package main

import (
	"fmt"
	"strings"

	ldap "bottin/ldapserver"

	message "github.com/lor00x/goldap/message"
)

// Add request ------------------------

func (server *Server) handleAdd(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
	state := s.(*State)
	r := m.GetAddRequest()

	code, err := server.handleAddInternal(state, &r)

	res := ldap.NewResponse(code)
	if err != nil {
		res.SetDiagnosticMessage(err.Error())
	}
	if code == ldap.LDAPResultSuccess {
		server.logger.Printf("Successfully added %s", string(r.Entry()))
	} else {
		server.logger.Printf("Failed to add %s (%s)", string(r.Entry()), err)
	}
	w.Write(message.AddResponse(res))
}

func (server *Server) handleAddInternal(state *State, r *message.AddRequest) (int, error) {
	dn, err := server.checkDN(string(r.Entry()), false)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	dnSplit, err := parseDN(dn)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	// Check permissions
	attrListStr := []string{}
	for _, attribute := range r.Attributes() {
		attrListStr = append(attrListStr, string(attribute.Type_()))
	}
	if !server.config.Acl.Check(&state.login, "add", dn, attrListStr) {
		return ldap.LDAPResultInsufficientAccessRights, nil
	}

	// Check that object does not already exist
	exists, err := server.objectExists(dn)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}
	if exists {
		return ldap.LDAPResultEntryAlreadyExists, nil
	}

	// TODO: check that parent object exists

	// If adding a group, track of who the members will be so that their memberOf field can be updated later
	members := []string{}

	// Check attributes
	entry := Entry{}
	for _, attribute := range r.Attributes() {
		key := string(attribute.Type_())
		vals_str := []string{}
		for _, val := range attribute.Vals() {
			vals_str = append(vals_str, string(val))
		}

		// Fail if they are trying to write memberOf, we manage this ourselves
		err = checkRestrictedAttr(key)
		if err != nil {
			return ldap.LDAPResultObjectClassViolation, err
		}
		// If they are writing a member key, we have to check they are adding valid members
		if strings.EqualFold(key, ATTR_MEMBER) {
			for _, member := range vals_str {
				member_canonical, err := server.checkDN(member, false)
				if err != nil {
					return ldap.LDAPResultInvalidDNSyntax, err
				}
				exists, err = server.objectExists(member_canonical)
				if err != nil {
					return ldap.LDAPResultOperationsError, err
				}
				if !exists {
					return ldap.LDAPResultNoSuchObject, fmt.Errorf(
						"Cannot add %s to members, it does not exist!",
						member_canonical)
				}
			}
			members = append(members, vals_str...)
		}
		if prev, ok := entry[key]; ok {
			entry[key] = append(prev, vals_str...)
		} else {
			entry[key] = vals_str
		}
	}

	entry[ATTR_CREATORSNAME] = []string{state.login.user}
	entry[ATTR_CREATETIMESTAMP] = []string{genTimestamp()}
	entry[ATTR_ENTRYUUID] = []string{genUuid()}
	entry[dnSplit[0].Type] = []string{dnSplit[0].Value}

	// Add our item in the DB
	err = server.addElements(dn, entry)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}
	// ~~ from this point on, our operation succeeded ~~
	// ~~ future errors cause inconsistencies in the DB and are logged ~~

	// If our item has a member list, add it to all of its member's memberOf attribute
	for _, member := range members {
		server.memberOfAdd(member, dn)
	}

	return ldap.LDAPResultSuccess, nil
}

// Delete request ------------------------

func (server *Server) handleDelete(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
	state := s.(*State)
	r := m.GetDeleteRequest()

	code, err := server.handleDeleteInternal(state, &r)

	res := ldap.NewResponse(code)
	if err != nil {
		res.SetDiagnosticMessage(err.Error())
	}
	if code == ldap.LDAPResultSuccess {
		server.logger.Printf("Successfully deleted %s", string(r))
	} else {
		server.logger.Printf("Failed to delete %s (%s)", string(r), err)
	}
	w.Write(message.DelResponse(res))
}

func (server *Server) handleDeleteInternal(state *State, r *message.DelRequest) (int, error) {
	dn, err := server.checkDN(string(*r), false)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	// Check for delete permission
	if !server.config.Acl.Check(&state.login, "delete", dn, []string{}) {
		return ldap.LDAPResultInsufficientAccessRights, nil
	}

