From 854ab783c80829a8ca76714f80fd2e88bc186fe1 Mon Sep 17 00:00:00 2001
From: neon <18559658+neonsolstice@users.noreply.github.com>
Date: Mon, 16 Mar 2026 08:33:03 -0600
Subject: [PATCH] feat: multi-format read and download support

- add split Read button on book detail page (primary format direct, dropdown for others)
- add useBookDownload composable with auth-aware blob download and ZIP export
- add BookDownloadButton component for detail page and files tab
- refactor useBookBulkActions to delegate export to useBookDownload
- add Open/Download submenus to book card dropdown
- group Edit/Refresh/Regenerate under Metadata submenu in book card
---
 .../book/components/BookCoverCard.vue         | 100 ++++++++++++----
 .../book/components/BookDownloadButton.vue    | 109 ++++++++++++++++++
 .../__tests__/BookCoverCard.spec.ts           |   3 +
 .../components/detail/tabs/DetailsTab.vue     |  74 +++++++++---
 .../book/components/detail/tabs/FilesTab.vue  |   7 +-
 .../book/composables/useBookBulkActions.ts    |  22 +---
 .../book/composables/useBookDownload.ts       |  65 +++++++++++
 7 files changed, 319 insertions(+), 61 deletions(-)
 create mode 100644 client/src/features/book/components/BookDownloadButton.vue
 create mode 100644 client/src/features/book/composables/useBookDownload.ts

diff --git a/client/src/features/book/components/BookCoverCard.vue b/client/src/features/book/components/BookCoverCard.vue
index 999c39413..ac9fb89db 100644
--- a/client/src/features/book/components/BookCoverCard.vue
+++ b/client/src/features/book/components/BookCoverCard.vue
@@ -8,6 +8,7 @@ import { useRouter } from 'vue-router'
 import {
   BookOpen,
   Check,
+  Download,
   ExternalLink,
   FolderPlus,
   Image,
@@ -21,12 +22,22 @@ import {
   Trash2,
   TriangleAlert,
 } from 'lucide-vue-next'
-import { DropdownMenu, DropdownMenuContent, DropdownMenuItem, DropdownMenuSeparator, DropdownMenuTrigger } from '@/components/ui/dropdown-menu'
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuSeparator,
+  DropdownMenuSub,
+  DropdownMenuSubContent,
+  DropdownMenuSubTrigger,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu'
 import { useCoverVersions } from '../composables/useCoverVersions'
 import { useRefreshMetadata } from '../composables/useRefreshMetadata'
 import { useRefreshingBooks } from '../composables/useRefreshingBooks'
 import { usePermissions } from '@/features/auth/composables/usePermissions'
 import { useDisplaySettings } from '@/composables/useDisplaySettings'
+import { useBookDownload } from '@/features/book/composables/useBookDownload'
 import SendBookDialog from '@/features/email/components/SendBookDialog.vue'
 
 const router = useRouter()
@@ -54,7 +65,6 @@ const seriesLine = computed(() => {
 
 const readableFiles = computed(() => props.book.files.filter((f) => f.format && f.format in FORMAT_TO_GROUP))
 const primaryFile = computed(() => readableFiles.value.find((f) => f.role === 'primary') ?? readableFiles.value[0] ?? null)
-const extraFiles = computed(() => readableFiles.value.filter((f) => f !== primaryFile.value))
 
 const { coverUrl, bumpVersion } = useCoverVersions()
 const coverSrc = computed(() => coverUrl(props.book.id))
@@ -129,6 +139,16 @@ function openAuthorBrowse() {
   if (!authorQuery.value) return
   void router.push({ name: 'authors', query: { q: authorQuery.value } })
 }
+
+const { downloadFile, exportBooks } = useBookDownload()
+
+function handleDownloadFile(file: BookFileRef) {
+  void downloadFile(file.id)
+}
+
+function handleExportAll() {
+  void exportBooks([props.book.id], true)
+}
 </script>
 
