import React, { useMemo } from 'react';
import { Transaction, TransactionType, ExpenseCategory } from '../types';
import { PieChart, Pie, Cell, ResponsiveContainer, Tooltip, Legend, BarChart, Bar, XAxis, YAxis, CartesianGrid } from 'recharts';

interface DashboardProps {
  expenses: Transaction[]; // Kept prop name as expenses for compatibility but type is Transaction
}

const COLORS = [
  '#6366f1', // Indigo
  '#ec4899', // Pink
  '#10b981', // Emerald
  '#f59e0b', // Amber
  '#8b5cf6', // Violet
  '#ef4444', // Red
  '#3b82f6', // Blue
  '#14b8a6', // Teal
  '#f97316', // Orange
  '#84cc16', // Lime
  '#06b6d4', // Cyan
  '#d946ef', // Fuchsia
  '#64748b', // Slate
  '#a855f7', // Purple
  '#fbbf24'  // Yellow
];

const Dashboard: React.FC<DashboardProps> = ({ expenses }) => {
  const today = new Date().toISOString().split('T')[0];

  // Filter only expenses for the dashboard visuals
  const expenseTransactions = useMemo(() => expenses.filter(e => e.type === TransactionType.EXPENSE), [expenses]);

  const todaysExpenses = useMemo(() => {
    return expenseTransactions.filter(e => e.date === today);
  }, [expenseTransactions, today]);

  const totalToday = useMemo(() => {
    return todaysExpenses.reduce((sum, e) => sum + e.amount, 0);
  }, [todaysExpenses]);

  const categoryData = useMemo(() => {
    const map = new Map<string, number>();
    todaysExpenses.forEach(e => {
      map.set(e.category, (map.get(e.category) || 0) + e.amount);
    });
    
    return Array.from(map.entries()).map(([name, value], index) => ({
      name,
      value,
      fill: COLORS[index % COLORS.length]
    }));
  }, [todaysExpenses]);

  const weeklyData = useMemo(() => {
    const data: { date: string; total: number }[] = [];
    for (let i = 6; i >= 0; i--) {
      const d = new Date();
      d.setDate(d.getDate() - i);
      const dateStr = d.toISOString().split('T')[0];
      const dailySum = expenseTransactions
        .filter(e => e.date === dateStr)
        .reduce((sum, e) => sum + e.amount, 0);
      data.push({ date: dateStr.slice(5), total: dailySum });
    }
    return data;
  }, [expenseTransactions]);

  return (
    <div className="flex flex-col h-full bg-white rounded-xl shadow-sm border border-gray-100 overflow-hidden">
      <div className="p-6 bg-gradient-to-r from-indigo-500 to-purple-600 text-white">
        <h2 className="text-xl font-bold mb-1">今日消费统计</h2>
        <div className="flex items-end gap-2">
            <span className="text-4xl font-extrabold tracking-tight">¥{totalToday.toFixed(2)}</span>
            <span className="text-indigo-100 mb-1 text-sm">{today}</span>
        </div>
      </div>

      <div className="flex-1 overflow-y-auto p-4 space-y-6 no-scrollbar">
        <div className="bg-gray-50 p-4 rounded-xl">
            <h3 className="text-gray-700 font-semibold mb-4 text-sm uppercase tracking-wider">今日分类占比</h3>
            {categoryData.length > 0 ? (
            <div className="h-64 w-full">
                <ResponsiveContainer width="100%" height="100%">
                <PieChart>
                    <Pie
                    data={categoryData}
                    cx="50%"
                    cy="50%"
                    innerRadius={60}
                    outerRadius={80}
                    paddingAngle={5}
                    dataKey="value"
                    >
                    {categoryData.map((entry, index) => (
                        <Cell key={`cell-${index}`} fill={entry.fill} />
                    ))}
                    </Pie>
                    <Tooltip formatter={(value: number) => `¥${value.toFixed(2)}`} />
                    <Legend />
                </PieChart>
                </ResponsiveContainer>
            </div>
            ) : (
            <div className="h-32 flex items-center justify-center text-gray-400 text-sm">
                今天还没有消费哦，小王表现不错！
            </div>
            )}
        </div>
      </div>
    </div>
  );
};

export default Dashboard;