// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package big

import (
	"bytes"
	"fmt"
	"math/rand/v2"
	"testing"
)

var stringTests = []struct {
	in   string
	out  string
	base int
	val  int64
	ok   bool
}{
	// invalid inputs
	{in: ""},
	{in: "a"},
	{in: "z"},
	{in: "+"},
	{in: "-"},
	{in: "0b"},
	{in: "0o"},
	{in: "0x"},
	{in: "0y"},
	{in: "2", base: 2},
	{in: "0b2", base: 0},
	{in: "08"},
	{in: "8", base: 8},
	{in: "0xg", base: 0},
	{in: "g", base: 16},

	// invalid inputs with separators
	// (smoke tests only - a comprehensive set of tests is in natconv_test.go)
	{in: "_"},
	{in: "0_"},
	{in: "_0"},
	{in: "-1__0"},
	{in: "0x10_"},
	{in: "1_000", base: 10}, // separators are not permitted for bases != 0
	{in: "d_e_a_d", base: 16},

	// valid inputs
	{"0", "0", 0, 0, true},
	{"0", "0", 10, 0, true},
	{"0", "0", 16, 0, true},
	{"+0", "0", 0, 0, true},
	{"-0", "0", 0, 0, true},
	{"10", "10", 0, 10, true},
	{"10", "10", 10, 10, true},
	{"10", "10", 16, 16, true},
	{"-10", "-10", 16, -16, true},
	{"+10", "10", 16, 16, true},
	{"0b10", "2", 0, 2, true},
	{"0o10", "8", 0, 8, true},
	{"0x10", "16", 0, 16, true},
	{in: "0x10", base: 16},
	{"-0x10", "-16", 0, -16, true},
	{"+0x10", "16", 0, 16, true},
	{"00", "0", 0, 0, true},
	{"0", "0", 8, 0, true},
	{"07", "7", 0, 7, true},
	{"7", "7", 8, 7, true},
	{"023", "19", 0, 19, true},
	{"23", "23", 8, 19, true},
	{"cafebabe", "cafebabe", 16, 0xcafebabe, true},
	{"0b0", "0", 0, 0, true},
	{"-111", "-111", 2, -7, true},
	{"-0b111", "-7", 0, -7, true},
	{"0b1001010111", "599", 0, 0x257, true},
	{"1001010111", "1001010111", 2, 0x257, true},
	{"A", "a", 36, 10, true},
	{"A", "A", 37, 36, true},
	{"ABCXYZ", "abcxyz", 36, 623741435, true},
	{"ABCXYZ", "ABCXYZ", 62, 33536793425, true},

	// valid input with separators
	// (smoke tests only - a comprehensive set of tests is in natconv_test.go)
	{"1_000", "1000", 0, 1000, true},
	{"0b_1010", "10", 0, 10, true},
	{"+0o_660", "432", 0, 0660, true},
	{"-0xF00D_1E", "-15731998", 0, -0xf00d1e, true},
}

func TestIntText(t *testing.T) {
	z := new(Int)
	for _, test := range stringTests {
		if !test.ok {
			continue
		}

		_, ok := z.SetString(test.in, test.base)
		if !ok {
			t.Errorf("%v: failed to parse", test)
			continue
		}

		base := test.base
		if base == 0 {
			base = 10
		}

		if got := z.Text(base); got != test.out {
			t.Errorf("%v: got %s; want %s", test, got, test.out)
		}
	}
}

func TestAppendText(t *testing.T) {
	z := new(Int)
	var buf []byte
	for _, test := range stringTests {
		if !test.ok {
			continue
		}

		_, ok := z.SetString(test.in, test.base)
		if !ok {
			t.Errorf("%v: failed to parse", test)
			continue
		}

		base := test.base
		if base == 0 {
			base = 10
		}

		i := len(buf)
		buf = z.Append(buf, base)
		if got := string(buf[i:]); got != test.out {
			t.Errorf("%v: got %s; want %s", test, got, test.out)
		}
	}
}

func format(base int) string {
	switch base {
	case 2:
		return "%b"
	case 8:
		return "%o"
	case 16:
		return "%x"
	}
	return "%d"
}

func TestGetString(t *testing.T) {
	z := new(Int)
	for i, test := range stringTests {
		if !test.ok {
			continue
		}
		z.SetInt64(test.val)

