import type { Metadata } from 'next'
import { Suspense } from 'react'
import Link from 'next/link'
import { notFound } from 'next/navigation'
import { db } from '@/lib/db'
import { requireUser } from '@/lib/auth/current'
import { recordRead, READ_AUDIT_FROM_LEVEL } from '@/lib/audit'
import { loadDocumentSections, loadVisibleDocument } from '@/lib/documents/service'
import {
  canEditDocument,
  canFinalizeDocument,
  canRetractDocument,
} from '@/lib/access/documentWrite'
import { de } from '@/lib/i18n/de'
import { StampMark, classificationEdgeStyle } from '@/components/StampMark'
import { SkeletonLine } from '@/components/Skeleton'
import { Sections } from '@/components/sections/Sections'
import { Sheet } from '@/components/documents/Sheet'
import { SheetSwitch } from '@/components/documents/SheetSwitch'
import { saveDocumentSectionAction } from '../actions'
import { DocumentActions } from './DocumentActions'
import { Attachments } from '@/components/files/Attachments'
import { listAttachments, resolvePhotoUrls } from '@/lib/files/service'
import { toAttachmentViews } from '@/lib/files/view'
import type { EffectivePermissions } from '@/lib/auth/permissions'

export const dynamic = 'force-dynamic'

export async function generateMetadata({
  params,
}: {
  params: Promise<{ documentNumber: string }>
}): Promise<Metadata> {
  const { documentNumber } = await params
  return { title: documentNumber }
}

async function Body({
  document,
  permissions,
  canEdit,
}: {
  document: {
    id: string
    templateId: string
    documentNumber: string
    title: string
    layout: string
    createdAt: Date
    caseId: string | null
  }
  permissions: EffectivePermissions
  canEdit: boolean
}) {
  const sections = await loadDocumentSections(permissions, document)
  const photoUrls = await resolvePhotoUrls(
    permissions,
    sections.map((section) => ({
      fieldKey: section.fieldKey,
      visible: section.visible,
      value: section.visible ? section.value : null,
      type: section.field.type,
    })),
  )

  const editor = (
    <Sections
      scope={`dokument:${document.documentNumber}`}
      save={saveDocumentSectionAction.bind(null, document.documentNumber)}
      sections={sections}
      canEdit={canEdit}
      documentNumber={document.documentNumber}
      topic={document.caseId ? `case:${document.caseId}` : `user:${permissions.userId}`}
      photoUrls={photoUrls}
    />
  )

  if (document.layout !== 'DOSSIER') return editor

  // Das Aktenblatt braucht die Kopfzeilen der Vorlage und die
  // Foundation-Stufen für den Balken. Beide steuern keinen Zugriff.
  const [template, foundationLevels] = await Promise.all([
    db.documentTemplate.findUnique({
      where: { id: document.templateId },
      select: { sheetTitle: true, sheetSubtitle: true, name: true },
    }),
    db.foundationClearance.findMany({ orderBy: { sortOrder: 'asc' } }),
  ])

  return (
    <SheetSwitch
      canEdit={canEdit}
      editor={editor}
      sheet={
        <Sheet
          sections={sections}
          title={template?.sheetTitle ?? de.app.name}
          subtitle={template?.sheetSubtitle ?? template?.name ?? document.title}
          documentNumber={document.documentNumber}
          issuedAt={document.createdAt}
          foundationLevels={foundationLevels}
          footerNote={de.document.footerNote}
          photoUrls={photoUrls}
        />
      }
    />
  )
}

async function AttachmentBlock({
  documentId,
  documentNumber,
  topic,
  permissions,
  canUpload,
}: {
  documentId: string
  documentNumber: string
  topic: string
  permissions: EffectivePermissions
  canUpload: boolean
}) {
  const anhaenge = await listAttachments(permissions, { documentId })
  return (
    <Attachments
      target={{ documentNumber }}
      topic={topic}
      initial={toAttachmentViews(anhaenge)}
      canUpload={canUpload}
      canRelease={permissions.isAdmin}
    />
  )
}

/**
 * Ein Dokument.
 *
 * Dieselbe Darstellung trägt einen Vorfallsbericht und einen mehrseitigen
 * Vertrag: was sie unterscheidet, steht in der Vorlage, nicht hier.
 * Siehe docs/13-entscheidungen.md.
 */
export default async function DocumentPage({
  params,
}: {
  params: Promise<{ documentNumber: string }>
}) {
  const user = await requireUser()
  const { documentNumber } = await params

  const doc = await loadVisibleDocument(user.permissions, documentNumber)
  // Kein Zugriff heisst 404, nicht 403.
  if (!doc) notFound()

  if (doc.classification >= READ_AUDIT_FROM_LEVEL) {
    recordRead({
      actorId: user.id,
      action: 'document.read',
      targetType: 'Document',
      targetId: doc.id,
      clearanceAtTime: user.permissions.clearanceLevel,
      meta: { documentNumber: doc.documentNumber, classification: doc.classification },
    })
  }

