List all users in the system (fixes #373)

Signed-off-by: AnErrupTion <anerruption@disroot.org>

src/tui/components/UserList.zig

@@ -0,0 +1,45 @@
+const std = @import("std");
+const TerminalBuffer = @import("../TerminalBuffer.zig");
+const generic = @import("generic.zig");
+
+const StringList = std.ArrayListUnmanaged([]const u8);
+const Allocator = std.mem.Allocator;
+
+const UsernameText = generic.CyclableLabel([]const u8);
+
+const UserList = @This();
+
+label: UsernameText,
+
+pub fn init(allocator: Allocator, buffer: *TerminalBuffer, usernames: StringList) !UserList {
+    var userList = UserList{
+        .label = UsernameText.init(allocator, buffer, drawItem),
+    };
+
+    for (usernames.items) |username| {
+        if (username.len == 0) continue;
+
+        try userList.label.addItem(username);
+    }
+
+    return userList;
+}
+
+pub fn deinit(self: *UserList) void {
+    self.label.deinit();
+}
+
+pub fn getCurrentUser(self: UserList) []const u8 {
+    return self.label.list.items[self.label.current];
+}
+
+fn drawItem(label: *UsernameText, username: []const u8, _: usize, _: usize) bool {
+    const length = @min(username.len, label.visible_length - 3);
+    if (length == 0) return false;
+
+    const x = if (label.text_in_center) (label.x + (label.visible_length - username.len) / 2) else (label.x + 2);
+    label.first_char_x = x + username.len;
+
+    label.buffer.drawLabel(username, x, label.y);
+    return true;
+}