'use client'

import { useCallback, useEffect, useMemo, useState } from 'react'
import { Language } from '@/lib/types'
import { t } from '@/lib/i18n'
import { useFinancialModel } from '@/lib/hooks/useFinancialModel'
import { computeAnnualKPIs } from '@/lib/finanzplan/annual-kpis'
import ProjectionFooter from '../ui/ProjectionFooter'
import GradientText from '../ui/GradientText'
import FadeInView from '../ui/FadeInView'
import GlassCard from '../ui/GlassCard'
import { RefreshCw, Download, ChevronLeft, ChevronRight, BarChart3, Target } from 'lucide-react'

interface FinanzplanSlideProps {
  lang: Language
  investorId?: string | null
}

interface SheetMeta {
  name: string
  label_de: string
  label_en: string
  rows: number
}

interface SheetRow {
  id: number
  row_label?: string
  person_name?: string
  item_name?: string
  category?: string
  section?: string
  is_editable?: boolean
  is_sum_row?: boolean
  values?: Record<string, number>
  values_total?: Record<string, number>
  values_brutto?: Record<string, number>
  brutto_monthly?: number
  position?: string
  start_date?: string
  purchase_amount?: number
}

const MONTH_LABELS = [
  'Jan', 'Feb', 'Mrz', 'Apr', 'Mai', 'Jun',
  'Jul', 'Aug', 'Sep', 'Okt', 'Nov', 'Dez',
]

function getLabel(row: SheetRow): string {
  return row.row_label || row.person_name || row.item_name || '—'
}

function getValues(row: SheetRow): Record<string, number> {
  return row.values || row.values_total || row.values_brutto || {}
}

function formatCell(v: number | undefined): string {
  if (v === undefined || v === null) return ''
  if (v === 0) return '—'
  return Math.round(v).toLocaleString('de-DE', { maximumFractionDigits: 0 })
}

export default function FinanzplanSlide({ lang, investorId }: FinanzplanSlideProps) {
  const [sheets, setSheets] = useState<SheetMeta[]>([])
  const [activeSheet, setActiveSheet] = useState<string>('personalkosten')
  const [rows, setRows] = useState<SheetRow[]>([])
  const [loading, setLoading] = useState(false)
  const [computing, setComputing] = useState(false)
  const [yearOffset, setYearOffset] = useState(0) // 0=2026, 1=2027, ...
  const de = lang === 'de'

  // Financial model — same source as FinancialsSlide (Slide 15)
  const fm = useFinancialModel(investorId || null)
  const annualKPIs = useMemo(
    () => computeAnnualKPIs(fm.activeResults?.results || []),
    [fm.activeResults],
  )

  // Load sheet list
  useEffect(() => {
    fetch('/api/finanzplan')
      .then(r => r.json())
      .then(data => setSheets(data.sheets || []))
      .catch(() => {})
  }, [])

  // Load sheet data
  const loadSheet = useCallback(async (name: string) => {
    if (name === 'kpis' || name === 'charts') {
      setRows([])
      setLoading(false)
      return
    }
    setLoading(true)
    try {
      const r = await fetch(`/api/finanzplan/${name}`)
      const data = await r.json()
      setRows(data.rows || [])
    } catch { /* ignore */ }
    setLoading(false)
  }, [])

  useEffect(() => { loadSheet(activeSheet) }, [activeSheet, loadSheet])

  // Compute
  const handleCompute = async () => {
    setComputing(true)
    try {
      await fetch('/api/finanzplan/compute', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: '{}' })
      await loadSheet(activeSheet)
    } catch { /* ignore */ }
    setComputing(false)
  }

  // Cell edit
  const handleCellEdit = async (rowId: number, monthKey: string, newValue: string) => {
    const numVal = parseFloat(newValue.replace(/[^\d.-]/g, ''))
    if (isNaN(numVal)) return

    try {
      await fetch(`/api/finanzplan/${activeSheet}`, {
        method: 'PUT',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ rowId, updates: { [monthKey]: numVal } }),
      })
      await loadSheet(activeSheet)
    } catch { /* ignore */ }
  }

  const currentYear = 2026 + yearOffset
  const monthStart = yearOffset * 12 + 1
  const monthEnd = monthStart + 11

  return (
    <div className="max-w-[95vw] mx-auto">
      <FadeInView className="text-center mb-4">
        <h2 className="text-3xl md:text-4xl font-bold mb-1">
          <GradientText>{de ? 'Finanzplan' : 'Financial Plan'}</GradientText>
        </h2>
        <p className="text-sm text-white/40">{de ? '2026–2030 · Monatliche Granularitaet · Editierbar' : '2026–2030 · Monthly Granularity · Editable'}</p>
      </FadeInView>

