// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package audit

import (
	"context"
	"io"

	"github.com/hashicorp/vault/sdk/logical"
)

// Formatter is an interface that is responsible for formatting a
// request/response into some format. Formatters write their output
// to an io.Writer.
//
// It is recommended that you pass data through Hash prior to formatting it.
type Formatter interface {
	FormatRequest(context.Context, io.Writer, FormatterConfig, *logical.LogInput) error
	FormatResponse(context.Context, io.Writer, FormatterConfig, *logical.LogInput) error
}

type FormatterConfig struct {
	Raw          bool
	HMACAccessor bool

	// Vault lacks pagination in its APIs. As a result, certain list operations can return **very** large responses.
	// The user's chosen audit sinks may experience difficulty consuming audit records that swell to tens of megabytes
	// of JSON. The responses of list operations are typically not very interesting, as they are mostly lists of keys,
	// or, even when they include a "key_info" field, are not returning confidential information. They become even less
	// interesting once HMAC-ed by the audit system.
	//
	// Some example Vault "list" operations that are prone to becoming very large in an active Vault installation are:
	//   auth/token/accessors/
	//   identity/entity/id/
	//   identity/entity-alias/id/
	//   pki/certs/
	//
	// This option exists to provide such users with the option to have response data elided from audit logs, only when
	// the operation type is "list". For added safety, the elision only applies to the "keys" and "key_info" fields
	// within the response data - these are conventionally the only fields present in a list response - see
	// logical.ListResponse, and logical.ListResponseWithInfo. However, other fields are technically possible if a
	// plugin author writes unusual code, and these will be preserved in the audit log even with this option enabled.
	// The elision replaces the values of the "keys" and "key_info" fields with an integer count of the number of
	// entries. This allows even the elided audit logs to still be useful for answering questions like
	// "Was any data returned?" or "How many records were listed?".
	ElideListResponses bool

	// This should only ever be used in a testing context
	OmitTime bool
}