refactor(server): extract AudioEffectsMappingDB into lib/audio_effects_db.py (R3)

[byrongamatos]

Second step of R3, following #830. Move-only, backend-only, zero behaviour change.

What moves

AudioEffectsMappingDB (273 lines) — the core-owned song/tone → audio-effect-provider routing index — leaves server.py for lib/audio_effects_db.py. Its only dependency on the host file was CONFIG_DIR.

server.py: 9,705 → 9,433 lines (14,037 at the start of R3).

The one non-verbatim change

The same seam as #830: __init__ takes config_dir explicitly rather than reading the module-level CONFIG_DIR, so the new module performs no IO at import (Principle V).

audio_effect_mappings = AudioEffectsMappingDB(CONFIG_DIR)

The class body is byte-identical, and server.py reconstructs exactly from origin/main minus the cut range, plus the import-back and the call site. No import went dead.

What deliberately does not move

The audio_effect_mappings singleton stays in server.py. No route moves, no test changes, and none of the monkeypatch.setattr(server, …) targets is touched.

Verification

• pyflakes: lib/audio_effects_db.py clean — zero undefined names, zero unused imports. server.py gains no new undefined name.
• pytest — 2341 passed, 4 skipped (unchanged; no test needed retargeting).
• npm run lint — 0 errors.
• Boot smoke drives the extracted DB end-to-end rather than just importing it: POST /api/audio-effects/mappings creates a row, GET reads it back, and audio_effects.db is created under CONFIG_DIR — which is what actually proves the config_dir seam. All three migrated plugins (stems, studio, editor) still serve their src/ module graphs over the R0 route.
• Codex preflight: 0 findings.

Register

docs/size-exemptions.md ratcheted: server.py → 9,433.

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added persistent storage and routing for audio-effect mappings across providers.
  • Added support for listing, creating, updating, activating, and deleting mappings.
  • Added filtering by song, tone, filename, and provider.

• Documentation

  • Updated changelog and project sizing documentation to reflect the audio-effects mapping improvements.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: f6824017-0b5c-4060-a80b-4039b880309d

📥 Commits

Reviewing files that changed from the base of the PR and between 5812074 and 0302671.

📒 Files selected for processing (4)

• CHANGELOG.md
• docs/size-exemptions.md
• lib/audio_effects_db.py
• server.py

---

📝 Walkthrough

Walkthrough

AudioEffectsMappingDB is moved from server.py into lib/audio_effects_db.py, where it owns config-scoped SQLite persistence and routing operations. server.py imports the class and initializes its singleton with CONFIG_DIR; related changelog and size documentation are updated.

Changes

Audio effects database extraction

Layer / File(s)	Summary
Database module foundation lib/audio_effects_db.py	Adds the SQLite schema, configuration-based database initialization, locking, input normalization, and active-state row decoding.
Mapping and activation operations lib/audio_effects_db.py	Implements filtered listing, retrieval, upsert, deletion, activation, and active-mapping clearing.
Server wiring and documentation server.py, CHANGELOG.md, docs/size-exemptions.md	Replaces the inline database implementation with the imported class and updates extraction and line-count documentation.

Estimated code review effort: 3 (Moderate) | ~20 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly states the main refactor: moving AudioEffectsMappingDB from server.py into lib/audio_effects_db.py.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch refactor/r3-audio-effects-db

---

_{Comment @coderabbitai help to get the list of available commands.}