fix(health): address follow-up issues from health check system reviews (#3189)

* fix(health): use math.Inf(-1) for temperature max init

Fixes Forgejo #739. maxTemp was initialized to 0, so environments
with only negative sensor readings reported 0 instead of the actual
maximum temperature.

* fix(health): distinguish disabled health checks from no providers

Fixes Forgejo #741. When notification providers are configured but
health_check.enabled is false, the check now reports 'Notification
health checks disabled' instead of the misleading 'No notification
providers configured'.

* feat(health): add EntriesSince to ErrorRingBuffer

Returns cloned log entries with timestamps at or after a threshold.
Preparation for enriching health check error reporting with grouped
error details (Forgejo #736).

* feat(health): enrich log checks with grouped error details

When RecentErrorsCheck or ErrorTrendCheck reports warning/critical
status, the Details map now includes a top_errors array grouping
errors by (Component, Message), sorted by count, capped at 10.
Addresses Forgejo #736.

* i18n: add health check error detail labels for all 15 locales

New keys under health.logs: topErrors, errorCount, errorComponent,
errorLevel, errorMessage. Addresses Forgejo #736.

* feat(health): add expandable error details to log checks

Log-category health checks that report warning/critical status now
show an expandable row with grouped error patterns including
component, message, count, and level. Addresses Forgejo #736.

* fix(health): address gate review findings

- Replace inline SVG chevron with Lucide ChevronDown icon
- Add aria-expanded attribute to expandable buttons
- Wire up unused health.logs.topErrors i18n key as table heading
- Use slices.SortFunc instead of sort.Slice for consistency
- Preallocate EntriesSince result slice
- Remove unnecessary order slice in groupErrors

* fix(health): map error log level to error color, not warning

Gemini review: error-level log entries should use var(--color-error)
(red) for visual consistency. Also added explicit warn/warning cases.

Author: tphakala

frontend/src/lib/desktop/views/SystemHealth.svelte

@@ -14,6 +14,7 @@
     Clock,
     Loader2,
     Info,
+    ChevronDown,
   } from '@lucide/svelte';
   import { onMount } from 'svelte';
   import { t } from '$lib/i18n';
@@ -71,6 +72,45 @@
   let error = $state<string | null>(null);
   let copied = $state(false);
   let copyTimer: ReturnType<typeof setTimeout> | null = null;
+  let expandedChecks = $state(new Set<string>());
+
+  function toggleExpand(checkName: string) {
+    const next = new Set(expandedChecks);
+    if (next.has(checkName)) {
+      next.delete(checkName);
+    } else {
+      next.add(checkName);
+    }
+    expandedChecks = next;
+  }
+
+  interface ErrorGroup {
+    component?: string;
+    message: string;
+    count: number;
+    level: string;
+    sample_fields?: Record<string, unknown>;
+  }
+
+  function getTopErrors(result: DiagnosticsResult): ErrorGroup[] | null {
+    const topErrors = result.details?.top_errors;
+    if (!Array.isArray(topErrors) || topErrors.length === 0) return null;
+    return topErrors as ErrorGroup[];
+  }
+
+  function levelColor(level: string): string {
+    switch (level) {
+      case 'fatal':
+      case 'panic':
+      case 'error':
+        return 'var(--color-error)';
+      case 'warn':
+      case 'warning':
+        return 'var(--color-warning)';
+      default:
+        return 'var(--color-base-content)';
+    }
+  }
 
