compaction

type CompactionOutcome string

type CompactionResult struct {
	Outcome    CompactionOutcome
	SchemaID   int16
	Version    int64
	DirtyRatio float64
	BaseMB     int64
	DeltaMB    int64

	// Rewrite metadata, populated only when Outcome is RewriteApplied.
	FilesMerged int    // source files folded into the new base
	RowsIn      int64  // rows read across all source files
	RowsOut     int64  // surviving LWW winners written to the new base
	NewBaseKey  string // S3 key of the merged base parquet
}

type Compactor struct {
	Logger     *zap.Logger
	Config     cdc.CompactionConfig
	Provider   FileProvider
	Merger     Merger
	S3         cdc.S3ObjectClient
	Bucket     string
	DataPrefix string // root prefix for parquet files
	Resolver   manifest.PathResolver

	// ObjectReader hashes published objects for manifest checksum stamping
	// and pre-merge input verification (#347). Nil disables both.
	ObjectReader cdc.S3GetClient
}

type DuckMerger struct {
	DB *sql.DB
	// CopyOptions overrides the parquet COPY options (defaults to the CDC
	// exporters' FORMAT PARQUET, V2, ZSTD level 3).
	CopyOptions string
	// Logger reports the best-effort manifest stamp probe (#256). Optional —
	// nil is safe and silences it.
	Logger *zap.Logger
	// contains filtered or unexported fields
}

type FileProvider interface {
	LoadManifest(ctx context.Context, schemaID int16) (*manifest.Manifest, string, error)
	// SaveManifest persists the manifest as a commit point.
	// Implementations must mutate the provided manifest pointer in-place on
	// successful save:
	// - Version must increase monotonically.
	// - UpdatedAtMs must move forward.
	// Compactor relies on the same pointer carrying updated metadata and does
	// not mutate those fields directly.
	SaveManifest(ctx context.Context, schemaID int16, m *manifest.Manifest, etag string) (string, error)
}

type ManifestProvider struct {
	Store    manifest.Store
	Resolver manifest.PathResolver
}

type MergeStats struct {
	RowsIn     int64  // version rows read across all source files
	RowsOut    int64  // surviving LWW winners written to the merged file
	RowIDMin   string // "" when the merge produced zero rows
	RowIDMax   string
	CreatedMin int64
	CreatedMax int64
	// Columns is the merged file's footer schema (name → DuckDB type),
	// stamped into the manifest entry (#256). Nil when the self-describe
	// failed; the entry then stays unstamped and reads fall back to probing.
	Columns map[string]string
}

type Merger interface {
	MergeToTmp(ctx context.Context, sourceURIs []string, tmpURI string) (MergeStats, error)
}

type UncoveredRow struct {
	RowID     string
	Tombstone bool
}