 mb-2">
                            {rowFilters.map(filter => {
                                const metricLabel = metricOptions.find(o => o.value === filter.metric)?.label || filter.metric;
                                const opLabel = filter.operator === 'gt' ? '>' : '<';
                                return (
                                    <div key={filter.id} className="flex items-center gap-2 bg-indigo-500/10 border border-indigo-500/30 text-indigo-300 px-3 py-1 rounded-full text-xs font-medium">
                                        <span>{metricLabel} {opLabel} {filter.value}</span>
                                        <button onClick={() => removeFilter(filter.id)} className="hover:text-white"><CloseIcon /></button>
                                    </div>
                                );
                            })}
                        </div>
                    )}

                    {/* Filter Creator Inputs */}
                    {showFilterBuilder && (
                        <div className="flex flex-wrap items-end gap-3">
                            <div className="flex flex-col gap-1">
                                <label className="text-xs text-slate-500 font-semibold uppercase">Metric</label>
                                <select 
                                    className="bg-slate-900 border border-slate-700 text-slate-200 text-sm rounded-md px-3 py-2 focus:ring-1 focus:ring-primary outline-none min-w-[220px]"
                                    value={newFilterMetric}
                                    onChange={(e) => setNewFilterMetric(e.target.value)}
                                >
                                    <option value="">Select Metric...</option>
                                    {metricOptions.map(opt => (
                                        <option key={opt.value} value={opt.value}>{opt.label}</option>
                                    ))}
                                </select>
                            </div>

                            <div className="flex flex-col gap-1">
                                <label className="text-xs text-slate-500 font-semibold uppercase">Operator</label>
                                <select 
                                    className="bg-slate-900 border border-slate-700 text-slate-200 text-sm rounded-md px-3 py-2 focus:ring-1 focus:ring-primary outline-none"
                                    value={newFilterOperator}
                                    onChange={(e) => setNewFilterOperator(e.target.value as 'gt' | 'lt')}
                                >
                                    <option value="gt">Greater Than ({'>'})</option>
                                    <option value="lt">Less Than ({'<'})</option>
                                </select>
                            </div>

                            <div className="flex flex-col gap-1">
                                <label className="text-xs text-slate-500 font-semibold uppercase">Value</label>
                                <input 
                                    type="number" 
                                    placeholder="0"
                                    className="w-full bg-slate-900 border border-slate-700 text-slate-200 text-sm rounded-md px-3 py-2 focus:ring-1 focus:ring-primary outline-none w-32"
                                    value={newFilterValue}
                                    onChange={(e) => setNewFilterValue(e.target.value)}
                                    onKeyDown={(e) => e.key === 'Enter' && addFilter()}
                                />
                            </div>

                            <button 
                                onClick={addFilter}
                                disabled={!newFilterMetric || !newFilterValue}
                                className="px-4 py-2 bg-indigo-600 hover:bg-indigo-500 disabled:opacity-50 disabled:hover:bg-indigo-600 text-white rounded-md text-sm font-medium transition-colors"
                            >
                                Apply
                            </button>
                        </div>
                    )}
                </div>
            )}
        </div>
        
