Return next set of query arguments

src/api/lib.zig

@@ -54,6 +54,7 @@ pub const NoteResponse = struct {
 };
 
 pub const CommunityQueryArgs = services.communities.QueryArgs;
+pub const CommunityQueryResult = services.communities.QueryResult;
 
 pub fn isAdminSetup(db: sql.Db) !bool {
     _ = services.communities.adminCommunityId(db) catch |err| switch (err) {
@@ -339,9 +340,9 @@ fn ApiConn(comptime DbConn: type) type {
             };
         }
 
-        pub fn queryCommunities(self: *Self, args: services.communities.QueryArgs) ![]services.communities.Community {
+        pub fn queryCommunities(self: *Self, args: services.communities.QueryArgs) !CommunityQueryResult {
             if (!self.isAdmin()) return error.PermissionDenied;
-            return services.communities.query(self.db, args, self.arena.allocator());
+            return try services.communities.query(self.db, args, self.arena.allocator());
         }
     };
 }

src/api/services/communities.zig

@@ -168,6 +168,7 @@ pub const QueryArgs = struct {
     };
 
     pub const Prev = std.meta.Child(std.meta.fieldInfo(QueryArgs, .prev).field_type);
+    pub const OrderVal = std.meta.fieldInfo(Prev, .order_val).field_type;
 
     // Max items to fetch
     max_items: usize = 20,
@@ -203,6 +204,13 @@ pub const QueryArgs = struct {
     page_direction: PageDirection = .forward,
 };
 
+pub const QueryResult = struct {
+    items: []const Community,
+
+    prev_page: QueryArgs,
+    next_page: QueryArgs,
+};
+
 const QueryBuilder = struct {
     array: std.ArrayList(u8),
     where_clauses_appended: usize = 0,
@@ -237,7 +245,7 @@ pub const QueryError = error{
 // Retrieves up to `args.max_items` Community entries matching the given query
 // arguments.
 // `args.max_items` is only a request, and fewer entries may be returned.
-pub fn query(db: anytype, args: QueryArgs, alloc: std.mem.Allocator) ![]Community {
+pub fn query(db: anytype, args: QueryArgs, alloc: std.mem.Allocator) !QueryResult {
     var builder = QueryBuilder.init(alloc);
     defer builder.deinit();
 
@@ -318,7 +326,38 @@ pub fn query(db: anytype, args: QueryArgs, alloc: std.mem.Allocator) ![]Communit
         count += 1;
     }
 
-    return result_buf[0..count];
+    var next_page = args;
+    var prev_page = args;
+    prev_page.page_direction = .backward;
+    next_page.page_direction = .forward;
+    if (count != 0) {
+        prev_page.prev = .{
+            .id = result_buf[0].id,
+            .order_val = getOrderVal(result_buf[0], args.order_by),
+        };
+
+        next_page.prev = .{
+            .id = result_buf[count - 1].id,
+            .order_val = getOrderVal(result_buf[count - 1], args.order_by),
+        };
+    } else {
+        prev_page.prev = null;
+    }
+
+    return QueryResult{
+        .items = result_buf[0..count],
+
+        .next_page = next_page,
+        .prev_page = prev_page,
+    };
+}
+
+fn getOrderVal(community: Community, order_val: QueryArgs.OrderBy) QueryArgs.OrderVal {
+    return switch (order_val) {
+        .name => .{ .name = community.name },
+        .host => .{ .host = community.host },
+        .created_at => .{ .created_at = community.created_at },
+    };
 }
 
 pub fn adminCommunityId(db: anytype) !Uuid {

src/util/DateTime.zig

@@ -76,7 +76,7 @@ pub fn isAfter(lhs: DateTime, rhs: DateTime) bool {
 }
 
 pub fn epochSeconds(value: DateTime) std.time.epoch.EpochSeconds {
-    return .{ .secs = @intCast(u64, value.seconds_since_epoch) };
+    return .{ .secs = std.math.cast(u64, value.seconds_since_epoch) orelse 0 };
 }
 
 pub fn year(value: DateTime) std.time.epoch.Year {