package fasthttp

import (
	"bufio"
	"bytes"
	"html"
	"net"
	"net/http"
	"net/url"
	"strconv"
	"testing"
	"time"

	"github.com/valyala/bytebufferpool"
)

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

	// Sync with url.QueryEscape
	allcases := make([]byte, 256)
	for i := range 256 {
		allcases[i] = byte(i)
	}
	res := string(AppendQuotedArg(nil, allcases))
	expect := url.QueryEscape(string(allcases))
	if res != expect {
		t.Fatalf("unexpected string %q. Expecting %q.", res, expect)
	}
}

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

	// Sync with html.EscapeString
	allcases := make([]byte, 256)
	for i := range 256 {
		allcases[i] = byte(i)
	}
	res := string(AppendHTMLEscape(nil, string(allcases)))
	expect := html.EscapeString(string(allcases))
	if res != expect {
		t.Fatalf("unexpected string %q. Expecting %q.", res, expect)
	}

	testAppendHTMLEscape(t, "", "")
	testAppendHTMLEscape(t, "<", "&lt;")
	testAppendHTMLEscape(t, "a", "a")
	testAppendHTMLEscape(t, `><"''`, "&gt;&lt;&#34;&#39;&#39;")
	testAppendHTMLEscape(t, "fo<b x='ss'>a</b>xxx", "fo&lt;b x=&#39;ss&#39;&gt;a&lt;/b&gt;xxx")
}

func testAppendHTMLEscape(t *testing.T, s, expectedS string) {
	buf := AppendHTMLEscapeBytes(nil, []byte(s))
	if string(buf) != expectedS {
		t.Fatalf("unexpected html-escaped string %q. Expecting %q. Original string %q", buf, expectedS, s)
	}
}

func TestParseIPv4(t *testing.T) {
	t.Parallel()

	testParseIPv4(t, net.IP{0}, "0.0.0.0", true)
	testParseIPv4(t, nil, "0.0.0.0", true)
	testParseIPv4(t, net.IP{0, 0, 0, 0, 0}, "0.0.0.0", true)
	testParseIPv4(t, nil, "255.255.255.255", true)
	testParseIPv4(t, nil, "123.45.67.89", true)

	// ipv6 shouldn't work
	testParseIPv4(t, nil, "2001:4860:0:2001::68", false)

	// invalid ip
	testParseIPv4(t, nil, "", false)
	testParseIPv4(t, nil, "foobar", false)
	testParseIPv4(t, nil, "1.2.3", false)
	testParseIPv4(t, nil, "123.456.789.11", false)
	testParseIPv4(t, nil, "b.1.2.3", false)
	testParseIPv4(t, nil, "1.2.3.b", false)
	testParseIPv4(t, nil, "1.2.3.456", false)
}

func testParseIPv4(t *testing.T, dst net.IP, ipStr string, isValid bool) {
	ip, err := ParseIPv4(dst, []byte(ipStr))
	if isValid {
		if err != nil {
			t.Fatalf("unexpected error when parsing ip %q: %v", ipStr, err)
		}
		s := string(AppendIPv4(nil, ip))
		if s != ipStr {
			t.Fatalf("unexpected ip parsed %q. Expecting %q", s, ipStr)
		}
	} else if err == nil {
		t.Fatalf("expecting error when parsing ip %q", ipStr)
	}
}

func TestAppendIPv4(t *testing.T) {
	t.Parallel()

	testAppendIPv4(t, "0.0.0.0", true)
	testAppendIPv4(t, "127.0.0.1", true)
	testAppendIPv4(t, "8.8.8.8", true)
	testAppendIPv4(t, "123.45.67.89", true)

	// ipv6 shouldn't work
	testAppendIPv4(t, "2001:4860:0:2001::68", false)
}

func testAppendIPv4(t *testing.T, ipStr string, isValid bool) {
	ip := net.ParseIP(ipStr)
	if ip == nil {
		t.Fatalf("cannot parse ip %q", ipStr)
	}
	s := string(AppendIPv4(nil, ip))
	if isValid {
		if s != ipStr {
			t.Fatalf("unexpected ip %q. Expecting %q", s, ipStr)
		}
	} else {
		ipStr = "non-v4 ip passed to AppendIPv4"
		if s != ipStr {
			t.Fatalf("unexpected ip %q. Expecting %q", s, ipStr)
		}
	}
}