        {/* Trend Chart */}
        {showChart && chartData.length > 1 && (
            <ExpandableChartCard title={chartTitle} className="mb-6">
                <div className="flex flex-col h-full min-h-[350px]">
                    <div className="flex justify-end mb-2 shrink-0">
                        <div className="bg-slate-900 p-1 rounded-lg border border-slate-800 flex text-xs font-medium">
                            <label className="flex items-center gap-2 px-3 py-1 rounded-md transition-colors cursor-pointer has-[:checked]:bg-indigo-600 has-[:checked]:text-white has-[:checked]:shadow-sm text-slate-400 hover:text-white">
                                <input type="checkbox" checked={visibleMetrics.includes('sellOut')} onChange={() => toggleMetric('sellOut')} className="hidden" />
                                Sell Out (€)
                            </label>
                             <label className="flex items-center gap-2 px-3 py-1 rounded-md transition-colors cursor-pointer has-[:checked]:bg-teal-600 has-[:checked]:text-white has-[:checked]:shadow-sm text-slate-400 hover:text-white">
                                <input type="checkbox" checked={visibleMetrics.includes('units')} onChange={() => toggleMetric('units')} className="hidden" />
                                Units
                            </label>
                        </div>
                    </div>
                    <div className="flex-1 w-full">
                        <ResponsiveContainer width="100%" height="100%">
                            <LineChart data={chartData} margin={{ top: 5, right: 30, left: 20, bottom: 5 }}>
                                <CartesianGrid strokeDasharray="3 3" stroke="#1e293b" />
                                <XAxis dataKey="name" stroke="#64748b" tick={{ fontSize: 12 }} />
                                
                                {visibleMetrics.includes('sellOut') && (
                                    <YAxis yAxisId="left" stroke={CHART_COLORS[0]} tickFormatter={(val) => `€${(val / 1000).toFixed(0)}k`} />
                                )}
                                {visibleMetrics.includes('units') && (
                                    <YAxis yAxisId="right" orientation="right" stroke={isComparisonView ? CHART_COLORS[1] : CHART_COLORS[2]} tickFormatter={(val) => `${(val / 1000).toFixed(0)}k`} />
                                )}
                                
                                <Tooltip content={isComparisonView ? <ComparisonTooltip /> : <WoWTooltip data={chartData} />} />
                                <Legend />

                                {isComparisonView ? (
                                    uniqueYears.map((year, index) => (
                                        <React.Fragment key={year}>
                                            {visibleMetrics.includes('sellOut') && (
                                                <Line yAxisId="left" type="monotone" dataKey={`${year}_sellOut`} name={`SO ${year}`} stroke={CHART_COLORS[index % CHART_COLORS.length]} strokeWidth={2} dot={false} activeDot={{ r: 6 }} />
                                            )}
                                            {visibleMetrics.includes('units') && (
                                                <Line yAxisId="right" type="monotone" dataKey={`${year}_units`} name={`Units ${year}`} stroke={CHART_COLORS[index % CHART_COLORS.length]} strokeWidth={2} strokeDasharray="5 5" dot={false} activeDot={{ r: 6 }} />
                                            )}
                                        </React.Fragment>
                                    ))
                                ) : (
                                    <>
                                        {visibleMetrics.includes('sellOut') && (
                                            <Line yAxisId="left" type="monotone" dataKey="sellOut" name="Sell Out" stroke={CHART_COLORS[0]} strokeWidth={2} dot={{ r: 3 }} activeDot={{ r: 6 }} />
                                        )}
                                        {visibleMetrics.includes('units') && (
                                            <Line yAxisId="right" type="monotone" dataKey="units" name="Units" stroke={CHART_COLORS[2]} strokeWidth={2} dot={{ r: 3 }} activeDot={{ r: 6 }} />
                                        )}
                                    </>
                                )}
                            </LineChart>
                        </ResponsiveContainer>
                    </div>
                </div>
            </ExpandableChartCard>
        )}
        
        {(!showChart || chartData.length <=1) && !isComparisonView && (
             <div className="p-4 border-b border-border text-center text-sm text-slate-500 italic bg-slate-900/30 mb-6">
                {isComparisonView 
                    ? "Not enough weekly data to compare these years." 
                    : "Not enough weekly data points to render a trend chart for the current selection."
                }
             </div>
        )}