      {/* Tab Bar */}
      <div className="flex items-center gap-1 mb-3 overflow-x-auto pb-1">
        {sheets.map(s => (
          <button
            key={s.name}
            onClick={() => setActiveSheet(s.name)}
            className={`px-3 py-1.5 text-[10px] font-medium rounded-lg whitespace-nowrap transition-colors ${
              activeSheet === s.name
                ? 'bg-indigo-500/20 text-indigo-300 border border-indigo-500/30'
                : 'text-white/40 hover:text-white/70 hover:bg-white/[0.05]'
            }`}
          >
            {de ? s.label_de : s.label_en}
            {s.rows > 0 && <span className="ml-1 text-[8px] opacity-50">({s.rows})</span>}
          </button>
        ))}
        {/* KPIs + Grafiken Tabs */}
        <span className="text-white/10 mx-1">|</span>
        {[
          { id: 'kpis', label: 'KPIs', icon: Target },
          { id: 'charts', label: de ? 'Grafiken' : 'Charts', icon: BarChart3 },
        ].map(tab => (
          <button
            key={tab.id}
            onClick={() => setActiveSheet(tab.id)}
            className={`px-3 py-1.5 text-[10px] font-medium rounded-lg whitespace-nowrap transition-colors flex items-center gap-1 ${
              activeSheet === tab.id
                ? 'bg-emerald-500/20 text-emerald-300 border border-emerald-500/30'
                : 'text-white/40 hover:text-white/70 hover:bg-white/[0.05]'
            }`}
          >
            <tab.icon className="w-3 h-3" />
            {tab.label}
          </button>
        ))}
        <div className="flex-1" />
        <button
          onClick={handleCompute}
          disabled={computing}
          className="flex items-center gap-1 px-3 py-1.5 text-[10px] bg-emerald-500/20 text-emerald-300 rounded-lg hover:bg-emerald-500/30 transition-colors disabled:opacity-50"
        >
          <RefreshCw className={`w-3 h-3 ${computing ? 'animate-spin' : ''}`} />
          {de ? 'Berechnen' : 'Compute'}
        </button>
      </div>

