From 083a0ebd6551c81895ec06f029f5bb647e6f2aac Mon Sep 17 00:00:00 2001
From: Ben Sarmiento <ben.sarmiento@forto.com>
Date: Mon, 6 Nov 2023 00:06:26 +0100
Subject: [PATCH] Implement file reads

---
 internal/zfs/object.go | 70 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/internal/zfs/object.go b/internal/zfs/object.go
index 469fb53..dc34dab 100644
--- a/internal/zfs/object.go
+++ b/internal/zfs/object.go
@@ -3,6 +3,8 @@ package zfs
 import (
 	"context"
 	"fmt"
+	"io"
+	"net/http"
 	"os"
 	"path/filepath"
 	"strings"
@@ -11,6 +13,7 @@ import (
 
 	"bazil.org/fuse"
 	"bazil.org/fuse/fs"
+	"github.com/debridmediamanager.com/zurg/pkg/realdebrid"
 )
 
 // define variable as rootObject id
@@ -26,6 +29,7 @@ type Object struct {
 	objType    int
 	parentName string
 	name       string
+	link       string
 	size       uint64
 	mtime      time.Time
 }
@@ -137,6 +141,7 @@ func (o Object) Lookup(ctx context.Context, name string) (fs.Node, error) {
 						objType:    FILE,
 						parentName: o.name,
 						name:       name,
+						link:       file.Link,
 						size:       uint64(file.Bytes),
 						mtime:      convertRFC3339toTime(item.Added),
 					}, nil
@@ -155,7 +160,70 @@ func (o Object) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.Open
 
 // Read reads some bytes or the whole file
 func (o Object) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
-	return fmt.Errorf("Read not yet implemented")
+	o.fs.log.Debugf("Reading offset %d size %d", req.Offset, req.Size)
+	unrestrictFn := func() (*realdebrid.UnrestrictResponse, error) {
+		return realdebrid.UnrestrictLink(o.fs.c.GetToken(), o.link)
+	}
+	unrestrictResp := realdebrid.RetryUntilOk(unrestrictFn)
+	if unrestrictResp == nil {
+		o.fs.log.Errorf("Cannot unrestrict link %s", o.link)
+		return syscall.EIO
+	} else if unrestrictResp.Filename != o.name {
+		actualExt := filepath.Ext(unrestrictResp.Filename)
+		expectedExt := filepath.Ext(o.name)
+		if actualExt != expectedExt {
+			o.fs.log.Errorf("File extension mismatch: expected %s, got %s", expectedExt, actualExt)
+		} else {
+			o.fs.log.Errorf("Filename mismatch: expected %s, got %s", o.name, unrestrictResp.Filename)
+		}
+	}
+	o.fs.log.Debugf("Unrestricted link: %s", unrestrictResp.Download)
+
+	httpClient := &http.Client{
+		Timeout: 30 * time.Second, // Set a timeout to prevent hanging
+	}
+
+	streamReq, err := http.NewRequest(http.MethodGet, unrestrictResp.Download, nil)
+	if err != nil {
+		o.fs.log.Errorf("Error creating new request %v", err)
+		return syscall.EIO
+	}
+
+	// Ensure that the byte range is correctly specified
+	endByte := req.Offset + int64(req.Size) - 1
+	streamReq.Header.Add("Range", fmt.Sprintf("bytes=%d-%d", req.Offset, endByte))
+	o.fs.log.Debugf("Requested bytes=%d-%d", req.Offset, endByte)
+
+	streamResp, err := httpClient.Do(streamReq.WithContext(ctx))
+	if err != nil {
+		o.fs.log.Errorf("Error downloading file %s %v", unrestrictResp.Download, err)
+		return syscall.EIO
+	}
+	defer streamResp.Body.Close()
+
+	// Check for successful status codes
+	if streamResp.StatusCode != http.StatusOK && streamResp.StatusCode != http.StatusPartialContent {
+		o.fs.log.Errorf("Received a non-ok status code %d for %s", streamResp.StatusCode, unrestrictResp.Download)
+		return syscall.EIO
+	}
+
+	// Optionally check if the server returned the expected byte range
+	contentRange := streamResp.Header.Get("Content-Range")
+	if contentRange == "" && streamResp.StatusCode == http.StatusPartialContent {
+		o.fs.log.Error("Content-Range header is missing in HTTP partial content response")
+		return syscall.EIO
+	}
+
+	// Process the stream in chunks.
+	// Allocate a buffer to read into.
+	respData, readErr := io.ReadAll(streamResp.Body)
+	if readErr != nil {
+		o.fs.log.Errorf("Error reading bytes from download response %v", readErr)
+		return syscall.EIO
+	}
+	resp.Data = respData
+	o.fs.log.Debugf("Read %d bytes in total", len(resp.Data))
+	return nil
 }
 
 // Remove deletes an element