package domain

import (
	"strings"
	"testing"
)

func TestNormalizeSessionID(t *testing.T) {
	tests := []struct {
		name    string
		raw     string
		want    string
		wantErr bool
	}{
		{
			name: "trims surrounding Unicode whitespace",
			raw:  "\u2003 session-123 \u2003",
			want: "session-123",
		},
		{
			name: "blank input is omitted",
			raw:  " \t\u2003 ",
			want: "",
		},
		{
			name: "maximum Unicode length is accepted",
			raw:  strings.Repeat("界", SessionIDMaxLength),
			want: strings.Repeat("界", SessionIDMaxLength),
		},
		{
			name:    "one Unicode code point over maximum is rejected",
			raw:     strings.Repeat("界", SessionIDMaxLength+1),
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := NormalizeSessionID(tt.raw)
			if tt.wantErr {
				if err == nil {
					t.Fatal("expected normalization error")
				}
				if !strings.Contains(err.Error(), "exceeds maximum") {
					t.Fatalf("expected useful length diagnostic, got %v", err)
				}
				return
			}
			if err != nil {
				t.Fatalf("normalize session id: %v", err)
			}
			if got != tt.want {
				t.Fatalf("normalized session id = %q, want %q", got, tt.want)
			}
		})
	}
}