	// Check that this LDAP entry exists and has no children
	path, err := dnToConsul(dn)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	items, _, err := server.kv.List(path+"/", nil)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}

	if len(items) == 0 {
		return ldap.LDAPResultNoSuchObject, fmt.Errorf("Not found: %s", dn)
	}
	for _, item := range items {
		itemDN, _, err := consulToDN(item.Key)
		if err != nil {
			continue
		}
		if itemDN != dn {
			return ldap.LDAPResultNotAllowedOnNonLeaf, fmt.Errorf(
				"Cannot delete %s as it has children", dn)
		}
	}

	// Retrieve group membership before we delete everything
	memberOf, err := server.getAttribute(dn, ATTR_MEMBEROF)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}
	memberList, err := server.getAttribute(dn, ATTR_MEMBER)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}

	// Delete the LDAP entry
	_, err = server.kv.DeleteTree(path+"/", nil)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}
	// ~~ from this point on, our operation succeeded ~~
	// ~~ future errors cause inconsistencies in the DB and are logged ~~

	// Delete it from the member list of all the groups it was a member of
	if memberOf != nil {
		for _, group := range memberOf {
			groupMembers, err := server.getAttribute(group, ATTR_MEMBER)
			if err != nil {
				server.logger.Warnf("Could not remove %s from members of %s: %s", dn, group, err)
				continue
			}

			newMembers := []string{}
			for _, memb := range groupMembers {
				if memb != dn {
					newMembers = append(newMembers, memb)
				}
			}

			err = server.addElements(group, Entry{
				ATTR_MEMBER: newMembers,
			})
			if err != nil {
				server.logger.Warnf("Could not remove %s from members of %s: %s", dn, group, err)
			}
		}
	}

	// Delete it from all of its member's memberOf info
	for _, member := range memberList {
		server.memberOfRemove(member, dn)
	}

	return ldap.LDAPResultSuccess, nil
}

// Modify request ------------------------

func (server *Server) handleModify(s ldap.UserState, w ldap.ResponseWriter, m *ldap.Message) {
	state := s.(*State)
	r := m.GetModifyRequest()

	code, err := server.handleModifyInternal(state, &r)

	res := ldap.NewResponse(code)
	if err != nil {
		res.SetDiagnosticMessage(err.Error())
	}
	if code == ldap.LDAPResultSuccess {
		server.logger.Printf("Successfully modified %s", string(r.Object()))
	} else {
		server.logger.Printf("Failed to modifiy %s (%s)", string(r.Object()), err)
	}
	w.Write(message.ModifyResponse(res))
}

func (server *Server) handleModifyInternal(state *State, r *message.ModifyRequest) (int, error) {
	dn, err := server.checkDN(string(r.Object()), false)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	dnSplit, err := parseDN(dn)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	// First permission check with no particular attributes
	if !server.config.Acl.Check(&state.login, "modify", dn, []string{}) {
		return ldap.LDAPResultInsufficientAccessRights, nil
	}

	// Retrieve previous values (by the way, check object exists)
	path, err := dnToConsul(dn)
	if err != nil {
		return ldap.LDAPResultInvalidDNSyntax, err
	}

	items, _, err := server.kv.List(path+"/attribute=", nil)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}

	if len(items) == 0 {
		return ldap.LDAPResultNoSuchObject, fmt.Errorf("Not found: %s", dn)
	}

	prevEntry := Entry{}
	for _, item := range items {
		itemDN, attr, err := consulToDN(item.Key)
		if err != nil {
			continue
		}
		if itemDN != dn {
			server.logger.Fatal("itemDN != dn in handleModifyInternal")
		}
		vals, err := parseValue(item.Value)
		if err != nil {
			return ldap.LDAPResultOperationsError, err
		}
		prevEntry[attr] = vals
	}

	// Keep track of group members added/deleted
	addMembers, delMembers := []string{}, []string{}