      {/* === KPIs Tab === */}
      {activeSheet === 'kpis' && (
        <GlassCard hover={false} className="p-4">
          <h3 className="text-sm font-bold text-emerald-400 uppercase tracking-wider mb-4">{de ? 'Wichtige Kennzahlen (pro Jahr)' : 'Key Metrics (per year)'}</h3>
          <table className="w-full text-xs">
            <thead>
              <tr className="border-b border-white/10">
                <th className="text-left py-2 px-2 text-white/60 font-medium">KPI</th>
                {[2026, 2027, 2028, 2029, 2030].map(y => (
                  <th key={y} className="text-right py-2 px-3 text-white/60 font-medium">{y}</th>
                ))}
              </tr>
            </thead>
            <tbody>
              {(() => {
                if (annualKPIs.length === 0) return (
                  <tr><td colSpan={6} className="text-center py-4 text-white/30">{de ? 'Finanzmodell wird geladen...' : 'Loading financial model...'}</td></tr>
                )
                const kpiRows = [
                  { label: 'MRR (Dez)', values: annualKPIs.map(k => k.mrr), unit: '€', bold: true },
                  { label: 'ARR', values: annualKPIs.map(k => k.arr), unit: '€', bold: true },
                  { label: de ? 'Kunden (Dez)' : 'Customers (Dec)', values: annualKPIs.map(k => k.customers), unit: '', bold: false },
                  { label: 'ARPU (MRR/Kunden)', values: annualKPIs.map(k => k.arpu), unit: '€', bold: false },
                  { label: de ? 'Mitarbeiter' : 'Employees', values: annualKPIs.map(k => k.employees), unit: '', bold: false },
                  { label: de ? 'Umsatz/Mitarbeiter' : 'Revenue/Employee', values: annualKPIs.map(k => k.revenuePerEmployee), unit: '€', bold: false },
                  { label: de ? 'Personalkosten' : 'Personnel Costs', values: annualKPIs.map(k => k.personnelCosts), unit: '€', bold: false },
                  { label: 'EBIT', values: annualKPIs.map(k => k.ebit), unit: '€', bold: true },
                  { label: de ? 'EBIT-Marge' : 'EBIT Margin', values: annualKPIs.map(k => k.ebitMargin), unit: '%', bold: false },
                  { label: de ? 'Steuern' : 'Taxes', values: annualKPIs.map(k => k.taxes), unit: '€', bold: false },
                  { label: de ? 'Jahresueberschuss' : 'Net Income', values: annualKPIs.map(k => k.netIncome), unit: '€', bold: true },
                  { label: de ? 'Serverkosten/Kunde' : 'Server Cost/Customer', values: annualKPIs.map(k => k.serverCostPerCustomer), unit: '€', bold: false },
                  { label: de ? 'Bruttomarge' : 'Gross Margin', values: annualKPIs.map(k => k.grossMargin), unit: '%', bold: false },
                  { label: 'Burn Rate (Dez)', values: annualKPIs.map(k => k.burnRate), unit: '€/Mo', bold: false },
                  { label: de ? 'Runway (Monate)' : 'Runway (months)', values: annualKPIs.map(k => k.runway === null ? '∞' : k.runway), unit: '', bold: false },
                ]
                return kpiRows.map((row, idx) => (
                  <tr key={idx} className={`border-b border-white/[0.03] ${row.bold ? 'bg-white/[0.03]' : ''}`}>
                    <td className={`py-1.5 px-2 ${row.bold ? 'font-bold text-white/80' : 'text-white/60'}`}>{row.label}</td>
                    {row.values.map((v, i) => {
                      const num = typeof v === 'number' ? v : 0
                      const display = typeof v === 'string' ? v : (
                        row.unit === '%' ? `${v}%` :
                        row.unit === '€/Mo' ? formatCell(num) + '/Mo' :
                        formatCell(num)
                      )
                      return (
                        <td key={i} className={`text-right py-1.5 px-3 font-mono ${num < 0 ? 'text-red-400' : row.bold ? 'text-white/80 font-bold' : 'text-white/50'}`}>
                          {display}
                        </td>
                      )
                    })}
                  </tr>
                ))
              })()}
            </tbody>
          </table>
        </GlassCard>
      )}

      {/* === Charts Tab === */}
      {activeSheet === 'charts' && (
        <div className="space-y-4">
          {/* MRR + Kunden Chart */}
          <GlassCard hover={false} className="p-4">
            <h3 className="text-xs font-bold text-indigo-400 uppercase tracking-wider mb-3">{de ? 'MRR & Kundenentwicklung' : 'MRR & Customer Growth'}</h3>
            <div className="grid grid-cols-5 gap-1 items-end h-48">
              {(() => {
                const maxMrr = Math.max(...annualKPIs.map(k => k.mrr), 1)
                const maxCust = Math.max(...annualKPIs.map(k => k.customers), 1)
                return annualKPIs.map(k => ({ year: String(k.year), mrr: k.mrr, cust: k.customers, max_mrr: maxMrr, max_cust: maxCust }))
              })().map((d, idx) => (
                <div key={idx} className="flex flex-col items-center gap-1">
                  <div className="flex items-end gap-1 w-full justify-center" style={{ height: '160px' }}>
                    {/* MRR bar */}
                    <div className="w-8 bg-indigo-500/60 rounded-t transition-all" style={{ height: `${(d.mrr / d.max_mrr) * 150}px` }}>
                      <div className="text-[7px] text-white/70 text-center -mt-3 whitespace-nowrap">
                        {d.mrr >= 100000 ? `${Math.round(d.mrr/1000)}k` : d.mrr.toLocaleString('de-DE')}
                      </div>
                    </div>
                    {/* Kunden bar */}
                    <div className="w-8 bg-emerald-500/60 rounded-t transition-all" style={{ height: `${(d.cust / d.max_cust) * 150}px` }}>
                      <div className="text-[7px] text-white/70 text-center -mt-3">{d.cust}</div>
                    </div>
                  </div>
                  <span className="text-[10px] text-white/40">{d.year}</span>
                </div>
              ))}
            </div>
            <div className="flex justify-center gap-6 mt-2 text-[10px]">
              <span className="flex items-center gap-1"><span className="w-3 h-2 bg-indigo-500/60 rounded inline-block" /> MRR (€)</span>
              <span className="flex items-center gap-1"><span className="w-3 h-2 bg-emerald-500/60 rounded inline-block" /> {de ? 'Kunden' : 'Customers'}</span>
            </div>
          </GlassCard>

