package db

import (
	"database/sql"
	_ "embed"
	"fmt"
	"os"
	"path/filepath"

	_ "github.com/ncruces/go-sqlite3/driver"
	_ "github.com/ncruces/go-sqlite3/embed"
)

//go:embed schema.sql
var schema string

func Open(dbPath string) (*sql.DB, error) {
	dir := filepath.Dir(dbPath)
	if err := os.MkdirAll(dir, 0750); err != nil {
		return nil, fmt.Errorf("create db dir: %w", err)
	}

	db, err := sql.Open("sqlite3", dbPath+"?_journal_mode=WAL&_busy_timeout=5000")
	if err != nil {
		return nil, fmt.Errorf("open db: %w", err)
	}

	db.SetMaxOpenConns(1) // SQLite single-writer

	if _, err := db.Exec(schema); err != nil {
		db.Close()
		return nil, fmt.Errorf("init schema: %w", err)
	}

	// Migrations for existing databases
	db.Exec("ALTER TABLE files ADD COLUMN batch_id TEXT")
	db.Exec("CREATE INDEX IF NOT EXISTS idx_files_batch_id ON files(batch_id) WHERE batch_id IS NOT NULL")

	return db, nil
}