Dereference remote replies (#132)

* decided where to put reply dereferencing

* fiddling with dereferencing threads

* further adventures

* tidy up some stuff

* move dereferencing functionality

* a bunch of refactoring

* go fmt

* more refactoring

* bleep bloop

* docs and linting

* start implementing replies collection on gts side

* fiddling around

* allow dereferencing our replies

* lint, fmt

1 files changed, 144 insertions, 1 deletions

diff --git a/internal/typeutils/internaltoas.go b/internal/typeutils/internaltoas.go
index b24b07e13..333f131d4 100644
--- a/internal/typeutils/internaltoas.go
+++ b/internal/typeutils/internaltoas.go
@@ -27,6 +27,7 @@ import (
 	"github.com/go-fed/activity/streams"
 	"github.com/go-fed/activity/streams/vocab"
 	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
 )
 
@@ -505,7 +506,14 @@ func (c *converter) StatusToAS(s *gtsmodel.Status) (vocab.ActivityStreamsNote, e
 	status.SetActivityStreamsAttachment(attachmentProp)
 
 	// replies
-	// TODO
+	repliesCollection, err := c.StatusToASRepliesCollection(s, false)
+	if err != nil {
+		return nil, fmt.Errorf("error creating repliesCollection: %s", err)
+	}
+
+	repliesProp := streams.NewActivityStreamsRepliesProperty()
+	repliesProp.SetActivityStreamsCollection(repliesCollection)
+	status.SetActivityStreamsReplies(repliesProp)
 
 	return status, nil
 }
@@ -850,3 +858,138 @@ func (c *converter) BlockToAS(b *gtsmodel.Block) (vocab.ActivityStreamsBlock, er
 
 	return block, nil
 }
+
+/*
+	the goal is to end up with something like this:
+
+	{
+		"@context": "https://www.w3.org/ns/activitystreams",
+		"id": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies",
+		"type": "Collection",
+		"first": {
+		"id": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies?page=true",
+		"type": "CollectionPage",
+		"next": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies?only_other_accounts=true&page=true",
+		"partOf": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies",
+		"items": []
+		}
+	}
+*/
+func (c *converter) StatusToASRepliesCollection(status *gtsmodel.Status, onlyOtherAccounts bool) (vocab.ActivityStreamsCollection, error) {
+	collectionID := fmt.Sprintf("%s/replies", status.URI)
+	collectionIDURI, err := url.Parse(collectionID)
+	if err != nil {
+		return nil, err
+	}
+
+	collection := streams.NewActivityStreamsCollection()
+
+	// collection.id
+	collectionIDProp := streams.NewJSONLDIdProperty()
+	collectionIDProp.SetIRI(collectionIDURI)
+	collection.SetJSONLDId(collectionIDProp)
+
+	// first
+	first := streams.NewActivityStreamsFirstProperty()
+	firstPage := streams.NewActivityStreamsCollectionPage()
+
+	// first.id
+	firstPageIDProp := streams.NewJSONLDIdProperty()
+	firstPageID, err := url.Parse(fmt.Sprintf("%s?page=true", collectionID))
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	firstPageIDProp.SetIRI(firstPageID)
+	firstPage.SetJSONLDId(firstPageIDProp)
+
+	// first.next
+	nextProp := streams.NewActivityStreamsNextProperty()
+	nextPropID, err := url.Parse(fmt.Sprintf("%s?only_other_accounts=%t&page=true", collectionID, onlyOtherAccounts))
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	nextProp.SetIRI(nextPropID)
+	firstPage.SetActivityStreamsNext(nextProp)
+
+	// first.partOf
+	partOfProp := streams.NewActivityStreamsPartOfProperty()
+	partOfProp.SetIRI(collectionIDURI)
+	firstPage.SetActivityStreamsPartOf(partOfProp)
+
+	first.SetActivityStreamsCollectionPage(firstPage)
+
+	// collection.first
+	collection.SetActivityStreamsFirst(first)
+
+	return collection, nil
+}
+
+/*
+	the goal is to end up with something like this:
+	{
+		"@context": "https://www.w3.org/ns/activitystreams",
+		"id": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies?only_other_accounts=true&page=true",
+		"type": "CollectionPage",
+		"next": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies?min_id=106720870266901180&only_other_accounts=true&page=true",
+		"partOf": "https://example.org/users/whatever/statuses/01FCNEXAGAKPEX1J7VJRPJP490/replies",
+		"items": [
+			"https://example.com/users/someone/statuses/106720752853216226",
+			"https://somewhere.online/users/eeeeeeeeeep/statuses/106720870163727231"
+		]
+	}
+*/
+func (c *converter) StatusURIsToASRepliesPage(status *gtsmodel.Status, onlyOtherAccounts bool, minID string, replies map[string]*url.URL) (vocab.ActivityStreamsCollectionPage, error) {
+	collectionID := fmt.Sprintf("%s/replies", status.URI)
+
+	page := streams.NewActivityStreamsCollectionPage()
+
+	// .id
+	pageIDProp := streams.NewJSONLDIdProperty()
+	pageIDString := fmt.Sprintf("%s?page=true&only_other_accounts=%t", collectionID, onlyOtherAccounts)
+	if minID != "" {
+		pageIDString = fmt.Sprintf("%s&min_id=%s", pageIDString, minID)
+	}
+
+	pageID, err := url.Parse(pageIDString)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	pageIDProp.SetIRI(pageID)
+	page.SetJSONLDId(pageIDProp)
+
+	// .partOf
+	collectionIDURI, err := url.Parse(collectionID)
+	if err != nil {
+		return nil, err
+	}
+	partOfProp := streams.NewActivityStreamsPartOfProperty()
+	partOfProp.SetIRI(collectionIDURI)
+	page.SetActivityStreamsPartOf(partOfProp)
+
+	// .items
+	items := streams.NewActivityStreamsItemsProperty()
+	var highestID string
+	for k, v := range replies {
+		items.AppendIRI(v)
+		if k > highestID {
+			highestID = k
+		}
+	}
+	page.SetActivityStreamsItems(items)
+
+	// .next
+	nextProp := streams.NewActivityStreamsNextProperty()
+	nextPropIDString := fmt.Sprintf("%s?only_other_accounts=%t&page=true", collectionID, onlyOtherAccounts)
+	if highestID != "" {
+		nextPropIDString = fmt.Sprintf("%s&min_id=%s", nextPropIDString, highestID)
+	}
+
+	nextPropID, err := url.Parse(nextPropIDString)
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(err)
+	}
+	nextProp.SetIRI(nextPropID)
+	page.SetActivityStreamsNext(nextProp)
+
+	return page, nil
+}