package database

// SchemaVersion is the current database schema version.
// When this changes, the database will be dropped and recreated.
const SchemaVersion = 1

// Common SQL statements shared between implementations.
const (
	// SchemaInfoTable creates the schema version tracking table.
	SchemaInfoTable = `
		CREATE TABLE IF NOT EXISTS schema_info (
			version INTEGER NOT NULL
		)`

	// RevisionsTable creates the revisions table.
	RevisionsTable = `
		CREATE TABLE IF NOT EXISTS revisions (
			id INTEGER PRIMARY KEY,
			git_hash TEXT NOT NULL UNIQUE,
			channel_name TEXT,
			commit_date TIMESTAMP,
			indexed_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
			option_count INTEGER NOT NULL DEFAULT 0
		)`

	// OptionsTable creates the options table.
	OptionsTable = `
		CREATE TABLE IF NOT EXISTS options (
			id INTEGER PRIMARY KEY,
			revision_id INTEGER NOT NULL REFERENCES revisions(id) ON DELETE CASCADE,
			name TEXT NOT NULL,
			parent_path TEXT NOT NULL,
			type TEXT,
			default_value TEXT,
			example TEXT,
			description TEXT,
			read_only BOOLEAN NOT NULL DEFAULT FALSE
		)`

	// DeclarationsTable creates the declarations table.
	DeclarationsTable = `
		CREATE TABLE IF NOT EXISTS declarations (
			id INTEGER PRIMARY KEY,
			option_id INTEGER NOT NULL REFERENCES options(id) ON DELETE CASCADE,
			file_path TEXT NOT NULL,
			line INTEGER
		)`

	// FilesTable creates the files table.
	FilesTable = `
		CREATE TABLE IF NOT EXISTS files (
			id INTEGER PRIMARY KEY,
			revision_id INTEGER NOT NULL REFERENCES revisions(id) ON DELETE CASCADE,
			file_path TEXT NOT NULL,
			extension TEXT,
			content TEXT NOT NULL
		)`
)

// Index creation statements.
const (
	// IndexOptionsRevisionName creates an index on options(revision_id, name).
	IndexOptionsRevisionName = `
		CREATE INDEX IF NOT EXISTS idx_options_revision_name
		ON options(revision_id, name)`

	// IndexOptionsRevisionParent creates an index on options(revision_id, parent_path).
	IndexOptionsRevisionParent = `
		CREATE INDEX IF NOT EXISTS idx_options_revision_parent
		ON options(revision_id, parent_path)`

	// IndexFilesRevisionPath creates an index on files(revision_id, file_path).
	IndexFilesRevisionPath = `
		CREATE UNIQUE INDEX IF NOT EXISTS idx_files_revision_path
		ON files(revision_id, file_path)`

	// IndexDeclarationsOption creates an index on declarations(option_id).
	IndexDeclarationsOption = `
		CREATE INDEX IF NOT EXISTS idx_declarations_option
		ON declarations(option_id)`
)

// Drop statements for schema recreation.
const (
	DropSchemaInfo   = `DROP TABLE IF EXISTS schema_info`
	DropDeclarations = `DROP TABLE IF EXISTS declarations`
	DropOptions      = `DROP TABLE IF EXISTS options`
	DropFiles        = `DROP TABLE IF EXISTS files`
	DropRevisions    = `DROP TABLE IF EXISTS revisions`
)

// ParentPath extracts the parent path from an option name.
// For example, "services.nginx.enable" returns "services.nginx".
// Top-level options return an empty string.
func ParentPath(name string) string {
	for i := len(name) - 1; i >= 0; i-- {
		if name[i] == '.' {
			return name[:i]
		}
	}
	return ""
}