package sample_test

import (
	"bytes"
	"io"
	"testing"

	"github.com/xxx/sample"
)

type nopCloser struct {
	io.Writer
}

func (nopCloser) Close() error { return nil }

func TestOutput(t *testing.T) {

	var outputMap map[string]*bytes.Buffer
	createFile := func(name string) (io.WriteCloser, error) {
		b := &bytes.Buffer{}
		outputMap[name] = b
		return nopCloser{b}, nil
	}
	resetFunc := sample.SetCreateFile(createFile)
	defer resetFunc()

	cases := []struct {
		caseName string
		multi    bool
		expected map[string]string // map[filename]contents
	}{
		{
			caseName: "multi", multi: true,
			expected: map[string]string{
				"sample_foo.txt": "foo\n",
				"sample_bar.txt": "bar\n",
			},
		},
		{
			caseName: "non-multi", multi: false,
			expected: map[string]string{
				"sample.txt": "foo\nbar\n",
			},
		},
	}

	for _, c := range cases {
		t.Run(c.caseName, func(t *testing.T) {
			outputMap = map[string]*bytes.Buffer{}
			sample.Output([]string{"foo", "bar"}, c.multi)

			if len(c.expected) != len(outputMap) {
				t.Errorf("the number of output files doesn't match (expected=%d, actual=%d)", len(c.expected), len(outputMap))
				return
			}
			for k, v := range c.expected {
				if a, ok := outputMap[k]; !ok {
					t.Errorf("file doesn't exist in output files (filename=%s)", k)
					return
				} else if a.String() != v {
					t.Errorf("file contents don't match (expected=%s, actual=%s)", v, a.String())
					return
				}
			}
		})
	}
}