package db

import (
	"context"
	"database/sql"
	"fmt"
	"os"

	_ "github.com/go-sql-driver/mysql"
)

func Open(ctx context.Context, url string) (*sql.DB, error) {
	d, err := sql.Open("mysql", url)
	if err != nil {
		return nil, err
	}
	if err := d.PingContext(ctx); err != nil {
		return nil, err
	}
	return d, nil
}

func Migrate(ctx context.Context, d *sql.DB) error {
	d.ExecContext(ctx, `SELECT GET_LOCK('trading_tool_migrate', 30)`)
	defer d.ExecContext(ctx, `SELECT RELEASE_LOCK('trading_tool_migrate')`)
	if _, err := d.ExecContext(ctx, `CREATE TABLE IF NOT EXISTS schema_migrations(version VARCHAR(255) PRIMARY KEY, applied_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP)`); err != nil {
		return err
	}
	files := []string{"migrations/001_init.sql", "migrations/002_admin.sql"}
	for _, f := range files {
		var exists bool
		if err := d.QueryRowContext(ctx, `SELECT EXISTS(SELECT 1 FROM schema_migrations WHERE version=?)`, f).Scan(&exists); err != nil {
			return err
		}
		if exists {
			continue
		}
		b, err := os.ReadFile(f)
		if err != nil {
			return err
		}
		if _, err := d.ExecContext(ctx, string(b)); err != nil {
			return fmt.Errorf("%s: %w", f, err)
		}
		if _, err := d.ExecContext(ctx, `INSERT INTO schema_migrations(version) VALUES(?)`, f); err != nil {
			return err
		}
	}
	return nil
}