 <template>
@@ -294,33 +314,71 @@ function openAuthorBrowse() {
               </button>
             </DropdownMenuTrigger>
             <DropdownMenuContent align="end">
-              <DropdownMenuItem v-if="primaryFile" @click="openFile(primaryFile)">
+              <!-- Open submenu (only when multiple readable files; single file = direct item) -->
+              <DropdownMenuItem v-if="readableFiles.length <= 1 && primaryFile && !isMissing" @click="openFile(primaryFile)">
                 <BookOpen class="size-4 mr-2" />
-                {{ extraFiles.length > 0 ? `Open as ${primaryFile.format?.toUpperCase() ?? 'primary'}` : 'Open' }}
+                Open
               </DropdownMenuItem>
-              <DropdownMenuItem v-for="file in extraFiles" :key="file.id" @click="openFile(file)">
-                <BookOpen class="size-4 mr-2" />
-                Open as {{ file.format?.toUpperCase() ?? '?' }}
+              <DropdownMenuSub v-else-if="readableFiles.length > 1 && !isMissing">
+                <DropdownMenuSubTrigger>
+                  <BookOpen class="size-4 mr-2" />
+                  Open
+                </DropdownMenuSubTrigger>
+                <DropdownMenuSubContent>
+                  <DropdownMenuItem v-for="file in readableFiles" :key="file.id" @click="openFile(file)">
+                    {{ file.format?.toUpperCase() ?? '?' }}
+                    <span v-if="file.role === 'primary'" class="ml-auto pl-4 text-[10px] text-primary/70">Primary</span>
+                  </DropdownMenuItem>
+                </DropdownMenuSubContent>
+              </DropdownMenuSub>
+
+              <!-- Download submenu -->
+              <DropdownMenuItem v-if="readableFiles.length === 1 && primaryFile" @click="handleDownloadFile(primaryFile)">
+                <Download class="size-4 mr-2" />
+                Download
               </DropdownMenuItem>
+              <DropdownMenuSub v-else-if="readableFiles.length > 1">
+                <DropdownMenuSubTrigger>
+                  <Download class="size-4 mr-2" />
+                  Download
+                </DropdownMenuSubTrigger>
+                <DropdownMenuSubContent>
+                  <DropdownMenuItem v-for="file in readableFiles" :key="file.id" @click="handleDownloadFile(file)">
+                    {{ file.format?.toUpperCase() ?? '?' }}
+                    <span v-if="file.role === 'primary'" class="ml-auto pl-4 text-[10px] text-primary/70">Primary</span>
+                  </DropdownMenuItem>
+                  <DropdownMenuSeparator />
+                  <DropdownMenuItem @click="handleExportAll"> All formats (ZIP) </DropdownMenuItem>
+                </DropdownMenuSubContent>
+              </DropdownMenuSub>
+
               <DropdownMenuItem @click="router.push({ name: 'book-detail', params: { bookId: book.id } })">
                 <ExternalLink class="size-4 mr-2" />
                 Book Details
               </DropdownMenuItem>
               <DropdownMenuSeparator />
-              <DropdownMenuItem @click="router.push({ name: 'book-edit', params: { bookId: book.id } })">
-                <Pencil class="size-4 mr-2" />
-                Edit Metadata
-              </DropdownMenuItem>
-              <DropdownMenuItem :disabled="anyRefreshing" @click="refreshWithFeedback(book.id)">
-                <Loader2 v-if="anyRefreshing" class="size-4 mr-2 animate-spin" />
-                <RefreshCw v-else class="size-4 mr-2" />
-                Refresh Metadata
-              </DropdownMenuItem>
-              <DropdownMenuItem v-if="hasPermission('library_edit_metadata')" :disabled="reExtractingCover" @click="reExtractCover()">
-                <Loader2 v-if="reExtractingCover" class="size-4 mr-2 animate-spin" />
-                <Image v-else class="size-4 mr-2" />
-                Regenerate Cover
-              </DropdownMenuItem>
+              <DropdownMenuSub>
+                <DropdownMenuSubTrigger>
+                  <Pencil class="size-4 mr-2" />
+                  Metadata
+                </DropdownMenuSubTrigger>
+                <DropdownMenuSubContent>
+                  <DropdownMenuItem @click="router.push({ name: 'book-edit', params: { bookId: book.id } })">
+                    <Pencil class="size-4 mr-2" />
+                    Edit Metadata
+                  </DropdownMenuItem>
+                  <DropdownMenuItem :disabled="anyRefreshing" @click="refreshWithFeedback(book.id)">
+                    <Loader2 v-if="anyRefreshing" class="size-4 mr-2 animate-spin" />
+                    <RefreshCw v-else class="size-4 mr-2" />
+                    Refresh Metadata
+                  </DropdownMenuItem>
+                  <DropdownMenuItem v-if="hasPermission('library_edit_metadata')" :disabled="reExtractingCover" @click="reExtractCover()">
+                    <Loader2 v-if="reExtractingCover" class="size-4 mr-2 animate-spin" />
+                    <Image v-else class="size-4 mr-2" />
+                    Regenerate Cover
+                  </DropdownMenuItem>
+                </DropdownMenuSubContent>
+              </DropdownMenuSub>
               <DropdownMenuItem @click="emit('action', 'add-to-collection')">
