package kconfig

import (
	"bytes"
	"encoding/binary"
	"os"
	"testing"

	"github.com/cilium/ebpf/btf"
	"github.com/cilium/ebpf/internal"

	"github.com/go-quicktest/qt"
)

func BenchmarkParse(b *testing.B) {
	f, err := os.Open("testdata/config-6.2.15-300.fc38.x86_64.gz")
	if err != nil {
		b.Fatal(err)
	}
	defer f.Close()

	b.ReportAllocs()
	b.ResetTimer()

	for n := 0; n < b.N; n++ {
		_, err := Parse(f, nil)
		if err != nil {
			b.Fatal(err)
		}
	}
}

func BenchmarkParseFiltered(b *testing.B) {
	f, err := os.Open("testdata/config-6.2.15-300.fc38.x86_64.gz")
	if err != nil {
		b.Fatal(err)
	}
	defer f.Close()

	b.ReportAllocs()
	b.ResetTimer()

	// CONFIG_ARCH_USE_MEMTEST is the last CONFIG_ in the file.
	// So, we will easily be able to see how many allocated bytes the filtering
	// permits reducing compared to unfiltered benchmark.
	filter := map[string]struct{}{"CONFIG_ARCH_USE_MEMTEST": {}}

	for n := 0; n < b.N; n++ {
		_, err := Parse(f, filter)
		if err != nil {
			b.Fatal(err)
		}
	}
}

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

	f, err := os.Open("testdata/test.kconfig")
	if err != nil {
		t.Fatal("Error reading /testdata/test.kconfig: ", err)
	}
	defer f.Close()

	config, err := Parse(f, nil)
	if err != nil {
		t.Fatal("Error parsing kconfig: ", err)
	}

	expected := map[string]string{
		"CONFIG_TRISTATE": "m",
		"CONFIG_BOOL":     "y",
		"CONFIG_CHAR":     "100",
		"CONFIG_USHORT":   "30000",
		"CONFIG_INT":      "123456",
		"CONFIG_ULONG":    "0xDEADBEEFC0DE",
		"CONFIG_STR":      `"abracad"`,
		"CONFIG_FOO":      `"foo"`,
	}
	qt.Assert(t, qt.DeepEquals(config, expected))
}

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

	f, err := os.Open("testdata/test.kconfig")
	if err != nil {
		t.Fatal("Error reading /testdata/test.kconfig: ", err)
	}
	defer f.Close()

	filter := map[string]struct{}{"CONFIG_FOO": {}}

	config, err := Parse(f, filter)
	if err != nil {
		t.Fatal("Error parsing gzipped kconfig: ", err)
	}

	expected := map[string]string{"CONFIG_FOO": `"foo"`}
	qt.Assert(t, qt.DeepEquals(config, expected))
}

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

	f, err := os.Open("testdata/config-6.2.15-300.fc38.x86_64.gz")
	if err != nil {
		t.Fatal("Error reading /testdata/config-6.2.15-300.fc38.x86_64.gz: ", err)
	}
	defer f.Close()

	_, err = Parse(f, nil)
	if err != nil {
		t.Fatal("Error parsing gzipped kconfig: ", err)
	}
}

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

	f, err := os.Open("testdata/config-6.2.15-300.fc38.x86_64.gz")
	if err != nil {
		t.Fatal("Error reading /testdata/config-6.2.15-300.fc38.x86_64.gz: ", err)
	}
	defer f.Close()

	filter := map[string]struct{}{"CONFIG_HZ": {}}

	config, err := Parse(f, filter)
	if err != nil {
		t.Fatal("Error parsing gzipped kconfig: ", err)
	}

	expected := map[string]string{"CONFIG_HZ": "1000"}
	qt.Assert(t, qt.DeepEquals(config, expected))
}

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

	m := make(map[string]string)

	err := processKconfigLine([]byte("CONFIG_FOO"), m, nil)
	qt.Assert(t, qt.IsNotNil(err), qt.Commentf("line has no '='"))

	err = processKconfigLine([]byte("CONFIG_FOO="), m, nil)
	qt.Assert(t, qt.IsNotNil(err), qt.Commentf("line has no value"))
}