        {/* Table Container */}
        <div className="overflow-auto flex-1 relative custom-scrollbar bg-slate-950">
          <table className="w-max text-left text-sm text-slate-300 border-collapse">
            <thead className="bg-slate-950 text-sm uppercase font-semibold text-slate-400 z-30 shadow-md">
              <tr className="border-b border-slate-800">
                {/* Dynamic Dimension Headers - STICKY TOP */}
                {effectiveDimensions.map((dim, index) => {
                    const label = getLabel(dim);
                    const isFirst = index === 0;
                    const isTitle = dim === 'title';
                    
                    return (
                        <th 
                            key={dim}
                            className={`p-3 border-r border-slate-800 cursor-pointer hover:text-white sticky top-0 bg-slate-950
                                ${isTitle ? 'min-w-[300px]' : 'min-w-[150px]'}
                                ${isFirst ? 'left-0 z-40 bg-slate-900' : 'z-30'}`}
                            onClick={() => requestSort(dim)}
                        >
                            {label} {sortConfig.key === dim && (sortConfig.direction === 'asc' ? '▲' : '▼')}
                        </th>
                    );
                })}

                {/* Dynamic Total Columns for each Year - STICKY TOP */}
                {years.map(year => (
                    <th 
                        key={`total_${year}`}
                        className="p-3 w-40 border-r border-indigo-500 text-right cursor-pointer text-white bg-indigo-700 hover:bg-indigo-600 transition-colors shadow-md sticky top-0 z-30" 
                        onClick={() => requestSort(`total_${year}`)}
                    >
                        Total {year} {sortConfig.key === `total_${year}` && (sortConfig.direction === 'asc' ? '▲' : '▼')}
                    </th>
                ))}

                {/* Monthly Headers - STICKY TOP */}
                {MONTH_NAMES.map(m => (
                    <th key={m} className="p-2 min-w-[150px] text-center border-r border-slate-800 bg-slate-900 sticky top-0 z-30">
                        {m}
                    </th>
                ))}
              </tr>

              {/* Grand Total Row (Sticky Top BELOW Headers) */}
              <tr className="border-b-2 border-indigo-400 bg-slate-950 text-white font-bold shadow-lg z-40 sticky top-[48px]">
                 {/* 
                    Anchor TOTAL label to the first column (sticky left).
                    This ensures "TOTAL" stays visible on the left even when scrolling horizontally.
                 */}
                 <td 
                    className="p-3 border-r border-slate-800 text-left sticky left-0 z-50 bg-slate-950 whitespace-nowrap"
                 >
                    TOTAL ({processedRows.length} Rows)
                 </td>
                 
                 {/* Spacer for remaining dimensions if any */}
                 {effectiveDimensions.length > 1 && (
                     <td 
                        colSpan={effectiveDimensions.length - 1} 
                        className="p-3 border-r border-slate-800 bg-slate-950"
                     />
                 )}
                 
                 {/* Totals for each year - HIGH CONTRAST (Indigo 800) */}
                 {years.map((year, yIdx) => {
                     const currentData = grandTotals.totalsByYear[year] || { sellOut: 0, units: 0 };
                     let sellOutGrowth = null;
                     let unitsGrowth = null;
                     
                     // Compare with next year in the list (chronologically previous)
                     if (yIdx < years.length - 1) {
                         const prevYear = years[yIdx + 1];
                         const prevData = grandTotals.totalsByYear[prevYear];
                         if (prevData) {
                             sellOutGrowth = renderGrowth(currentData.sellOut, prevData.sellOut, 'sm');
                             unitsGrowth = renderGrowth(currentData.units, prevData.units, 'sm');
                         }
                     }

                     return (
                         <td key={`grand_${year}`} className="p-3 border-r border-indigo-500 text-right bg-indigo-800">
                            <div className="flex justify-end items-center mb-1">
                                <span className="text-base text-white">€{currentData.sellOut.toLocaleString(undefined, { maximumFractionDigits: 0 })}</span>
                                {sellOutGrowth}
                            </div>
                            <div className="flex justify-end items-center">
                                <span className="text-sm text-violet-300 font-normal">{currentData.units.toLocaleString()} u</span>
                                {unitsGrowth}
                            </div>
                         </td>
                     );
                 })}

