package service

import (
	"errors"
	"testing"
)

func TestGenerate16CharSecure(t *testing.T) {
	for i := 0; i < 100; i++ {
		code := Generate16CharSecure()
		if len(code) != cdkCodeLength {
			t.Fatalf("expected code length %d, got %d", cdkCodeLength, len(code))
		}

		for _, ch := range code {
			if !containsRune(charsetWithSymbol, ch) {
				t.Fatalf("unexpected character %q in code %q", ch, code)
			}
		}
	}
}

func TestBuildUniqueCodesSkipsDuplicatesAndExisting(t *testing.T) {
	sequence := []string{
		"DUPLICATE-000001",
		"DUPLICATE-000001",
		"EXISTING-000001",
		"VALID-000000001",
		"VALID-000000002",
		"VALID-000000003",
		"VALID-000000004",
		"VALID-000000005",
		"VALID-000000006",
	}
	index := 0

	codes, err := buildUniqueCodes(3, func() (string, error) {
		if index >= len(sequence) {
			return "", errors.New("generator exhausted")
		}
		code := sequence[index]
		index++
		return code, nil
	}, func(candidates []string) (map[string]struct{}, error) {
		return map[string]struct{}{
			"EXISTING-000001": {},
		}, nil
	})
	if err != nil {
		t.Fatalf("buildUniqueCodes returned error: %v", err)
	}

	if len(codes) != 3 {
		t.Fatalf("expected 3 codes, got %d", len(codes))
	}

	want := []string{
		"VALID-000000001",
		"VALID-000000002",
		"VALID-000000003",
	}
	for i, code := range want {
		if codes[i] != code {
			t.Fatalf("expected code %q at index %d, got %q", code, i, codes[i])
		}
	}
}

func containsRune(value string, target rune) bool {
	for _, ch := range value {
		if ch == target {
			return true
		}
	}
	return false
}