Add resumable downloads, download paths, queue controls and history

internal/preferences/preferences.go

@@ -3,22 +3,27 @@ package preferences
 import (
 	"errors"
 	"fmt"
+	"path/filepath"
 )
 
 const (
 	gigabyte             = int64(1) << 30
 	maxConcurrentLimit   = 10
+	maxConnectionsLimit  = 16
 	maxReservedGigabytes = 100000
+	maxDownloadPaths     = 50
 )
 
 var ErrInvalid = errors.New("invalid settings")
 
 type Preferences struct {
 	MaxConcurrentDownloads int      `json:"maxConcurrentDownloads"`
+	ConnectionsPerDownload int      `json:"connectionsPerDownload"`
 	MinFreeGB              int      `json:"minFreeGB"`
 	AllowedPorts           []uint16 `json:"allowedPorts"`
 	AutoExtract            bool     `json:"autoExtract"`
 	CleanupAfterMove       bool     `json:"cleanupAfterMove"`
+	DownloadPaths          []string `json:"downloadPaths"`
 }
 
 func (preferences Preferences) MinFreeBytes() int64 {
@@ -29,7 +34,10 @@ func (preferences Preferences) Validate() error {
 	if preferences.MaxConcurrentDownloads < 1 || preferences.MaxConcurrentDownloads > maxConcurrentLimit {
 		return fmt.Errorf("%w: parallel downloads must be between 1 and %d", ErrInvalid, maxConcurrentLimit)
 	}
-	if preferences.MinFreeGB < 0 || preferences.MinFreeGB > maxReservedGigabytes {
+	if preferences.ConnectionsPerDownload < 1 || preferences.ConnectionsPerDownload > maxConnectionsLimit {
+		return fmt.Errorf("%w: connections per download must be between 1 and %d", ErrInvalid, maxConnectionsLimit)
+	}
+	if preferences.MinFreeGB < 0|| preferences.MinFreeGB > maxReservedGigabytes {
 		return fmt.Errorf("%w: free space to keep must be between 0 and %d GB", ErrInvalid, maxReservedGigabytes)
 	}
 	for _, port := range preferences.AllowedPorts {
@@ -37,5 +45,13 @@ func (preferences Preferences) Validate() error {
 			return fmt.Errorf("%w: port 0 is not allowed", ErrInvalid)
 		}
 	}
+	if len(preferences.DownloadPaths) > maxDownloadPaths {
+		return fmt.Errorf("%w: at most %d download paths are allowed", ErrInvalid, maxDownloadPaths)
+	}
+	for _, downloadPath := range preferences.DownloadPaths {
+		if !filepath.IsAbs(downloadPath) {
+			return fmt.Errorf("%w: download path %q must be an absolute path", ErrInvalid, downloadPath)
+		}
+	}
 	return nil
 }

internal/preferences/store.go

@@ -6,9 +6,10 @@ import (
 	"fmt"
 	"io/fs"
 	"os"
-	"path/filepath"
 	"slices"
 	"sync"
+
+	"ddc/internal/files"
 )
 
 type Store struct {
@@ -47,6 +48,10 @@ func (store *Store) Get() Preferences {
 	if current.AllowedPorts == nil {
 		current.AllowedPorts = []uint16{}
 	}
+	current.DownloadPaths = slices.Clone(current.DownloadPaths)
+	if current.DownloadPaths == nil {
+		current.DownloadPaths = []string{}
+	}
 	return current
 }
 
@@ -61,27 +66,9 @@ func (store *Store) Update(next Preferences) error {
 
 	store.mutex.Lock()
 	defer store.mutex.Unlock()
-	if err := writeAtomically(store.path, data); err != nil {
+	if err := files.WriteAtomically(store.path, data); err != nil {
 		return err
 	}
 	store.current = next
 	return nil
 }
-
-func writeAtomically(path string, data []byte) error {
-	temporary, err := os.CreateTemp(filepath.Dir(path), ".settings-*.tmp")
-	if err != nil {
-		return err
-	}
-	_, writeErr := temporary.Write(data)
-	closeErr := temporary.Close()
-	if writeErr != nil || closeErr != nil {
-		os.Remove(temporary.Name())
-		return errors.Join(writeErr, closeErr)
-	}
-	if err := os.Rename(temporary.Name(), path); err != nil {
-		os.Remove(temporary.Name())
-		return err
-	}
-	return nil
-}