	// Produce new entry values to be saved
	newEntry := Entry{}
	for _, change := range r.Changes() {
		attr := string(change.Modification().Type_())
		values := change.Modification().Vals()

		err = checkRestrictedAttr(attr)
		if err != nil {
			return ldap.LDAPResultObjectClassViolation, err
		}
		if strings.EqualFold(attr, dnSplit[0].Type) {
			return ldap.LDAPResultObjectClassViolation, fmt.Errorf("%s may not be changed as it is part of object path", attr)
		}

		// Check for permission to modify this attribute
		if !server.config.Acl.Check(&state.login, "modify", dn, []string{attr}) {
			return ldap.LDAPResultInsufficientAccessRights, nil
		}

		if change.Operation() == ldap.ModifyRequestChangeOperationAdd {
			newEntry[attr] = prevEntry[attr]
			for _, val := range values {
				present := false
				for _, prevVal := range newEntry[attr] {
					if prevVal == string(val) {
						present = true
						break
					}
				}
				if !present {
					newEntry[attr] = append(newEntry[attr], string(val))
					if strings.EqualFold(attr, ATTR_MEMBER) {
						addMembers = append(addMembers, string(val))
					}
				}
			}
		} else if change.Operation() == ldap.ModifyRequestChangeOperationDelete {
			if len(values) == 0 {
				// Delete everything
				newEntry[attr] = []string{}
				if strings.EqualFold(attr, ATTR_MEMBER) {
					delMembers = append(delMembers, prevEntry[attr]...)
				}
			} else {
				// Delete only those specified
				newEntry[attr] = []string{}
				for _, prevVal := range prevEntry[attr] {
					keep := true
					for _, delVal := range values {
						if string(delVal) == prevVal {
							keep = false
							break
						}
					}
					if keep {
						newEntry[attr] = append(newEntry[attr], prevVal)
					} else {
						if strings.EqualFold(attr, ATTR_MEMBER) {
							delMembers = append(delMembers, prevVal)
						}
					}
				}
			}
		} else if change.Operation() == ldap.ModifyRequestChangeOperationReplace {
			newEntry[attr] = []string{}
			for _, newVal := range values {
				newEntry[attr] = append(newEntry[attr], string(newVal))
			}
			if strings.EqualFold(attr, ATTR_MEMBER) {
				for _, newMem := range newEntry[attr] {
					mustAdd := true
					for _, prevMem := range prevEntry[attr] {
						if prevMem == newMem {
							mustAdd = false
							break
						}
					}
					if mustAdd {
						addMembers = append(addMembers, newMem)
					}
				}
				for _, prevMem := range prevEntry[attr] {
					mustDel := true
					for _, newMem := range newEntry[attr] {
						if newMem == prevMem {
							mustDel = false
							break
						}
					}
					if mustDel {
						delMembers = append(delMembers, prevMem)
					}
				}
			}
		}
	}

	// Check that added members actually exist
	for i := range addMembers {
		addMem, err := server.checkDN(addMembers[i], false)
		if err != nil {
			return ldap.LDAPResultInvalidDNSyntax, err
		}
		exists, err := server.objectExists(addMem)
		if err != nil {
			return ldap.LDAPResultOperationsError, err
		}
		if !exists {
			return ldap.LDAPResultNoSuchObject, fmt.Errorf(
				"Cannot add member %s, it does not exist", addMem)
		}
		addMembers[i] = addMem
	}

	// Now, the modification has been processed and accepted and we want to commit it
	newEntry[ATTR_MODIFIERSNAME] = []string{state.login.user}
	newEntry[ATTR_MODIFYTIMESTAMP] = []string{genTimestamp()}

	// Save the edited values
	err = server.addElements(dn, newEntry)
	if err != nil {
		return ldap.LDAPResultOperationsError, err
	}
	// ~~ from this point on, our operation succeeded ~~
	// ~~ future errors cause inconsistencies in the DB and are logged ~~

	// Update memberOf for added members and deleted members
	for _, addMem := range addMembers {
		server.memberOfAdd(addMem, dn)
	}

	for _, delMem := range delMembers {
		server.memberOfRemove(delMem, dn)
	}

	return ldap.LDAPResultSuccess, nil
}