package notify

import (
	"bytes"
	"encoding/binary"
	"io"
	"net"
	"testing"
	"time"
)

type shortWriteBulkRecordConn struct {
	maxPerWrite int
	buf         bytes.Buffer
}

func (c *shortWriteBulkRecordConn) Read([]byte) (int, error) { return 0, io.EOF }

func (c *shortWriteBulkRecordConn) Write(p []byte) (int, error) {
	if len(p) == 0 {
		return 0, nil
	}
	n := c.maxPerWrite
	if n <= 0 || n > len(p) {
		n = len(p)
	}
	_, _ = c.buf.Write(p[:n])
	return n, nil
}

func (c *shortWriteBulkRecordConn) Close() error                { return nil }
func (c *shortWriteBulkRecordConn) LocalAddr() net.Addr         { return shortWriteBulkRecordAddr("local") }
func (c *shortWriteBulkRecordConn) RemoteAddr() net.Addr        { return shortWriteBulkRecordAddr("remote") }
func (c *shortWriteBulkRecordConn) SetDeadline(time.Time) error { return nil }
func (c *shortWriteBulkRecordConn) SetReadDeadline(time.Time) error {
	return nil
}
func (c *shortWriteBulkRecordConn) SetWriteDeadline(time.Time) error {
	return nil
}

type shortWriteBulkRecordAddr string

func (a shortWriteBulkRecordAddr) Network() string { return "tcp" }
func (a shortWriteBulkRecordAddr) String() string  { return string(a) }

func TestWriteBulkDedicatedRecordWithDeadlineHandlesShortWrite(t *testing.T) {
	conn := &shortWriteBulkRecordConn{maxPerWrite: 3}
	payload := []byte("abcdefghijklmnopqrstuvwxyz")
	if err := writeBulkDedicatedRecordWithDeadline(conn, payload, time.Time{}); err != nil {
		t.Fatalf("writeBulkDedicatedRecordWithDeadline failed: %v", err)
	}
	raw := conn.buf.Bytes()
	if got, want := len(raw), bulkDedicatedRecordHeaderLen+len(payload); got != want {
		t.Fatalf("record length = %d, want %d", got, want)
	}
	if got := string(raw[:4]); got != bulkDedicatedRecordMagic {
		t.Fatalf("record magic = %q, want %q", got, bulkDedicatedRecordMagic)
	}
	if got, want := int(binary.BigEndian.Uint32(raw[4:8])), len(payload); got != want {
		t.Fatalf("record payload length = %d, want %d", got, want)
	}
	if got := raw[bulkDedicatedRecordHeaderLen:]; !bytes.Equal(got, payload) {
		t.Fatalf("record payload mismatch")
	}
}