fix blocking during scans

src/lib/comic-metadata.ts

@@ -3,7 +3,8 @@ import crypto from 'crypto'
 import type { Library, ImportedTag, TagMapping } from '@/types'
 import { getDb } from './db'
 import { resolveLibraryRoot } from './libraries'
-import { parseComicInfo } from './comic-info'
+import { parseComicInfoAsync } from './comic-info'
+import { mapConcurrent } from './zip-utils'
 
 // ─── Metadata Import ──────────────────────────────────────────────────────────
 
@@ -13,7 +14,7 @@ import { parseComicInfo } from './comic-info'
  * - For each tag: if a mapping exists, assigns the real tag; otherwise creates
  *   an imported tag entry.
  */
-export function importComicMetadata(library: Library): void {
+export async function importComicMetadata(library: Library): Promise<void> {
   const db = getDb()
   const libraryRoot = resolveLibraryRoot(library)
 
@@ -56,53 +57,65 @@ export function importComicMetadata(library: Library): void {
 
   let importedCount = 0
 
-  db.transaction(() => {
-    for (const issue of issues) {
-      const absPath = path.join(libraryRoot, issue.file_path)
-      const info = parseComicInfo(absPath)
-      if (!info) continue
+  // Process in batches: async file reads (10 concurrent) followed by batch DB writes,
+  // with an event-loop yield between batches to keep the app responsive.
+  const BATCH_SIZE = 50
+  for (let i = 0; i < issues.length; i += BATCH_SIZE) {
+    const batch = issues.slice(i, i + BATCH_SIZE)
 
-      // Merge with existing metadata JSON (preserve pageCount, coverUrl, etc.)
-      const existingMeta = issue.metadata ? JSON.parse(issue.metadata) : {}
-      const mergedMeta = {
-        ...existingMeta,
-        writer: info.writer,
-        publisher: info.publisher,
-        translator: info.translator,
-        web: info.web,
-        month: info.month,
-        day: info.day,
-      }
+    // Async: read ComicInfo.xml from each archive concurrently (10 at a time).
+    // Uses async ZIP central-directory reader — no full-file reads.
+    const infos = await mapConcurrent(batch, 10, (issue) =>
+      parseComicInfoAsync(path.join(libraryRoot, issue.file_path))
+    )
 
-      updateItem.run({
-        item_key: issue.item_key,
-        title: info.title ?? existingMeta.title ?? null,
-        year: info.year,
-        genres: info.genre,
-        metadata: JSON.stringify(mergedMeta),
-      })
+    // Sync: write this batch to the DB in one transaction.
+    db.transaction(() => {
+      for (let j = 0; j < batch.length; j++) {
+        const issue = batch[j]
+        const info = infos[j]
+        if (!info) continue
 
-      // Process tags
-      for (const tagName of info.tags) {
-        const mappedTagId = mappings.get(tagName)
-        if (mappedTagId) {
-          // Mapping exists — assign the real tag
-          addMediaTag.run(issue.item_key, mappedTagId)
-        } else {
-          // No mapping — create imported tag
-          const importedTagId = crypto.randomUUID()
-          const row = upsertImportedTag.get({
-            id: importedTagId,
-            library_id: library.id,
-            name: tagName,
-          }) as { id: string }
-          addItemImportedTag.run(issue.item_key, row.id)
+        const existingMeta = issue.metadata ? JSON.parse(issue.metadata) : {}
+        const mergedMeta = {
+          ...existingMeta,
+          writer: info.writer,
+          publisher: info.publisher,
+          translator: info.translator,
+          web: info.web,
+          month: info.month,
+          day: info.day,
         }
-      }
 
-      importedCount++
-    }
-  })()
+        updateItem.run({
+          item_key: issue.item_key,
+          title: info.title ?? existingMeta.title ?? null,
+          year: info.year,
+          genres: info.genre,
+          metadata: JSON.stringify(mergedMeta),
+        })
+
+        for (const tagName of info.tags) {
+          const mappedTagId = mappings.get(tagName)
+          if (mappedTagId) {
+            addMediaTag.run(issue.item_key, mappedTagId)
+          } else {
+            const importedTagId = crypto.randomUUID()
+            const row = upsertImportedTag.get({
+              id: importedTagId,
+              library_id: library.id,
+              name: tagName,
+            }) as { id: string }
+            addItemImportedTag.run(issue.item_key, row.id)
+          }
+        }
+
+        importedCount++
+      }
+    })()
+
+    await new Promise<void>((r) => setImmediate(r))
+  }
 
   console.log(`[comic-metadata] Imported metadata for ${importedCount}/${issues.length} issues in "${library.name}"`)
 }