  const [levels, besitzer, verfasser] = await Promise.all([
    db.clearanceLevelConfig.findMany({ orderBy: { level: 'asc' } }),
    doc.caseId
      ? db.case.findUnique({ where: { id: doc.caseId }, select: { caseNumber: true, title: true } })
      : doc.personnelFileId
        ? db.personnelFile.findUnique({
            where: { id: doc.personnelFileId },
            select: { id: true, displayName: true },
          })
        : Promise.resolve(null),
    db.user.findMany({
      where: {
        id: {
          in: [doc.createdById, doc.finalizedById, doc.retractedById].filter(
            (id): id is string => id !== null,
          ),
        },
      },
      select: { id: true, displayName: true },
    }),
  ])

  const level = levels.find((l) => l.level === doc.classification)
  const nameOf = new Map(verfasser.map((v) => [v.id, v.displayName]))
  const canEdit = canEditDocument(user.permissions, doc).ok

  return (
    <main className="mx-auto max-w-5xl px-6 py-10">
      <header className="pl-3" style={classificationEdgeStyle(doc.classification)}>
        <div className="flex flex-wrap items-baseline gap-x-4 gap-y-2">
          <span className="font-mono text-xs text-text-dim">{doc.documentNumber}</span>
          <StampMark level={doc.classification} name={level?.name ?? de.common.unknown} />
        </div>
        <h1 className="mt-2 font-condensed">{doc.title}</h1>

        <dl className="mt-3 flex flex-wrap gap-x-8 gap-y-1 text-xs text-text-dim">
          <div className="flex gap-2">
            <dt className="font-condensed">{de.case.status}</dt>
            <dd>{de.document.statusNames[doc.status] ?? doc.status}</dd>
          </div>
          <div className="flex gap-2">
            <dt className="font-condensed">{de.document.kind}</dt>
            <dd>{doc.templateKey}</dd>
          </div>
          <div className="flex gap-2">
            <dt className="font-condensed">{de.case.createdBy}</dt>
            <dd>{nameOf.get(doc.createdById) ?? doc.createdById}</dd>
          </div>
        </dl>

        <p className="no-print mt-2 text-xs">
          <Link href={`/dokumente/${doc.documentNumber}/export`}>{de.export.asPdf}</Link>
        </p>

        {besitzer ? (
          <p className="mt-2 text-xs">
            {'caseNumber' in besitzer ? (
              <Link href={`/faelle/${besitzer.caseNumber}`}>
                {de.document.ownerCase} · {besitzer.title}
              </Link>
            ) : (
              <Link href={`/personalakten/${besitzer.id}`}>
                {de.document.ownerPersonnel} · {besitzer.displayName}
              </Link>
            )}
          </p>
        ) : (
          <p className="mt-2 text-xs text-text-dim">{de.document.ownerNone}</p>
        )}

        {doc.retractedAt ? (
          <p className="mt-3 border-l-(length:--spacing-edge) border-stamp-4 pl-3 text-sm text-text-dim">
            {de.document.retracted(
              doc.retractedAt.toLocaleDateString('de-DE'),
              nameOf.get(doc.retractedById ?? '') ?? doc.retractedById ?? de.common.unknown,
              doc.retractionReason ?? '',
            )}
          </p>
        ) : doc.finalizedAt ? (
          <p className="mt-3 font-condensed text-2xs text-text-dim">
            {de.document.finalized(
              doc.finalizedAt.toLocaleDateString('de-DE'),
              nameOf.get(doc.finalizedById ?? '') ?? doc.finalizedById ?? de.common.unknown,
            )}
          </p>
        ) : null}

        <DocumentActions
          documentNumber={doc.documentNumber}
          classification={doc.classification}
          canFinalize={canFinalizeDocument(user.permissions, doc).ok}
          canRetract={canRetractDocument(user.permissions, doc).ok}
          canReclassify={canEdit}
          levels={levels
            .filter((l) => l.level <= user.permissions.clearanceLevel)
            .map((l) => ({ level: l.level, name: l.name }))}
        />
      </header>

      <section className="mt-10">
        <Suspense
          fallback={
            <div className="space-y-6">
              <SkeletonLine width="10rem" />
              <SkeletonLine />
              <SkeletonLine width="12rem" />
              <SkeletonLine />
            </div>
          }
        >
          <Body document={doc} permissions={user.permissions} canEdit={canEdit} />
        </Suspense>
      </section>

      <section className="no-print mt-10">
        <h2 className="font-condensed">{de.attachment.heading}</h2>
        <div className="mt-4">
          <Suspense fallback={<SkeletonLine width="50%" />}>
            <AttachmentBlock
              documentId={doc.id}
              documentNumber={doc.documentNumber}
              topic={doc.caseId ? `case:${doc.caseId}` : `user:${user.id}`}
              permissions={user.permissions}
              canUpload={canEdit}
            />
          </Suspense>
        </div>
      </section>
    </main>
  )
}