import { useMemo } from 'react'
import type { Property } from '../domain/property'
import type { FutureSignal } from '../domain/futureSignal'
import { SignalType, RiskLevel, ResultType } from '../domain/enums'

// Matches the mock date used throughout the prototype (currentDate context: 2026-05-20)
const MOCK_TODAY = new Date('2026-05-20')

export function useSchattenmarktSignals(properties: Property[]): FutureSignal[] {
  return useMemo(() => {
    const signals: FutureSignal[] = []
    for (const p of properties) {
      if (p.resultType !== ResultType.VERIFIED_PORTFOLIO) continue
      const rel = p.schattenmarktRelease
      if (!rel?.enabled) continue
      const triggerDate = getEarliestTriggerDate(p, rel.leadTimeMonths)
      if (!triggerDate || MOCK_TODAY < triggerDate) continue
      signals.push(buildSignal(p))
    }
    return signals
  }, [properties])
}

function getEarliestTriggerDate(p: Property, leadTimeMonths: number): Date | null {
  const candidates: Date[] = []
  if (p.leaseEndDate) {
    const d = new Date(p.leaseEndDate)
    d.setMonth(d.getMonth() - leadTimeMonths)
    candidates.push(d)
  }
  if (p.breakoutOption && p.breakoutOptionDate) {
    const d = new Date(p.breakoutOptionDate)
    d.setMonth(d.getMonth() - leadTimeMonths)
    candidates.push(d)
  }
  return candidates.length ? candidates.reduce((a, b) => (a < b ? a : b)) : null
}

function buildSignal(p: Property): FutureSignal {
  const targetDate = p.breakoutOption && p.breakoutOptionDate
    ? new Date(p.breakoutOptionDate)
    : p.leaseEndDate ? new Date(p.leaseEndDate) : new Date()

  const monthsUntil = Math.max(1, Math.round(
    (targetDate.getTime() - MOCK_TODAY.getTime()) / (1000 * 60 * 60 * 24 * 30)
  ))

  const locationLabel = `${p.location.city}${p.location.district ? `, ${p.location.district}` : ''}`
  const monthName = targetDate.toLocaleDateString('de-CH', { month: 'long', year: 'numeric' })

  return {
    id: `schattenmarkt-${p.id}`,
    signalType: SignalType.LEASE_EXPIRY,
    propertyId: p.id,
    title: `${p.title} — frei ab ${monthName}`,
    locationHint: locationLabel,
    areaSqmEstimate: p.areaSqm,
    probability: 0.92,
    confidenceScore: 0.92,
    timeHorizonMonths: monthsUntil,
    source: { type: 'LEASE_CONTRACT', credibility: 'HIGH' },
    sensitivityLevel: 'INTERNAL',
    disclaimer: 'Verwaltung hat diese Fläche für Pre-Market-Sichtbarkeit freigegeben. Vertragsende aus internem ERP bestätigt — höchste Signalqualität.',
    riskLevel: RiskLevel.LOW,
    relevanceScore: 0.92,
    isVerified: true,
    organizationId: p.organizationId,
    createdAt: MOCK_TODAY.toISOString(),
    updatedAt: MOCK_TODAY.toISOString(),
    aiSummary: `Vertrag der ${p.currentTenant ?? 'aktuellen Mietpartei'} läuft in ${monthsUntil} Monaten aus (${monthName}). Fläche: ${p.areaSqm.toLocaleString('de-CH')} m² · ${locationLabel}. Die Verwaltung hat dieses Objekt explizit für den Markt freigegeben — vertraglich bestätigt, keine Schätzung.`,
    marketIndicators: [
      `Vertragsende ${monthName} aus Verwaltungssystem bestätigt`,
      `Fläche ${p.areaSqm.toLocaleString('de-CH')} m² — ${locationLabel}`,
      `Pre-Market-Freigabe durch Verwaltung erteilt`,
    ],
    confirmedFacts: [
      `Vertragsende ${monthName} aus ERP bestätigt`,
      `Fläche ${p.areaSqm.toLocaleString('de-CH')} m² — bestätigt`,
      `Standort ${locationLabel} — bestätigt`,
    ],
    unconfirmedFacts: [
      'Ob Nachmieter bereits bekannt',
      'Ob Umbaumassnahmen geplant',
    ],
  }
}