[feature] Implement `/api/v2/instance` endpoint (#1409)

* interim: start adding /api/v2/instance

* finish up

1 files changed, 189 insertions, 0 deletions

diff --git a/internal/api/model/instancev2.go b/internal/api/model/instancev2.go
new file mode 100644
index 000000000..df69eeffe
--- /dev/null
+++ b/internal/api/model/instancev2.go
@@ -0,0 +1,189 @@
+/*
+   GoToSocial
+   Copyright (C) 2021-2023 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package model
+
+// InstanceV2 models information about this instance.
+//
+// swagger:model instanceV2
+type InstanceV2 struct {
+	// The domain of the instance.
+	// example: gts.example.org
+	Domain string `json:"domain"`
+	// The domain of accounts on this instance.
+	// This will not necessarily be the same as
+	// domain.
+	// example: example.org
+	AccountDomain string `json:"account_domain"`
+	// The title of the instance.
+	// example: GoToSocial Example Instance
+	Title string `json:"title"`
+	// The version of GoToSocial installed on the instance.
+	//
+	// This will contain at least a semantic version number.
+	//
+	// It may also contain, after a space, the short git commit ID of the running software.
+	//
+	// example: 0.1.1 cb85f65
+	Version string `json:"version"`
+	// The URL for the source code of the software running on this instance, in keeping with AGPL license requirements.
+	// example: https://github.com/superseriousbusiness/gotosocial
+	SourceURL string `json:"source_url"`
+	// Description of the instance.
+	//
+	// Should be HTML formatted, but might be plaintext.
+	//
+	// This should be displayed on the 'about' page for an instance.
+	Description string `json:"description"`
+	// Basic anonymous usage data for this instance.
+	Usage InstanceV2Usage `json:"usage"`
+	// An image used to represent this instance.
+	Thumbnail InstanceV2Thumbnail `json:"thumbnail"`
+	// Primary languages of the instance + moderators/admins.
+	// example: ["en"]
+	Languages []string `json:"languages"`
+	// Configured values and limits for this instance.
+	Configuration InstanceV2Configuration `json:"configuration"`
+	// Information about registering for this instance.
+	Registrations InstanceV2Registrations `json:"registrations"`
+	//  Hints related to contacting a representative of the instance.
+	Contact InstanceV2Contact `json:"contact"`
+	// An itemized list of rules for this website.
+	// Currently not implemented (will always be empty array).
+	Rules []interface{} `json:"rules"`
+}
+
+// Usage data for this instance.
+//
+// swagger:model instanceV2Usage
+type InstanceV2Usage struct {
+	Users InstanceV2Users `json:"users"`
+}
+
+// Usage data related to users on this instance.
+//
+// swagger:model instanceV2Users
+type InstanceV2Users struct {
+	// The number of active users in the past 4 weeks.
+	// Currently not implemented: will always be 0.
+	// example: 0
+	ActiveMonth int `json:"active_month"`
+}
+
+// An image used to represent this instance.
+//
+// swagger:model instanceV2Thumbnail
+type InstanceV2Thumbnail struct {
+	// The URL for the thumbnail image.
+	// example: https://example.org/fileserver/01BPSX2MKCRVMD4YN4D71G9CP5/attachment/original/01H88X0KQ2DFYYDSWYP93VDJZA.png
+	URL string `json:"url"`
+	// MIME type of the instance thumbnail.
+	// Key/value not set if thumbnail image type unknown.
+	// example: image/png
+	Type string `json:"thumbnail_type,omitempty"`
+	// Description of the instance thumbnail.
+	// Key/value not set if no description available.
+	// example: picture of a cute lil' friendly sloth
+	Description string `json:"thumbnail_description,omitempty"`
+	// A hash computed by the BlurHash algorithm, for generating colorful preview thumbnails when media has not been downloaded yet.
+	// Key/value not set if no blurhash available.
+	// example: UeKUpFxuo~R%0nW;WCnhF6RjaJt757oJodS$
+	Blurhash string `json:"blurhash,omitempty"`
+	// Links to scaled resolution images, for high DPI screens.
+	// Key/value not set if no extra versions available.
+	Versions *InstanceV2ThumbnailVersions `json:"versions,omitempty"`
+}
+
+// Links to scaled resolution images, for high DPI screens.
+//
+// swagger:model instanceV2ThumbnailVersions
+type InstanceV2ThumbnailVersions struct {
+	// The URL for the thumbnail image at 1x resolution.
+	// Key/value not set if scaled versions not available.
+	Size1URL string `json:"@1x,omitempty"`
+	// The URL for the thumbnail image at 2x resolution.
+	// Key/value not set if scaled versions not available.
+	Size2URL string `json:"@2x,omitempty"`
+}
+
+// InstanceV2URLs models instance-relevant URLs for client application consumption.
+//
+// swagger:model instanceV1URLs
+type InstanceV2URLs struct {
+	// Websockets address for status and notification streaming.
+	// example: wss://example.org
+	Streaming string `json:"streaming"`
+}
+
+// Hints related to translation.
+//
+// swagger:model instanceV2ConfigurationTranslation
+type InstanceV2ConfigurationTranslation struct {
+	// Whether the Translations API is available on this instance.
+	// Not implemented so this value is always false.
+	Enabled bool `json:"enabled"`
+}
+
+// Configured values and limits for this instance.
+//
+// swagger:model instanceV2Configuration
+type InstanceV2Configuration struct {
+	// URLs of interest for clients apps.
+	URLs InstanceV2URLs `json:"urls"`
+	// Limits related to accounts.
+	Accounts InstanceConfigurationAccounts `json:"accounts"`
+	// Limits related to authoring statuses.
+	Statuses InstanceConfigurationStatuses `json:"statuses"`
+	// Hints for which attachments will be accepted.
+	MediaAttachments InstanceConfigurationMediaAttachments `json:"media_attachments"`
+	// Limits related to polls.
+	Polls InstanceConfigurationPolls `json:"polls"`
+	// Hints related to translation.
+	Translation InstanceV2ConfigurationTranslation `json:"translation"`
+	// Instance configuration pertaining to emojis.
+	Emojis InstanceConfigurationEmojis `json:"emojis"`
+}
+
+// Information about registering for this instance.
+//
+// swagger:model instanceV2Registrations
+type InstanceV2Registrations struct {
+	// Whether registrations are enabled.
+	// example: false
+	Enabled bool `json:"enabled"`
+	// Whether registrations require moderator approval.
+	// example: true
+	ApprovalRequired bool `json:"approval_required"`
+	// A custom message (html string) to be shown when registrations are closed.
+	// Value will be null if no message is set.
+	// example: <p>Registrations are currently closed on example.org because of spam bots!</p>
+	Message *string `json:"message"`
+}
+
+// Hints related to contacting a representative of the instance.
+//
+// swagger:model instanceV2Contact
+type InstanceV2Contact struct {
+	// An email address that can be messaged regarding inquiries or issues.
+	// Empty string if no email address set.
+	// example: someone@example.org
+	Email string `json:"email"`
+	// An account that can be contacted regarding inquiries or issues.
+	// Key/value not present if no contact account set.
+	Account *Account `json:"account,omitempty"`
+}