goap/parser.go

package goap

import (
	"fmt"
	"slices"

	"github.com/piprate/json-gold/ld"
)

// Internal so that others don't mess with this and potentially accidentally overwrite it, breaking everything
var allInternalParsersExceptBase []UnmarshalFunc = []UnmarshalFunc{
	ParseUDIdData,
	ParseUDTypeData,
	ParseASActorData,
	ParseASAlsoKnownAsData,
	ParseASAttachmentsData,
	ParseASAttributedToData,
	ParseASCCData,
	ParseASContentData,
	ParseASEndpointsData,
	ParseASFollowersData,
	ParseASFollowingData,
	ParseASHrefData,
	ParseASIconData,
	ParseASImageData,
	ParseASMediaTypeData,
	ParseASNameData,
	ParseASOutboxData,
	ParseASObjectData,
	ParseASPreferredNameData,
	ParseASPublishedData,
	ParseASRestrictedData,
	ParseASRepliesData,
	ParseASSharedInboxData,
	ParseASSummaryData,
	ParseASSensitiveData,
	ParseASTagData,
	ParseASToData,
	ParseASUrlData,
	ParseASUpdatedData,

	ParseOstatusAtomUriData,
	ParseOstatusConversationData,

	ParseW3InboxData,

	ParseW3VcardAddressData,
	ParseW3VcardBirthdayData,

	ParseW3SecurityOwnerData,
	ParseW3SecurityPublicKeyPemData,
	ParseW3SecurityPublicKeyData,

	ParseMastoDevicesData,
	ParseMastoDiscoverableData,
	ParseMastoFeaturedData,
	ParseMastoDiscoverableData,
	ParseMastoIndexableData,
	ParseMastoMemorialData,

	ParseSchemaValueData,

	ParseMKIsCatData,
	ParseMKSummaryData,

	ParseFFSpeakAsCatData,
}

func chainParse(
	raw map[string]any,
	start BaseApChain,
	parsers ...UnmarshalFunc,
) (BaseApChain, []error) {
	var current BaseApChain = start
	errors := []error{}

	for _, p := range parsers {
		next, err := p(raw, current)
		current = next
		errors = append(errors, err)
	}

	return current, errors
}

// Unmarshal raw data into an Activitypub object in the form of a recursive BaseApChain
// Each element corresponds to one attribute the object contained
// If ldOptions or processor are nil, the following defaults are used:
// - ldOptions: `ld.NewJsonLdOptions("")`
// - processor: `ld.NewJsonLdProcessor()`
// Returns an ActivityPub object and a list of errors produced by the parser functions
// Not each function has to produce an error. Those will have nil as error value
// Those errors (or nils) come in the order of the parser functions
// which can be inspected in the `allInternalParsersExceptBase` internal variable
func Unmarshal(
	raw []byte,
	ldOptions *ld.JsonLdOptions,
	processor *ld.JsonLdProcessor,
	extraParsers ...UnmarshalFunc,
) (BaseApChain, []error) {
	if ldOptions == nil {
		ldOptions = ld.NewJsonLdOptions("")
	}
	if processor == nil {
		processor = ld.NewJsonLdProcessor()
	}
	rawData, err := processor.Expand(raw, ldOptions)
	if err != nil {
		return nil, []error{err}
	}
	data, ok := rawData[0].(map[string]any)
	if !ok {
		return nil, []error{fmt.Errorf("failed to cast expand result into map[string]any")}
	}
	return UnmarshalPreprocessed(data, extraParsers...)
}

// Unmarshal a preproccessed object. Preproccessed meaning being first parsed as json and then expanded by json-gold
// Otherwise the same as Unmarshal
func UnmarshalPreprocessed(
	raw map[string]any,
	extraParsers ...UnmarshalFunc,
) (BaseApChain, []error) {
	base := EmptyBaseObject{}
	allParsers := slices.Concat(allInternalParsersExceptBase, extraParsers)
	return chainParse(raw, &base, allParsers...)
}

// Find an attribute in an ActivityPub object of the given type
// Returns a pointer to the found attribute and whether it found it
// 2nd parameter is true if the attribute was found, false otherwise
func FindAttribute[T BaseApChain](object BaseApChain) (*T, bool) {
	var obj T
	var ok bool
	// Try and cast object into wanted type
	// If cast failed, do inner codeblock
	// Try and cast again
	for obj, ok = object.(T); !ok; obj, ok = object.(T) {
		// Get the next attribute in the chain
		object, ok = object.GetSelfOrBase()
		// If this is the final object in the chain, cancel and return false
		if !ok {
			return nil, false
		}
	}
	return &obj, true
}