		if test.base == 10 {
			if got := z.String(); got != test.out {
				t.Errorf("#%da got %s; want %s", i, got, test.out)
			}
		}

		f := format(test.base)
		got := fmt.Sprintf(f, z)
		if f == "%d" {
			if got != fmt.Sprintf("%d", test.val) {
				t.Errorf("#%db got %s; want %d", i, got, test.val)
			}
		} else {
			if got != test.out {
				t.Errorf("#%dc got %s; want %s", i, got, test.out)
			}
		}
	}
}

func TestSetString(t *testing.T) {
	tmp := new(Int)
	for i, test := range stringTests {
		// initialize to a non-zero value so that issues with parsing
		// 0 are detected
		tmp.SetInt64(1234567890)
		n1, ok1 := new(Int).SetString(test.in, test.base)
		n2, ok2 := tmp.SetString(test.in, test.base)
		expected := NewInt(test.val)
		if ok1 != test.ok || ok2 != test.ok {
			t.Errorf("#%d (input '%s') ok incorrect (should be %t)", i, test.in, test.ok)
			continue
		}
		if !ok1 {
			if n1 != nil {
				t.Errorf("#%d (input '%s') n1 != nil", i, test.in)
			}
			continue
		}
		if !ok2 {
			if n2 != nil {
				t.Errorf("#%d (input '%s') n2 != nil", i, test.in)
			}
			continue
		}

		if ok1 && !isNormalized(n1) {
			t.Errorf("#%d (input '%s'): %v is not normalized", i, test.in, *n1)
		}
		if ok2 && !isNormalized(n2) {
			t.Errorf("#%d (input '%s'): %v is not normalized", i, test.in, *n2)
		}

		if n1.Cmp(expected) != 0 {
			t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n1, test.val)
		}
		if n2.Cmp(expected) != 0 {
			t.Errorf("#%d (input '%s') got: %s want: %d", i, test.in, n2, test.val)
		}
	}
}

var formatTests = []struct {
	input  string
	format string
	output string
}{
	{"<nil>", "%x", "<nil>"},
	{"<nil>", "%#x", "<nil>"},
	{"<nil>", "%#y", "%!y(big.Int=<nil>)"},

	{"10", "%b", "1010"},
	{"10", "%o", "12"},
	{"10", "%d", "10"},
	{"10", "%v", "10"},
	{"10", "%x", "a"},
	{"10", "%X", "A"},
	{"-10", "%X", "-A"},
	{"10", "%y", "%!y(big.Int=10)"},
	{"-10", "%y", "%!y(big.Int=-10)"},

	{"10", "%#b", "0b1010"},
	{"10", "%#o", "012"},
	{"10", "%O", "0o12"},
	{"-10", "%#b", "-0b1010"},
	{"-10", "%#o", "-012"},
	{"-10", "%O", "-0o12"},
	{"10", "%#d", "10"},
	{"10", "%#v", "10"},
	{"10", "%#x", "0xa"},
	{"10", "%#X", "0XA"},
	{"-10", "%#X", "-0XA"},
	{"10", "%#y", "%!y(big.Int=10)"},
	{"-10", "%#y", "%!y(big.Int=-10)"},

	{"1234", "%d", "1234"},
	{"1234", "%3d", "1234"},
	{"1234", "%4d", "1234"},
	{"-1234", "%d", "-1234"},
	{"1234", "% 5d", " 1234"},
	{"1234", "%+5d", "+1234"},
	{"1234", "%-5d", "1234 "},
	{"1234", "%x", "4d2"},
	{"1234", "%X", "4D2"},
	{"-1234", "%3x", "-4d2"},
	{"-1234", "%4x", "-4d2"},
	{"-1234", "%5x", " -4d2"},
	{"-1234", "%-5x", "-4d2 "},
	{"1234", "%03d", "1234"},
	{"1234", "%04d", "1234"},
	{"1234", "%05d", "01234"},
	{"1234", "%06d", "001234"},
	{"-1234", "%06d", "-01234"},
	{"1234", "%+06d", "+01234"},
	{"1234", "% 06d", " 01234"},
	{"1234", "%-6d", "1234  "},
	{"1234", "%-06d", "1234  "},
	{"-1234", "%-06d", "-1234 "},