   onMount(() => {
     return () => {
@@ -338,27 +378,102 @@
       >
         <div class="space-y-2">
           {#each results as result (result.name)}
-            <div
-              class="flex items-center gap-3 px-3 py-2.5 rounded-lg bg-[var(--color-base-200)]/50"
-            >
-              <StatusPill
-                variant={statusToVariant(result.status)}
-                label={t(`health.status.${result.status}`)}
-                size="sm"
+            {@const topErrors = getTopErrors(result)}
+            {@const isExpandable =
+              topErrors !== null && (result.status === 'warning' || result.status === 'critical')}
+            {@const isExpanded = expandedChecks.has(result.name)}
+            <div>
+              <button
+                type="button"
+                class="flex items-center gap-3 w-full px-3 py-2.5 rounded-lg bg-[var(--color-base-200)]/50 text-left {isExpandable
+                  ? 'cursor-pointer hover:bg-[var(--color-base-200)]'
+                  : 'cursor-default'}"
+                onclick={() => isExpandable && toggleExpand(result.name)}
+                disabled={!isExpandable}
+                aria-expanded={isExpandable ? isExpanded : undefined}
               >
-                {#snippet leadingIcon()}
-                  {@render statusIcon(result.status, 'size-3.5')}
-                {/snippet}
-              </StatusPill>
-              <div class="flex-1 min-w-0">
-                <span class="text-sm font-medium">{formatCheckName(result.name)}</span>
-                <p class="text-xs text-[var(--color-base-content)] opacity-60 truncate">
-                  {result.message}
-                </p>
-              </div>
-              <span class="text-xs text-[var(--color-base-content)] opacity-40 shrink-0">
-                {result.duration_ms.toFixed(1)}ms
-              </span>
+                <StatusPill
+                  variant={statusToVariant(result.status)}
+                  label={t(`health.status.${result.status}`)}
+                  size="sm"
+                >
+                  {#snippet leadingIcon()}
+                    {@render statusIcon(result.status, 'size-3.5')}
+                  {/snippet}
+                </StatusPill>
+                <div class="flex-1 min-w-0">
+                  <span class="text-sm font-medium">{formatCheckName(result.name)}</span>
+                  <p class="text-xs text-[var(--color-base-content)] opacity-60 truncate">
+                    {result.message}
+                  </p>
+                </div>
+                <span class="text-xs text-[var(--color-base-content)] opacity-40 shrink-0">
+                  {result.duration_ms.toFixed(1)}ms
+                </span>
+                {#if isExpandable}
+                  <ChevronDown
+                    class="size-4 shrink-0 opacity-40 transition-transform {isExpanded
+                      ? 'rotate-180'
+                      : ''}"
+                  />
+                {/if}
+              </button>
+
+              {#if isExpanded && topErrors}
+                <div
+                  class="mt-1 ml-3 mr-3 mb-2 rounded-lg bg-[var(--color-base-200)]/30 overflow-hidden"
+                >
+                  <p
+                    class="px-3 py-1.5 text-xs font-medium text-[var(--color-base-content)] opacity-60"
+                  >
+                    {t('health.logs.topErrors')}
+                  </p>
+                  <table class="w-full text-xs">
+                    <thead>
+                      <tr
+                        class="text-left text-[var(--color-base-content)] opacity-50 border-b border-[var(--color-base-200)]"
+                      >
+                        <th class="px-3 py-1.5 font-medium">{t('health.logs.errorComponent')}</th>
+                        <th class="px-3 py-1.5 font-medium">{t('health.logs.errorMessage')}</th>
+                        <th class="px-3 py-1.5 font-medium text-right"
+                          >{t('health.logs.errorCount')}</th
+                        >
+                        <th class="px-3 py-1.5 font-medium">{t('health.logs.errorLevel')}</th>
+                      </tr>
+                    </thead>
+                    <tbody>
+                      {#each topErrors as group (group.component + ':' + group.message)}
+                        <tr class="border-b border-[var(--color-base-200)]/50 last:border-0">
+                          <td class="px-3 py-1.5">
+                            {#if group.component}
+                              <span
+                                class="inline-flex items-center px-1.5 py-0.5 rounded text-[10px] font-medium bg-[var(--color-base-300)] text-[var(--color-base-content)]"
+                              >
+                                {group.component}
+                              </span>
+                            {:else}
+                              <span class="opacity-30">-</span>
+                            {/if}
+                          </td>
+                          <td class="px-3 py-1.5 max-w-[300px] truncate" title={group.message}>
+                            {group.message}
+                          </td>
+                          <td class="px-3 py-1.5 text-right font-mono">{group.count}</td>
+                          <td class="px-3 py-1.5">
+                            <span
+                              class="inline-flex items-center px-1.5 py-0.5 rounded text-[10px] font-medium"
+                              style:color={levelColor(group.level)}
+                              style:background="color-mix(in srgb, {levelColor(group.level)} 10%, transparent)"
+                            >
+                              {group.level}
+                            </span>
+                          </td>
+                        </tr>
+                      {/each}
+                    </tbody>
+                  </table>
+                </div>
+              {/if}
             </div>
           {/each}
         </div>

frontend/static/messages/cs.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Nejčastější chyby",
+      "errorCount": "Počet",
+      "errorComponent": "Komponenta",
+      "errorLevel": "Úroveň",
+      "errorMessage": "Zpráva"
     }
   }
 }

frontend/static/messages/da.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Hyppigste fejl",
+      "errorCount": "Antal",
+      "errorComponent": "Komponent",
+      "errorLevel": "Niveau",
+      "errorMessage": "Besked"
     }
   }
 }

frontend/static/messages/de.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Häufigste Fehler",
+      "errorCount": "Anzahl",
+      "errorComponent": "Komponente",
+      "errorLevel": "Stufe",
+      "errorMessage": "Nachricht"
     }
   }
 }

frontend/static/messages/en.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Top error patterns",
+      "errorCount": "Count",
+      "errorComponent": "Component",
+      "errorLevel": "Level",
+      "errorMessage": "Message"
     }
   }
 }

frontend/static/messages/es.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Errores frecuentes",
+      "errorCount": "Cantidad",
+      "errorComponent": "Componente",
+      "errorLevel": "Nivel",
+      "errorMessage": "Mensaje"
     }
   }
 }

frontend/static/messages/fi.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Yleisimmät virheet",
+      "errorCount": "Lukumäärä",
+      "errorComponent": "Komponentti",
+      "errorLevel": "Taso",
+      "errorMessage": "Viesti"
     }
   }
 }

frontend/static/messages/fr.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Erreurs fréquentes",
+      "errorCount": "Nombre",
+      "errorComponent": "Composant",
+      "errorLevel": "Niveau",
+      "errorMessage": "Message"
     }
   }
 }

frontend/static/messages/hu.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Leggyakoribb hibák",
+      "errorCount": "Darab",
+      "errorComponent": "Komponens",
+      "errorLevel": "Szint",
+      "errorMessage": "Üzenet"
     }
   }
 }

frontend/static/messages/it.json

@@ -4818,6 +4818,13 @@
       "timeLabel": "Time",
       "durationLabel": "Duration",
       "checksLabel": "Checks"
+    },
+    "logs": {
+      "topErrors": "Errori frequenti",
+      "errorCount": "Conteggio",
+      "errorComponent": "Componente",
+      "errorLevel": "Livello",
+      "errorMessage": "Messaggio"
     }
   }
 }