package fileUtilities

import (
	"bytes"
	"io"
	"testing"
)

func Test_createParityFile(t *testing.T) {
	type args struct {
		in1 io.Reader
		in2 io.Reader
	}
	tests := []struct {
		name    string
		args    args
		wantOut string
		wantErr bool
	}{
		{
			name: "create parity file",
			args: args{
				in1: bytes.NewBuffer([]byte{0, 1, 2, 3, 4, 5, 6, 7}),
				in2: bytes.NewBuffer([]byte{7, 6, 5, 4, 3, 2, 1, 0}),
			},
			wantOut: string([]byte{7, 7, 7, 7, 7, 7, 7, 7}),
			wantErr: false,
		},
		{
			name: "in1 is longer than in2",
			args: args{
				in1: bytes.NewBuffer([]byte{0, 1, 2, 3, 4, 5, 6, 7, 8}),
				in2: bytes.NewBuffer([]byte{7, 6, 5, 4, 3, 2, 1, 0}),
			},
			wantOut: string([]byte{7, 7, 7, 7, 7, 7, 7, 7, 8}),
			wantErr: false,
		},
		{
			name: "in2 is longer than in1",
			args: args{
				in1: bytes.NewBuffer([]byte{0, 1, 2, 3, 4, 5, 6, 7}),
				in2: bytes.NewBuffer([]byte{7, 6, 5, 4, 3, 2, 1, 0, 54}),
			},
			wantOut: string([]byte{7, 7, 7, 7, 7, 7, 7, 7, 54}),
			wantErr: false,
		},
		{
			name: "parity recreates original file",
			args: args{
				in1: bytes.NewBuffer([]byte{0, 1, 2, 3, 4, 5, 6, 7}),
				in2: bytes.NewBuffer([]byte{7, 7, 7, 7, 7, 7, 7, 7, 54}),
			},
			wantOut: string([]byte{7, 6, 5, 4, 3, 2, 1, 0, 54}),
			wantErr: false,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			out := &bytes.Buffer{}
			err := parityStream(tt.args.in1, tt.args.in2, out)
			if (err != nil) != tt.wantErr {
				t.Errorf("parityStream() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if gotOut := out.String(); gotOut != tt.wantOut {
				t.Errorf("parityStream() gotOut = %v, want %v", gotOut, tt.wantOut)
			}
		})
	}
}