Podcast insertion order into Queue is broken (In my opinion)

[udif]

App version: 1.6.4.0 , Commit 7b496d5 (from Google Play)

Android version: 6.0.1

Device model: Nexus 5

Expected behaviour:
When selecting several episodes in succession (so that they download in parallel), for example from a feed just added, they should be added to the queue by the order which they were selected for download, or by the chronological order.
This is especially irritating when you download a multi-part podcast, and expect to hear the chapters in the order which you have selected them.

Current behaviour:
They episodes are added by the order in which they have finished downloading.

First occured: As far as I remember into the past

Steps to reproduce:

1. Add a new feed, or choose one with more than one unloaded episodes
2. select episodes for download in quick succession in a specific order, preferrably selecting the longest episodes first, and the shortest last.
3. Go to the "Downloads" screen / "Running" tab and watch the order in which the episodes complete downloading. hopefully they will download out of order due to their length difference.
4. Go to the "Queue" screen and note the order the episodes were added, and you will notice that they are sorted by the download finish order, not by the download start order.

[mfietz]

related to #2006

[orionlee]

It seems to be the same as #2006.

To clarify the desired behavior (for various scenario), please review the following:

1. Assume the user has the following in the queue:

   • episode A
   • episode B
   • episode C

2. The user then clicks download on episode D, and episode E soon afterwards. ("Enqueue Downloaded" preference is enabled.)

3. The desired order in the queue will then be:

Default Enqueue	Enqueue at Front
episode A	episode D
episode B	episode E
episode C	episode A
episode D	episode B
episode E	episode C

• The order is independent of:
  • when download is complete.
  • if download is complete, e.g., if download of episode E fails, it remains in the queue (See note below)
• Episode D and E appear in the queue while they are being downloaded (new behavior).

4. auto download is treated the same way, as if the users has chosen to download the episodes in the specific order.

Note on case download fails:

• Using the example in (3), if download of episode E fails, another option would be removing it from the queue (effectively same as the current one, which it won't be added in the first place).
• I suggest leave it in the queue, rather than removing it, because when the user chooses to re-download again, its proper position in the queue can become confusing. E.g., for variation "Enqueue at Front", should the re-downloaded episode E be moved to the front? What if yet another episode, say, an episode F, has been downloaded in the meantime?
• Thus, leaving the not-yet-downloaded episode E in the queue will make its position clear to end users when the users choose to re-download it: it remains to be where it is.

[orionlee]

I plan to work on it, given another item I'm working on, #2652 (keep in-progress at front), touches the same section of the code. It'd be good to have consensus on the desired behavior.