import { useState, useEffect } from 'react'
import { api } from '../api'
import { PageHeader, Card, Btn, StatusBadge } from '../components/Layout'
import { fmtGBP } from '../types'

interface SalesCol { gl_code: string; category: string; net_amount: number; vat_amount: number; gross_amount: number }
interface ReconRow { category: string; banked_amount: number; reported_amount: number }
interface DayData {
  date: string
  cash_up: { id: number; status: 'draft' | 'final'; total_cash_counted: string } | null
  reconciliation: ReconRow[]
  daily_stats: { gross_sales: number; transaction_count: number } | null
  sales_breakdown: SalesCol[]
}
interface OccupancyItem { period?: string; date?: string; rooms_sold?: number; total_rooms?: number; total_people?: number }
interface ReportResult {
  report_data: DayData[]
  sales_columns: Array<{ gl_code: string; display_name: string }>
  occupancy_data: OccupancyItem[]
  bookings_data: Array<{ date?: string; period?: string; arrivals?: number; departures?: number; [k: string]: unknown }>
}
interface DebtorBalance { creditors: number; debtors: number; overall: number }
interface DebtorsResult {
  period_open_balance: DebtorBalance
  balances_by_date: Record<string, DebtorBalance>
}

const RECON_LABELS: Record<string, string> = {
  cash: 'Cash',
  gateway_visa_mc: 'Gateway V/MC',
  gateway_amex: 'Gateway Amex',
  pdq_visa_mc: 'PDQ V/MC',
  pdq_amex: 'PDQ Amex',
  bacs: 'BACS',
}

const VARIANCE_CATEGORIES = new Set(['cash', 'pdq_visa_mc', 'pdq_amex'])

function fmtDate(d: string) {
  const s = (d ?? '').slice(0, 10)
  if (!s) return '—'
  return new Date(s + 'T12:00:00').toLocaleDateString('en-GB', { weekday: 'short', day: '2-digit', month: 'short' })
}

function variance(banked: number, reported: number) {
  return banked - reported
}

function varStyle(v: number): React.CSSProperties {
  if (Math.abs(v) < 0.005) return { textAlign: 'right', color: 'var(--text-mid)' }
  return { textAlign: 'right', color: v < 0 ? 'var(--danger)' : '#16a34a', fontWeight: 600 }
}

export function MultiDayReport() {
  const [startDate, setStartDate] = useState(() => {
    const d = new Date(); d.setDate(d.getDate() - 6); return d.toISOString().slice(0, 10)
  })
  const [numDays, setNumDays] = useState(7)
  const [result, setResult] = useState<ReportResult | null>(null)
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState('')
  const [debtors, setDebtors] = useState<DebtorsResult | null>(null)
  const [debtorsLoading, setDebtorsLoading] = useState(false)

  async function generate() {
    setLoading(true); setError(''); setResult(null); setDebtors(null)
    try {
      const data = await api.post<ReportResult>('/reports/multiday', { start_date: startDate, num_days: numDays })
      setResult(data)
    } catch (e: unknown) {
      setError(e instanceof Error ? e.message : 'Failed to generate report')
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    if (!result) return
    setDebtorsLoading(true)
    api.post<DebtorsResult>('/reports/debtors-creditors', { start_date: startDate, num_days: numDays })
      .then(d => setDebtors(d))
      .catch(() => {})
      .finally(() => setDebtorsLoading(false))
  }, [result, startDate, numDays])

  const dates = result?.report_data.map(d => d.date) ?? []
  const salesCols = result?.sales_columns ?? []

  return (
    <div style={{ padding: '1.5rem' }}>
      <PageHeader title="Weekly / Multi-Day Report" />

      {/* Controls */}
      <Card style={{ marginBottom: '1.5rem', display: 'flex', gap: '1rem', alignItems: 'flex-end', flexWrap: 'wrap' }}>
        <div>
          <label style={labelSt}>Start Date</label>
          <input type="date" value={startDate} onChange={e => setStartDate(e.target.value)} style={inpSt} />
        </div>
        <div>
          <label style={labelSt}>Number of Days</label>
          <input type="number" value={numDays} min={1} max={365}
            onChange={e => setNumDays(Math.max(1, Math.min(365, parseInt(e.target.value) || 7)))}
            style={{ ...inpSt, width: '80px' }} />
        </div>
        <Btn onClick={generate} disabled={loading}>
          {loading ? 'Generating…' : 'Generate Report'}
        </Btn>
      </Card>

      {error && (
        <div style={{ background: '#fee2e2', color: 'var(--danger)', border: '1px solid #fecaca', borderRadius: '6px', padding: '0.75rem 1rem', marginBottom: '1rem' }}>
          {error}
        </div>
      )}