          {/* EBIT + Cash Chart */}
          <div className="grid md:grid-cols-2 gap-4">
            <GlassCard hover={false} className="p-4">
              <h3 className="text-xs font-bold text-purple-400 uppercase tracking-wider mb-3">EBIT</h3>
              <div className="grid grid-cols-5 gap-1 items-end h-36">
                {(() => {
                  const maxAbs = Math.max(...annualKPIs.map(k => Math.abs(k.ebit)), 1)
                  return annualKPIs.map((k, idx) => {
                    const h = Math.abs(k.ebit) / maxAbs * 100
                    return (
                      <div key={idx} className="flex flex-col items-center">
                        <div className="w-10 flex flex-col justify-end" style={{ height: '110px' }}>
                          {k.ebit >= 0 ? (
                            <div className="bg-emerald-500/60 rounded-t w-full" style={{ height: `${h}px` }}>
                              <div className="text-[7px] text-emerald-300 text-center -mt-3 whitespace-nowrap">{Math.round(k.ebit/1000)}k</div>
                            </div>
                          ) : (
                            <div className="flex flex-col justify-end h-full">
                              <div className="bg-red-500/60 rounded-b w-full" style={{ height: `${h}px` }}>
                                <div className="text-[7px] text-red-300 text-center mt-1 whitespace-nowrap">{Math.round(k.ebit/1000)}k</div>
                              </div>
                            </div>
                          )}
                        </div>
                        <span className="text-[10px] text-white/40 mt-1">{k.year}</span>
                      </div>
                    )
                  })
                })()}
              </div>
            </GlassCard>

            <GlassCard hover={false} className="p-4">
              <h3 className="text-xs font-bold text-amber-400 uppercase tracking-wider mb-3">{de ? 'Personalaufbau' : 'Headcount'}</h3>
              <div className="grid grid-cols-5 gap-1 items-end h-36">
                {(() => {
                  const maxEmp = Math.max(...annualKPIs.map(k => k.employees), 1)
                  return annualKPIs.map(k => ({ year: String(k.year), val: k.employees }))
                    .map((d, idx) => (
                      <div key={idx} className="flex flex-col items-center">
                        <div className="w-10 flex flex-col justify-end" style={{ height: '110px' }}>
                          <div className="bg-amber-500/60 rounded-t w-full" style={{ height: `${(d.val / maxEmp) * 100}px` }}>
                            <div className="text-[8px] text-amber-300 text-center -mt-3 font-bold">{d.val}</div>
                          </div>
                        </div>
                        <span className="text-[10px] text-white/40 mt-1">{d.year}</span>
                      </div>
                    ))
                })()}
              </div>
            </GlassCard>
          </div>
        </div>
      )}

      {/* Year Navigation — not for GuV, KPIs, Charts (annual views) */}
      {!['guv', 'kpis', 'charts'].includes(activeSheet) && (
        <div className="flex items-center justify-center gap-4 mb-2">
          <button onClick={() => setYearOffset(Math.max(0, yearOffset - 1))} disabled={yearOffset === 0}
            className="p-1 text-white/40 hover:text-white/70 disabled:opacity-20">
            <ChevronLeft className="w-4 h-4" />
          </button>
          <span className="text-sm font-bold text-white">{currentYear}</span>
          <button onClick={() => setYearOffset(Math.min(4, yearOffset + 1))} disabled={yearOffset === 4}
            className="p-1 text-white/40 hover:text-white/70 disabled:opacity-20">
            <ChevronRight className="w-4 h-4" />
          </button>
        </div>
      )}

