Initial commit

backend/services/versions.py

@@ -0,0 +1,211 @@
+"""
+Generation versions management module.
+
+Each generation can have multiple audio versions: a clean (unprocessed)
+version and any number of processed versions with different effects chains.
+"""
+
+from __future__ import annotations
+
+import json
+import uuid
+from pathlib import Path
+from typing import List, Optional
+
+from sqlalchemy.orm import Session
+
+from ..database import (
+    GenerationVersion as DBGenerationVersion,
+    Generation as DBGeneration,
+)
+from ..models import GenerationVersionResponse, EffectConfig
+from .. import config
+
+
+def _version_response(v: DBGenerationVersion) -> GenerationVersionResponse:
+    """Convert a DB version row to a Pydantic response."""
+    effects_chain = None
+    if v.effects_chain:
+        raw = json.loads(v.effects_chain)
+        effects_chain = [EffectConfig(**e) for e in raw]
+    return GenerationVersionResponse(
+        id=v.id,
+        generation_id=v.generation_id,
+        label=v.label,
+        audio_path=v.audio_path,
+        effects_chain=effects_chain,
+        source_version_id=v.source_version_id,
+        is_default=v.is_default,
+        created_at=v.created_at,
+    )
+
+
+def list_versions(generation_id: str, db: Session) -> List[GenerationVersionResponse]:
+    """List all versions for a generation."""
+    versions = (
+        db.query(DBGenerationVersion)
+        .filter_by(generation_id=generation_id)
+        .order_by(DBGenerationVersion.created_at)
+        .all()
+    )
+    return [_version_response(v) for v in versions]
+
+
+def get_version(version_id: str, db: Session) -> Optional[GenerationVersionResponse]:
+    """Get a specific version by ID."""
+    v = db.query(DBGenerationVersion).filter_by(id=version_id).first()
+    if not v:
+        return None
+    return _version_response(v)
+
+
+def get_default_version(generation_id: str, db: Session) -> Optional[GenerationVersionResponse]:
+    """Get the default version for a generation."""
+    v = (
+        db.query(DBGenerationVersion)
+        .filter_by(generation_id=generation_id, is_default=True)
+        .first()
+    )
+    if not v:
+        # Fallback: return the first version
+        v = (
+            db.query(DBGenerationVersion)
+            .filter_by(generation_id=generation_id)
+            .order_by(DBGenerationVersion.created_at)
+            .first()
+        )
+    if not v:
+        return None
+    return _version_response(v)
+
+
+def create_version(
+    generation_id: str,
+    label: str,
+    audio_path: str,
+    db: Session,
+    effects_chain: Optional[List[dict]] = None,
+    is_default: bool = False,
+    source_version_id: Optional[str] = None,
+) -> GenerationVersionResponse:
+    """Create a new version for a generation.
+
+    If ``is_default`` is True, all other versions for this generation
+    are un-defaulted first.
+    """
+    if is_default:
+        _clear_defaults(generation_id, db)
+
+    version = DBGenerationVersion(
+        id=str(uuid.uuid4()),
+        generation_id=generation_id,
+        label=label,
+        audio_path=audio_path,
+        effects_chain=json.dumps(effects_chain) if effects_chain else None,
+        source_version_id=source_version_id,
+        is_default=is_default,
+    )
+    db.add(version)
+    db.commit()
+    db.refresh(version)
+
+    # If this version is the default, update the generation's audio_path
+    if is_default:
+        gen = db.query(DBGeneration).filter_by(id=generation_id).first()
+        if gen:
+            gen.audio_path = audio_path
+            db.commit()
+
+    return _version_response(version)
+
+
+def set_default_version(version_id: str, db: Session) -> Optional[GenerationVersionResponse]:
+    """Set a version as the default for its generation."""
+    version = db.query(DBGenerationVersion).filter_by(id=version_id).first()
+    if not version:
+        return None
+
+    _clear_defaults(version.generation_id, db)
+    version.is_default = True
+    db.commit()
+    db.refresh(version)
+
+    # Update generation's audio_path to point to this version
+    gen = db.query(DBGeneration).filter_by(id=version.generation_id).first()
+    if gen:
+        gen.audio_path = version.audio_path
+        db.commit()
+
+    return _version_response(version)
+
+
+def delete_version(version_id: str, db: Session) -> bool:
+    """Delete a version. Cannot delete the last remaining version."""
+    version = db.query(DBGenerationVersion).filter_by(id=version_id).first()
+    if not version:
+        return False
+
+    # Don't allow deleting the last version
+    count = (
+        db.query(DBGenerationVersion)
+        .filter_by(generation_id=version.generation_id)
+        .count()
+    )
+    if count <= 1:
+        return False
+
+    was_default = version.is_default
+    gen_id = version.generation_id
+
+    # Delete audio file
+    audio_path = config.resolve_storage_path(version.audio_path)
+    if audio_path is not None and audio_path.exists():
+        audio_path.unlink()
+
+    db.delete(version)
+    db.commit()
+
+    # If this was the default, promote the first remaining version
+    if was_default:
+        first = (
+            db.query(DBGenerationVersion)
+            .filter_by(generation_id=gen_id)
+            .order_by(DBGenerationVersion.created_at)
+            .first()
+        )
+        if first:
+            first.is_default = True
+            db.commit()
+            gen = db.query(DBGeneration).filter_by(id=gen_id).first()
+            if gen:
+                gen.audio_path = first.audio_path
+                db.commit()
+
+    return True
+
+
+def delete_versions_for_generation(generation_id: str, db: Session) -> int:
+    """Delete all versions for a generation (used when deleting a generation)."""
+    versions = (
+        db.query(DBGenerationVersion)
+        .filter_by(generation_id=generation_id)
+        .all()
+    )
+    count = 0
+    for v in versions:
+        audio_path = config.resolve_storage_path(v.audio_path)
+        if audio_path is not None and audio_path.exists():
+            audio_path.unlink()
+        db.delete(v)
+        count += 1
+    if count > 0:
+        db.commit()
+    return count
+
+
+def _clear_defaults(generation_id: str, db: Session) -> None:
+    """Clear the is_default flag on all versions for a generation."""
+    db.query(DBGenerationVersion).filter_by(
+        generation_id=generation_id, is_default=True
+    ).update({"is_default": False})
+    db.flush()