mirror of
https://github.com/zarzet/SpotiFLAC-Mobile.git
synced 2026-09-28 12:22:12 +02:00
92 lines
3.2 KiB
Dart
92 lines
3.2 KiB
Dart
import 'dart:math' as math;
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import 'package:spotiflac_android/models/track.dart';
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import 'package:spotiflac_android/providers/extension_provider.dart';
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class DownloadSizeEstimate {
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final int minBytes;
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final int maxBytes;
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const DownloadSizeEstimate({required this.minBytes, required this.maxBytes});
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}
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/// Unknown durations must not make a batch estimate look like a complete total.
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Duration? totalDownloadDuration(Iterable<Track> tracks) {
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var seconds = 0;
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for (final track in tracks) {
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if (track.isCollection || track.duration <= 0) return null;
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seconds += track.duration;
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}
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return seconds > 0 ? Duration(seconds: seconds) : null;
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}
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DownloadSizeEstimate? estimateDownloadSize({
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required Duration? duration,
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required QualityOption quality,
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}) {
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if (duration == null || duration <= Duration.zero) return null;
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final parameters = quality.sizeEstimate ?? _legacyParameters(quality);
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if (parameters == null) return null;
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final seconds = duration.inMilliseconds / 1000;
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final bitrate = parameters.bitrateKbps;
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if (bitrate != null) {
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if (bitrate <= 0 || parameters.isMaximum) return null;
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final bytes = (seconds * bitrate * 1000 / 8).round();
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return DownloadSizeEstimate(minBytes: bytes, maxBytes: bytes);
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}
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final depth = parameters.bitDepth;
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final rate = parameters.sampleRate;
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if (depth == null ||
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depth <= 0 ||
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rate == null ||
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rate <= 0 ||
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parameters.channels <= 0) {
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return null;
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}
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final minDepth = parameters.isMaximum ? math.min(depth, 16) : depth;
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final minRate = parameters.isMaximum ? math.min(rate, 44100) : rate;
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// A rough compressed-lossless range (50–80% of PCM), not a bound or a
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// guarantee. Capped tiers can deliver CD quality instead of their maximum.
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// Artwork, tags, container overhead and later conversion are excluded.
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return DownloadSizeEstimate(
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minBytes: (seconds * minDepth * minRate * parameters.channels / 8 * 0.5)
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.round(),
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maxBytes: (seconds * depth * rate * parameters.channels / 8 * 0.8).round(),
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);
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}
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QualitySizeEstimate? _legacyParameters(QualityOption quality) {
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// These are the same legacy tiers already labelled by the picker. Custom
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// IDs (including best/high/low and spatial audio) need declared parameters.
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switch (quality.id.toUpperCase()) {
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case 'LOSSLESS':
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return const QualitySizeEstimate(bitDepth: 16, sampleRate: 44100);
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case 'HI_RES':
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return const QualitySizeEstimate(
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bitDepth: 24,
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sampleRate: 96000,
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isMaximum: true,
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);
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case 'HI_RES_LOSSLESS':
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return const QualitySizeEstimate(
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bitDepth: 24,
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sampleRate: 192000,
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isMaximum: true,
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);
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}
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// Only explicit codec/bitrate labels or IDs; never infer a bitrate from a
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// vague tier name or a description mentioning other fallback formats.
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final bitratePattern = RegExp(
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r'^(?:mp3|opus|aac)[ _-]+(\d+)(?:\s*(?:kbps|kb/s|kbit/s|k))?$',
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caseSensitive: false,
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);
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for (final value in [quality.id, quality.label]) {
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final match = bitratePattern.firstMatch(value.trim());
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if (match != null) {
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return QualitySizeEstimate(bitrateKbps: int.tryParse(match.group(1)!));
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}
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}
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return null;
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}
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