      {/* Data Grid — not shown for KPIs and Charts */}
      {!['kpis', 'charts'].includes(activeSheet) && (
      <GlassCard hover={false} className="p-2 overflow-x-auto">
        {loading ? (
          <div className="text-center py-8 text-white/30 text-sm">{de ? 'Lade...' : 'Loading...'}</div>
        ) : activeSheet === 'guv' ? (
          /* === GuV: Annual table (y2026-y2030) === */
          <table className="w-full text-[10px]">
            <thead>
              <tr className="border-b border-white/10">
                <th className="text-left py-1.5 px-2 text-white/60 font-medium sticky left-0 bg-slate-900/90 backdrop-blur min-w-[220px]">
                  {de ? 'GuV-Position' : 'P&L Item'}
                </th>
                {[2026, 2027, 2028, 2029, 2030].map(y => (
                  <th key={y} className="text-right py-1.5 px-3 text-white/60 font-medium min-w-[100px]">{y}</th>
                ))}
              </tr>
            </thead>
            <tbody>
              {rows.map(row => {
                const values = getValues(row)
                const label = getLabel(row)
                const isSumRow = row.is_sum_row || label.includes('EBIT') || label.includes('Summe') || label.includes('Rohergebnis') || label.includes('Gesamtleistung') || label.includes('Jahresüberschuss') || label.includes('Ergebnis')

                return (
                  <tr key={row.id} className={`border-b border-white/[0.03] ${isSumRow ? 'bg-white/[0.03]' : ''} hover:bg-white/[0.02]`}>
                    <td className={`py-1.5 px-2 sticky left-0 bg-slate-900/90 backdrop-blur ${isSumRow ? 'font-bold text-white/80' : 'text-white/60'}`}>
                      {label}
                    </td>
                    {[2026, 2027, 2028, 2029, 2030].map(y => {
                      const v = values[`y${y}`] || 0
                      return (
                        <td key={y} className={`text-right py-1.5 px-3 ${v < 0 ? 'text-red-400' : v > 0 ? (isSumRow ? 'text-white/80' : 'text-white/50') : 'text-white/15'} ${isSumRow ? 'font-bold' : ''}`}>
                          {v === 0 ? '—' : Math.round(v).toLocaleString('de-DE', { maximumFractionDigits: 0 })}
                        </td>
                      )
                    })}
                  </tr>
                )
              })}
            </tbody>
          </table>
        ) : (
          /* === Monthly Grid (all other sheets) === */
          <table className="w-full text-[10px]">
            <thead>
              <tr className="border-b border-white/10">
                <th className="text-left py-1.5 px-2 text-white/60 font-medium sticky left-0 bg-slate-900/90 backdrop-blur min-w-[160px]">
                  {de ? 'Position' : 'Item'}
                </th>
                <th className="text-right py-1.5 px-2 text-white/60 font-medium min-w-[70px]">
                  {currentYear}
                </th>
                {MONTH_LABELS.map((label, idx) => (
                  <th key={idx} className="text-right py-1.5 px-1.5 text-white/50 font-normal min-w-[55px]">
                    {label}
                  </th>
                ))}
              </tr>
            </thead>
            <tbody>
              {rows.map(row => {
                const values = getValues(row)
                const label = getLabel(row)
                const isSumRow = row.is_sum_row || label.includes('GESAMT') || label.includes('Summe') || label.includes('ÜBERSCHUSS') || label.includes('LIQUIDITÄT') || label.includes('UEBERSCHUSS') || label.includes('LIQUIDITAET')
                const isEditable = row.is_editable
                // Balance rows show Dec value, flow rows show annual sum
                const isBalanceRow = label.includes('Kontostand') || label === 'LIQUIDITÄT' || label === 'LIQUIDITAET'

                let annual = 0
                if (isBalanceRow) {
                  // Point-in-time: show last month (December) value
                  annual = values[`m${monthEnd}`] || 0
                } else {
                  // Flow: sum all 12 months
                  for (let m = monthStart; m <= monthEnd; m++) annual += values[`m${m}`] || 0
                }

