/*
Copyright The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package flag

import (
	"crypto/tls"
	"reflect"
	"testing"
)

func TestTLSCurvePreferences(t *testing.T) {
	tests := []struct {
		name        string
		input       []int32
		expected    []tls.CurveID
		expectError bool
	}{
		{
			name:     "multiple curves",
			input:    []int32{23, 24, 29},
			expected: []tls.CurveID{tls.CurveP256, tls.CurveP384, tls.X25519},
		},
		{
			name:     "single curve",
			input:    []int32{29},
			expected: []tls.CurveID{tls.X25519},
		},
		{
			name:     "empty input",
			input:    []int32{},
			expected: nil,
		},
		{
			name:     "nil input",
			input:    nil,
			expected: nil,
		},
		{
			name:     "all standard curves",
			input:    []int32{23, 24, 25, 29, 4588},
			expected: []tls.CurveID{tls.CurveP256, tls.CurveP384, tls.CurveP521, tls.X25519, tls.X25519MLKEM768},
		},
		{
			name:        "duplicate curve",
			input:       []int32{23, 29, 23},
			expectError: true,
		},
		{
			name:        "zero value",
			input:       []int32{0},
			expectError: true,
		},
		{
			name:        "negative value",
			input:       []int32{-1},
			expectError: true,
		},
		{
			name:        "exceeds uint16 range",
			input:       []int32{70000},
			expectError: true,
		},
		{
			name:        "unknown curve ID",
			input:       []int32{9999},
			expectError: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got, err := TLSCurvePreferences(tt.input)
			if tt.expectError {
				if err == nil {
					t.Errorf("TLSCurvePreferences(%v) expected error, got nil", tt.input)
				}
				return
			}
			if err != nil {
				t.Errorf("TLSCurvePreferences(%v) unexpected error: %v", tt.input, err)
				return
			}
			if !reflect.DeepEqual(got, tt.expected) {
				t.Errorf("TLSCurvePreferences(%v) = %v, want %v", tt.input, got, tt.expected)
			}
		})
	}
}