package errors

import (
	"fmt"
	"reflect"
)

func Wrap(err error, message string) error {
	return &UniverseErrorImpl{
		msg:   message,
		cause: err,
		stack: CaptureStackIfEnabled(),
	}
}

func Wrapf(err error, format string, args ...interface{}) error {
	return Wrap(err, fmt.Sprintf(format, args...))
}

func Get[T *any](err error, field string) T {
	if err == nil {
		return nil
	}

	var uerr UniverseError
	if As(err, &uerr) {
		value := uerr.GetAny(field)
		if value, ok := value.(T); ok {
			return value
		}
	}

	return nil
}

func Unwrap(err error) error {
	u, ok := err.(interface {
		Unwrap() error
	})
	if !ok {
		return nil
	}
	return u.Unwrap()
}

func Is(err, target error) bool {
	if err == nil || target == nil {
		return err == target
	}

	isComparable := reflect.TypeOf(target).Comparable()
	return is(err, target, isComparable)
}

func is(err, target error, targetComparable bool) bool {
	for {
		if targetComparable && err == target {
			return true
		}
		if x, ok := err.(interface{ Is(error) bool }); ok && x.Is(target) {
			return true
		}
		switch x := err.(type) {
		case interface{ Unwrap() error }:
			err = x.Unwrap()
			if err == nil {
				return false
			}
		case interface{ Unwrap() []error }:
			for _, err := range x.Unwrap() {
				if is(err, target, targetComparable) {
					return true
				}
			}
			return false
		default:
			return false
		}
	}
}

func As(err error, target any) bool {
	if err == nil {
		return false
	}
	if target == nil {
		panic("errors: target cannot be nil")
	}
	val := reflect.ValueOf(target)
	typ := val.Type()
	if typ.Kind() != reflect.Ptr || val.IsNil() {
		panic("errors: target must be a non-nil pointer")
	}
	targetType := typ.Elem()
	if targetType.Kind() != reflect.Interface && !targetType.Implements(errorType) {
		panic("errors: *target must be interface or implement error")
	}
	return as(err, target, val, targetType)
}

func as(err error, target any, targetVal reflect.Value, targetType reflect.Type) bool {
	for {
		if reflect.TypeOf(err).AssignableTo(targetType) {
			targetVal.Elem().Set(reflect.ValueOf(err))
			return true
		}
		if x, ok := err.(interface{ As(any) bool }); ok && x.As(target) {
			return true
		}
		switch x := err.(type) {
		case interface{ Unwrap() error }:
			err = x.Unwrap()
			if err == nil {
				return false
			}
		case interface{ Unwrap() []error }:
			for _, err := range x.Unwrap() {
				if err == nil {
					continue
				}
				if as(err, target, targetVal, targetType) {
					return true
				}
			}
			return false
		default:
			return false
		}
	}
}

var errorType = reflect.TypeOf((*error)(nil)).Elem()