Add resumable downloads, download paths, queue controls and history

internal/history/history.go

@@ -0,0 +1,82 @@
+package history
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"slices"
+	"sync"
+	"time"
+
+	"ddc/internal/files"
+)
+
+const maxEntries = 500
+
+type Entry struct {
+	FileName    string    `json:"fileName"`
+	SourceURL   string    `json:"sourceUrl"`
+	Destination string    `json:"destination"`
+	Items       []string  `json:"items"`
+	MovedAt     time.Time `json:"movedAt"`
+}
+
+type Store struct {
+	mutex   sync.Mutex
+	path    string
+	entries []Entry
+}
+
+func Open(path string) (*Store, error) {
+	store := &Store{path: path, entries: []Entry{}}
+	data, err := os.ReadFile(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return store, nil
+	}
+	if err != nil {
+		return nil, err
+	}
+	if err := json.Unmarshal(data, &store.entries); err != nil {
+		return nil, fmt.Errorf("history file %s: %w", path, err)
+	}
+	if store.entries == nil {
+		store.entries = []Entry{}
+	}
+	return store, nil
+}
+
+func (store *Store) List() []Entry {
+	store.mutex.Lock()
+	defer store.mutex.Unlock()
+	return slices.Clone(store.entries)
+}
+
+func (store *Store) Add(entry Entry) error {
+	store.mutex.Lock()
+	defer store.mutex.Unlock()
+	next := append([]Entry{entry}, store.entries...)
+	if len(next) > maxEntries {
+		next = next[:maxEntries]
+	}
+	return store.save(next)
+}
+
+func (store *Store) Clear() error {
+	store.mutex.Lock()
+	defer store.mutex.Unlock()
+	return store.save([]Entry{})
+}
+
+func (store *Store) save(entries []Entry) error {
+	data, err := json.MarshalIndent(entries, "", "  ")
+	if err != nil {
+		return err
+	}
+	if err := files.WriteAtomically(store.path, data); err != nil {
+		return err
+	}
+	store.entries = entries
+	return nil
+}