package auth

import (
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestGeneratePairingToken_Format(t *testing.T) {
	tok, err := GeneratePairingToken()
	require.NoError(t, err)

	assert.True(t, IsValidPairingToken(tok), "產生的 token 應符合 pairing 正則：got %q", tok)
	assert.Len(t, tok, len(PairingTokenPrefix)+PairingTokenHexLen)
}

func TestGenerateSessionToken_Format(t *testing.T) {
	tok, err := GenerateSessionToken()
	require.NoError(t, err)

	assert.True(t, IsValidSessionToken(tok), "產生的 token 應符合 session 正則：got %q", tok)
	assert.Len(t, tok, len(SessionTokenPrefix)+SessionTokenHexLen)
}

func TestGeneratePairingToken_Unique(t *testing.T) {
	// 產生 100 次應不會碰撞（熵極低）。
	seen := make(map[string]struct{}, 100)
	for i := 0; i < 100; i++ {
		tok, err := GeneratePairingToken()
		require.NoError(t, err)
		_, dup := seen[tok]
		require.False(t, dup, "pairing token 不應重複產生：%s", tok)
		seen[tok] = struct{}{}
	}
}

func TestIsValidPairingToken(t *testing.T) {
	cases := []struct {
		name  string
		token string
		valid bool
	}{
		{"正確格式", "vAc_0123456789abcdef0123456789abcdef", true},
		{"大寫 hex 不允許", "vAc_0123456789ABCDEF0123456789ABCDEF", false},
		{"前綴錯誤", "vAs_0123456789abcdef0123456789abcdef", false},
		{"長度太短", "vAc_0123456789abcdef", false},
		{"長度太長", "vAc_0123456789abcdef0123456789abcdef00", false},
		{"含非 hex 字元", "vAc_0123456789abcdef0123456789abcdeZ0", false},
		{"空字串", "", false},
		{"僅前綴", "vAc_", false},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			assert.Equal(t, tc.valid, IsValidPairingToken(tc.token))
		})
	}
}

func TestIsValidSessionToken(t *testing.T) {
	goodSession := "vAs_" + "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"
	assert.True(t, IsValidSessionToken(goodSession))
	assert.False(t, IsValidSessionToken("vAs_short"))
	assert.False(t, IsValidSessionToken("vAc_0123456789abcdef0123456789abcdef"))
}

func TestHashToken_Deterministic(t *testing.T) {
	h1 := HashToken("vAc_abc")
	h2 := HashToken("vAc_abc")
	assert.Equal(t, h1, h2, "同樣輸入應得同樣 hash")
	assert.NotEqual(t, HashToken("vAc_abc"), HashToken("vAc_def"))
	assert.Len(t, h1, 64, "sha256 hex 長度應為 64")
}