feat: investigation workspace — 5-Why/fishbone RCA, transitions triaged→investigating→capa_pending

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FFDuBhMKvoWjrWT3ZnGmmr

app/(protected)/hse/incidents/[id]/investigation/page.tsx

@@ -0,0 +1,54 @@
+export const dynamic = 'force-dynamic'
+
+import { notFound, redirect } from 'next/navigation'
+import Link from 'next/link'
+import { createClient } from '@/lib/supabase/server'
+import { InvestigationForm } from '@/components/incidents/investigation-form'
+
+interface Props {
+  params: Promise<{ id: string }>
+}
+
+export default async function InvestigationPage({ params }: Props) {
+  const { id } = await params
+  const supabase = await createClient()
+
+  const { data, error: authError } = await supabase.auth.getUser()
+  if (authError || !data?.user) redirect(`/login?redirect=/hse/incidents/${id}/investigation`)
+
+  const { data: profile } = await supabase
+    .from('users').select('role').eq('id', data.user.id).single()
+  if (!profile || profile.role !== 'hse') redirect('/hse/incidents')
+
+  const { data: incident } = await supabase
+    .from('incidents')
+    .select('id, reference_no, status')
+    .eq('id', id)
+    .single()
+
+  if (!incident) notFound()
+  if (!['triaged', 'investigating'].includes((incident as { status: string }).status))
+    redirect(`/hse/incidents/${id}`)
+
+  const { data: existing } = await supabase
+    .from('investigations')
+    .select('id')
+    .eq('incident_id', id)
+    .order('created_at', { ascending: false })
+    .limit(1)
+    .maybeSingle()
+
+  return (
+    <main className="max-w-2xl mx-auto px-4 py-6">
+      <Link href={`/hse/incidents/${id}`} className="text-sm text-blue-600 hover:underline mb-4 inline-block">
+        ← Back to incident
+      </Link>
+      <h1 className="text-xl font-bold text-gray-900 mb-1">Investigation Workspace</h1>
+      <p className="text-sm text-gray-500 mb-6">{(incident as { reference_no: string | null }).reference_no ?? id}</p>
+      <InvestigationForm
+        incidentId={id}
+        existingInvestigationId={(existing as { id: string } | null)?.id ?? null}
+      />
+    </main>
+  )
+}

app/api/incidents/[id]/investigation/route.ts

@@ -0,0 +1,112 @@
+export const dynamic = 'force-dynamic'
+
+import { NextRequest, NextResponse } from 'next/server'
+import { createClient } from '@/lib/supabase/server'
+
+export async function POST(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params
+  const supabase = await createClient()
+
+  const { data: { user }, error: authError } = await supabase.auth.getUser()
+  if (authError || !user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const { data: profile } = await supabase
+    .from('users').select('role').eq('id', user.id).single()
+  if (!profile || profile.role !== 'hse')
+    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
+
+  const { data: incident } = await supabase
+    .from('incidents').select('status').eq('id', id).single()
+  if (!incident) return NextResponse.json({ error: 'Not found' }, { status: 404 })
+  if (incident.status !== 'triaged')
+    return NextResponse.json({ error: 'Incident must be triaged first' }, { status: 409 })
+
+  const body = await request.json()
+  const method: 'five_why' | 'fishbone' | 'other' = body.method ?? 'five_why'
+
+  const { data: inv, error } = await supabase
+    .from('investigations')
+    .insert({
+      incident_id: id,
+      investigator_id: user.id,
+      method,
+      findings_text: body.findings_text ?? null,
+      root_cause_summary: body.root_cause_summary ?? null,
+      five_why_steps: method === 'five_why' ? (body.five_why_steps ?? []) : null,
+      fishbone_categories: method === 'fishbone' ? (body.fishbone_categories ?? []) : null,
+    })
+    .select('id')
+    .single()
+
+  if (error || !inv) return NextResponse.json({ error: 'Insert failed' }, { status: 500 })
+
+  await supabase
+    .from('incidents')
+    .update({ status: 'investigating' })
+    .eq('id', id)
+
+  await supabase.rpc('write_audit_log', {
+    p_table_name: 'incidents',
+    p_record_id: id,
+    p_action: 'investigation_started',
+    p_new_value: { status: 'investigating', investigation_id: inv.id },
+  })
+
+  return NextResponse.json({ id: inv.id })
+}
+
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ id: string }> }
+) {
+  const { id } = await params
+  const supabase = await createClient()
+
+  const { data: { user }, error: authError } = await supabase.auth.getUser()
+  if (authError || !user) return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+
+  const { data: profile } = await supabase
+    .from('users').select('role').eq('id', user.id).single()
+  if (!profile || profile.role !== 'hse')
+    return NextResponse.json({ error: 'Forbidden' }, { status: 403 })
+
+  const body = await request.json()
+  const { investigation_id, complete, ...fields } = body
+
+  if (!investigation_id) return NextResponse.json({ error: 'investigation_id required' }, { status: 422 })
+
+  const updateData: Record<string, unknown> = {
+    findings_text: fields.findings_text ?? null,
+    root_cause_summary: fields.root_cause_summary ?? null,
+    five_why_steps: fields.five_why_steps ?? null,
+    fishbone_categories: fields.fishbone_categories ?? null,
+  }
+  if (complete) updateData.completed_at = new Date().toISOString()
+
+  const { error } = await supabase
+    .from('investigations')
+    .update(updateData)
+    .eq('id', investigation_id)
+    .eq('incident_id', id)
+
+  if (error) return NextResponse.json({ error: 'Update failed' }, { status: 500 })
+
+  if (complete) {
+    await supabase
+      .from('incidents')
+      .update({ status: 'capa_pending' })
+      .eq('id', id)
+
+    await supabase.rpc('write_audit_log', {
+      p_table_name: 'incidents',
+      p_record_id: id,
+      p_action: 'investigation_completed',
+      p_new_value: { status: 'capa_pending' },
+    })
+  }
+
+  return NextResponse.json({ ok: true })
+}