From 328b962572e4decb5280541c6d01495af440799d Mon Sep 17 00:00:00 2001
From: Adam Malczewski <github@tradam.dev>
Date: Fri, 10 Apr 2026 00:13:45 +0900
Subject: better debug info

---
 src/lib/cache/imageCache.ts          | 27 +++++++++++++++--
 src/lib/components/CacheDebug.svelte | 59 ++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 3 deletions(-)

diff --git a/src/lib/cache/imageCache.ts b/src/lib/cache/imageCache.ts
index 2326974..5ff7393 100644
--- a/src/lib/cache/imageCache.ts
+++ b/src/lib/cache/imageCache.ts
@@ -109,6 +109,10 @@ async function idbGet(key: CacheKey): Promise<StoredRecord | undefined> {
   });
 }
 
+/** Last write error (if any) — exposed via getStats() for diagnostics. */
+let lastWriteError: string | undefined;
+let writeErrorCount = 0;
+
 /** Write a record to IndexedDB (best-effort). */
 async function idbPut(record: StoredRecord): Promise<void> {
   const db = await openDb();
@@ -119,9 +123,22 @@ async function idbPut(record: StoredRecord): Promise<void> {
       const tx = db.transaction(STORE_NAME, 'readwrite');
       const store = tx.objectStore(STORE_NAME);
       store.put(record);
-      tx.oncomplete = () => resolve();
-      tx.onerror = () => resolve();
-    } catch {
+      tx.oncomplete = () => {
+        lastWriteError = undefined;
+        resolve();
+      };
+      tx.onerror = () => {
+        const msg = tx.error?.message ?? 'unknown write error';
+        lastWriteError = msg;
+        writeErrorCount++;
+        console.warn(`[imageCache] IDB write failed: ${msg}`);
+        resolve();
+      };
+    } catch (e) {
+      const msg = e instanceof Error ? e.message : String(e);
+      lastWriteError = msg;
+      writeErrorCount++;
+      console.warn(`[imageCache] IDB write exception: ${msg}`);
       resolve();
     }
   });
@@ -280,6 +297,8 @@ export const imageCache = {
     idbEntries: number;
     idbBytes: number;
     idbError: string | undefined;
+    idbLastWriteError: string | undefined;
+    idbWriteErrorCount: number;
   }> {
     let fullCount = 0;
     let thumbCount = 0;
@@ -332,6 +351,8 @@ export const imageCache = {
       idbEntries,
       idbBytes,
       idbError,
+      idbLastWriteError: lastWriteError,
+      idbWriteErrorCount: writeErrorCount,
     };
   },
 
diff --git a/src/lib/components/CacheDebug.svelte b/src/lib/components/CacheDebug.svelte
index 293ff62..09e859d 100644
--- a/src/lib/components/CacheDebug.svelte
+++ b/src/lib/components/CacheDebug.svelte
@@ -9,6 +9,8 @@
     idbEntries: number;
     idbBytes: number;
     idbError: string | undefined;
+    idbLastWriteError: string | undefined;
+    idbWriteErrorCount: number;
   }
 
   let stats = $state<CacheStats | undefined>(undefined);
@@ -24,11 +26,44 @@
     return `${val.toFixed(1)} ${sizes[i]}`;
   }
 
+  let storageEstimate = $state<{ usage: number; quota: number } | undefined>(undefined);
+  let storageError = $state<string | undefined>(undefined);
+
   async function refresh() {
     refreshing = true;
     try {
       stats = await imageCache.getStats();
     } catch { /* ignore */ }
+
+    // Try standard Storage API first, then webkit fallback
+    storageEstimate = undefined;
+    storageError = undefined;
+    try {
+      if (navigator.storage && navigator.storage.estimate) {
+        const est = await navigator.storage.estimate();
+        storageEstimate = { usage: est.usage ?? 0, quota: est.quota ?? 0 };
+      } else if ('webkitTemporaryStorage' in navigator) {
+        // Chrome HTTP fallback
+        const wk = (navigator as Record<string, unknown>)['webkitTemporaryStorage'] as
+          { queryUsageAndQuota: (ok: (u: number, q: number) => void, err: (e: unknown) => void) => void } | undefined;
+        if (wk !== undefined) {
+          const result = await new Promise<{ usage: number; quota: number }>((resolve, reject) => {
+            wk.queryUsageAndQuota(
+              (usage, quota) => resolve({ usage, quota }),
+              (err) => reject(err),
+            );
+          });
+          storageEstimate = result;
+        } else {
+          storageError = 'Storage API not available (HTTP origin)';
+        }
+      } else {
+        storageError = 'Storage API not available';
+      }
+    } catch (e) {
+      storageError = e instanceof Error ? e.message : String(e);
+    }
+
     refreshing = false;
   }
 
@@ -65,6 +100,12 @@
         {:else}
           <div>Entries: <span class="text-info">{stats.idbEntries}</span></div>
           <div>Size: <span class="text-info">{formatBytes(stats.idbBytes)}</span></div>
+          {#if stats.idbWriteErrorCount > 0}
+            <div class="text-error mt-1">❌ {stats.idbWriteErrorCount} write errors</div>
+            {#if stats.idbLastWriteError !== undefined}
+              <div class="text-error text-[10px] break-all">{stats.idbLastWriteError}</div>
+            {/if}
+          {/if}
           <div class="mt-1">
             {#if stats.idbEntries === stats.entries}
               <span class="text-success">✅ In sync with memory</span>
@@ -76,6 +117,24 @@
           </div>
         {/if}
       </div>
+      <!-- Storage Quota -->
+      <div class="border-t border-base-300 pt-2">
+        <div class="font-semibold text-accent">Storage Quota</div>
+        {#if storageEstimate !== undefined}
+          <div>Used: <span class="text-info">{formatBytes(storageEstimate.usage)}</span> / {formatBytes(storageEstimate.quota)}</div>
+          {#if storageEstimate.quota > 0}
+            {@const pct = (storageEstimate.usage / storageEstimate.quota * 100)}
+            <div>
+              <progress class="progress progress-primary w-full h-2" value={pct} max="100"></progress>
+              <span class:text-error={pct > 90} class:text-warning={pct > 70 && pct <= 90}>{pct.toFixed(1)}%</span>
+            </div>
+          {/if}
+        {:else if storageError !== undefined}
+          <div class="text-warning">{storageError}</div>
+        {:else}
+          <div class="text-base-content/50">Querying…</div>
+        {/if}
+      </div>
     </div>
   {:else if !collapsed}
     <div class="text-base-content/50">
-- 
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