// Package storage provides the SQLite-backed persistence layer for
// multi-tenant user state. It owns the database connection, migrations,
// and CRUD repositories.
package storage

import (
	"database/sql"
	"fmt"

	_ "modernc.org/sqlite"
)

// Open opens (or creates) the SQLite database at path, configures WAL
// mode and pragmas suitable for concurrent reads, and applies migrations.
func Open(path string) (*sql.DB, error) {
	dsn := fmt.Sprintf("file:%s?_pragma=journal_mode(WAL)&_pragma=busy_timeout(5000)&_pragma=foreign_keys(1)", path)
	db, err := sql.Open("sqlite", dsn)
	if err != nil {
		return nil, fmt.Errorf("open sqlite: %w", err)
	}
	if err := db.Ping(); err != nil {
		_ = db.Close()
		return nil, fmt.Errorf("ping sqlite: %w", err)
	}
	if err := migrate(db); err != nil {
		_ = db.Close()
		return nil, fmt.Errorf("migrate: %w", err)
	}
	return db, nil
}

func migrate(db *sql.DB) error {
	for _, stmt := range migrations {
		if _, err := db.Exec(stmt); err != nil {
			return fmt.Errorf("exec migration: %w\nstmt: %s", err, stmt)
		}
	}
	return nil
}

var migrations = []string{
	`CREATE TABLE IF NOT EXISTS users (
		id            TEXT PRIMARY KEY,
		email         TEXT NOT NULL UNIQUE,
		created_at    INTEGER NOT NULL,
		last_login_at INTEGER,
		storage_path  TEXT NOT NULL
	)`,
	`CREATE INDEX IF NOT EXISTS idx_users_email ON users(email)`,
}