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

	type testCase struct {
		typ      btf.Type
		value    string
		expected any
		comment  string
	}

	cases := []testCase{
		{
			typ: &btf.Int{
				Size:     1,
				Encoding: btf.Bool,
			},
			value:    "n",
			expected: int8(0),
		},
		{
			typ: &btf.Int{
				Size:     1,
				Encoding: btf.Bool,
			},
			value:    "y",
			expected: int8(1),
		},
		{
			typ: &btf.Int{
				Size:     1,
				Encoding: btf.Bool,
			},
			value:   "foo",
			comment: "Bad value",
		},
		{
			typ:     &btf.Int{},
			comment: "Encoding is not Bool",
		},
		{
			typ: &btf.Int{
				Encoding: btf.Bool,
			},
			comment: "Size is not 1",
		},
		{
			typ: &btf.Enum{
				Name: "libbpf_tristate",
			},
			value:    "y",
			expected: int32(TriYes),
		},
		{
			typ: &btf.Enum{
				Name: "libbpf_tristate",
			},
			value:    "n",
			expected: int32(TriNo),
		},
		{
			typ: &btf.Enum{
				Name: "libbpf_tristate",
			},
			value:    "m",
			expected: int32(TriModule),
		},
		{
			typ: &btf.Enum{
				Name: "libbpf_tristate",
			},
			value:   "foo",
			comment: "Bad value",
		},
		{
			typ: &btf.Enum{
				Name: "error",
			},
			comment: "Enum name is wrong",
		},
		{
			typ:     &btf.Array{},
			value:   "y",
			comment: "Type is not btf.Int",
		},
		{
			typ: &btf.Int{
				Size: 1,
			},
			value:    "255",
			expected: uint8(255),
		},
		{
			typ: &btf.Int{
				Size: 2,
			},
			value:    "0xcafe",
			expected: uint16(0xcafe),
		},
		{
			typ: &btf.Int{
				Size: 2,
			},
			value:    "0755",
			expected: uint16(0755),
		},
		{
			typ: &btf.Int{
				Size:     4,
				Encoding: btf.Signed,
			},
			value:    "-2147483648",
			expected: int32(-2147483648),
		},
		{
			typ: &btf.Int{
				Size:     4,
				Encoding: btf.Signed,
			},
			value:    "+2147483647",
			expected: int32(+2147483647),
		},
		{
			typ: &btf.Int{
				Size: 4,
			},
			value:    "0xcafec0de",
			expected: uint32(0xcafec0de),
		},
		{
			typ: &btf.Int{
				Size:     8,
				Encoding: btf.Signed,
			},
			value:    "+1000000000000",
			expected: int64(1000000000000),
		},
		{
			typ: &btf.Int{
				Size: 8,
			},
			value:    "1000000000000",
			expected: uint64(1000000000000),
		},
		{
			typ: &btf.Int{
				Size: 1,
			},
			value:   "foo",
			comment: "Value is not an int",
		},
		{
			typ:     &btf.Array{},
			value:   "1",
			comment: "Type is not btf.Int",
		},
		{
			typ: &btf.Int{
				Size: 16,
			},
			value:   "1",
			comment: "Size is wrong",
		},
		{
			typ: &btf.Typedef{
				Type: &btf.Int{
					Size: 1,
				},
			},
			value:    "1",
			expected: uint8(1),
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     1,
					Encoding: btf.Char,
				},
				Nelems: 6,
			},
			value:    `"foobar"`,
			expected: []byte("foobar"),
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     1,
					Encoding: btf.Unsigned,
				},
				Nelems: 3,
			},
			value:    `"foobar"`,
			expected: []byte("foo"),
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     1,
					Encoding: btf.Signed,
				},
				Nelems: 2,
			},
			value:    `"42"`,
			expected: []byte("42"),
		},
		{
			typ:     &btf.Int{},
			value:   `"foo"`,
			comment: "Type is not btf.Array",
		},
		{
			typ:     &btf.Array{},
			value:   `"foo"`,
			comment: "Type is not btf.Array of btf.Int",
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     1,
					Encoding: btf.Bool,
				},
			},
			comment: "Type is not btf.Array of btf.Int of size 1 which is not btf.Bool",
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     4,
					Encoding: btf.Char,
				},
			},
			value:   `"foo"`,
			comment: "Type is not btf.Array of btf.Char of size 1",
		},
		{
			typ: &btf.Array{
				Type: &btf.Int{
					Size:     1,
					Encoding: btf.Char,
				},
			},
			value:   `"foo`,
			comment: `Value does not start and end with '"'`,
		},
	}

