pastilhas
9fb948fe83
The app shuffled by flattening every album's meta.json in scope into one array and choosing from it. On a hundred-thousand-track library that meant a six-figure object array living in the phone's JS heap — marked by every garbage collection — and copied again on each draw. Measured on device: the JS thread never went idle during playback and the phone reached 'serious' thermal state. Picking twenty songs never required any of that. The manifest already holds per-album track counts, so the choice is arithmetic over numbers and only the albums actually picked are read. Uniform over TRACKS, not albums: choosing an album first would make a two-track EP as likely as a sixty-track box set, so albums are weighted by count via a running total and a binary search. Same distribution as shuffling everything and taking the first n, which is what a shuffle means. Results are re-shuffled before returning, because grouping the reads by album would otherwise hand back something sorted by album.