Feat/boost

apps/backend/db/migrations/20260608_add_post_boosts.down.sql

@@ -0,0 +1,4 @@
+DROP INDEX IF EXISTS idx_posts_unique_pure_boost;
+DROP INDEX IF EXISTS idx_posts_reference;
+ALTER TABLE posts DROP CONSTRAINT IF EXISTS posts_reference_not_self;
+ALTER TABLE posts DROP COLUMN IF EXISTS reference_id;

apps/backend/db/migrations/20260608_add_post_boosts.up.sql

@@ -0,0 +1,18 @@
+-- Add reference_id column for boosts/quotes
+ALTER TABLE posts
+    ADD COLUMN reference_id UUID REFERENCES posts(id) ON DELETE SET NULL;
+
+-- Prevent self-reference
+ALTER TABLE posts
+    ADD CONSTRAINT posts_reference_not_self
+    CHECK (reference_id IS NULL OR reference_id <> id);
+
+-- Index for counting boosts of a post
+CREATE INDEX idx_posts_reference
+    ON posts(reference_id)
+    WHERE reference_id IS NOT NULL AND deleted_at IS NULL;
+
+-- Prevent duplicate pure boosts (same user boosting same post with no content)
+CREATE UNIQUE INDEX idx_posts_unique_pure_boost
+    ON posts(user_id, reference_id)
+    WHERE reference_id IS NOT NULL AND content = '' AND deleted_at IS NULL;

apps/backend/db/queries.sql

@@ -225,9 +225,9 @@ DELETE FROM users
 WHERE id = $1;
 
 -- name: CreatePost :one
-INSERT INTO posts (user_id, content, parent_id, root_id)
-VALUES ($1, $2, sqlc.narg('parent_id'), sqlc.narg('root_id'))
-RETURNING id, user_id, content, parent_id, root_id, created_at, deleted_at;
+INSERT INTO posts (user_id, content, parent_id, root_id, reference_id)
+VALUES ($1, $2, sqlc.narg('parent_id'), sqlc.narg('root_id'), sqlc.narg('reference_id'))
+RETURNING id, user_id, content, parent_id, root_id, reference_id, created_at, deleted_at;
 
 -- name: GetPostWithAuthorByID :one
 SELECT
@@ -236,6 +236,7 @@ SELECT
 	p.content,
 	p.parent_id,
 	p.root_id,
+	p.reference_id,
 	p.created_at,
 	p.deleted_at,
 	u.username,
@@ -255,7 +256,7 @@ FROM posts
 WHERE id = $1;
 
 -- name: GetPostThreadInfoByID :one
-SELECT id, parent_id, root_id, deleted_at
+SELECT id, parent_id, root_id, reference_id, deleted_at
 FROM posts
 WHERE id = $1;
 
@@ -266,6 +267,7 @@ SELECT
 	p.content,
 	p.parent_id,
 	p.root_id,
+	p.reference_id,
 	p.created_at,
 	p.deleted_at,
 	u.username,
@@ -310,6 +312,7 @@ SELECT
 	child.content,
 	child.parent_id,
 	child.root_id,
+	child.reference_id,
 	child.created_at,
 	child.deleted_at,
 	child.username,
@@ -327,6 +330,7 @@ JOIN LATERAL (
 		p.content,
 		p.parent_id,
 		p.root_id,
+		p.reference_id,
 		p.created_at,
 		p.deleted_at,
 		u.username,
@@ -478,6 +482,7 @@ SELECT
 	p.content,
 	p.parent_id,
 	p.root_id,
+	p.reference_id,
 	p.created_at,
 	p.deleted_at,
 	u.username,
@@ -505,6 +510,7 @@ SELECT
 	p.content,
 	p.parent_id,
 	p.root_id,
+	p.reference_id,
 	p.created_at,
 	p.deleted_at,
 	u.username,
@@ -576,6 +582,7 @@ SELECT
 	p.content,
 	p.parent_id,
 	p.root_id,
+	p.reference_id,
 	p.created_at,
 	p.deleted_at,
 	u.username,
@@ -1603,3 +1610,12 @@ LIMIT $1 OFFSET $2;
 
 -- name: CountCustomEmojis :one
 SELECT COUNT(*) FROM custom_emojis;
+
+-- ==================== Post Boosts ====================
+
+-- name: CountBoostsByPostIDs :many
+SELECT reference_id, COUNT(*)::int AS boost_count
+FROM posts
+WHERE reference_id = ANY($1::uuid[])
+  AND deleted_at IS NULL
+GROUP BY reference_id;

apps/backend/db/schema.sql

@@ -86,14 +86,16 @@ CREATE TABLE IF NOT EXISTS posts (
   content TEXT NOT NULL,
   parent_id UUID REFERENCES posts(id) ON DELETE SET NULL,
   root_id UUID REFERENCES posts(id) ON DELETE SET NULL,
+  reference_id UUID REFERENCES posts(id) ON DELETE SET NULL,
   created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
   deleted_at TIMESTAMPTZ NULL,
   visibility TEXT NOT NULL DEFAULT 'public',
   deleted_by UUID REFERENCES users(id) ON DELETE SET NULL,
   deletion_reason TEXT,
   CHECK (visibility IN ('public', 'hidden', 'deleted')),
   CHECK (parent_id IS NULL OR parent_id <> id),
-  CHECK (root_id IS NULL OR root_id <> id)
+  CHECK (root_id IS NULL OR root_id <> id),
+  CHECK (reference_id IS NULL OR reference_id <> id)
 );
 