func testAppendUint(t *testing.T, n int) {
	expectedS := strconv.Itoa(n)
	s := AppendUint(nil, n)
	if string(s) != expectedS {
		t.Fatalf("unexpected uint %q. Expecting %q. n=%d", s, expectedS, n)
	}
}

func testWriteHexInt(t *testing.T, n int, expectedS string) {
	var w bytebufferpool.ByteBuffer
	bw := bufio.NewWriter(&w)
	if err := writeHexInt(bw, n); err != nil {
		t.Fatalf("unexpected error when writing hex %x: %v", n, err)
	}
	if err := bw.Flush(); err != nil {
		t.Fatalf("unexpected error when flushing hex %x: %v", n, err)
	}
	s := string(w.B)
	if s != expectedS {
		t.Fatalf("unexpected hex after writing %q. Expected %q", s, expectedS)
	}
}

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

	testReadHexIntError(t, "")
	testReadHexIntError(t, "ZZZ")
	testReadHexIntError(t, "-123")
	testReadHexIntError(t, "+434")
}

func testReadHexIntError(t *testing.T, s string) {
	r := bytes.NewBufferString(s)
	br := bufio.NewReader(r)
	n, err := readHexInt(br)
	if err == nil {
		t.Fatalf("expecting error when reading hex int %q", s)
	}
	if n >= 0 {
		t.Fatalf("unexpected hex value read %d for hex int %q. must be negative", n, s)
	}
}

func testReadHexIntSuccess(t *testing.T, s string, expectedN int) {
	r := bytes.NewBufferString(s)
	br := bufio.NewReader(r)
	n, err := readHexInt(br)
	if err != nil {
		t.Fatalf("unexpected error: %v. s=%q", err, s)
	}
	if n != expectedN {
		t.Fatalf("unexpected hex int %d. Expected %d. s=%q", n, expectedN, s)
	}
}

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

	d := time.Date(2009, time.November, 10, 23, 0, 0, 0, time.UTC)
	s := string(AppendHTTPDate(nil, d))
	expectedS := "Tue, 10 Nov 2009 23:00:00 GMT"
	if s != expectedS {
		t.Fatalf("unexpected date %q. Expecting %q", s, expectedS)
	}

	b := []byte("prefix")
	s = string(AppendHTTPDate(b, d))
	if s[:len(b)] != string(b) {
		t.Fatalf("unexpected prefix %q. Expecting %q", s[:len(b)], b)
	}
	s = s[len(b):]
	if s != expectedS {
		t.Fatalf("unexpected date %q. Expecting %q", s, expectedS)
	}
}

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

	testCases := []struct {
		name      string
		value     string
		hasError  bool
		roundTrip bool
	}{
		{name: "gmt-fast-path", value: "Tue, 10 Nov 2009 23:00:00 GMT", roundTrip: true},
		{name: "epoch", value: "Thu, 01 Jan 1970 00:00:00 GMT", roundTrip: true},
		{name: "year-boundary", value: "Fri, 31 Dec 1999 23:59:59 GMT", roundTrip: true},
		{name: "leap-year", value: "Mon, 29 Feb 2016 12:34:56 GMT", roundTrip: true},
		{name: "utc-fallback", value: "Tue, 10 Nov 2009 23:00:00 UTC", hasError: true},
		{name: "mixedcase-weekday-month", value: "tUe, 10 nOv 2009 23:00:00 GMT"},
		{name: "day-zero", value: "Tue, 00 Nov 2009 23:00:00 GMT", hasError: true},
		{name: "invalid-day", value: "Tue, 31 Feb 2009 23:00:00 GMT", hasError: true},
		{name: "invalid-weekday", value: "Xxx, 10 Nov 2009 23:00:00 GMT", hasError: true},
		{name: "invalid-month", value: "Tue, 10 Foo 2009 23:00:00 GMT", hasError: true},
		{name: "invalid-hour", value: "Tue, 10 Nov 2009 24:00:00 GMT", hasError: true},
		{name: "invalid-minute", value: "Tue, 10 Nov 2009 23:60:00 GMT", hasError: true},
		{name: "invalid-second", value: "Tue, 10 Nov 2009 23:00:60 GMT", hasError: true},
		{name: "invalid-separator", value: "Tue 10 Nov 2009 23:00:00 GMT", hasError: true},
		{name: "invalid-time-separator", value: "Tue, 10 Nov 2009 23-00-00 GMT", hasError: true},
		{name: "non-leap-year", value: "Tue, 29 Feb 2019 23:00:00 GMT", hasError: true},
	}