                 {/* Monthly Grand Totals */}
                 {MONTH_NAMES.map((_, idx) => (
                     <td key={`grand_m_${idx}`} className="p-2 border-r border-slate-800 text-right min-w-[150px] bg-slate-900">
                         {years.map((year, yIdx) => {
                             const data = grandTotals.months[idx][year];
                             if(!data || (data.sellOut === 0 && data.units === 0)) return null;

                             let sellOutGrowth = null;
                             let unitsGrowth = null;

                             if (yIdx < years.length - 1) {
                                 const prevYear = years[yIdx + 1];
                                 const prevData = grandTotals.months[idx][prevYear];
                                 if (prevData) {
                                     sellOutGrowth = renderGrowth(data.sellOut, prevData.sellOut);
                                     unitsGrowth = renderGrowth(data.units, prevData.units);
                                 }
                             }

                             return (
                                 <div key={year} className="flex justify-between items-center text-xs mb-1 border-b border-white/5 last:border-0 pb-1 last:pb-0">
                                     <div className="flex items-center text-slate-400 mr-2 min-w-[32px]">
                                         <span>{year}</span>
                                     </div>
                                     <div className="text-right flex-1">
                                         <div className="flex items-center justify-end">
                                             <span>€{data.sellOut.toLocaleString(undefined, { maximumFractionDigits: 0 })}</span>
                                             {sellOutGrowth}
                                         </div>
                                         <div className="flex items-center justify-end text-violet-400 font-mono mt-0.5">
                                             <span>{data.units.toLocaleString()}u</span>
                                             {unitsGrowth}
                                         </div>
                                     </div>
                                 </div>
                             );
                         })}
                     </td>
                 ))}
              </tr>
            </thead>

            <tbody className="divide-y divide-border">
              {currentRows.map((row, index) => {
                const isAlternate = index % 2 === 1;
                // Alternate row color: Default dark (slate-950) vs Alternate lighter (slate-800) for high contrast
                const rowClass = isAlternate ? 'bg-slate-800' : 'bg-slate-950';
                
                return (
                <tr key={row.id} className={`${rowClass} hover:bg-slate-700 transition-colors group`}>
                  
                  {/* Dimensions */}
                  {effectiveDimensions.map((dim, index) => {
                      const isFirst = index === 0;
                      // @ts-ignore
                      const val = row[dim];
                      const isTitle = dim === 'title';
                      
                      const textColor = isTitle ? 'text-white font-semibold' : (isFirst ? 'text-slate-200 font-medium' : 'text-slate-400');

                      let cellContent: React.ReactNode = val;

                      if (isTitle && typeof val === 'string') {
                          cellContent = (
                              <div className="overflow-x-auto whitespace-nowrap custom-scrollbar pb-1">
                                  {val}
                              </div>
                          );
                      } else {
                          let displayVal = val;
                          if (typeof val === 'string' && val.length > 30) {
                              displayVal = val.substring(0, 30) + '...';
                          }
                          cellContent = displayVal;
                      }

                      return (
                          <td 
                             key={dim} 
                             className={`p-3 border-r border-slate-800 text-sm ${textColor}
                                ${isTitle ? 'min-w-[300px] max-w-[300px]' : 'truncate max-w-[220px]'}
                                ${isFirst ? `sticky left-0 z-20 ${rowClass} group-hover:bg-slate-700` : ''}
                             `}
                             title={val}
                          >
                            {cellContent}
                          </td>
                      );
                  })}
                  
