package utils

import (
	goldap "github.com/go-ldap/ldap/v3"
	ber "github.com/nmcclain/asn1-ber"
	"github.com/nmcclain/ldap"
	"goauthentik.io/api"
	"goauthentik.io/internal/outpost/ldap/constants"
)

func ParseFilterForGroup(req api.ApiCoreGroupsListRequest, f *ber.Packet, skip bool) (api.ApiCoreGroupsListRequest, bool) {
	switch f.Tag {
	case ldap.FilterEqualityMatch:
		return parseFilterForGroupSingle(req, f)
	case ldap.FilterAnd:
		for _, child := range f.Children {
			r, s := ParseFilterForGroup(req, child, skip)
			skip = skip || s
			req = r
		}
		return req, skip
	}
	return req, skip
}

func parseFilterForGroupSingle(req api.ApiCoreGroupsListRequest, f *ber.Packet) (api.ApiCoreGroupsListRequest, bool) {
	// We can only handle key = value pairs here
	if len(f.Children) < 2 {
		return req, false
	}
	k := f.Children[0].Value
	// Ensure key is string
	if _, ok := k.(string); !ok {
		return req, false
	}
	v := f.Children[1].Value
	// Null values are ignored
	if v == nil {
		return req, false
	}
	// Switch on type of the value, then check the key
	switch vv := v.(type) {
	case string:
		switch k {
		case "cn":
			return req.Name(vv), false
		case "member":
			fallthrough
		case "memberOf":
			userDN, err := goldap.ParseDN(vv)
			if err != nil {
				return req.MembersByUsername([]string{vv}), false
			}
			username := userDN.RDNs[0].Attributes[0].Value
			// If the DN's first ou is virtual-groups, ignore this filter
			if len(userDN.RDNs) > 1 {
				if userDN.RDNs[1].Attributes[0].Value == constants.OUVirtualGroups || userDN.RDNs[1].Attributes[0].Value == constants.OUGroups {
					// Since we know we're not filtering anything, skip this request
					return req, true
				}
			}
			return req.MembersByUsername([]string{username}), false
		}
	// TODO: Support int
	default:
		return req, false
	}
	return req, false
}