      {result && (
        <>
          {/* Daily Status Row */}
          <Card style={{ marginBottom: '1.5rem' }}>
            <h2 style={sectionTitle}>Daily Cash Up Status</h2>
            <div style={{ display: 'flex', gap: '0.75rem', flexWrap: 'wrap' }}>
              {result.report_data.map(day => (
                <div key={day.date} style={{
                  textAlign: 'center', padding: '0.75rem 1rem',
                  background: 'var(--body-bg)', borderRadius: '6px',
                  border: '1px solid var(--card-border)', minWidth: '80px',
                }}>
                  <div style={{ fontSize: '0.75rem', color: 'var(--text-mid)', marginBottom: '0.375rem' }}>{fmtDate(day.date)}</div>
                  {day.cash_up
                    ? <StatusBadge status={day.cash_up.status} />
                    : <span style={{ fontSize: '0.7rem', color: 'var(--text-mid)', fontWeight: 600, textTransform: 'uppercase', background: 'var(--card-border)', padding: '0.2rem 0.5rem', borderRadius: '4px' }}>None</span>
                  }
                  {day.cash_up && (
                    <div style={{ fontSize: '0.8rem', fontWeight: 700, marginTop: '0.375rem' }}>
                      {fmtGBP(day.cash_up.total_cash_counted)}
                    </div>
                  )}
                </div>
              ))}
            </div>
          </Card>

          {/* Table 1: Reconciliation */}
          <Card style={{ marginBottom: '1.5rem', overflowX: 'auto' }}>
            <h2 style={sectionTitle}>Payment Reconciliation</h2>
            <table style={{ borderCollapse: 'collapse', fontSize: '0.8rem', minWidth: '600px', width: '100%' }}>
              <thead>
                <tr style={{ borderBottom: '2px solid var(--card-border)' }}>
                  <th style={{ ...th, textAlign: 'left' }}>Category</th>
                  {dates.map(d => (
                    <th key={d} style={th} colSpan={VARIANCE_CATEGORIES.has('') ? 1 : 1}>
                      {fmtDate(d)}
                    </th>
                  ))}
                  <th style={th}>Total</th>
                </tr>
              </thead>
              <tbody>
                {Object.entries(RECON_LABELS).map(([key, label]) => {
                  const rows = result.report_data.map(day => day.reconciliation.find(r => r.category === key))
                  const bankedVals = rows.map(r => r?.banked_amount ?? 0)
                  const reportedVals = rows.map(r => r?.reported_amount ?? 0)
                  const hasVariance = VARIANCE_CATEGORIES.has(key)
                  const totalBanked = bankedVals.reduce((s, v) => s + v, 0)
                  const totalReported = reportedVals.reduce((s, v) => s + v, 0)

                  if (bankedVals.every(v => v === 0) && reportedVals.every(v => v === 0)) return null

                  return [
                    /* Reported row */
                    hasVariance && (
                      <tr key={`${key}-reported`} style={{ borderBottom: '1px solid transparent' }}>
                        <td style={{ ...td, paddingLeft: '0.5rem', color: 'var(--text-mid)', fontSize: '0.75rem' }}>
                          {label} — Newbook
                        </td>
                        {reportedVals.map((v, i) => (
                          <td key={i} style={{ ...td, textAlign: 'right', color: 'var(--text-mid)', fontSize: '0.75rem' }}>
                            {v ? fmtGBP(v) : '—'}
                          </td>
                        ))}
                        <td style={{ ...td, textAlign: 'right', color: 'var(--text-mid)', fontSize: '0.75rem' }}>
                          {fmtGBP(totalReported)}
                        </td>
                      </tr>
                    ),
                    /* Banked / main row */
                    <tr key={`${key}-banked`} style={{ borderBottom: '1px solid var(--card-border)' }}>
                      <td style={{ ...td, fontWeight: 600 }}>
                        {hasVariance ? `${label} — Banked` : label}
                      </td>
                      {bankedVals.map((v, i) => {
                        const rep = reportedVals[i]
                        const v2 = hasVariance ? variance(v, rep) : null
                        return (
                          <td key={i} style={{ ...td, textAlign: 'right' }}>
                            {v ? fmtGBP(v) : '—'}
                            {v2 !== null && Math.abs(v2) > 0.005 && (
                              <div style={{ fontSize: '0.7rem', color: v2 < 0 ? 'var(--danger)' : '#16a34a' }}>
                                {v2 > 0 ? '+' : ''}{fmtGBP(v2)}
                              </div>
                            )}
                          </td>
                        )
                      })}
                      <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>
                        {fmtGBP(totalBanked)}
                        {hasVariance && Math.abs(totalBanked - totalReported) > 0.005 && (
                          <div style={varStyle(totalBanked - totalReported)}>
                            {totalBanked - totalReported > 0 ? '+' : ''}{fmtGBP(totalBanked - totalReported)}
                          </div>
                        )}
                      </td>
                    </tr>
                  ].filter(Boolean)
                })}
                {/* Total row */}
                <tr style={{ borderTop: '2px solid var(--card-border)', background: 'var(--body-bg)' }}>
                  <td style={{ ...td, fontWeight: 700 }}>Total</td>
                  {result.report_data.map((day, i) => {
                    const t = day.reconciliation.reduce((s, r) => s + r.banked_amount, 0)
                    return <td key={i} style={{ ...td, textAlign: 'right', fontWeight: 700 }}>{t ? fmtGBP(t) : '—'}</td>
                  })}
                  <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>
                    {fmtGBP(result.report_data.reduce((s, d) => s + d.reconciliation.reduce((ss, r) => ss + r.banked_amount, 0), 0))}
                  </td>
                </tr>
              </tbody>
            </table>
          </Card>