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

			got, gotErr := ParseHTTPDate([]byte(tc.value))
			want, wantErr := time.Parse(http.TimeFormat, tc.value)

			if (gotErr != nil) != (wantErr != nil) {
				t.Fatalf("error mismatch for %q: ParseHTTPDate err=%v, ParseInLocation err=%v", tc.value, gotErr, wantErr)
			}
			if tc.hasError != (gotErr != nil) {
				t.Fatalf("unexpected error state for %q: gotErr=%v, expectedError=%v", tc.value, gotErr, tc.hasError)
			}
			if gotErr != nil {
				return
			}
			if !got.Equal(want) {
				t.Fatalf("parsed time mismatch for %q: got=%v want=%v", tc.value, got, want)
			}
			if tc.roundTrip && got.Format(time.RFC1123) != tc.value {
				t.Fatalf("unexpected formatted date %q. Expecting %q", got.Format(time.RFC1123), tc.value)
			}
		})
	}
}

func BenchmarkParseHTTPDate(b *testing.B) {
	date := []byte("Tue, 10 Nov 2009 23:00:00 GMT")

	b.Run("fast-path", func(b *testing.B) {
		b.ReportAllocs()
		for range b.N {
			_, _ = ParseHTTPDate(date)
		}
	})

	b.Run("stdlib-only", func(b *testing.B) {
		b.ReportAllocs()
		s := string(date)
		for range b.N {
			_, _ = time.Parse(http.TimeFormat, s)
		}
	})
}

func FuzzParseHTTPDate(f *testing.F) {
	// Seed corpus: valid RFC1123 dates.
	seeds := []string{
		"Tue, 10 Nov 2009 23:00:00 GMT",
		"Thu, 01 Jan 1970 00:00:00 GMT",
		"Fri, 31 Dec 1999 23:59:59 GMT",
		"Mon, 29 Feb 2016 12:34:56 GMT",
		"Sun, 06 Nov 1994 08:49:37 GMT",
		// Invalid inputs to exercise rejection paths.
		"Tue, 10 Nov 2009 23:00:00 UTC",
		"Tue, 31 Feb 2009 23:00:00 GMT",
		"Xxx, 10 Nov 2009 23:00:00 GMT",
		"Tue, 00 Nov 2009 23:00:00 GMT",
		"Tue, 10 Nov 2009 24:00:00 GMT",
		"not a date at all",
		"",
	}
	for _, s := range seeds {
		f.Add(s)
	}

	f.Fuzz(func(t *testing.T, s string) {
		b := []byte(s)

		// Reference: time.Parse with http.TimeFormat is what ParseHTTPDate falls back to.
		stdTime, stdErr := time.Parse(http.TimeFormat, s)

		// The public API must always agree with time.Parse.
		got, gotErr := ParseHTTPDate(b)
		if (gotErr != nil) != (stdErr != nil) {
			t.Fatalf("ParseHTTPDate error mismatch for %q: got err=%v, std err=%v", s, gotErr, stdErr)
		}
		if gotErr == nil && !got.Equal(stdTime) {
			t.Fatalf("ParseHTTPDate time mismatch for %q: got=%v std=%v", s, got, stdTime)
		}
	})
}

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

	// empty string
	testParseUintError(t, "")

	// negative value
	testParseUintError(t, "-123")

	// non-num
	testParseUintError(t, "foobar234")

	// non-num chars at the end
	testParseUintError(t, "123w")

	// floating point num
	testParseUintError(t, "1234.545")

	// too big num
	testParseUintError(t, "12345678901234567890")
	testParseUintError(t, "1234567890123456789012")
}

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

	testParseUfloatSuccess(t, "0", 0)
	testParseUfloatSuccess(t, "1.", 1.)
	testParseUfloatSuccess(t, ".1", 0.1)
	testParseUfloatSuccess(t, "123.456", 123.456)
	testParseUfloatSuccess(t, "123", 123)
	testParseUfloatSuccess(t, "1234e2", 1234e2)
	testParseUfloatSuccess(t, "1234E-5", 1234e-5)
	testParseUfloatSuccess(t, "1.234e+3", 1.234e+3)
	testParseUfloatSuccess(t, "1234e23", 1234e23)
	testParseUfloatSuccess(t, "1.234e+32", 1.234e+32)
	testParseUfloatSuccess(t, "123456789123456789.987654321", 123456789123456789.987654321)
	testParseUfloatSuccess(t, "1.23456789123456789987654321", 1.23456789123456789987654321)
	testParseUfloatSuccess(t, "340282346638528859811704183484516925440", 340282346638528859811704183484516925440)
	testParseUfloatSuccess(t, "00000000000000000001", 1)
}