	{"1234", "%.3d", "1234"},
	{"1234", "%.4d", "1234"},
	{"1234", "%.5d", "01234"},
	{"1234", "%.6d", "001234"},
	{"-1234", "%.3d", "-1234"},
	{"-1234", "%.4d", "-1234"},
	{"-1234", "%.5d", "-01234"},
	{"-1234", "%.6d", "-001234"},

	{"1234", "%8.3d", "    1234"},
	{"1234", "%8.4d", "    1234"},
	{"1234", "%8.5d", "   01234"},
	{"1234", "%8.6d", "  001234"},
	{"-1234", "%8.3d", "   -1234"},
	{"-1234", "%8.4d", "   -1234"},
	{"-1234", "%8.5d", "  -01234"},
	{"-1234", "%8.6d", " -001234"},

	{"1234", "%+8.3d", "   +1234"},
	{"1234", "%+8.4d", "   +1234"},
	{"1234", "%+8.5d", "  +01234"},
	{"1234", "%+8.6d", " +001234"},
	{"-1234", "%+8.3d", "   -1234"},
	{"-1234", "%+8.4d", "   -1234"},
	{"-1234", "%+8.5d", "  -01234"},
	{"-1234", "%+8.6d", " -001234"},

	{"1234", "% 8.3d", "    1234"},
	{"1234", "% 8.4d", "    1234"},
	{"1234", "% 8.5d", "   01234"},
	{"1234", "% 8.6d", "  001234"},
	{"-1234", "% 8.3d", "   -1234"},
	{"-1234", "% 8.4d", "   -1234"},
	{"-1234", "% 8.5d", "  -01234"},
	{"-1234", "% 8.6d", " -001234"},

	{"1234", "%.3x", "4d2"},
	{"1234", "%.4x", "04d2"},
	{"1234", "%.5x", "004d2"},
	{"1234", "%.6x", "0004d2"},
	{"-1234", "%.3x", "-4d2"},
	{"-1234", "%.4x", "-04d2"},
	{"-1234", "%.5x", "-004d2"},
	{"-1234", "%.6x", "-0004d2"},

	{"1234", "%8.3x", "     4d2"},
	{"1234", "%8.4x", "    04d2"},
	{"1234", "%8.5x", "   004d2"},
	{"1234", "%8.6x", "  0004d2"},
	{"-1234", "%8.3x", "    -4d2"},
	{"-1234", "%8.4x", "   -04d2"},
	{"-1234", "%8.5x", "  -004d2"},
	{"-1234", "%8.6x", " -0004d2"},

	{"1234", "%+8.3x", "    +4d2"},
	{"1234", "%+8.4x", "   +04d2"},
	{"1234", "%+8.5x", "  +004d2"},
	{"1234", "%+8.6x", " +0004d2"},
	{"-1234", "%+8.3x", "    -4d2"},
	{"-1234", "%+8.4x", "   -04d2"},
	{"-1234", "%+8.5x", "  -004d2"},
	{"-1234", "%+8.6x", " -0004d2"},

	{"1234", "% 8.3x", "     4d2"},
	{"1234", "% 8.4x", "    04d2"},
	{"1234", "% 8.5x", "   004d2"},
	{"1234", "% 8.6x", "  0004d2"},
	{"1234", "% 8.7x", " 00004d2"},
	{"1234", "% 8.8x", " 000004d2"},
	{"-1234", "% 8.3x", "    -4d2"},
	{"-1234", "% 8.4x", "   -04d2"},
	{"-1234", "% 8.5x", "  -004d2"},
	{"-1234", "% 8.6x", " -0004d2"},
	{"-1234", "% 8.7x", "-00004d2"},
	{"-1234", "% 8.8x", "-000004d2"},

	{"1234", "%-8.3d", "1234    "},
	{"1234", "%-8.4d", "1234    "},
	{"1234", "%-8.5d", "01234   "},
	{"1234", "%-8.6d", "001234  "},
	{"1234", "%-8.7d", "0001234 "},
	{"1234", "%-8.8d", "00001234"},
	{"-1234", "%-8.3d", "-1234   "},
	{"-1234", "%-8.4d", "-1234   "},
	{"-1234", "%-8.5d", "-01234  "},
	{"-1234", "%-8.6d", "-001234 "},
	{"-1234", "%-8.7d", "-0001234"},
	{"-1234", "%-8.8d", "-00001234"},

