package decoders

import (
	"fmt"
	"reflect"
	"strings"
	"testing"
)

func TestGoodChunkDecoding(t *testing.T) {
	testCases := []struct {
		description string
		bytes       []byte
		expected    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: Chunk{
				Header: 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: Chunk{
				Header: 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 {

		actual, err := DecodeChunk(testCase.bytes)

		if err != nil {
			t.Errorf("Test '%s' failed to decode chunk properly", testCase.description)
			fmt.Println(err)
		}

		if !reflect.DeepEqual(actual, testCase.expected) {
			t.Errorf("Test '%s' failed to decode chunk properly", testCase.description)
			fmt.Printf("expected: %v\n", testCase.expected)
			fmt.Printf("actual: %v\n", 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 {

		_, err := DecodeChunk(testCase.bytes)

		if err == nil {
			t.Errorf("Test '%s' should have failed fail to decode chunk properly", testCase.description)
		}

		if !strings.Contains(err.Error(), testCase.errorShouldContain) {
			t.Errorf("Test '%s' did not return the correct error", testCase.description)
			fmt.Printf("expected: %v\n", testCase.errorShouldContain)
			fmt.Printf("actual: %v\n", err.Error())
		}

	}
}