                return (
                  <tr
                    key={row.id}
                    className={`border-b border-white/[0.03] ${isSumRow ? 'bg-white/[0.03]' : ''} hover:bg-white/[0.02]`}
                  >
                    <td className={`py-1 px-2 sticky left-0 bg-slate-900/90 backdrop-blur ${isSumRow ? 'font-bold text-white/80' : 'text-white/60'}`}>
                      <div className="flex items-center gap-1">
                        {isEditable && <span className="w-1 h-1 rounded-full bg-indigo-400 flex-shrink-0" />}
                        <span className="truncate">{label}</span>
                        {row.position && <span className="text-white/50 ml-1">({row.position})</span>}
                        {row.section && <span className="text-white/50 ml-1">[{row.section}]</span>}
                      </div>
                    </td>
                    <td className={`text-right py-1 px-2 font-medium ${annual < 0 ? 'text-red-400' : isSumRow ? 'text-white/80' : 'text-white/50'}`}>
                      {formatCell(annual)}
                    </td>
                    {Array.from({ length: 12 }, (_, idx) => {
                      const mKey = `m${monthStart + idx}`
                      const v = values[mKey] || 0

                      return (
                        <td
                          key={idx}
                          className={`text-right py-1 px-1.5 ${
                            v < 0 ? 'text-red-400/70' : v > 0 ? (isSumRow ? 'text-white/70' : 'text-white/50') : 'text-white/15'
                          } ${isEditable ? 'cursor-pointer hover:bg-indigo-500/10' : ''}`}
                          onDoubleClick={() => {
                            if (!isEditable) return
                            const input = prompt(`${label} — ${MONTH_LABELS[idx]} ${currentYear}`, String(v))
                            if (input !== null) handleCellEdit(row.id, mKey, input)
                          }}
                        >
                          {formatCell(v)}
                        </td>
                      )
                    })}
                  </tr>
                )
              })}
            </tbody>
            {/* Summenzeile für relevante Sheets */}
            {['personalkosten', 'materialaufwand', 'betriebliche', 'investitionen', 'sonst_ertraege', 'umsatzerloese', 'kunden', 'kunden_summary'].includes(activeSheet) && rows.length > 0 && (() => {
              // Berechne Summe über alle Zeilen die keine Summenzeilen sind
              const sumValues: Record<string, number> = {}
              let sumAnnual = 0
              const nonSumRows = rows.filter(r => {
                const l = getLabel(r)
                return !(r.is_sum_row || l.includes('GESAMT') || l.includes('Summe') || l.includes('Gesamtkosten') || l === 'SUMME')
              })
              for (let idx = 0; idx < 12; idx++) {
                const mKey = `m${monthStart + idx}`
                let colSum = 0
                for (const row of nonSumRows) {
                  const v = getValues(row)
                  colSum += v[mKey] || 0
                }
                sumValues[mKey] = colSum
                sumAnnual += colSum
              }
              return (
                <tfoot>
                  <tr className="border-t-2 border-white/20 bg-white/[0.05]">
                    <td className="py-1.5 px-2 sticky left-0 bg-slate-900/90 backdrop-blur font-bold text-white/80 text-xs">
                      {de ? 'SUMME' : 'TOTAL'}
                    </td>
                    <td className={`text-right py-1.5 px-2 font-bold text-xs ${sumAnnual < 0 ? 'text-red-400' : 'text-white/80'}`}>
                      {['kunden', 'kunden_summary'].includes(activeSheet)
                        ? formatCell(sumValues[`m${monthEnd}`] || 0)
                        : formatCell(sumAnnual)
                      }
                    </td>
                    {Array.from({ length: 12 }, (_, idx) => {
                      const mKey = `m${monthStart + idx}`
                      const v = sumValues[mKey] || 0
                      return (
                        <td key={idx} className={`text-right py-1.5 px-1.5 font-bold text-xs ${v < 0 ? 'text-red-400' : v > 0 ? 'text-white/70' : 'text-white/15'}`}>
                          {formatCell(v)}
                        </td>
                      )
                    })}
                  </tr>
                </tfoot>
              )
            })()}
          </table>
        )}
      </GlassCard>
      )}

      <ProjectionFooter lang={lang} />
    </div>
  )
}