feat: retain anime in -c without new episodes and show nextep countdown

[sghoshm]

Type of change

• Bug fix
• Feature
• Documentation update

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Description

This PR improves the behavior of -c (continue watching) for ongoing anime.

Background

While using ani-cli -c, I noticed that ongoing anime disappear from the history menu when there is no new episode available. This makes it difficult to:

• keep track of currently watched shows
• reselect an anime to check release status
• use nextep functionality naturally from history

This PR is based on the feature request by @port19x (Mar 14), suggesting that ongoing anime should remain selectable and trigger nextep countdown when selected.

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What this PR changes

• Keeps anime visible in the -c menu even if no new episode exists
• Selecting such entries:
  • does not attempt playback
  • instead runs nextep countdown
• Normal playback behavior is unchanged when a next episode exists

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Implementation details

• Uses episodes_list to determine if a next episode exists
• If no next episode is found:
  • redirects flow to time_until_next_ep
• History entries are treated as persistent instead of conditional

Additional improvements:

• Fixes race condition in history processing (removes background execution &)
• Replaces fragile string matching with structured history lookup using awk
• Improves time_until_next_ep():
  • avoids silent failures
  • adds fallback when API does not return countdown data
• Ensures POSIX compatibility (no bash-specific features)

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Issues faced during development

• Race condition in history processing
  Background execution caused inconsistent and corrupted titles

• Title parsing issues
  Re-parsing formatted strings led to broken titles (e.g. 1P)

• Shell compatibility
  Some constructs worked in bash but failed under /bin/sh

• API inconsistency
  animeschedule does not always return countdown data
  → handled with fallback instead of failing silently

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Testing

Tested manually across multiple flows:

Core feature

• ani-cli -c
  • anime with next episode → plays normally
  • anime without next episode → shows nextep countdown

Playback regression

• ani-cli one piece
• ani-cli detective conan
  → playback unaffected

Nextep

• ani-cli -N one piece
  → returns countdown or fallback (never empty output)

Edge cases

• Single-entry history
• Multiple anime in history
• Finished anime
• Long-running anime (e.g. One Piece)

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Why this approach

• Keeps changes minimal and scoped to history flow
• Avoids complex matching or heuristics
• Reuses existing logic (episodes_list, nextep)
• Does not affect existing playback or CLI behavior

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Credits

Shoutout to @port19x for the original idea and discussion — this implementation is based on that suggestion 👍

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Checklist

• any anime playing
• bumped version

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• next, prev and replay work
• -c history and continue work
• -d downloads work
• -s syncplay works
• -q quality works
• -v vlc works
• -e (select episode) aka -r (range selection) works
• -S select index works
• --skip ani-skip works
• --skip-title ani-skip title argument works
• --no-detach no detach works
• --exit-after-play auto exit after playing works
• --nextep-countdown countdown to next ep works
• --dub and regular (sub) mode both work
• all providers return links (not necessarily on a single anime, use debug mode to confirm)

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• -h help info is up to date
• Readme is up to date
• Man page is up to date

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Additional Testcases

• The safe bet: One Piece
• Episode 0: Saenai Heroine no Sodatekata ♭
• Unicode: Saenai Heroine no Sodatekata ♭
• Non-whole episodes: Tensei shitara slime datta ken (ep. 24.5, ep. 24.9)
• All Providers: Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e
• The examples of the help text

[port19x]

What happened here that this is a PR that adds a provider on top of your own feature PR?

[sghoshm]

Ah, good catch... that wasn’t intentional.

I created the branch on top of a commit that already included the provider changes, so it ended up in this PR as well.

I’ll clean this up and update the PR to only include the -c / nextep integration changes.

[sghoshm]

Closing this PR in favor of a clean version without unrelated provider changes.

New PR: #1707