package adb

import (
	"bytes"
	"testing"
	"time"

	"encoding/binary"
	"strings"

	"github.com/Evrins/goadb/wire"

	"github.com/stretchr/testify/assert"
)

func TestFileWriterWriteSingleChunk(t *testing.T) {
	var buf bytes.Buffer
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), MtimeOfClose)

	n, err := writer.Write([]byte("hello"))
	assert.NoError(t, err)
	assert.Equal(t, 5, n)

	assert.Equal(t, "DATA\005\000\000\000hello", buf.String())
}

func TestFileWriterWriteMultiChunk(t *testing.T) {
	var buf bytes.Buffer
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), MtimeOfClose)

	n, err := writer.Write([]byte("hello"))
	assert.NoError(t, err)
	assert.Equal(t, 5, n)

	n, err = writer.Write([]byte(" world"))
	assert.NoError(t, err)
	assert.Equal(t, 6, n)

	assert.Equal(t, "DATA\005\000\000\000helloDATA\006\000\000\000 world", buf.String())
}

func TestFileWriterWriteLargeChunk(t *testing.T) {
	var buf bytes.Buffer
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), MtimeOfClose)

	// Send just enough data to get 2 chunks.
	data := make([]byte, wire.SyncMaxChunkSize+1)
	n, err := writer.Write(data)

	assert.NoError(t, err)
	assert.Equal(t, wire.SyncMaxChunkSize+1, n)
	assert.Equal(t, 8+8+wire.SyncMaxChunkSize+1, buf.Len())

	// First header.
	chunk := buf.Bytes()[:8+wire.SyncMaxChunkSize]
	expectedHeader := []byte("DATA----")
	binary.LittleEndian.PutUint32(expectedHeader[4:], wire.SyncMaxChunkSize)
	assert.Equal(t, expectedHeader, chunk[:8])
	assert.Equal(t, data[:wire.SyncMaxChunkSize], chunk[8:])

	// Second header.
	chunk = buf.Bytes()[wire.SyncMaxChunkSize+8 : wire.SyncMaxChunkSize+8+1]
	expectedHeader = []byte("DATA\000\000\000\000")
	binary.LittleEndian.PutUint32(expectedHeader[4:], 1)
	assert.Equal(t, expectedHeader, chunk[:8])
}

func TestFileWriterCloseEmpty(t *testing.T) {
	var buf bytes.Buffer
	mtime := time.Unix(1, 0)
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), mtime)

	assert.NoError(t, writer.Close())

	assert.Equal(t, "DONE\x01\x00\x00\x00", buf.String())
}

func TestFileWriterWriteClose(t *testing.T) {
	var buf bytes.Buffer
	mtime := time.Unix(1, 0)
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), mtime)

	writer.Write([]byte("hello"))
	assert.NoError(t, writer.Close())

	assert.Equal(t, "DATA\005\000\000\000helloDONE\x01\x00\x00\x00", buf.String())
}

func TestFileWriterCloseAutoMtime(t *testing.T) {
	var buf bytes.Buffer
	writer := newSyncFileWriter(wire.NewSyncSender(&buf), MtimeOfClose)

	assert.NoError(t, writer.Close())
	assert.Len(t, buf.String(), 8)
	assert.True(t, strings.HasPrefix(buf.String(), "DONE"))

	mtimeBytes := buf.Bytes()[4:]
	mtimeActual := time.Unix(int64(binary.LittleEndian.Uint32(mtimeBytes)), 0)

	// Delta has to be a whole second since adb only supports second granularity for mtimes.
	assert.WithinDuration(t, time.Now(), mtimeActual, 1*time.Second)
}