package dbx

import (
	"database/sql"
	"reflect"
	"strings"

	"gitea.auvem.com/go-toolkit/app"
	"github.com/go-jet/jet/v2/qrm"
	_ "github.com/go-sql-driver/mysql"
)

// ModuleDBName is the name of the database module.
const ModuleDBName = "database"

var (
	// ErrNoRows is returned when a query returns no rows.
	ErrNoRows = qrm.ErrNoRows

	// sqlDB stores the current SQL database handle.
	sqlDB *sql.DB

	// config stores the database connection configuration.
	config DBConfig

	// dbModule is the singleton module instance for the database connection.
	dbModule *app.Module
)

// SQLO returns the current SQL database handle.
func SQLO() *sql.DB {
	dbModule.RequireLoaded("dbx.SQLO requires database module") // ensure the module is loaded before accessing the database
	if sqlDB == nil {
		panic("SQL database not initialized")
	}
	return sqlDB
}

// Queryable interface is an SQL driver object that can execute SQL statements
// for Jet.
type Queryable interface {
	qrm.Queryable
	Query(string, ...any) (*sql.Rows, error)
}

// Executable interface is an SQL driver object that can execute SQL statements
// for Jet.
type Executable interface {
	qrm.Executable
	Exec(string, ...any) (sql.Result, error)
}

// ExecutableTx interface is an SQL driver object that implements the Executable
// interface and can also begin a transaction.
type ExecutableTx interface {
	Executable
	Begin() (*sql.Tx, error)
}

// DestName returns the name of the type passed as `destTypeStruct` as a string,
// normalized for compatibility with the Jet QRM.
func DestName(destTypeStruct any, path ...string) string {
	v := reflect.ValueOf(destTypeStruct)
	for v.Kind() == reflect.Ptr {
		v = v.Elem()
	}

	destIdent := v.Type().String()
	destIdent = destIdent[strings.LastIndex(destIdent, ".")+1:]

	for i, p := range path {
		if v.Kind() != reflect.Struct {
			dbModule.Logger().Error("DestName: path parent is not a struct", "path", destIdent+"."+strings.Join(path[:i+1], "."))
			return ""
		}

		v = v.FieldByName(p)

		if !v.IsValid() {
			dbModule.Logger().Error("DestName: field does not exist", "path", destIdent+"."+strings.Join(path[:i+1], "."))
			return ""
		}

		destIdent += "." + p
	}

	return destIdent
}

// StringToFilter processes a string to be used as a filter in an SQL LIKE
// statement. It replaces all spaces with % and adds % to the beginning and
// end of the string.
func StringToFilter(str string) string {
	// Remove any existing leading or trailing % characters
	str = strings.Trim(str, "%")

	// Replace all spaces with % and add % to the beginning and end of the string
	str = strings.ReplaceAll(str, " ", "%")
	str = "%" + str + "%"

	return str
}