[feature] Public list of suspended domains (#1362)

* basic rendered domain blocklist (unauthenticated!)

* style basic domain block list

* better formatting for domain blocklist

* add opt-in config option for showing suspended domains

* format/linter

* re-use InstancePeersGet for web-accessible domain blocklist

* reword explanation, border styling

* always attach blocklist handler, update error message

* domain blocklist error message grammar

4 files changed, 132 insertions, 48 deletions

diff --git a/web/source/css/_colors.css b/web/source/css/_colors.css
index 13a75c9f5..6d4b056b8 100644
--- a/web/source/css/_colors.css
+++ b/web/source/css/_colors.css
@@ -114,6 +114,6 @@ $settings-nav-bg-active: $gray2;
 $error-fg: $error1;
 $error-bg: $error2;
 
-$settings-entry-bg: $gray2;
-$settings-entry-alternate-bg: $gray3;
-$settings-entry-hover-bg: $gray4;
\ No newline at end of file
+$list-entry-bg: $gray2;
+$list-entry-alternate-bg: $gray3;
+$list-entry-hover-bg: $gray4;
\ No newline at end of file
diff --git a/web/source/css/base.css b/web/source/css/base.css
index ef7eb2e36..9289f18f8 100644
--- a/web/source/css/base.css
+++ b/web/source/css/base.css
@@ -413,4 +413,80 @@ label {
 	text-overflow: ellipsis;
 	overflow: hidden;
 	white-space: nowrap;
+}
+
+.list {
+	display: flex;
+	flex-direction: column;
+
+	&.scrolling {
+		max-height: 40rem;
+		overflow: auto;
+	}
+
+	.header, .entry {
+		padding: 0.5rem;
+	}
+
+	.header {
+		border: 0.1rem solid transparent !important; /* for alignment with .entry border padding */
+		background: $gray1 !important;
+		display: flex;
+		font-weight: bold;
+	}
+
+	input[type=checkbox] {
+		margin-left: 0.5rem;
+	}
+
+	.entry {
+		display: flex;
+		flex-wrap: wrap;
+		background: $list-entry-bg;
+		border: 0.1rem solid transparent;
+
+		&:nth-child(even) {
+			background: $list-entry-alternate-bg;
+		}
+	
+		&:hover {
+			background: $list-entry-hover-bg;
+		}
+	
+		&:active, &:focus, &:hover, &:target {
+			border-color: $fg-accent;
+		}
+	}
+}
+
+.domain-blocklist {
+	box-shadow: $boxshadow;
+
+	.entry {
+		display: grid;
+		grid-template-columns: 15rem 1fr;
+		gap: 0.5rem;
+		align-items: start;
+		border: $boxshadow-border;
+		border-top-color: transparent;
+
+		& > div {
+			display: flex;
+			align-items: center
+		}
+
+		.domain a {
+			font-weight: bold;
+			text-decoration: none;
+			display: inline-block; /* so it wraps properly */
+		}
+
+		.public_comment p {
+			margin: 0;
+		}
+	}
+
+	.header .domain {
+		color: $fg;
+	}
 }
\ No newline at end of file
diff --git a/web/source/settings/style.css b/web/source/settings/style.css
index 2d569759f..745021418 100644
--- a/web/source/settings/style.css
+++ b/web/source/settings/style.css
@@ -368,49 +368,6 @@ span.form-info {
 	font-weight: initial;
 }
 
-.list {
-	display: flex;
-	flex-direction: column;
-
-	&.scrolling {
-		max-height: 40rem;
-		overflow: auto;
-	}
-
-	.header, .entry {
-		padding: 0.5rem;
-	}
-
-	.header {
-		border: 0.1rem solid transparent; /* for alignment with .entry border padding */
-		background: $gray2;
-		display: flex;
-	}
-
-	input[type=checkbox] {
-		margin-left: 0.5rem;
-	}
-
-	.entry {
-		display: flex;
-		flex-wrap: wrap;
-		background: $settings-entry-bg;
-		border: 0.1rem solid transparent;
-
-		&:nth-child(even) {
-			background: $settings-entry-alternate-bg;
-		}
-	
-		&:hover {
-			background: $settings-entry-hover-bg;
-		}
-	
-		&:active, &:focus, &:hover {
-			border-color: $fg-accent;
-		}
-	}
-}
-
 .checkbox-list {
 	.header, .entry {
 		gap: 1rem;
@@ -446,7 +403,7 @@ span.form-info {
 }
 
 .emoji-list {
-	background: $settings-entry-bg;
+	background: $list-entry-bg;
 
 	.entry {
 		flex-direction: column;
@@ -472,7 +429,7 @@ span.form-info {
 				}
 
 				&:hover {
-					background: $settings-entry-hover-bg;
+					background: $list-entry-hover-bg;
 				}
 			}
 		}
diff --git a/web/template/domain-blocklist.tmpl b/web/template/domain-blocklist.tmpl
new file mode 100644
index 000000000..5e8a19491
--- /dev/null
+++ b/web/template/domain-blocklist.tmpl
@@ -0,0 +1,51 @@
+{{- /*
+	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/>.
+*/ -}}
+
+{{ template "header.tmpl" .}}
+<main>
+	<section>
+		<h1>Suspended Instances</h1>
+		<p>
+			The following list of domains have been suspended by the administrator(s) of this server.
+		</p>
+		<p>
+			All current and future accounts on these instances are blocked, and no more data is federated to the remote
+			servers.
+			This extends to subdomains, so an entry for 'example.com' includes 'social.example.com' as well.
+		</p>
+		<div class="list domain-blocklist">
+			<div class="header entry">
+				<div class="domain">Domain</div>
+				<div class="public_comment">Public comment</div>
+			</div>
+			{{range .blocklist}}
+			<div class="entry" id="{{.Domain}}">
+				<div class="domain">
+					<a class="text-cutoff" href="#{{.Domain}}" title="{{.Domain}}">{{.Domain}}</a>
+				</div>
+				<div class="public_comment">
+					<p>
+						{{.PublicComment}}
+					</p>
+				</div>
+			</div>
+			{{end}}
+		</div>
+	</section>
+</main>
+{{ template "footer.tmpl" .}}
\ No newline at end of file