export const dynamic = 'force-dynamic'

import { NextRequest, NextResponse } from 'next/server'
import { getSession } from '@/lib/auth/get-session'
import { withUser } from '@/lib/db/with-user'
import { writeAuditLog } from '@/lib/db/audit'
import { incidents, sites, zones, users, doshReports } from '@/lib/db/schema'
import { buildJkkp8Rows, jkkp8Csv, type Jkkp8Incident } from '@/lib/reports/jkkp8'
import { aliasedTable, eq, and, gte, lt, asc, inArray } from 'drizzle-orm'

export async function GET(request: NextRequest) {
  const session = await getSession()
  if (!session) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
  if (!['hse', 'admin'].includes(session.role))
    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })

  const yearParam = request.nextUrl.searchParams.get('year')
  const year = Number.parseInt(yearParam ?? '', 10) || new Date().getFullYear()

  const reporterAlias = aliasedTable(users, 'reporter')

  const incidentRows = await withUser(session.sub, async tx =>
    tx.select({
      referenceNo: incidents.referenceNo,
      incidentType: incidents.incidentType,
      description: incidents.description,
      reportedAt: incidents.reportedAt,
      medicalStatus: incidents.medicalStatus,
      lostDays: incidents.lostDays,
      isFatality: incidents.isFatality,
      isSeriousBodilyInjury: incidents.isSeriousBodilyInjury,
      isDangerousOccurrence: incidents.isDangerousOccurrence,
      isOccupationalDisease: incidents.isOccupationalDisease,
      incidentId: incidents.id,
      siteName: sites.name,
      zoneName: zones.name,
      reporterName: reporterAlias.name,
    })
    .from(incidents)
    .leftJoin(sites, eq(incidents.siteId, sites.id))
    .leftJoin(zones, eq(incidents.zoneId, zones.id))
    .leftJoin(reporterAlias, eq(incidents.reportedBy, reporterAlias.id))
    .where(and(
      gte(incidents.reportedAt, new Date(`${year}-01-01T00:00:00Z`)),
      lt(incidents.reportedAt, new Date(`${year + 1}-01-01T00:00:00Z`)),
    ))
    .orderBy(asc(incidents.reportedAt))
  )

  // Fetch dosh_reports for all incidents in a single query
  const incidentIds = incidentRows.map(r => r.incidentId)
  const doshRows = incidentIds.length > 0
    ? await withUser(session.sub, async tx =>
        tx.select({
          incidentId: doshReports.incidentId,
          formType: doshReports.formType,
          status: doshReports.status,
          submittedAt: doshReports.submittedAt,
        })
        .from(doshReports)
        .where(inArray(doshReports.incidentId, incidentIds))
      )
    : []

  // Group dosh rows by incidentId
  const doshByIncident = new Map<string, Array<{ form_type: string; status: string; submitted_at: string | null }>>()
  for (const d of doshRows) {
    const existing = doshByIncident.get(d.incidentId) ?? []
    existing.push({
      form_type: d.formType,
      status: d.status,
      submitted_at: d.submittedAt ? d.submittedAt.toISOString() : null,
    })
    doshByIncident.set(d.incidentId, existing)
  }

  // Map Drizzle camelCase rows to Jkkp8Incident snake_case shape
  const jkkp8Incidents: Jkkp8Incident[] = incidentRows.map(r => ({
    reference_no: r.referenceNo,
    incident_type: r.incidentType,
    description: r.description ?? '',
    reported_at: r.reportedAt ? r.reportedAt.toISOString() : '',
    medical_status: r.medicalStatus,
    lost_days: r.lostDays,
    is_fatality: r.isFatality ?? false,
    is_serious_bodily_injury: r.isSeriousBodilyInjury ?? false,
    is_dangerous_occurrence: r.isDangerousOccurrence ?? false,
    is_occupational_disease: r.isOccupationalDisease ?? false,
    sites: r.siteName ? { name: r.siteName } : null,
    zones: r.zoneName ? { name: r.zoneName } : null,
    reporter: r.reporterName ? { name: r.reporterName } : null,
    dosh_reports: doshByIncident.get(r.incidentId) ?? [],
  }))

  const rows = buildJkkp8Rows(jkkp8Incidents)
  const csv = jkkp8Csv(rows)

  await withUser(session.sub, async tx =>
    writeAuditLog(tx, 'incidents', session.sub, 'jkkp8_register_export', { year, row_count: rows.length })
  )

  return new NextResponse(csv, {
    status: 200,
    headers: {
      'Content-Type': 'text/csv; charset=utf-8',
      'Content-Disposition': `attachment; filename="jkkp8-register-${year}.csv"`,
    },
  })
}