Initial Nuxt data explorer setup

nuxt4-app/server/services/query-parser.ts

@@ -0,0 +1,53 @@
+import type { ParsedQuery, QueryFilter } from '../data-sources/types'
+
+function isValidFilter(filter: Partial<QueryFilter>): filter is QueryFilter {
+  return typeof filter.field === 'string' && filter.field.length > 0 && filter.value !== undefined
+}
+
+function decodeBase64Url(value: string) {
+  const normalized = value.replace(/-/g, '+').replace(/_/g, '/')
+  const paddingNeeded = (4 - (normalized.length % 4)) % 4
+  const padded = normalized + '='.repeat(paddingNeeded)
+  return Buffer.from(padded, 'base64').toString('utf-8')
+}
+
+export function parseQuerySegment(segment?: string | string[]): ParsedQuery | null {
+  if (!segment) {
+    return null
+  }
+
+  const value = Array.isArray(segment) ? segment[0] : segment
+
+  try {
+    const decoded = decodeBase64Url(value)
+    const parsed = JSON.parse(decoded)
+
+    const result: ParsedQuery = {
+      filters: []
+    }
+
+    if (Array.isArray(parsed.filters)) {
+      result.filters = parsed.filters.filter(isValidFilter)
+    }
+
+    if (parsed.limit && Number.isInteger(parsed.limit) && parsed.limit > 0) {
+      result.limit = Math.min(parsed.limit, 500)
+    }
+
+    if (parsed.offset && Number.isInteger(parsed.offset) && parsed.offset >= 0) {
+      result.offset = parsed.offset
+    }
+
+    if (parsed.orderBy && typeof parsed.orderBy.field === 'string') {
+      result.orderBy = {
+        field: parsed.orderBy.field,
+        ascending: parsed.orderBy.ascending !== false
+      }
+    }
+
+    return result
+  } catch (error) {
+    console.warn('Failed to parse query segment', error)
+    return null
+  }
+}