// plugin definition as above

async function factory(manager) {
  await manager.register('query', queryPlugin(manager))
}

function queryPlugin(manager) {
  return {
    name: 'acmeQuery',
    order: 1,
    // Get simple text search from plugin
    // entry is the database entry
    textFn(entry) {
      return entry.plugin.acme?.value || ''
    },
    // Transform ther query AST before filter and sort function
    transformRules: [
      {
        transform(ast, queryContext) {
          return ast
        }
      }
    ],
    // Add plugin filter or sort functions from query AST
    queryHandler(ast, queryContext) {
      // Create filter on acme keyword in condition to support 'acme = value' or 'acme:value'
      if (ast.type == 'cmp' && ast.key == 'acme' && ast.op == '=') {
        ast.filter = (entry) => {
          return entry.plugin?.acme?.value == ast?.value?.value
        }
        // The ast node could be handled. Return true to prevent further chain calls
        return true
      }

      // Create custom sort key 'order by acme'
      if (ast.type == 'orderKey' && ast.value == 'acme') {
        ast.scoreFn = e => e.plugin.acme.created || '0000-00-00'
        ast.direction = 'desc'
        return true
      }

      // Check ast and return if ast node can be resolved
      return false
    }
  }
}