import type { Db } from '../db/client.ts'
import { auditLog } from '../db/schema.ts'

interface AuditEntry {
  organizationId: string
  actorId: string | null
  entityType: string
  entityId: string
  action: string
  changes?: Record<string, unknown> | null
}

export async function audit(db: Db, entry: AuditEntry): Promise<void> {
  await db.insert(auditLog).values({ ...entry, changes: entry.changes ?? null })
}

const comparable = (value: unknown) => (value instanceof Date ? value.toISOString() : (value ?? null))

/** `{ field: [before, after] }` for each field in `next` whose value differs from `current`. */
export function diff(current: Record<string, unknown>, next: Record<string, unknown>): Record<string, [unknown, unknown]> {
  const changes: Record<string, [unknown, unknown]> = {}
  for (const [key, value] of Object.entries(next)) {
    if (value === undefined) continue
    const before = comparable(current[key])
    const after = comparable(value)
    if (JSON.stringify(before) !== JSON.stringify(after)) changes[key] = [before, after]
  }
  return changes
}