package vote

import (
	"testing"
)

// TestAppendUniqueValue 钉住多选字段的去重语义：
// 客户端重复提交同一选项时，落库与统计都只能算一次。
func TestAppendUniqueValue(t *testing.T) {
	t.Run("重复值只保留第一次", func(t *testing.T) {
		seen := map[string]bool{}
		var got []string
		for _, v := range []string{"A", "A", "B", "A", "B", "C"} {
			got = appendUniqueValue(got, seen, v)
		}
		want := []string{"A", "B", "C"}
		if len(got) != len(want) {
			t.Fatalf("got %v, want %v", got, want)
		}
		for i := range want {
			if got[i] != want[i] {
				t.Fatalf("got %v, want %v（顺序应按首次出现）", got, want)
			}
		}
	})

	t.Run("空切片与单值", func(t *testing.T) {
		seen := map[string]bool{}
		var got []string
		got = appendUniqueValue(got, seen, "只有一项")
		if len(got) != 1 || got[0] != "只有一项" {
			t.Fatalf("got %v", got)
		}
	})

	t.Run("seen 复用时跨批次仍然去重", func(t *testing.T) {
		// checkbox 的「其他」文本与预置值走同一条追加路径，
		// seen 必须在整个字段解析期间共享，而不是每轮新建。
		seen := map[string]bool{}
		var got []string
		got = appendUniqueValue(got, seen, "预置")
		got = appendUniqueValue(got, seen, "其他文本")
		got = appendUniqueValue(got, seen, "预置")
		if len(got) != 2 {
			t.Fatalf("got %v, want 2 项", got)
		}
	})
}