From ca5bd29a04d8a90224ac7a3c524354b9171a599c Mon Sep 17 00:00:00 2001
From: liwei <liwei-8466@qq.com>
Date: Sun, 23 Jul 2023 00:30:45 +0800
Subject: [PATCH] fix: torrent file real time completed bytes

---
 file.go      | 65 +++++++++++++++++++++++++++++++++++++---------------
 file_test.go |  4 +++-
 2 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/file.go b/file.go
index ed2f5da9..bea4b136 100644
--- a/file.go
+++ b/file.go
@@ -62,31 +62,58 @@ func fileBytesLeft(
 	fileTorrentOffset int64,
 	fileLength int64,
 	torrentCompletedPieces *roaring.Bitmap,
+	pieceSizeCompletedFn func(pieceIndex int) int64,
 ) (left int64) {
-	numPiecesSpanned := fileEndPieceIndex - fileFirstPieceIndex
-	switch numPiecesSpanned {
-	case 0:
-	case 1:
-		if !torrentCompletedPieces.Contains(bitmap.BitIndex(fileFirstPieceIndex)) {
-			left += fileLength
-		}
-	default:
-		if !torrentCompletedPieces.Contains(bitmap.BitIndex(fileFirstPieceIndex)) {
-			left += torrentUsualPieceSize - (fileTorrentOffset % torrentUsualPieceSize)
-		}
-		if !torrentCompletedPieces.Contains(bitmap.BitIndex(fileEndPieceIndex - 1)) {
-			left += fileTorrentOffset + fileLength - int64(fileEndPieceIndex-1)*torrentUsualPieceSize
-		}
-		completedMiddlePieces := torrentCompletedPieces.Clone()
-		completedMiddlePieces.RemoveRange(0, bitmap.BitRange(fileFirstPieceIndex+1))
-		completedMiddlePieces.RemoveRange(bitmap.BitRange(fileEndPieceIndex-1), bitmap.ToEnd)
-		left += int64(numPiecesSpanned-2-pieceIndex(completedMiddlePieces.GetCardinality())) * torrentUsualPieceSize
+	if fileLength == 0 {
+		return
 	}
+
+	noCompletedMiddlePieces := roaring.New()
+	noCompletedMiddlePieces.AddRange(bitmap.BitRange(fileFirstPieceIndex), bitmap.BitRange(fileEndPieceIndex))
+	noCompletedMiddlePieces.AndNot(torrentCompletedPieces)
+	noCompletedMiddlePieces.Iterate(func(pieceIndex uint32) bool {
+		i := int(pieceIndex)
+		pieceSizeCompleted := pieceSizeCompletedFn(i)
+		if i == fileFirstPieceIndex {
+			beginOffset := fileTorrentOffset % torrentUsualPieceSize
+			beginSize := torrentUsualPieceSize - beginOffset
+			beginDownLoaded := pieceSizeCompleted - beginOffset
+			if beginDownLoaded < 0 {
+				beginDownLoaded = 0
+			}
+			left += beginSize - beginDownLoaded
+		} else if i == fileEndPieceIndex-1 {
+			endSize := (fileTorrentOffset + fileLength) % torrentUsualPieceSize
+			if endSize == 0 {
+				endSize = torrentUsualPieceSize
+			}
+			endDownloaded := pieceSizeCompleted
+			if endDownloaded > endSize {
+				endDownloaded = endSize
+			}
+			left += endSize - endDownloaded
+		} else {
+			left += torrentUsualPieceSize - pieceSizeCompleted
+		}
+		return true
+	})
+
+	if left > fileLength {
+		left = fileLength
+	}
+	//
+	//numPiecesSpanned := f.EndPieceIndex() - f.BeginPieceIndex()
+	//completedMiddlePieces := f.t._completedPieces.Clone()
+	//completedMiddlePieces.RemoveRange(0, bitmap.BitRange(f.BeginPieceIndex()+1))
+	//completedMiddlePieces.RemoveRange(bitmap.BitRange(f.EndPieceIndex()-1), bitmap.ToEnd)
+	//left += int64(numPiecesSpanned-2-pieceIndex(completedMiddlePieces.GetCardinality())) * torrentUsualPieceSize
 	return
 }
 
 func (f *File) bytesLeft() (left int64) {
-	return fileBytesLeft(int64(f.t.usualPieceSize()), f.BeginPieceIndex(), f.EndPieceIndex(), f.offset, f.length, &f.t._completedPieces)
+	return fileBytesLeft(int64(f.t.usualPieceSize()), f.BeginPieceIndex(), f.EndPieceIndex(), f.offset, f.length, &f.t._completedPieces, func(pieceIndex int) int64 {
+		return int64(f.t.piece(pieceIndex).numDirtyBytes())
+	})
 }
 
 // The relative file path for a multi-file torrent, and the torrent name for a
diff --git a/file_test.go b/file_test.go
index e0df62b4..2f57bcf4 100644
--- a/file_test.go
+++ b/file_test.go
@@ -35,7 +35,9 @@ type testFileBytesLeft struct {
 
 func (me testFileBytesLeft) Run(t *testing.T) {
 	t.Run(me.name, func(t *testing.T) {
-		assert.EqualValues(t, me.expected, fileBytesLeft(me.usualPieceSize, me.firstPieceIndex, me.endPieceIndex, me.fileOffset, me.fileLength, &me.completedPieces))
+		assert.EqualValues(t, me.expected, fileBytesLeft(me.usualPieceSize, me.firstPieceIndex, me.endPieceIndex, me.fileOffset, me.fileLength, &me.completedPieces, func(pieceIndex int) int64 {
+			return 0
+		}))
 	})
 }