package fan

import (
	"bytes"
	"sync"
	"testing"

	"github.com/drhodes/golorem"
)

// We will be reading some random lorem ipsum text.
var data = []byte(lorem.Paragraph(500, 600))

func TestReader(t *testing.T) {
	r := bytes.NewReader(data)
	fr := Reader{r, // fan.Reader

		// Because this is an internal test we need to completely intialise
		// the struct. But note the API would look like `fan.Reader{r}`
		[]byte(nil), *new(sync.Mutex),
	}
	wg := new(sync.WaitGroup)

	// Start 10x goroutines
	for i := 0; i < 10; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			buf := new(bytes.Buffer)
			n, err := buf.ReadFrom(fr.View())
			// Check the error
			if err != nil {
				t.Errorf("Goroutine %d err: %v", i, err)
				return
			}
			// Validate the result
			if int(n) != len(data) {
				t.Errorf("Goroutine %d err: expected %d bytes, got %d", i, len(data), n)
				return
			}
			t.Logf("Goroutine %d ok: got %d bytes\n", i, len(buf.Bytes()))
		}(i)
	}
	wg.Wait()
}