package bootdb

import (
	"database/sql"
	"embed"
	"fmt"
	"log/slog"

	"github.com/golang-migrate/migrate/v4"
	"github.com/golang-migrate/migrate/v4/database/sqlite3"
	"github.com/golang-migrate/migrate/v4/source/iofs"
	_ "github.com/mattn/go-sqlite3"
)

func Database(path string) (*sql.DB, error) {
	db, err := sql.Open("sqlite3", path)
	if err != nil {
		return nil, fmt.Errorf("opening database: %w", err)
	}

	if err = db.Ping(); err != nil {
		return nil, fmt.Errorf("pinging database: %w", err)
	}

	// Enable WAL mode and foreign keys for SQLite.
	_, err = db.Exec("PRAGMA journal_mode=WAL")
	if err != nil {
		return nil, fmt.Errorf("setting journal mode: %w", err)
	}
	_, err = db.Exec("PRAGMA foreign_keys=ON")
	if err != nil {
		return nil, fmt.Errorf("enabling foreign keys: %w", err)
	}

	slog.Info("Database connected", "path", path)

	err = runMigrations(db)
	if err != nil {
		return nil, err
	}

	// TODO revisit concurrency.
	//      running any sqlite queries outside of a tx seems to run into "database is locked" errors.
	db.SetMaxOpenConns(1)

	return db, nil
}

//go:embed migrations/*.sql
var migrations embed.FS

func runMigrations(db *sql.DB) error {
	source, err := iofs.New(migrations, "migrations")
	if err != nil {
		return fmt.Errorf("creating migration source: %w", err)
	}

	driver, err := sqlite3.WithInstance(db, &sqlite3.Config{})
	if err != nil {
		return fmt.Errorf("creating migration driver: %w", err)
	}

	m, err := migrate.NewWithInstance("iofs", source, "sqlite3", driver)
	if err != nil {
		return fmt.Errorf("creating migration instance: %w", err)
	}

	if err := m.Up(); err != nil && err != migrate.ErrNoChange {
		return fmt.Errorf("running migrations: %w", err)
	}

	slog.Info("Migrations completed")
	return nil
}