//go:build mysql
// +build mysql

package mysql

import (
	"context"
	"database/sql"
	"errors"

	"github.com/jmoiron/sqlx"
)

const userPrivacyMigrationLock = "CONCAT('im_user_privacy:', LEFT(SHA2(DATABASE(), 256), 40))"

// ensureUserPrivacySchema adds columns of im_user_privacy_settings that were
// introduced after the table's initial release. Databases created fresh by
// createIMUserProductTables already have them; legacy databases are upgraded
// in place. A missing table is skipped: it is created by the fresh-install
// path and there is nothing to upgrade yet.
func ensureUserPrivacySchema(db *sqlx.DB) error {
	ctx := context.Background()
	conn, err := db.Connx(ctx)
	if err != nil {
		return err
	}
	defer conn.Close()

	var locked sql.NullInt64
	if err = conn.QueryRowContext(ctx, "SELECT GET_LOCK("+userPrivacyMigrationLock+", 60)").Scan(&locked); err != nil {
		return err
	}
	if !locked.Valid || locked.Int64 != 1 {
		return errors.New("mysql: timed out waiting for user privacy migration lock")
	}
	defer conn.ExecContext(ctx, "SELECT RELEASE_LOCK("+userPrivacyMigrationLock+")")

	tableExists, err := identityTableExists(ctx, conn, "im_user_privacy_settings")
	if err != nil || !tableExists {
		return err
	}

	// Column definitions mirror createIMUserProductTables; the SELECT in
	// userPrivacyByUID references every one of them.
	columns := []struct{ name, ddl string }{
		{"profile_visibility", "VARCHAR(32) NOT NULL DEFAULT 'friends'"},
		{"last_seen_visibility", "VARCHAR(32) NOT NULL DEFAULT 'friends'"},
		{"read_receipts", "TINYINT NOT NULL DEFAULT 1"},
		{"friend_request_verification", "TINYINT NOT NULL DEFAULT 1"},
		{"group_invite_verification", "TINYINT NOT NULL DEFAULT 0"},
	}
	for _, col := range columns {
		exists, err := identityColumnExists(ctx, conn, "im_user_privacy_settings", col.name)
		if err != nil {
			return err
		}
		if !exists {
			if _, err = conn.ExecContext(ctx, "ALTER TABLE im_user_privacy_settings ADD COLUMN "+col.name+" "+col.ddl); err != nil {
				return err
			}
		}
	}
	return nil
}