 -- Uploaded media (images and videos). Images stored as WebP, videos as MP4.
@@ -154,6 +156,8 @@ CREATE INDEX IF NOT EXISTS idx_posts_user_created ON posts (user_id, created_at
 CREATE INDEX IF NOT EXISTS idx_posts_parent ON posts(parent_id) WHERE parent_id IS NOT NULL;
 CREATE INDEX IF NOT EXISTS idx_posts_parent_created ON posts(parent_id, created_at ASC, id ASC) WHERE parent_id IS NOT NULL AND deleted_at IS NULL;
 CREATE INDEX IF NOT EXISTS idx_posts_root ON posts(root_id) WHERE root_id IS NOT NULL;
+CREATE INDEX IF NOT EXISTS idx_posts_reference ON posts(reference_id) WHERE reference_id IS NOT NULL AND deleted_at IS NULL;
+CREATE UNIQUE INDEX IF NOT EXISTS idx_posts_unique_pure_boost ON posts(user_id, reference_id) WHERE reference_id IS NOT NULL AND content = '' AND deleted_at IS NULL;
 
 CREATE TABLE IF NOT EXISTS post_mentions (
   post_id UUID NOT NULL REFERENCES posts(id) ON DELETE CASCADE,

apps/backend/internal/service/mentions.go

@@ -1,6 +1,10 @@
 package service
 
-import "regexp"
+import (
+	"regexp"
+
+	"github.com/google/uuid"
+)
 
 // MaxMentionsPerPost caps the number of usernames extracted from a single post body.
 // Mentions beyond this limit are silently dropped to prevent abuse.
@@ -11,6 +15,29 @@ const MaxMentionsPerPost = 50
 // alphanumeric plus underscore, 3 to 32 characters.
 var mentionPattern = regexp.MustCompile(`(^|[^a-zA-Z0-9_])@([a-zA-Z0-9_]{3,32})`)
 
+// postURLPattern matches any http(s) URL with a /posts/{uuid} path.
+var postURLPattern = regexp.MustCompile(
+	`https?://[^\s/]+(?:/[^\s/]+)*/posts/([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12})`,
+)
+
+// ExtractPostReference extracts the first post UUID referenced by a URL in content.
+// It matches any http(s) URL containing /posts/{uuid} regardless of domain,
+// so it works when frontend and backend are on different hosts.
+func ExtractPostReference(content string) *uuid.UUID {
+	if content == "" {
+		return nil
+	}
+	m := postURLPattern.FindStringSubmatch(content)
+	if m == nil {
+		return nil
+	}
+	id, err := uuid.Parse(m[1])
+	if err != nil {
+		return nil
+	}
+	return &id
+}
+
 // ExtractMentions returns up to cap unique usernames mentioned in content.
 // The order of the returned slice matches the first-occurrence order in content.
 // Comparison is case-sensitive — ciel usernames are stored case-sensitively.

apps/backend/internal/service/mentions_test.go

@@ -4,6 +4,8 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+
+	"github.com/google/uuid"
 )
 
 func TestExtractMentions(t *testing.T) {
@@ -131,6 +133,85 @@ func TestExtractMentions(t *testing.T) {
 	}
 }
 
+func TestExtractPostReference(t *testing.T) {
+	t.Parallel()
+
+	validID := uuid.MustParse("550e8400-e29b-41d4-a716-446655440000")
+
+	tests := []struct {
+		name    string
+		content string
+		want    *uuid.UUID
+	}{
+		{
+			name:    "empty content",
+			content: "",
+			want:    nil,
+		},
+		{
+			name:    "no URL",
+			content: "just a normal post",
+			want:    nil,
+		},
+		{
+			name:    "unrelated URL",
+			content: "check out https://example.com/foo",
+			want:    nil,
+		},
+		{
+			name:    "valid post URL",
+			content: "look at this https://example.com/posts/" + validID.String(),
+			want:    &validID,
+		},
+		{
+			name:    "different domain",
+			content: "see https://other-frontend.example.org/posts/" + validID.String(),
+			want:    &validID,
+		},
+		{
+			name:    "with subpath",
+			content: "https://example.com/app/posts/" + validID.String(),
+			want:    &validID,
+		},
+		{
+			name:    "post URL in middle of text",
+			content: "I saw https://example.com/posts/" + validID.String() + " and it was great",
+			want:    &validID,
+		},
+		{
+			name:    "multiple post URLs returns first",
+			content: "https://a.com/posts/" + validID.String() + " and https://b.com/posts/00000000-0000-0000-0000-000000000001",
+			want:    &validID,
+		},
+		{
+			name:    "invalid UUID format",
+			content: "https://example.com/posts/not-a-uuid",
+			want:    nil,
+		},
+		{
+			name:    "path without scheme",
+			content: "/posts/" + validID.String(),
+			want:    nil,
+		},
+		{
+			name:    "http scheme",
+			content: "http://localhost:3000/posts/" + validID.String(),
+			want:    &validID,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ExtractPostReference(tt.content)
+			if tt.want == nil && got != nil {
+				t.Errorf("ExtractPostReference(%q) = %v, want nil", tt.content, got)
+			} else if tt.want != nil && (got == nil || *got != *tt.want) {
+				t.Errorf("ExtractPostReference(%q) = %v, want %v", tt.content, got, tt.want)
+			}
+		})
+	}
+}
+
 func TestExtractMentions_MaxMentionsPerPostCap(t *testing.T) {
 	t.Parallel()