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

	// empty num
	testParseUfloatError(t, "")

	// negative num
	testParseUfloatError(t, "-123.53")

	// non-num chars
	testParseUfloatError(t, "123sdfsd")
	testParseUfloatError(t, "sdsf234")
	testParseUfloatError(t, "sdfdf")

	// non-num chars in exponent
	testParseUfloatError(t, "123e3s")
	testParseUfloatError(t, "12.3e-op")
	testParseUfloatError(t, "123E+SS5")

	// duplicate point
	testParseUfloatError(t, "1.3.4")

	// duplicate exponent
	testParseUfloatError(t, "123e5e6")

	// missing exponent
	testParseUfloatError(t, "123534e")

	// negative number
	testParseUfloatError(t, "-1")
	testParseUfloatError(t, "-Inf")
}

func testParseUfloatError(t *testing.T, s string) {
	n, err := ParseUfloat([]byte(s))
	if err == nil {
		t.Fatalf("Expecting error when parsing %q. obtained %f", s, n)
	}
	if n >= 0 {
		t.Fatalf("Expecting negative num instead of %f when parsing %q", n, s)
	}
}

func testParseUfloatSuccess(t *testing.T, s string, expectedF float64) {
	f, err := ParseUfloat([]byte(s))
	if err != nil {
		t.Fatalf("Unexpected error when parsing %q: %v", s, err)
	}
	delta := f - expectedF
	if delta < 0 {
		delta = -delta
	}
	if delta > expectedF*1e-10 {
		t.Fatalf("Unexpected value when parsing %q: %f. Expected %f", s, f, expectedF)
	}
}

func testParseUintError(t *testing.T, s string) {
	n, err := ParseUint([]byte(s))
	if err == nil {
		t.Fatalf("Expecting error when parsing %q. obtained %d", s, n)
	}
	if n >= 0 {
		t.Fatalf("Unexpected n=%d when parsing %q. Expected negative num", n, s)
	}
}

func testParseUintSuccess(t *testing.T, s string, expectedN int) {
	n, err := ParseUint([]byte(s))
	if err != nil {
		t.Fatalf("Unexpected error when parsing %q: %v", s, err)
	}
	if n != expectedN {
		t.Fatalf("Unexpected value %d. Expected %d. num=%q", n, expectedN, s)
	}
}

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

	testAppendUnquotedArg(t, "", "")
	testAppendUnquotedArg(t, "abc", "abc")
	testAppendUnquotedArg(t, "тест.abc", "тест.abc")
	testAppendUnquotedArg(t, "%D1%82%D0%B5%D1%81%D1%82%20%=&;:", "тест %=&;:")
}

func testAppendUnquotedArg(t *testing.T, s, expectedS string) {
	// test appending to nil
	result := AppendUnquotedArg(nil, []byte(s))
	if string(result) != expectedS {
		t.Fatalf("Unexpected AppendUnquotedArg(%q)=%q, want %q", s, result, expectedS)
	}

	// test appending to prefix
	prefix := "prefix"
	dst := []byte(prefix)
	dst = AppendUnquotedArg(dst, []byte(s))
	if !bytes.HasPrefix(dst, []byte(prefix)) {
		t.Fatalf("Unexpected prefix for AppendUnquotedArg(%q)=%q, want %q", s, dst, prefix)
	}
	result = dst[len(prefix):]
	if string(result) != expectedS {
		t.Fatalf("Unexpected AppendUnquotedArg(%q)=%q, want %q", s, result, expectedS)
	}

	// test in-place appending
	result = []byte(s)
	result = AppendUnquotedArg(result[:0], result)
	if string(result) != expectedS {
		t.Fatalf("Unexpected AppendUnquotedArg(%q)=%q, want %q", s, result, expectedS)
	}

	// verify AppendQuotedArg <-> AppendUnquotedArg conversion
	quotedS := AppendQuotedArg(nil, []byte(s))
	unquotedS := AppendUnquotedArg(nil, quotedS)
	if s != string(unquotedS) {
		t.Fatalf("Unexpected AppendUnquotedArg(AppendQuotedArg(%q))=%q, want %q", s, unquotedS, s)
	}
}
