package csrf

import (
	"testing"

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

// go test -run -v Test_normalizeOrigin
func Test_normalizeOrigin(t *testing.T) {
	t.Parallel()

	testCases := []struct {
		origin         string
		expectedOrigin string
		expectedValid  bool
	}{
		{origin: "http://example.com", expectedValid: true, expectedOrigin: "http://example.com"},                       // Simple case should work.
		{origin: "HTTP://EXAMPLE.COM", expectedValid: true, expectedOrigin: "http://example.com"},                       // Case should be normalized.
		{origin: "http://example.com/", expectedValid: true, expectedOrigin: "http://example.com"},                      // Trailing slash should be removed.
		{origin: "http://example.com:3000", expectedValid: true, expectedOrigin: "http://example.com:3000"},             // Port should be preserved.
		{origin: "http://example.com:3000/", expectedValid: true, expectedOrigin: "http://example.com:3000"},            // Trailing slash should be removed.
		{origin: "http://", expectedValid: false, expectedOrigin: ""},                                                   // Invalid origin should not be accepted.
		{origin: "file:///etc/passwd", expectedValid: false, expectedOrigin: ""},                                        // File scheme should not be accepted.
		{origin: "https://*example.com", expectedValid: false, expectedOrigin: ""},                                      // Wildcard domain should not be accepted.
		{origin: "http://*.example.com", expectedValid: false, expectedOrigin: ""},                                      // Wildcard subdomain should not be accepted.
		{origin: "http://example.com/path", expectedValid: false, expectedOrigin: ""},                                   // Path should not be accepted.
		{origin: "http://example.com?query=123", expectedValid: false, expectedOrigin: ""},                              // Query should not be accepted.
		{origin: "http://example.com#fragment", expectedValid: false, expectedOrigin: ""},                               // Fragment should not be accepted.
		{origin: "http://user:pass@example.com", expectedValid: false, expectedOrigin: ""},                              // Userinfo should not be accepted.
		{origin: "http://localhost", expectedValid: true, expectedOrigin: "http://localhost"},                           // Localhost should be accepted.
		{origin: "http://127.0.0.1", expectedValid: true, expectedOrigin: "http://127.0.0.1"},                           // IPv4 address should be accepted.
		{origin: "http://[::1]", expectedValid: true, expectedOrigin: "http://[::1]"},                                   // IPv6 address should be accepted.
		{origin: "http://[::1]:8080", expectedValid: true, expectedOrigin: "http://[::1]:8080"},                         // IPv6 address with port should be accepted.
		{origin: "http://[::1]:8080/", expectedValid: true, expectedOrigin: "http://[::1]:8080"},                        // IPv6 address with port and trailing slash should be accepted.
		{origin: "http://[::1]:8080/path", expectedValid: false, expectedOrigin: ""},                                    // IPv6 address with port and path should not be accepted.
		{origin: "http://[::1]:8080?query=123", expectedValid: false, expectedOrigin: ""},                               // IPv6 address with port and query should not be accepted.
		{origin: "http://[::1]:8080#fragment", expectedValid: false, expectedOrigin: ""},                                // IPv6 address with port and fragment should not be accepted.
		{origin: "http://[::1]:8080/path?query=123#fragment", expectedValid: false, expectedOrigin: ""},                 // IPv6 address with port, path, query, and fragment should not be accepted.
		{origin: "http://[::1]:8080/path?query=123#fragment/", expectedValid: false, expectedOrigin: ""},                // IPv6 address with port, path, query, fragment, and trailing slash should not be accepted.
		{origin: "http://[::1]:8080/path?query=123#fragment/invalid", expectedValid: false, expectedOrigin: ""},         // IPv6 address with port, path, query, fragment, trailing slash, and invalid segment should not be accepted.
		{origin: "http://[::1]:8080/path?query=123#fragment/invalid/", expectedValid: false, expectedOrigin: ""},        // IPv6 address with port, path, query, fragment, trailing slash, and invalid segment with trailing slash should not be accepted.
		{origin: "http://[::1]:8080/path?query=123#fragment/invalid/segment", expectedValid: false, expectedOrigin: ""}, // IPv6 address with port, path, query, fragment, trailing slash, and invalid segment with additional segment should not be accepted.
	}

	for _, tc := range testCases {
		valid, normalizedOrigin := normalizeOrigin(tc.origin)

		if valid != tc.expectedValid {
			t.Errorf("Expected origin '%s' to be valid: %v, but got: %v", tc.origin, tc.expectedValid, valid)
		}

		if normalizedOrigin != tc.expectedOrigin {
			t.Errorf("Expected normalized origin '%s' for origin '%s', but got: '%s'", tc.expectedOrigin, tc.origin, normalizedOrigin)
		}
	}
}

// go test -run -v TestSubdomainMatch
func TestSubdomainMatch(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name     string
		sub      subdomain
		origin   string
		expected bool
	}{
		{
			name:     "match with different scheme",
			sub:      subdomain{prefix: "http://api.", suffix: "example.com"},
			origin:   "https://api.service.example.com",
			expected: false,
		},
		{
			name:     "match with different scheme",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "http://api.service.example.com",
			expected: false,
		},
		{
			name:     "match with valid subdomain",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://api.service.example.com",
			expected: true,
		},
		{
			name:     "match with valid nested subdomain",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://1.2.api.service.example.com",
			expected: true,
		},

