- Revamp decypharr arch \n

- Add callback_ur, download_folder to addContent API \n
- Fix few bugs \n
- More declarative UI keywords
- Speed up repairs
- Few other improvements/bug fixes

internal/utils/file.go

@@ -1,7 +1,10 @@
 package utils
 
 import (
+	"fmt"
+	"io"
 	"net/url"
+	"os"
 	"strings"
 )
 
@@ -19,3 +22,65 @@ func PathUnescape(path string) string {
 
 	return unescapedPath
 }
+
+func PreCacheFile(filePaths []string) error {
+	if len(filePaths) == 0 {
+		return fmt.Errorf("no file paths provided")
+	}
+
+	for _, filePath := range filePaths {
+		err := func(f string) error {
+
+			file, err := os.Open(f)
+			if err != nil {
+				if os.IsNotExist(err) {
+					// File has probably been moved by arr, return silently
+					return nil
+				}
+				return fmt.Errorf("failed to open file: %s: %v", f, err)
+			}
+			defer file.Close()
+
+			// Pre-cache the file header (first 256KB) using 16KB chunks.
+			if err := readSmallChunks(file, 0, 256*1024, 16*1024); err != nil {
+				return err
+			}
+			if err := readSmallChunks(file, 1024*1024, 64*1024, 16*1024); err != nil {
+				return err
+			}
+			return nil
+		}(filePath)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func readSmallChunks(file *os.File, startPos int64, totalToRead int, chunkSize int) error {
+	_, err := file.Seek(startPos, 0)
+	if err != nil {
+		return err
+	}
+
+	buf := make([]byte, chunkSize)
+	bytesRemaining := totalToRead
+
+	for bytesRemaining > 0 {
+		toRead := chunkSize
+		if bytesRemaining < chunkSize {
+			toRead = bytesRemaining
+		}
+
+		n, err := file.Read(buf[:toRead])
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		bytesRemaining -= n
+	}
+	return nil
+}