'use client'

import { useState } from 'react'
import { Info, X } from 'lucide-react'
import { Card, CardContent } from '@/components/ui/card'
import { formatCurrency } from '@/lib/utils'
import { KPI_DEFINITIONS, getDefaultPreferences } from '@/lib/reports/kpi-definitions'
import type { KPIReport, KPIPreferences } from '@/types'

interface KPIHeroCardsProps {
  report: KPIReport
  preferences?: KPIPreferences
}

function getKPIValue(
  report: KPIReport,
  id: string
): { value: number | null; subtitle: string } {
  switch (id) {
    case 'netResult':
      return { value: report.netResult, subtitle: 'netto' }
    case 'cashPosition':
      return { value: report.cashPosition, subtitle: 'likvida medel' }
    case 'outstandingReceivables':
      return {
        value: report.outstandingReceivables,
        subtitle:
          report.overdueReceivables > 0
            ? `varav förfallet: ${formatCurrency(report.overdueReceivables)}`
            : 'utestående',
      }
    case 'vatLiability':
      return {
        value: report.vatLiability,
        subtitle:
          report.vatLiability > 0
            ? 'att betala'
            : report.vatLiability < 0
              ? 'att återfå'
              : 'jämnt',
      }
    case 'grossMargin':
      return { value: report.grossMargin, subtitle: 'av intäkter' }
    case 'expenseRatio':
      return { value: report.expenseRatio, subtitle: 'av intäkter' }
    case 'avgPaymentDays':
      return { value: report.avgPaymentDays, subtitle: 'snitt' }
    default:
      return { value: null, subtitle: '' }
  }
}

function formatKPIValue(value: number | null, format: string, id: string): string {
  if (value === null) return '—'
  if (format === 'currency') {
    if (id === 'vatLiability') return formatCurrency(Math.abs(value))
    return formatCurrency(value)
  }
  if (format === 'percentage') return `${value}%`
  if (format === 'days') return `${value} dagar`
  return String(value)
}

function getValueColor(
  value: number | null,
  colorLogic: string
): string {
  if (value === null) return 'text-muted-foreground'
  if (colorLogic === 'neutral') return ''
  if (colorLogic === 'positive-good') {
    return value >= 0
      ? 'text-[hsl(var(--chart-1))]'
      : 'text-[hsl(var(--chart-2))]'
  }
  // negative-good (e.g. VAT: negative = refund = good, expense ratio: lower = better)
  if (colorLogic === 'negative-good') {
    return value <= 0
      ? 'text-[hsl(var(--chart-1))]'
      : 'text-[hsl(var(--chart-2))]'
  }
  return ''
}

export function KPIHeroCards({ report, preferences }: KPIHeroCardsProps) {
  const prefs = preferences ?? getDefaultPreferences()
  const [infoOpen, setInfoOpen] = useState<string | null>(null)

  // Build ordered, visible list
  const visibleDefs = prefs.kpiOrder
    .map((id) => KPI_DEFINITIONS.find((d) => d.id === id))
    .filter((d) => d && prefs.visibleKpis.includes(d.id)) as typeof KPI_DEFINITIONS

  if (visibleDefs.length === 0) {
    return (
      <Card>
        <CardContent className="py-8 text-center text-muted-foreground text-sm">
          Inga nyckeltal valda. Klicka på &quot;Anpassa&quot; för att välja vilka som ska visas.
        </CardContent>
      </Card>
    )
  }

  // Responsive grid: 2 cols on mobile, up to 4 on desktop
  const gridCols =
    visibleDefs.length <= 2
      ? 'grid-cols-2'
      : visibleDefs.length === 3
        ? 'grid-cols-2 md:grid-cols-3'
        : 'grid-cols-2 md:grid-cols-4'

  return (
    <div className={`grid ${gridCols} gap-4`}>
      {visibleDefs.map((def) => {
        const { value, subtitle } = getKPIValue(report, def.id)
        const formatted = formatKPIValue(value, def.format, def.id)
        const color = getValueColor(value, def.colorLogic)
        const showInfo = infoOpen === def.id
        const hasOverride =
          prefs.accountOverrides[def.id] &&
          prefs.accountOverrides[def.id].length > 0

        return (
          <Card key={def.id} className="relative">
            <CardContent className="p-5">
              <div className="flex items-start justify-between">
                <p className="text-xs text-muted-foreground mb-1">
                  {def.label}
                </p>
                <button
                  type="button"
                  onClick={() =>
                    setInfoOpen(showInfo ? null : def.id)
                  }
                  className="text-muted-foreground/50 hover:text-muted-foreground transition-colors -mt-0.5 -mr-1 p-1"
                  aria-label={`Visa formel för ${def.label}`}
                >
                  {showInfo ? (
                    <X className="h-3 w-3" />
                  ) : (
                    <Info className="h-3 w-3" />
                  )}
                </button>
              </div>

              {showInfo ? (
                <div className="space-y-1.5 text-[11px] text-muted-foreground mt-1">
                  <p className="text-xs text-foreground/80">{def.description}</p>
                  <div>
                    <span className="font-medium">Formel: </span>
                    <span className="font-mono">{def.formula}</span>
                  </div>
                  <div>
                    <span className="font-medium">Konton: </span>
                    {def.accountDescription}
                  </div>
                  {hasOverride && (
                    <div className="text-primary">
                      <span className="font-medium">Anpassade konton: </span>
                      <span className="font-mono">
                        {prefs.accountOverrides[def.id].join(', ')}
                      </span>
                    </div>
                  )}
                </div>
              ) : (
                <>
                  <p
                    className={`font-display text-xl tabular-nums tracking-tight ${color}`}
                  >
                    {formatted}
                  </p>
                  <p className="text-xs text-muted-foreground mt-1">
                    {subtitle}
                  </p>
                </>
              )}
            </CardContent>
          </Card>
        )
      })}
    </div>
  )
}