MeBox/docs/superpowers/plans/2026-09-24-segment-coverage.md

Segment Coverage Implementation Plan

For Claude: REQUIRED SUB-SKILL: Use superpowers:executing-plans to implement this plan task-by-task.

Goal: IntroDB prewarm + same-season intro propagation + shorter miss TTL + playback-only duration probe (option C).

Architecture: Extend MediaSegmentService for merge/propagate/prewarm; add scheduler job segment_prewarm; repository queries for candidates and season siblings.

Tech Stack: Go, GORM/SQLite, existing SchedulerService + IntroDB client.

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Task 1: Negative cache TTL + ledgerFresh tests

Files: internal/service/media_segment.go, internal/service/media_segment_test.go

• Change segmentMissingTTL to 24h; update tests for fresh/stale miss.

Task 2: Playback merge + propagation

Files: media_segment.go, media_segment_repository.go, media_repository.go, tests

• Constant PropagatedSource = "propagated".
• ListForPlayback merges sources with priority manual > theintrodb > propagated.
• After successful IntroDB refresh with intro, propagate to same-season siblings (shared tm_db_id or series_id).

Task 3: Prewarm API + scheduler job

Files: media_segment.go, media_segment_repository.go, scheduler.go, scheduler_segment_jobs.go, service_builder.go, tests

• Prewarm(ctx, limit) rate-limited refreshes.
• Job segment_prewarm every 6h.

Task 4: Verify

• go test for affected packages.