import { NextResponse } from 'next/server'
import { withRouteContext } from '@/lib/api/with-route-context'
import { errorResponseFromCode } from '@/lib/errors/get-structured-error'
import { findRcBasisGaps } from '@/lib/reports/rc-basis-gaps'
import type { VatPeriodType } from '@/types'

export const GET = withRouteContext(
  'report.vat_declaration.rc_basis_gaps',
  async (request, ctx) => {
    const { supabase, companyId, log, requestId } = ctx

    const { searchParams } = new URL(request.url)
    const periodType = searchParams.get('periodType') as VatPeriodType | null
    const yearStr = searchParams.get('year')
    const periodStr = searchParams.get('period')

    if (!periodType || !yearStr || !periodStr) {
      return errorResponseFromCode('VAT_REPORT_MISSING_PARAMS', log, { requestId })
    }
    if (!['monthly', 'quarterly', 'yearly'].includes(periodType)) {
      return errorResponseFromCode('VAT_REPORT_INVALID_PERIOD_TYPE', log, {
        requestId,
        details: { received: periodType },
      })
    }

    const year = parseInt(yearStr, 10)
    const period = parseInt(periodStr, 10)
    if (isNaN(year) || isNaN(period)) {
      return errorResponseFromCode('VAT_REPORT_INVALID_PERIOD', log, {
        requestId,
        details: { year: yearStr, period: periodStr },
      })
    }

    try {
      const gaps = await findRcBasisGaps(supabase, companyId, periodType, year, period)
      return NextResponse.json({ data: { gaps } })
    } catch (err) {
      log.error('rc-basis-gaps detection failed', err as Error, { periodType, year, period })
      return errorResponseFromCode('VAT_REPORT_GENERATION_FAILED', log, {
        requestId,
        details: { reason: err instanceof Error ? err.message : 'unknown' },
      })
    }
  },
)