          {/* Table 2: Sales Breakdown */}
          {salesCols.length > 0 && (
            <Card style={{ marginBottom: '1.5rem', overflowX: 'auto' }}>
              <h2 style={sectionTitle}>Sales Breakdown</h2>
              <table style={{ borderCollapse: 'collapse', fontSize: '0.8rem', minWidth: '600px', width: '100%' }}>
                <thead>
                  <tr style={{ borderBottom: '2px solid var(--card-border)' }}>
                    <th style={{ ...th, textAlign: 'left' }}>Category</th>
                    {dates.map(d => <th key={d} style={th}>{fmtDate(d)}</th>)}
                    <th style={th}>Total</th>
                  </tr>
                </thead>
                <tbody>
                  {salesCols.map(col => {
                    const vals = result.report_data.map(day => {
                      const sb = day.sales_breakdown.find(s => s.gl_code === col.gl_code)
                      return { net: sb?.net_amount ?? 0, gross: sb?.gross_amount ?? 0, vat: sb?.vat_amount ?? 0 }
                    })
                    const totalGross = vals.reduce((s, v) => s + v.gross, 0)
                    if (vals.every(v => v.gross === 0)) return null
                    return (
                      <tr key={col.gl_code} style={{ borderBottom: '1px solid var(--card-border)' }}>
                        <td style={td}>{col.display_name}</td>
                        {vals.map((v, i) => (
                          <td key={i} style={{ ...td, textAlign: 'right' }}>
                            {v.gross ? fmtGBP(v.gross) : '—'}
                            {v.vat > 0 && (
                              <div style={{ fontSize: '0.7rem', color: 'var(--text-mid)' }}>
                                net {fmtGBP(v.net)}
                              </div>
                            )}
                          </td>
                        ))}
                        <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>{fmtGBP(totalGross)}</td>
                      </tr>
                    )
                  })}
                  <tr style={{ borderTop: '2px solid var(--card-border)', background: 'var(--body-bg)' }}>
                    <td style={{ ...td, fontWeight: 700 }}>Total Gross</td>
                    {result.report_data.map((day, i) => {
                      const t = day.sales_breakdown.reduce((s, sb) => s + (sb.gross_amount ?? 0), 0)
                      return <td key={i} style={{ ...td, textAlign: 'right', fontWeight: 700 }}>{t ? fmtGBP(t) : '—'}</td>
                    })}
                    <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>
                      {fmtGBP(result.report_data.reduce((s, d) => s + d.sales_breakdown.reduce((ss, sb) => ss + (sb.gross_amount ?? 0), 0), 0))}
                    </td>
                  </tr>
                  <tr style={{ background: 'var(--body-bg)' }}>
                    <td style={{ ...td, fontWeight: 700, color: 'var(--text-mid)', fontSize: '0.75rem' }}>Total Net</td>
                    {result.report_data.map((day, i) => {
                      const t = day.sales_breakdown.reduce((s, sb) => s + (sb.net_amount ?? 0), 0)
                      return <td key={i} style={{ ...td, textAlign: 'right', color: 'var(--text-mid)', fontSize: '0.75rem' }}>{t ? fmtGBP(t) : '—'}</td>
                    })}
                    <td style={{ ...td, textAlign: 'right', color: 'var(--text-mid)', fontSize: '0.75rem' }}>
                      {fmtGBP(result.report_data.reduce((s, d) => s + d.sales_breakdown.reduce((ss, sb) => ss + (sb.net_amount ?? 0), 0), 0))}
                    </td>
                  </tr>
                </tbody>
              </table>
            </Card>
          )}