                 <FolderPlus class="size-4 mr-2" />
                 Add to Collection
diff --git a/client/src/features/book/components/BookDownloadButton.vue b/client/src/features/book/components/BookDownloadButton.vue
new file mode 100644
index 000000000..92c7c9b5d
--- /dev/null
+++ b/client/src/features/book/components/BookDownloadButton.vue
@@ -0,0 +1,109 @@
+<script setup lang="ts">
+import { computed } from 'vue'
+import { ChevronDown, Download } from 'lucide-vue-next'
+import { FORMAT_TO_GROUP } from '@projectx/types'
+import type { BookDetailFile } from '@projectx/types'
+import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
+import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip'
+import { getFormatColor } from '@/features/book/lib/format-colors'
+import { useBookDownload } from '@/features/book/composables/useBookDownload'
+
+const props = defineProps<{
+  files: BookDetailFile[]
+  bookId: number
+}>()
+
+const { isDownloading, downloadFile, exportBooks } = useBookDownload()
+
+const readableFiles = computed(() => props.files.filter((f) => f.format && f.format in FORMAT_TO_GROUP))
+
+const primaryFile = computed(() => readableFiles.value.find((f) => f.role === 'primary') ?? readableFiles.value[0] ?? null)
+
+const hasMultiple = computed(() => readableFiles.value.length > 1)
+
+function formatBadgeStyle(fmt: string) {
+  const color = getFormatColor(fmt)
+  return { color, borderColor: `${color}66`, backgroundColor: `${color}1a` }
+}
+
+function formatFileSize(bytes: number | null | undefined): string {
+  if (!bytes) return '-'
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+function handleSingleDownload() {
+  if (primaryFile.value) downloadFile(primaryFile.value.id)
+}
+
+function handleFileDownload(file: BookDetailFile) {
+  downloadFile(file.id)
+}
+
+function handleExportAll() {
+  exportBooks([props.bookId], true)
+}
+
+function handleExportPrimary() {
+  exportBooks([props.bookId], false)
+}
+</script>
+
+<template>
+  <Tooltip v-if="!hasMultiple">
+    <TooltipTrigger as-child>
+      <button
+        class="flex w-full items-center justify-center h-9 rounded-md border border-input bg-background text-sm hover:bg-muted transition-colors disabled:opacity-50"
+        :disabled="!primaryFile || isDownloading"
+        @click="handleSingleDownload"
+      >
+        <Download class="size-3.5" />
+      </button>
+    </TooltipTrigger>
+    <TooltipContent>Download</TooltipContent>
+  </Tooltip>
+
+  <Popover v-else>
+    <PopoverTrigger as-child>
+      <button
+        class="flex w-full items-center justify-center gap-1.5 h-9 rounded-md border border-input bg-background text-sm hover:bg-muted transition-colors disabled:opacity-50"
+        :disabled="!primaryFile || isDownloading"
+        title="Download"
+      >
+        <Download class="size-3.5" />
+        <ChevronDown class="size-3" />
+      </button>
+    </PopoverTrigger>
+    <PopoverContent class="w-52 p-1" align="start">
+      <button
+        v-for="file in readableFiles"
+        :key="file.id"
+        class="flex w-full items-center gap-2.5 px-2 py-1.5 rounded text-sm hover:bg-muted transition-colors"
+        @click="handleFileDownload(file)"
+      >
+        <span
+          class="text-[10px] font-bold uppercase tracking-wider px-1.5 py-0.5 rounded border shrink-0"
+          :style="formatBadgeStyle(file.format ?? '?')"
+          >{{ file.format ?? '?' }}</span
+        >
+        <span class="flex-1 text-left text-muted-foreground text-xs truncate">{{ formatFileSize(file.sizeBytes) }}</span>
+        <span v-if="file.role === 'primary'" class="text-[10px] text-primary font-medium shrink-0">Primary</span>
+      </button>
+      <div class="my-1 border-t border-border" />
+      <button
+        class="flex w-full items-center gap-2 px-2 py-1.5 rounded text-sm hover:bg-muted transition-colors text-muted-foreground"
+        @click="handleExportAll"
+      >
+        <Download class="size-3.5 shrink-0" />
+        <span>All formats (ZIP)</span>
+      </button>
+      <button
+        class="flex w-full items-center gap-2 px-2 py-1.5 rounded text-sm hover:bg-muted transition-colors text-muted-foreground"
+        @click="handleExportPrimary"
+      >
+        <Download class="size-3.5 shrink-0" />
+        <span>Primary only (ZIP)</span>
+      </button>
+    </PopoverContent>
+  </Popover>
+</template>
diff --git a/client/src/features/book/components/__tests__/BookCoverCard.spec.ts b/client/src/features/book/components/__tests__/BookCoverCard.spec.ts
index d2dad7edb..f513d8ac0 100644
--- a/client/src/features/book/components/__tests__/BookCoverCard.spec.ts
+++ b/client/src/features/book/components/__tests__/BookCoverCard.spec.ts
@@ -22,6 +22,9 @@ const globalStubs = {
     DropdownMenuItem: { template: '<div><slot /></div>' },
     DropdownMenuTrigger: { template: '<div><slot /></div>' },
     DropdownMenuSeparator: { template: '<div />' },
+    DropdownMenuSub: { template: '<div><slot /></div>' },
+    DropdownMenuSubTrigger: { template: '<div><slot /></div>' },
+    DropdownMenuSubContent: { template: '<div><slot /></div>' },
   },
 }
 
