package store

import (
	"database/sql"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	_ "modernc.org/sqlite"
)

// OpenWriter 按 DEVELOPMENT 7.7 打开写连接（带 _txlock=immediate）。
func OpenWriter(dataDir, synchronous string) (*sql.DB, error) {
	if err := os.MkdirAll(dataDir, 0o755); err != nil {
		return nil, fmt.Errorf("mkdir data_dir: %w", err)
	}
	dsn, err := writeDSN(dataDir, synchronous)
	if err != nil {
		return nil, err
	}
	db, err := sql.Open("sqlite", dsn)
	if err != nil {
		return nil, fmt.Errorf("open sqlite: %w", err)
	}
	db.SetMaxOpenConns(1)
	db.SetMaxIdleConns(1)
	if err := db.Ping(); err != nil {
		_ = db.Close()
		return nil, fmt.Errorf("ping sqlite: %w", err)
	}
	return db, nil
}

func writeDSN(dataDir, synchronous string) (string, error) {
	sync := strings.ToUpper(strings.TrimSpace(synchronous))
	if sync == "" {
		sync = "FULL"
	}
	if sync != "FULL" && sync != "NORMAL" {
		return "", fmt.Errorf("invalid sqlite_synchronous: %s", synchronous)
	}
	dbPath := filepath.ToSlash(filepath.Join(dataDir, "nixmsg.db"))
	return fmt.Sprintf(
		"file:%s?_pragma=journal_mode(WAL)&_pragma=busy_timeout(5000)&_pragma=synchronous(%s)&_pragma=foreign_keys(ON)&_pragma=secure_delete(ON)&_txlock=immediate",
		dbPath,
		sync,
	), nil
}