Add PebbleDB backend with migration

[jdfalk]

Summary

• implement SubtitleStore interface with SQLite and Pebble implementations
• allow choosing backend via new --db-backend flag
• add migration command and functions to move data from SQLite to Pebble
• document backend selection and migration steps

Testing

• go test ./...

---

https://chatgpt.com/codex/tasks/task_e_6845d83256808321bf7000209224bf9f

[Copilot]

Pull Request Overview

This PR introduces a PebbleDB backend alongside the existing SQLite store, adds a factory and migration command, and updates the CLI, tests, and docs to support choosing between backends.

• Define and wire up a SubtitleStore interface with OpenStore factory
• Implement PebbleStore (with tests) and a MigrateToPebble function (with tests)
• Update SQL store, CLI commands, docs, and dependencies for backend selection and migration

Reviewed Changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
pkg/database/store_factory.go	Add OpenStore factory to select SQLite or Pebble by flag
pkg/database/store.go	Define the SubtitleStore interface
pkg/database/pebble.go	Implement PebbleStore with JSON storage, List, Delete, etc.
pkg/database/pebble_test.go	Unit tests for PebbleStore insert/list and delete
pkg/database/migrate.go	Add MigrateToPebble to copy data from SQLite to PebbleDB
pkg/database/migrate_test.go	Test the migration of records from SQLite to Pebble
pkg/database/database.go	Refactor SQL store into SQLStore, add new fields and methods
pkg/database/database_test.go	Update legacy tests to new InsertSubtitle signature
cmd/translate.go	Use OpenStore and new SubtitleStore API in translate cmd
cmd/root.go	Add --db-backend flag and bind to Viper
cmd/migrate.go	Add migrate Cobra command for SQLite→Pebble migration
cmd/history.go	Switch history command to use OpenStore and interface methods
cmd/delete.go	Switch delete command to use OpenStore and interface methods
go.mod	Add Pebble and related deps (cockroachdb/pebble, google/uuid)
docs/TECHNICAL_DESIGN.md	Document new backend option and updated schema functions
README.md	Update usage docs for --db-backend and migrate command
CHANGELOG.md	Record new PebbleDB backend version bump
TODO.md	Note completion of PebbleDB work

Comments suppressed due to low confidence (1)

pkg/database/database.go:125

• There are no unit tests for the new SQLStore methods (InsertSubtitle, ListSubtitles, DeleteSubtitle). Add tests that exercise those methods and verify the schema and data round-trip.

func (s *SQLStore) InsertSubtitle(rec *SubtitleRecord) error {

[Copilot]

OpenSQLStore never calls initSchema to create or migrate the SQLite schema, so tables won’t exist on first use. Add a call to initSchema(s.db) after opening the database.

[Copilot]

[nitpick] The free function InsertSubtitle overlaps with the SQLStore method and has a long argument list, which can be confusing. Consider deprecating or renaming legacy functions and consolidating to the SubtitleStore interface.

Suggested change

	// InsertSubtitle stores a new subtitle record with associated metadata.
	func InsertSubtitle(db *sql.DB, file, video, lang, service, release string, embedded bool) error {
	_, err := db.Exec(`INSERT INTO subtitles (file, video_file, release, language, service, embedded, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
	file, video, release, lang, service, boolToInt(embedded), time.Now())
	return err
	}
	// Deprecated: Use SQLStore.InsertSubtitle instead.
	// func InsertSubtitle(db *sql.DB, file, video, lang, service, release string, embedded bool) error {
	// _, err := db.Exec(`INSERT INTO subtitles (file, video_file, release, language, service, embedded, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`,
	// file, video, release, lang, service, boolToInt(embedded), time.Now())
	// return err
	// }