diff --git a/client/src/features/book/components/detail/tabs/DetailsTab.vue b/client/src/features/book/components/detail/tabs/DetailsTab.vue
index 25a2c5891..b114d99f9 100644
--- a/client/src/features/book/components/detail/tabs/DetailsTab.vue
+++ b/client/src/features/book/components/detail/tabs/DetailsTab.vue
@@ -1,13 +1,15 @@
 <script setup lang="ts">
 import { computed, onMounted, ref, watch } from 'vue'
 import { useRouter } from 'vue-router'
-import { BookOpen, Download, FolderPlus, MoreHorizontal, Pencil, Star, Trash2, TriangleAlert, X } from 'lucide-vue-next'
+import { BookOpen, ChevronDown, FolderPlus, MoreHorizontal, Pencil, Star, Trash2, TriangleAlert, X } from 'lucide-vue-next'
 import { DialogClose, DialogContent, DialogOverlay, DialogPortal, DialogRoot } from 'reka-ui'
 import { bookCoverStyle } from '@/features/book/lib/book-cover'
 import { getFormatColor } from '@/features/book/lib/format-colors'
 import { getProviderColor } from '@/lib/provider-colors'
 import { useCoverVersions } from '@/features/book/composables/useCoverVersions'
+import { FORMAT_TO_GROUP } from '@projectx/types'
 import type { BookDetail, BookKoboState } from '@projectx/types'
+import BookDownloadButton from '@/features/book/components/BookDownloadButton.vue'
 import RecommendedBooksRow from '@/features/book/components/detail/RecommendedBooksRow.vue'
 import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip'
 import { Popover, PopoverContent, PopoverTrigger } from '@/components/ui/popover'
@@ -48,6 +50,7 @@ const router = useRouter()
 const addToCollectionOpen = ref(false)
 const scoreBreakdownOpen = ref(false)
 const moreMenuOpen = ref(false)
+const readMenuOpen = ref(false)
 
