import { useEffect, useState } from 'react';
import { useBillingStore } from '../../store/billingStore';
import ComponentCard from '../common/ComponentCard';

export default function UsageChartWidget() {
  const { usageSummary, loading, loadUsageSummary } = useBillingStore();
  const [dateRange, setDateRange] = useState<'week' | 'month' | 'year'>('month');
  
  useEffect(() => {
    const now = new Date();
    let startDate: string;
    
    if (dateRange === 'week') {
      const weekAgo = new Date(now.getTime() - 7 * 24 * 60 * 60 * 1000);
      startDate = weekAgo.toISOString().split('T')[0];
    } else if (dateRange === 'month') {
      startDate = new Date(now.getFullYear(), now.getMonth(), 1).toISOString().split('T')[0];
    } else {
      startDate = new Date(now.getFullYear(), 0, 1).toISOString().split('T')[0];
    }
    
    const endDate = now.toISOString().split('T')[0];
    loadUsageSummary(startDate, endDate);
  }, [dateRange, loadUsageSummary]);
  
  if (loading && !usageSummary) {
    return (
      <ComponentCard title="Usage Summary" desc="Loading...">
        <div className="animate-pulse">Loading usage data...</div>
      </ComponentCard>
    );
  }
  
  if (!usageSummary) return null;
  
  return (
    <ComponentCard 
      title="Usage Summary" 
      desc="Credit usage breakdown by operation and model"
    >
      <div className="space-y-4">
        <div className="flex justify-end items-center mb-4">
          <select
            className="h-9 rounded-lg border border-gray-300 bg-transparent px-3 py-2 text-sm shadow-theme-xs text-gray-800 focus:border-brand-300 focus:outline-hidden focus:ring-3 focus:ring-brand-500/10 dark:border-gray-700 dark:bg-gray-900 dark:text-white/90 dark:focus:border-brand-800"
            value={dateRange}
            onChange={(e) => setDateRange(e.target.value as 'week' | 'month' | 'year')}
          >
            <option value="week">Last 7 Days</option>
            <option value="month">This Month</option>
            <option value="year">This Year</option>
          </select>
        </div>
        
        <div className="grid grid-cols-2 gap-4">
          <div>
            <div className="text-sm text-gray-600 dark:text-gray-400">Total Credits Used</div>
            <div className="text-2xl font-bold">{usageSummary.total_credits_used}</div>
          </div>
          <div>
            <div className="text-sm text-gray-600 dark:text-gray-400">Total Cost</div>
            <div className="text-2xl font-bold">${(Number(usageSummary.total_cost_usd) || 0).toFixed(2)}</div>
          </div>
        </div>
        
        <div>
          <h4 className="text-sm font-semibold mb-2">By Operation</h4>
          <div className="space-y-2">
            {Object.entries(usageSummary.by_operation).map(([op, stats]) => (
              <div key={op} className="flex justify-between items-center text-sm">
                <span className="capitalize">{op.replace('_', ' ')}</span>
                <span className="font-medium">{stats.credits} credits (${(Number(stats.cost) || 0).toFixed(2)})</span>
              </div>
            ))}
            {Object.keys(usageSummary.by_operation).length === 0 && (
              <div className="text-sm text-gray-500 dark:text-gray-400">No usage data available</div>
            )}
          </div>
        </div>
      </div>
    </ComponentCard>
  );
}