	{"16777215", "%b", "111111111111111111111111"}, // 2**24 - 1

	{"0", "%.d", ""},
	{"0", "%.0d", ""},
	{"0", "%3.d", ""},
}

func TestFormat(t *testing.T) {
	for i, test := range formatTests {
		var x *Int
		if test.input != "<nil>" {
			var ok bool
			x, ok = new(Int).SetString(test.input, 0)
			if !ok {
				t.Errorf("#%d failed reading input %s", i, test.input)
			}
		}
		output := fmt.Sprintf(test.format, x)
		if output != test.output {
			t.Errorf("#%d got %q; want %q, {%q, %q, %q}", i, output, test.output, test.input, test.format, test.output)
		}
	}
}

type scanTest struct {
	input     string
	format    string
	output    string
	remaining int
}

var scanTests = []scanTest{
	{"1010", "%b", "10", 0},
	{"0b1010", "%v", "10", 0},
	{"12", "%o", "10", 0},
	{"012", "%v", "10", 0},
	{"10", "%d", "10", 0},
	{"10", "%v", "10", 0},
	{"a", "%x", "10", 0},
	{"0xa", "%v", "10", 0},
	{"A", "%X", "10", 0},
	{"-A", "%X", "-10", 0},
	{"+0b1011001", "%v", "89", 0},
	{"0xA", "%v", "10", 0},
	{"0 ", "%v", "0", 1},
	{"2+3", "%v", "2", 2},
	{"0XABC 12", "%v", "2748", 3},

	{"10000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000ffffffffffffffffffffffffffffffff00000000000022222223333333333444444444", "%x", "72999049881955123498258745691204661198291656115976958889267080286388402675338838184094604981077942396458276955120179409196748346461468914795561487752253275293347599221664790586512596660792869956", 0},
	{"ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff33377fffffffffffffffffffffffffffffffffffffffffffff0000000000022222eee1", "%x", "1167984798111281975972139931059274579172666497855631342228273284582214442805421410945513679697247078343332431249286160621687557589604464869034163736183926240549918956767671325412748661204059352801", 0},
	{"5c0d52f451aec609b15da8e5e5626c4eaa88723bdeac9d25ca9b961269400410ca208a16af9c2fb07d7a11c7772cba02c22f9711078d51a3797eb18e691295293284d988e349fa6deba46b25a4ecd9f715", "%x", "419981998319789881681348172155240145539175961318447822049735313481433836043208347786919222066492311384432264836938599791362288343314139526391998172436831830624710446410781662672086936222288181013", 0},
	{"92fcad4b5c0d52f451aec609b15da8e5e5626c4eaa88723bdeac9d25ca9b961269400410ca208a16af9c2fb07d799c32fe2f3cc5422f9711078d51a3797eb18e691295293284d8f5e69caf6decddfe1df6", "%x", "670619546945481998414061201992255225716434798957375727890607516800039934374391281275121813279544891602026798031004764406015624866771554937391445093144221697436880587924204655403711377861305572854", 0},
	{"10000000000000000000000200000000000000000000003000000000000000000000040000000000000000000000500000000000000000000006", "%d", "10000000000000000000000200000000000000000000003000000000000000000000040000000000000000000000500000000000000000000006", 0},
}

func init() {
	for i := range 200 {
		d := make([]byte, i+1)
		for j := range d {
			d[j] = '0' + rand.N(byte(10))
		}
		if d[0] == '0' {
			d[0] = '1'
		}
		scanTests = append(scanTests, scanTest{input: string(d), format: "%d", output: string(d)})
	}
}

func TestScan(t *testing.T) {
	var buf bytes.Buffer
	for i, test := range scanTests {
		x := new(Int)
		buf.Reset()
		buf.WriteString(test.input)
		if _, err := fmt.Fscanf(&buf, test.format, x); err != nil {
			t.Errorf("#%d error: %s", i, err)
		}
		if x.String() != test.output {
			t.Errorf("#%d got %s; want %s", i, x.String(), test.output)
		}
		if buf.Len() != test.remaining {
			t.Errorf("#%d got %d bytes remaining; want %d", i, buf.Len(), test.remaining)
		}
	}
}