 const { weights: scoreWeights, fetchWeights } = useMetadataScoreWeights()
 
@@ -77,6 +80,8 @@ const { coverUrl } = useCoverVersions()
 const coverSrc = computed(() => coverUrl(props.book.id, 'cover'))
 
 const primaryFile = computed(() => props.book.files.find((f) => f.role === 'primary') ?? props.book.files[0] ?? null)
+const readableFiles = computed(() => props.book.files.filter((f) => f.format && f.format in FORMAT_TO_GROUP))
+const hasMultipleFiles = computed(() => readableFiles.value.length > 1)
 const authorLine = computed(() => props.book.authors.map((a) => a.name).join(', ') || null)
 const formats = computed(() => [...new Set(props.book.files.map((f) => f.format ?? '?'))])
 
@@ -302,11 +307,13 @@ function openBook() {
   })
 }
 
-function downloadFile() {
-  if (!primaryFile.value) return
-  const a = document.createElement('a')
-  a.href = `/api/v1/books/files/${primaryFile.value.id}/serve?download=1`
-  a.click()
+function openBookFile(file: BookDetail['files'][number]) {
+  readMenuOpen.value = false
+  router.push({
+    name: 'reader',
+    params: { bookId: props.book.id, fileId: file.id },
+    query: { format: file.format ?? 'epub' },
+  })
 }
 
 let supplementalRequestId = 0
@@ -444,7 +451,46 @@ watch(
         </div>
 
         <div class="mt-4 space-y-2">
+          <!-- Read button: split when multiple files, plain when single -->
+          <div v-if="hasMultipleFiles" class="flex w-full h-9 rounded-md overflow-hidden">
+            <button
+              class="flex flex-1 items-center justify-center gap-2 bg-primary text-primary-foreground text-sm font-medium hover:bg-primary/90 transition-colors disabled:opacity-50"
+              :disabled="!primaryFile"
+              @click="openBook"
+            >
+              <BookOpen class="size-4" />
+              Read
+            </button>
+            <div class="w-px bg-primary-foreground/20 shrink-0" />
+            <Popover :open="readMenuOpen" @update:open="(v) => (readMenuOpen = v)">
+              <PopoverTrigger as-child>
+                <button
+                  class="w-8 shrink-0 flex items-center justify-center bg-primary text-primary-foreground hover:bg-primary/90 transition-colors"
+                  title="Choose format"
+                >
+                  <ChevronDown class="size-3.5" />
+                </button>
+              </PopoverTrigger>
+              <PopoverContent class="w-52 p-1" align="end">
+                <button
+                  v-for="file in readableFiles"
+                  :key="file.id"
+                  class="flex w-full items-center gap-2.5 px-2 py-1.5 rounded text-sm hover:bg-muted transition-colors"
+                  @click="openBookFile(file)"
+                >
+                  <span
+                    class="text-[10px] font-bold uppercase tracking-wider px-1.5 py-0.5 rounded border shrink-0"
+                    :style="formatBadgeStyle(file.format ?? '?')"
+                    >{{ file.format ?? '?' }}</span
+                  >
+                  <span class="flex-1 text-left text-muted-foreground text-xs truncate">{{ formatFileSize(file.sizeBytes) }}</span>
+                  <span v-if="file.role === 'primary'" class="text-[10px] text-primary font-medium shrink-0">Primary</span>
+                </button>
+              </PopoverContent>
+            </Popover>
+          </div>
           <button
+            v-else
             class="flex w-full items-center justify-center gap-2 h-9 rounded-md bg-primary text-primary-foreground text-sm font-medium hover:bg-primary/90 transition-colors disabled:opacity-50"
             :disabled="!primaryFile"
             @click="openBook"
@@ -452,19 +498,11 @@ watch(
             <BookOpen class="size-4" />
             Read
           </button>
+
           <div class="flex gap-2">
-            <Tooltip>
-              <TooltipTrigger as-child>
-                <button
-                  class="flex flex-1 items-center justify-center h-9 rounded-md border border-input bg-background text-sm hover:bg-muted transition-colors disabled:opacity-50"
-                  :disabled="!primaryFile"
-                  @click="downloadFile"
-                >
-                  <Download class="size-3.5" />
-                </button>
-              </TooltipTrigger>
-              <TooltipContent>Download</TooltipContent>
-            </Tooltip>
+            <div class="flex-1">
+              <BookDownloadButton :files="book.files" :book-id="book.id" />
+            </div>
             <Tooltip>
               <TooltipTrigger as-child>
                 <button
diff --git a/client/src/features/book/components/detail/tabs/FilesTab.vue b/client/src/features/book/components/detail/tabs/FilesTab.vue
index 9dd3c8645..d2621e0f2 100644
--- a/client/src/features/book/components/detail/tabs/FilesTab.vue
+++ b/client/src/features/book/components/detail/tabs/FilesTab.vue
@@ -5,10 +5,13 @@ import { BookOpen, Download, Files, History } from 'lucide-vue-next'
 import type { BookDetail, BookDetailFile, WriteLogEntry } from '@projectx/types'
 import { Tooltip, TooltipContent, TooltipTrigger } from '@/components/ui/tooltip'
 import { api } from '@/lib/api'
+import { useBookDownload } from '@/features/book/composables/useBookDownload'
 
 const props = defineProps<{ book: BookDetail }>()
 const router = useRouter()
 
