import { TrendingUp, AlertCircle, Clock, CheckCircle2, Settings2, type LucideIcon } from 'lucide-react';
import { cn, fmt } from '@/lib/utils';
import type { Dollars } from '@/lib/money';
import { MetricCard } from '@/components/ui/app-primitives';

type CardType = 'starting' | 'paid' | 'remaining' | 'overdue';

interface CardDef {
  label: string;
  icon: LucideIcon;
  valueClass: string;
  tone: 'neutral' | 'good' | 'warn' | 'danger' | 'info';
  activateWhen: (v: number) => boolean;
}

const CARD_DEFS: Record<CardType, CardDef> = {
  starting:  {
    label: 'Starting',
    icon: TrendingUp,
    valueClass: 'text-foreground',
    tone: 'neutral',
    activateWhen: () => true,
  },
  paid:      {
    label: 'Total Paid',
    icon: CheckCircle2,
    valueClass: 'text-emerald-600 dark:text-emerald-200',
    tone: 'good',
    activateWhen: (v) => v > 0,
  },
  remaining: {
    label: 'Remaining',
    icon: Clock,
    valueClass: 'text-foreground',
    tone: 'info',
    activateWhen: () => true,
  },
  overdue:   {
    label: 'Overdue',
    icon: AlertCircle,
    valueClass: 'text-red-500 dark:text-rose-200',
    tone: 'danger',
    activateWhen: (v) => v > 0,
  },
};

interface TrendInfo {
  direction: string;
  percent_change: number;
}

export function TrendIndicator({ trend }: { trend?: TrendInfo | null }) {
  if (!trend) return null;

  const { direction, percent_change } = trend;

  let icon: string, color: string, text: string;
  switch (direction) {
    case 'up':
      icon = '↑';
      color = 'text-emerald-500';
      text = `${icon} ${percent_change}%`;
      break;
    case 'down':
      icon = '↓';
      color = 'text-red-500';
      text = `${icon} ${Math.abs(percent_change)}%`;
      break;
    default:
      icon = '→';
      color = 'text-muted-foreground';
      text = `${icon} ${percent_change}%`;
  }

  return (
    <div className="flex items-center gap-1.5">
      <span className={`text-lg font-bold ${color}`}>
        {text}
      </span>
      <span className="text-[10px] text-muted-foreground whitespace-nowrap">
        vs 3-mo avg
      </span>
    </div>
  );
}

interface SummaryCardProps {
  type: CardType;
  value?: Dollars;
  onEdit?: () => void;
  hint?: string;
  label?: string;
}

export function SummaryCard({ type, value, onEdit, hint, label }: SummaryCardProps) {
  const def      = CARD_DEFS[type];
  const isActive = def.activateWhen(value || 0);
  const Icon     = def.icon;
  const displayLabel = label || def.label;

  return (
    <MetricCard
      className="min-w-0 flex-1"
      tone={isActive ? def.tone : 'neutral'}
      icon={Icon}
      label={displayLabel}
      value={(
        <span className={cn(isActive ? def.valueClass : 'text-foreground')}>
          {fmt(value)}
        </span>
      )}
      hint={hint}
      action={type === 'starting' && onEdit ? (
          <button
            onClick={onEdit}
            className="ml-auto h-4 w-4 text-muted-foreground hover:text-foreground transition-colors"
            title="Edit monthly starting amounts"
            aria-label="Edit monthly starting amounts"
          >
            <Settings2 className="h-4 w-4" />
          </button>
      ) : undefined}
    />
  );
}

export function TrendCard({ trend }: { trend?: TrendInfo | null }) {
  if (!trend) return null;

  return (
    <MetricCard
      className="min-w-0 flex-1"
      tone="info"
      icon={TrendingUp}
      label="3-Month Trend"
      value={(
        <span className="flex min-h-10 items-center justify-center">
        <TrendIndicator trend={trend} />
        </span>
      )}
    />
  );
}