	for _, c := range cases {
		if len(c.comment) > 0 {
			err := PutValue(make([]byte, 0), c.typ, c.value)

			qt.Assert(t, qt.IsNotNil(err), qt.Commentf(c.comment))

			continue
		}

		var buf bytes.Buffer
		err := binary.Write(&buf, internal.NativeEndian, c.expected)
		if err != nil {
			t.Fatal(err)
		}

		expected := buf.Bytes()
		data := make([]byte, len(expected))
		err = PutValue(data, c.typ, c.value)

		qt.Assert(t, qt.IsNil(err))

		qt.Assert(t, qt.DeepEquals(data, expected))
	}
}

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

	type testCase struct {
		expected []byte
		integer  *btf.Int
		n        uint64
		err      bool
		comment  string
	}

	cases := []testCase{
		{
			integer:  &btf.Int{Size: 1, Encoding: btf.Unsigned},
			n:        0x01,
			expected: []byte{0x01},
		},
		{
			integer:  &btf.Int{Size: 2, Encoding: btf.Unsigned},
			n:        0x902a,
			expected: []byte{0x2a, 0x90},
		},
		{
			integer:  &btf.Int{Size: 4, Encoding: btf.Unsigned},
			n:        0x01234567,
			expected: []byte{0x67, 0x45, 0x23, 0x01},
		},
		{
			integer: &btf.Int{Size: 1, Encoding: btf.Signed},
			n:       0x80,
			err:     true,
			comment: "outside of range int8 -128 ~ 127",
		},
		{
			integer: &btf.Int{Size: 2, Encoding: btf.Signed},
			n:       0xabcdabcd,
			err:     true,
			comment: "outside of range int16 -32768 ~ 32767",
		},
		{
			integer: &btf.Int{Size: 4, Encoding: btf.Signed},
			n:       0x1234567890,
			err:     true,
			comment: "outside of range int32 -2147483648 ~ 2147483647",
		},
		{
			integer:  &btf.Int{Size: 2, Encoding: btf.Signed},
			n:        0xffffffffffffffff,
			expected: []byte{0xff, 0xff, 0x00, 0x00},
			comment:  "n means -1",
		},
		{
			integer: &btf.Int{Size: 2, Encoding: btf.Signed},
			n:       0xffffffffffffffff - 0x8000,
			err:     true,
			comment: "n means -32768(-MinInt16) - 1 in signed value",
		},
		{
			integer:  &btf.Int{Size: 2, Encoding: btf.Signed},
			n:        0x7fff,
			expected: []byte{0xff, 0x7f},
			comment:  "maximum value of int16",
		},
		{
			integer:  &btf.Int{Size: 2, Encoding: btf.Unsigned},
			n:        0xffff,
			expected: []byte{0xff, 0xff},
		},
		{
			integer:  &btf.Int{Size: 4, Encoding: btf.Unsigned},
			n:        0xffffffff,
			expected: []byte{0xff, 0xff, 0xff, 0xff},
		},
		{
			integer: &btf.Int{Size: 4, Encoding: btf.Signed},
			n:       0x80000000,
			err:     true,
			comment: "outside of range int32 ~2147483648 ~ 2147483647",
		},
		{
			integer: &btf.Int{Size: 4, Encoding: btf.Signed},
			n:       0xffffffffffffffff - 0x80000000,
			err:     true,
			comment: "outside of range int32 ~2147483648 ~ 2147483647",
		},
		{
			integer:  &btf.Int{Size: 8, Encoding: btf.Unsigned},
			n:        0xffffffffffffffff,
			expected: []byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
		},
	}

	for _, c := range cases {
		data := make([]byte, len(c.expected))
		err := PutInteger(data, c.integer, c.n)

		if c.err {
			qt.Assert(t, qt.IsNotNil(err))
			continue
		}

		qt.Assert(t, qt.IsNil(err))
		qt.Assert(t, qt.DeepEquals(data, c.expected), qt.Commentf(c.comment))
	}
}

func TestPutIntegerError(t *testing.T) {
	qt.Assert(t, qt.IsNotNil(PutInteger(nil, &btf.Int{Size: 2}, 0)), qt.Commentf("slice too small for int"))
	qt.Assert(t, qt.IsNotNil(PutInteger(nil, &btf.Int{Encoding: btf.Bool}, 2)), qt.Commentf("n too big for bool"))
}