+const { downloadFile: downloadBookFile } = useBookDownload()
+
 const READABLE_FORMATS = new Set(['epub', 'pdf', 'cbz'])
 
 function formatBytes(bytes: number | null): string {
@@ -44,9 +47,7 @@ function openFile(file: BookDetailFile) {
 }
 
 function downloadFile(file: BookDetailFile) {
-  const a = document.createElement('a')
-  a.href = `/api/v1/books/files/${file.id}/serve?download=1`
-  a.click()
+  void downloadBookFile(file.id)
 }
 
 function fileIconBg(format: string | null): string {
diff --git a/client/src/features/book/composables/useBookBulkActions.ts b/client/src/features/book/composables/useBookBulkActions.ts
index 32ac19eb5..f93a6a321 100644
--- a/client/src/features/book/composables/useBookBulkActions.ts
+++ b/client/src/features/book/composables/useBookBulkActions.ts
@@ -3,10 +3,12 @@ import { api } from '@/lib/api'
 import { toast } from 'vue-sonner'
 import { useCoverVersions } from './useCoverVersions'
 import { useRefreshingBooks } from './useRefreshingBooks'
+import { useBookDownload } from './useBookDownload'
 
 export function useBookBulkActions(selectedIds: Ref<Set<number>>, onDeleted: (ids: number[]) => void) {
   const { bumpVersion } = useCoverVersions()
   const { markRefreshing, clearRefreshing } = useRefreshingBooks()
+  const { exportBooks } = useBookDownload()
 
   async function handleBulkRefreshMetadata() {
     const ids = [...selectedIds.value]
@@ -104,25 +106,7 @@ export function useBookBulkActions(selectedIds: Ref<Set<number>>, onDeleted: (id
 
   async function handleExport(allFormats: boolean) {
     const ids = [...selectedIds.value]
-    if (ids.length === 0) return
-    const toastId = toast.loading(`Preparing ${ids.length} book${ids.length === 1 ? '' : 's'} for download...`)
-    const res = await api('/api/v1/books/export', {
-      method: 'POST',
-      headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ bookIds: ids, allFormats }),
-    })
-    toast.dismiss(toastId)
-    if (!res.ok) {
-      toast.error('Export failed')
-      return
-    }
-    const blob = await res.blob()
-    const url = URL.createObjectURL(blob)
-    const a = document.createElement('a')
-    a.href = url
-    a.download = 'books.zip'
-    a.click()
-    URL.revokeObjectURL(url)
+    await exportBooks(ids, allFormats)
   }
 
   async function handleDeleteSelected() {
diff --git a/client/src/features/book/composables/useBookDownload.ts b/client/src/features/book/composables/useBookDownload.ts
new file mode 100644
index 000000000..3ba6f46c7
--- /dev/null
+++ b/client/src/features/book/composables/useBookDownload.ts
@@ -0,0 +1,65 @@
+import { ref } from 'vue'
+import { toast } from 'vue-sonner'
+import { api } from '@/lib/api'
+
+export function useBookDownload() {
+  const isDownloading = ref(false)
+
+  async function downloadFile(fileId: number): Promise<void> {
+    isDownloading.value = true
+    try {
+      const res = await api(`/api/v1/books/files/${fileId}/serve?download=1`)
+      if (!res.ok) {
+        toast.error('Download failed')
+        return
+      }
+      const disposition = res.headers.get('Content-Disposition') ?? ''
+      const match = disposition.match(/filename\*?=(?:UTF-8'')?["']?([^"';\r\n]+)["']?/i)
+      const filename = match?.[1] ? decodeURIComponent(match[1].trim()) : 'download'
+      const blob = await res.blob()
+      const url = URL.createObjectURL(blob)
+      const a = document.createElement('a')
+      a.href = url
+      a.download = filename
+      a.click()
+      URL.revokeObjectURL(url)
+    } catch {
+      toast.error('Download failed')
+    } finally {
+      isDownloading.value = false
+    }
+  }
+
+  async function exportBooks(bookIds: number[], allFormats: boolean): Promise<void> {
+    if (bookIds.length === 0) return
+    const label = `${bookIds.length} book${bookIds.length === 1 ? '' : 's'}`
+    const toastId = toast.loading(`Preparing ${label} for download...`)
+    isDownloading.value = true
+    try {
+      const res = await api('/api/v1/books/export', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ bookIds, allFormats }),
+      })
+      toast.dismiss(toastId)
+      if (!res.ok) {
+        toast.error('Export failed')
+        return
+      }
+      const blob = await res.blob()
+      const url = URL.createObjectURL(blob)
+      const a = document.createElement('a')
+      a.href = url
+      a.download = 'books.zip'
+      a.click()
+      URL.revokeObjectURL(url)
+    } catch {
+      toast.dismiss(toastId)
+      toast.error('Export failed')
+    } finally {
+      isDownloading.value = false
+    }
+  }
+
+  return { isDownloading, downloadFile, exportBooks }
+}