		{
			name:     "no match with invalid prefix",
			sub:      subdomain{prefix: "https://abc.", suffix: "example.com"},
			origin:   "https://service.example.com",
			expected: false,
		},
		{
			name:     "no match with invalid suffix",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://api.example.org",
			expected: false,
		},
		{
			name:     "no match with empty origin",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "",
			expected: false,
		},
		{
			name:     "no match with malformed subdomain",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://evil.comexample.com",
			expected: false,
		},
		{
			name:     "partial match not considered a match",
			sub:      subdomain{prefix: "https://service.", suffix: "example.com"},
			origin:   "https://api.example.com",
			expected: false,
		},
		{
			name:     "no match with empty host label",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://.example.com",
			expected: false,
		},
		{
			name:     "no match with malformed host label",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://..example.com",
			expected: false,
		},
		{
			name:     "no match with empty label before suffix",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://foo..example.com",
			expected: false,
		},
		{
			name:     "no match with malformed origin port before suffix",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://evil.com:any.example.com",
			expected: false,
		},
		{
			name:     "no match with userinfo in origin",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://user@api.example.com",
			expected: false,
		},
		{
			name:     "no match with non-normalized origin",
			sub:      subdomain{prefix: "https://", suffix: "example.com"},
			origin:   "https://API.example.com",
			expected: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()
			got := tt.sub.match(tt.origin)
			assert.Equal(t, tt.expected, got, "subdomain.match()")
		})
	}
}

// go test -v -run=^$ -bench=Benchmark_CSRF_SubdomainMatch -benchmem -count=4
func Benchmark_CSRF_SubdomainMatch(b *testing.B) {
	s := subdomain{
		prefix: "www",
		suffix: "example.com",
	}

	o := "www.example.com"

	b.ReportAllocs()

	for b.Loop() {
		s.match(o)
	}
}

func benchSubdomains(n int) []subdomain {
	subs := make([]subdomain, n)
	for i := range subs {
		subs[i] = subdomain{prefix: "https://", suffix: "example.com"}
	}
	return subs
}

func Benchmark_CSRF_SubdomainMatch_PerPatternNormalize(b *testing.B) {
	subdomains := benchSubdomains(16)
	origin := "https://api.service.example.org"

	b.ReportAllocs()

	for b.Loop() {
		for _, sub := range subdomains {
			isValid, normalized := normalizeOrigin(origin)
			if isValid && normalized == origin && sub.matchNormalized(origin) {
				break
			}
		}
	}
}

func Benchmark_CSRF_MatchSubdomainOrigin(b *testing.B) {
	subdomains := benchSubdomains(16)
	origin := "https://api.service.example.org"

	b.ReportAllocs()

	for b.Loop() {
		matchSubdomainOrigin(subdomains, origin)
	}
}

func Test_CSRF_MatchSubdomainOrigin(t *testing.T) {
	t.Parallel()

	subdomains := []subdomain{
		{prefix: "https://", suffix: "example.net"},
		{prefix: "https://", suffix: "example.org"},
		{prefix: "https://", suffix: "example.com"},
	}

	tests := []struct {
		name     string
		origin   string
		expected bool
	}{
		{
			name:     "matches later pattern",
			origin:   "https://api.service.example.com",
			expected: true,
		},
		{
			name:     "rejects invalid origin once",
			origin:   "https://user@api.example.com",
			expected: false,
		},
		{
			name:     "rejects non-normalized origin",
			origin:   "https://API.service.example.com",
			expected: false,
		},
		{
			name:     "rejects unmatched origin",
			origin:   "https://api.service.example.dev",
			expected: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			got := matchSubdomainOrigin(subdomains, tt.origin)
			assert.Equal(t, tt.expected, got)
		})
	}
}

func Test_CSRF_Security_CompareConstantTime(t *testing.T) {
	t.Parallel()

	t.Run("strings", func(t *testing.T) {
		t.Parallel()
		require.True(t, compareStrings("abc123", "abc123"))
		require.False(t, compareStrings("abc123", "abc124"))
		require.False(t, compareStrings("abc", "abcd"))      // different length
		require.False(t, compareStrings("", "x"))            // empty vs non-empty
		require.True(t, compareStrings("", ""))              // both empty
		require.False(t, compareStrings("Abc123", "abc123")) // case sensitive
	})

	t.Run("tokens", func(t *testing.T) {
		t.Parallel()
		require.True(t, compareTokens([]byte("raw-token"), []byte("raw-token")))
		require.False(t, compareTokens([]byte("raw-token"), []byte("raw-tokeX")))
		require.False(t, compareTokens([]byte("short"), []byte("shorter")))
		require.False(t, compareTokens([]byte(nil), []byte("x")))
		require.True(t, compareTokens([]byte(nil), []byte(nil)))
	})
}
