refactor: consolidate download domain into download package

internal/download/download.go

@@ -0,0 +1,117 @@
+package download
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/mathismqn/godeez/internal/config"
+	"github.com/mathismqn/godeez/internal/deezer"
+	"github.com/mathismqn/godeez/internal/fsutil"
+	"github.com/mathismqn/godeez/internal/store"
+)
+
+type Downloader struct {
+	appConfig    *config.Config
+	store        *store.Store
+	kind         deezer.Kind
+	deezerClient *deezer.Client
+
+	hashIndexOnce sync.Once
+	hashIndex     *hashIndex
+	hashIndexErr  error
+}
+
+func New(appConfig *config.Config, st *store.Store, kind deezer.Kind) *Downloader {
+	return &Downloader{
+		appConfig: appConfig,
+		store:     st,
+		kind:      kind,
+	}
+}
+
+func (d *Downloader) Run(ctx context.Context, opts Options, id string) error {
+	if err := d.initDeezerClient(ctx, opts); err != nil {
+		return err
+	}
+
+	resource, outputDir, err := d.prepareResource(ctx, id, opts)
+	if err != nil {
+		return err
+	}
+
+	return d.downloadAllTracks(ctx, resource, opts, outputDir)
+}
+
+func (d *Downloader) initDeezerClient(ctx context.Context, opts Options) error {
+	var err error
+	d.deezerClient, err = deezer.NewClient(ctx, d.appConfig.ARLCookie)
+	if err != nil {
+		return err
+	}
+
+	if !d.deezerClient.Session.Premium && (opts.Quality == "mp3_320" || opts.Quality == "flac") {
+		return fmt.Errorf("premium account required for '%s' quality", opts.Quality)
+	}
+
+	return nil
+}
+
+func (d *Downloader) prepareResource(ctx context.Context, id string, opts Options) (deezer.Resource, string, error) {
+	resource, err := d.deezerClient.FetchResource(ctx, d.kind, id)
+	if err != nil {
+		return nil, "", fmt.Errorf("failed to fetch resource: %w", err)
+	}
+
+	tracks := resource.GetTracks()
+	if len(tracks) == 0 {
+		if d.kind == deezer.KindTrack {
+			return nil, "", fmt.Errorf("track with ID %s not found", id)
+		}
+		return nil, "", fmt.Errorf("%s has no tracks", d.kind)
+	}
+
+	if d.kind == deezer.KindArtist && len(tracks) > opts.Limit {
+		resource.SetTracks(tracks[:opts.Limit])
+	}
+
+	outputDir := resource.GetOutputDir(d.appConfig.OutputDir)
+	if err := fsutil.EnsureDir(outputDir); err != nil {
+		return nil, "", fmt.Errorf("failed to create output directory: %w", err)
+	}
+
+	return resource, outputDir, nil
+}
+
+func (d *Downloader) downloadAllTracks(ctx context.Context, resource deezer.Resource, opts Options, outputDir string) error {
+	tracks := resource.GetTracks()
+	startTime := time.Now()
+
+	if d.kind != deezer.KindTrack {
+		fmt.Printf("%s\n\nStarting download...\n\n", resourceInfo(resource))
+	}
+
+	progress := newProgressTracker(len(tracks), d.kind)
+
+	for i, track := range tracks {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		sp := progress.startDownload(i, track)
+		result := d.downloadTrack(ctx, resource, track, opts, outputDir)
+		sp.Stop()
+
+		if result.err != nil && errors.Is(result.err, context.Canceled) {
+			return result.err
+		}
+
+		progress.handleResult(i, track, result)
+	}
+
+	progress.printSummary(outputDir, time.Since(startTime))
+
+	return nil
+}