package decoders

import (
	"reflect"
	"strings"
	"testing"

	"github.com/jwetzell/psn-go/internal/chunks"
)

func TestGoodChunkDecoding(t *testing.T) {
	testCases := []struct {
		description string
		bytes       []byte
		expected    chunks.Chunk
	}{
		{
			description: "info packet",
			bytes: []byte{
				0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
				0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
				0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
			},
			expected: chunks.Chunk{
				Header: chunks.ChunkHeader{
					Id:           uint16(26454),
					DataLen:      uint16(52),
					HasSubchunks: true,
				},
				ChunkData: []byte{
					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
					0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
					0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
				},
			},
		},
		{
			description: "data packet",
			bytes: []byte{
				0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
				0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
				0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
			},
			expected: chunks.Chunk{
				Header: chunks.ChunkHeader{
					Id:           uint16(26453),
					DataLen:      uint16(40),
					HasSubchunks: true,
				},
				ChunkData: []byte{
					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
					0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
					0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
				},
			},
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.description, func(t *testing.T) {
			actual, err := DecodeChunk(testCase.bytes)

			if err != nil {
				t.Errorf("failed to decode chunk properly, error: %v", err)
			}

			if !reflect.DeepEqual(actual, testCase.expected) {
				t.Errorf("failed to decode chunk properly, expected: %+v, actual: %+v", testCase.expected, actual)
			}
		})
	}
}

func TestBadChunkDecoding(t *testing.T) {
	testCases := []struct {
		description        string
		bytes              []byte
		errorShouldContain string
	}{
		{
			description:        "empty packet",
			bytes:              []byte{},
			errorShouldContain: "must be at least 4 bytes",
		},
	}

	for _, testCase := range testCases {
		t.Run(testCase.description, func(t *testing.T) {
			_, err := DecodeChunk(testCase.bytes)

			if err == nil {
				t.Error("should have failed fail to decode chunk properly")
			}

			if !strings.Contains(err.Error(), testCase.errorShouldContain) {
				t.Errorf("did not return the correct error expected: %s, got: %s", testCase.errorShouldContain, err.Error())
			}
		})
	}
}

func BenchmarkChunkDecoding(b *testing.B) {
	data := []byte{
		0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
		0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
		0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
	}
	for b.Loop() {
		_, err := DecodeChunk(data)
		if err != nil {
			b.Errorf("failed to decode chunk properly, error: %v", err)
		}
	}
}

func FuzzChunkDecoding(f *testing.F) {
	seedCases := [][]byte{
		{
			0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
			0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
			0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
		},
		{
			0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
			0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
			0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
		},
	}

	for _, seed := range seedCases {
		f.Add(seed)
	}

	f.Fuzz(func(t *testing.T, bytes []byte) {
		_, _ = DecodeChunk(bytes)
	})
}