          {/* Table 3: Occupancy */}
          {result.occupancy_data.length > 0 && (
            <Card style={{ marginBottom: '1.5rem', overflowX: 'auto' }}>
              <h2 style={sectionTitle}>Occupancy</h2>
              <table style={{ borderCollapse: 'collapse', fontSize: '0.8rem', minWidth: '400px', width: '100%' }}>
                <thead>
                  <tr style={{ borderBottom: '2px solid var(--card-border)' }}>
                    <th style={{ ...th, textAlign: 'left' }}>Date</th>
                    <th style={th}>Rooms Sold</th>
                    <th style={th}>Total Rooms</th>
                    <th style={th}>Guests</th>
                    <th style={th}>Occ %</th>
                  </tr>
                </thead>
                <tbody>
                  {result.occupancy_data.map((row, i) => {
                    const date = row.period ?? row.date ?? ''
                    const occ = row.total_rooms && row.rooms_sold
                      ? ((row.rooms_sold / row.total_rooms) * 100).toFixed(1)
                      : '—'
                    return (
                      <tr key={i} style={{ borderBottom: '1px solid var(--card-border)' }}>
                        <td style={td}>{fmtDate(date)}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{row.rooms_sold ?? '—'}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{row.total_rooms ?? '—'}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{row.total_people ?? '—'}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{occ}{occ !== '—' ? '%' : ''}</td>
                      </tr>
                    )
                  })}
                </tbody>
              </table>
            </Card>
          )}

          {/* Table 4: Debtors / Creditors */}
          <Card style={{ marginBottom: '1.5rem', overflowX: 'auto' }}>
            <h2 style={sectionTitle}>Debtors / Creditors</h2>
            {debtorsLoading ? (
              <p style={{ color: 'var(--text-mid)', fontSize: '0.875rem' }}>Loading balances…</p>
            ) : debtors ? (
              <table style={{ borderCollapse: 'collapse', fontSize: '0.8rem', minWidth: '400px', width: '100%' }}>
                <thead>
                  <tr style={{ borderBottom: '2px solid var(--card-border)' }}>
                    <th style={{ ...th, textAlign: 'left' }}>Date</th>
                    <th style={th}>Debtors</th>
                    <th style={th}>Creditors</th>
                    <th style={th}>Net</th>
                  </tr>
                </thead>
                <tbody>
                  <tr style={{ borderBottom: '1px solid var(--card-border)', background: 'var(--body-bg)' }}>
                    <td style={{ ...td, fontWeight: 600, color: 'var(--text-mid)' }}>Opening Balance</td>
                    <td style={{ ...td, textAlign: 'right' }}>{fmtGBP(debtors.period_open_balance.debtors)}</td>
                    <td style={{ ...td, textAlign: 'right' }}>{fmtGBP(debtors.period_open_balance.creditors)}</td>
                    <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>{fmtGBP(debtors.period_open_balance.overall)}</td>
                  </tr>
                  {dates.map(d => {
                    const b = debtors.balances_by_date[d]
                    if (!b) return null
                    return (
                      <tr key={d} style={{ borderBottom: '1px solid var(--card-border)' }}>
                        <td style={td}>{fmtDate(d)}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{fmtGBP(b.debtors)}</td>
                        <td style={{ ...td, textAlign: 'right' }}>{fmtGBP(b.creditors)}</td>
                        <td style={{ ...td, textAlign: 'right', fontWeight: 700 }}>{fmtGBP(b.overall)}</td>
                      </tr>
                    )
                  })}
                </tbody>
              </table>
            ) : (
              <p style={{ color: 'var(--text-mid)', fontSize: '0.875rem' }}>Balances unavailable.</p>
            )}
          </Card>
        </>
      )}
    </div>
  )
}

const labelSt: React.CSSProperties = { fontSize: '0.75rem', color: 'var(--text-mid)', display: 'block', marginBottom: '0.25rem' }
const inpSt: React.CSSProperties = { border: '1px solid var(--card-border)', borderRadius: '6px', padding: '0.4rem 0.6rem', fontSize: '0.875rem' }
const sectionTitle: React.CSSProperties = { fontSize: '1rem', fontWeight: 700, marginBottom: '1rem' }
const th: React.CSSProperties = { padding: '0.5rem 0.625rem', textAlign: 'right', color: 'var(--text-mid)', fontWeight: 600, whiteSpace: 'nowrap' }
const td: React.CSSProperties = { padding: '0.45rem 0.625rem' }