package provider

import (
	"fmt"
	"regexp"
	"testing"

	"k8s.io/apimachinery/pkg/types"
)

var nameRegexp = regexp.MustCompile(`^proxy-[a-z2-7]{16}$`)

func TestNameFromUID_idempotent(t *testing.T) {
	t.Parallel()
	uid := types.UID("f47ac10b-58cc-4372-a567-0e02b2c3d479")
	got1 := NameFromUID(uid)
	got2 := NameFromUID(uid)
	if got1 != got2 {
		t.Errorf("NameFromUID(%q) is not idempotent: %q != %q", uid, got1, got2)
	}
}

func TestNameFromUID_charsetAndLength(t *testing.T) {
	t.Parallel()
	tests := []types.UID{
		"f47ac10b-58cc-4372-a567-0e02b2c3d479",
		"",
		"a",
		"00000000-0000-0000-0000-000000000000",
		"ffffffff-ffff-ffff-ffff-ffffffffffff",
	}
	for _, uid := range tests {
		t.Run(string(uid), func(t *testing.T) {
			t.Parallel()
			name := NameFromUID(uid)
			if !nameRegexp.MatchString(name) {
				t.Errorf("NameFromUID(%q) = %q, does not match %s", uid, name, nameRegexp)
			}
			if len(name) > 63 {
				t.Errorf("NameFromUID(%q) = %q, length %d exceeds GCP's 63-char limit", uid, name, len(name))
			}
			if len(name) != len(namePrefix)+16 {
				t.Errorf("NameFromUID(%q) = %q, length %d, want %d", uid, name, len(name), len(namePrefix)+16)
			}
		})
	}
}

func TestNameFromUID_distinctAcrossFleet(t *testing.T) {
	t.Parallel()
	const n = 10000
	seen := make(map[string]types.UID, n)
	for i := range n {
		uid := types.UID(fmt.Sprintf("00000000-0000-0000-0000-%012d", i))
		name := NameFromUID(uid)
		if prior, ok := seen[name]; ok {
			t.Fatalf("collision: NameFromUID(%q) == NameFromUID(%q) == %q", uid, prior, name)
		}
		seen[name] = uid
	}
}