                  {/* Dynamic Total Columns per Year - HIGH CONTRAST BODY (Indigo 900/60) */}
                  {years.map((year, yIdx) => {
                      const yData = row.totalsByYear[year] || { sellOut: 0, units: 0 };
                      let sellOutGrowth = null;
                      let unitsGrowth = null;

                      if (yIdx < years.length - 1) {
                          const prevYear = years[yIdx + 1];
                          const prevData = row.totalsByYear[prevYear];
                          if (prevData) {
                              sellOutGrowth = renderGrowth(yData.sellOut, prevData.sellOut);
                              unitsGrowth = renderGrowth(yData.units, prevData.units);
                          }
                      }

                      return (
                        <td key={`row_tot_${year}`} className="p-3 border-r border-indigo-500/40 text-right font-bold text-white bg-indigo-900/60">
                            <div className="flex justify-end items-center mb-1">
                                <span className="text-base">€{yData.sellOut.toLocaleString(undefined, { maximumFractionDigits: 0 })}</span>
                                {sellOutGrowth}
                            </div>
                            <div className="flex justify-end items-center text-sm text-violet-200 font-normal">
                                <span>{yData.units.toLocaleString()} u</span>
                                {unitsGrowth}
                            </div>
                        </td>
                      );
                  })}

                  {/* Monthly Data Columns (Listing all years) */}
                  {row.months.map((m, idx) => (
                    <td key={idx} className="p-2 border-r border-slate-800 text-right min-w-[150px]">
                        {years.map((year, yIdx) => {
                            const yData = m.byYear[year];
                            // Skip if year has no data, unless it's the only year selected
                            if (!yData && years.length > 1) return null;
                            const sellOut = yData?.sellOut || 0;
                            const units = yData?.units || 0;
                            
                            let sellOutGrowthEl = null;
                            let unitsGrowthEl = null;

                            if (yIdx < years.length - 1) {
                                const nextYear = years[yIdx + 1];
                                const nextData = m.byYear[nextYear];
                                if (nextData) {
                                    if (nextData.sellOut > 0) {
                                        sellOutGrowthEl = renderGrowth(sellOut, nextData.sellOut);
                                    }
                                    if (nextData.units > 0) {
                                        unitsGrowthEl = renderGrowth(units, nextData.units);
                                    }
                                }
                            }

                            return (
                                <div key={year} className="mb-2 last:mb-0 border-b border-slate-800 last:border-0 pb-1 last:pb-0">
                                     <div className="flex justify-between items-center text-xs text-slate-500 mb-0.5">
                                         <span>{year}</span>
                                         {sellOutGrowthEl}
                                     </div>
                                     <div className="flex justify-end items-center text-sm font-medium text-slate-300">
                                        €{sellOut.toLocaleString(undefined, { maximumFractionDigits: 0 })}
                                     </div>
                                     <div className="flex justify-between items-center mt-0.5">
                                         <div className="flex-1"></div>
                                         <div className="flex items-center gap-1">
                                             <span className="text-xs text-violet-400 font-mono">{units} u</span>
                                             {unitsGrowthEl}
                                         </div>
                                     </div>
                                </div>
                            );
                        })}
                    </td>
                  ))}
                </tr>
              )})}
            </tbody>
          </table>
        </div>

        {/* Footer */}
        <div className="bg-slate-900 border-t border-border p-3 flex justify-between items-center text-sm shrink-0 rounded-b-xl z-40">
          <div className="text-slate-500">
            Showing {((currentPage - 1) * ROWS_PER_PAGE) + 1} - {Math.min(currentPage * ROWS_PER_PAGE, processedRows.length)} of {processedRows.length} Rows
          </div>
          <div className="flex gap-2">
            <button 
              onClick={handlePrev} 
              disabled={currentPage === 1}
              className="px-3 py-1 rounded bg-slate-800 border border-border hover:bg-slate-700 disabled:opacity-50 transition-colors"
            >
              Previous
            </button>
            <span className="flex items-center px-2 text-slate-300">
              Page {currentPage} of {totalPages}
            </span>
            <button 
              onClick={handleNext} 
              disabled={currentPage === totalPages}
              className="px-3 py-1 rounded bg-slate-800 border border-border hover:bg-slate-700 disabled:opacity-50 transition-colors"
            >
              Next
            </button>
          </div>
        </div>
      </div>
    </div>
  );
};

export default DataGrid;