def trac2youtrack(target_url, target_login, target_password, project_ID, project_name, env_path):
    # creating connection to trac to import issues to
    client = Client(env_path)
    # creating connection to util to import issues in
    target = Connection(target_url, target_login, target_password)

    # create project
    print("Creating project[%s]" % project_name)
    try:
        target.getProject(project_ID)
    except youtrack.YouTrackException:
        target.createProjectDetailed(project_ID, project_name, client.get_project_description(), target_login)

    # importing users
    trac_users = client.get_users()
    print("Importing users")
    yt_users = list([])

    # converting trac users to yt users
    registered_users = set([])
    for user in trac_users :
        print("Processing user [ %s ]" % user.name)
        registered_users.add(user.name)
        yt_users.append(to_youtrack_user(user))
        # adding users to yt project
    target.importUsers(yt_users)
    print("Importing users finished")

    print("Creating project custom fields")

    create_yt_custom_field(target, project_ID, "Priority", client.get_issue_priorities())

    create_yt_custom_field(target, project_ID, "Type", client.get_issue_types())

    trac_resolution_to_yt_state = lambda track_field, yt_bundle : to_youtrack_state(track_field, yt_bundle)
    create_yt_bundle_custom_field(target, project_ID, "Resolution", client.get_issue_resolutions(), trac_resolution_to_yt_state)

    trac_version_to_yt_version = lambda trac_field, yt_bundle : to_youtrack_version(trac_field, yt_bundle)

    trac_versions = client.get_versions()
    create_yt_bundle_custom_field(target, project_ID, "Affected versions", trac_versions, trac_version_to_yt_version)

    trac_milestones = client.get_milestones()
    create_yt_bundle_custom_field(target, project_ID, "Fix versions", trac_milestones, trac_version_to_yt_version)

    trac_components = client.get_components()
    for cmp in trac_components :
        if cmp.owner not in registered_users :
            cmp.owner, registered_users = process_non_authorised_user(target, registered_users, cmp.owner)
    trac_component_to_yt_subsystem = lambda trac_field, yt_bundle : to_youtrack_subsystem(trac_field, yt_bundle)
    create_yt_bundle_custom_field(target, project_ID, "Component", trac_components, trac_component_to_yt_subsystem)

    create_yt_custom_field(target, project_ID, "Severity", client.get_severities())

    trac_custom_fields = client.get_custom_fields_declared()
    check_box_fields = dict([])
    for elem in trac_custom_fields:
        print("Processing custom field [ %s ]" % elem.name)
        if elem.type == "checkbox":
            if len(elem.label) > 0:
                opt = elem.label
            else:
                opt = elem.name
            options = list([opt])
            check_box_fields[elem.name] = opt
        else:
            options = elem.options

        values = None
        if len(options):
            values = options

        field_name = elem.name
        if field_name in youtrackutils.tracLib.FIELD_NAMES.keys() :
            field_name = youtrackutils.tracLib.FIELD_NAMES[field_name]

        field_type = youtrackutils.tracLib.CUSTOM_FIELD_TYPES[elem.type]
        if field_name in youtrackutils.tracLib.FIELD_TYPES.keys():
            field_type = youtrackutils.tracLib.FIELD_TYPES[field_name]

        process_custom_field(target, project_ID, field_type, field_name, trac_values_to_youtrack_values(field_name, values))
        print("Creating project custom fields finished")

    print("Importing issues")
    trac_issues = client.get_issues()
    yt_issues = list([])
    counter = 0
    max = 100
    for issue in trac_issues:
        print("Processing issue [ %s ]" % (str(issue.id)))
        counter += 1
        if not (issue.reporter in registered_users):
            yt_user, registered_users = process_non_authorised_user(target, registered_users, issue.reporter)
            if yt_user is None :
                issue.reporter = "guest"
            else:
                issue.reporter = yt_user
        if not (issue.owner in registered_users):
            yt_user, registered_users = process_non_authorised_user(target, registered_users, issue.owner)
            if yt_user is None :
                issue.owner = ""
            else:
                issue.owner = yt_user
        legal_cc = set([])
        for cc in issue.cc:
            if cc in registered_users:
                legal_cc.add(cc)
        issue.cc = legal_cc

        yt_issues.append(to_youtrack_issue(project_ID, issue, check_box_fields))
        if counter == max:
            counter = 0
            print(target.importIssues(project_ID, project_name + ' Assignees', yt_issues))
            yt_issues = list([])
    print(target.importIssues(project_ID, project_name + ' Assignees', yt_issues))
    print('Importing issues finished')

    # importing tags
    print("Importing keywords")
    for issue in trac_issues:
        print("Importing tags from issue [ %s ]" % (str(issue.id)))
        tags = issue.keywords
        for t in tags:
            target.executeCommand(str(project_ID) + "-" + str(issue.id), "tag " + t.encode('utf-8'))
    print("Importing keywords finished")

    print("Importing attachments")
    for issue in trac_issues:
        print("Processing issue [ %s ]" % (str(issue.id)))
        issue_attach = issue.attachment
        for attach in issue_attach:
            print("Processing attachment [ %s ]" % attach.filename.encode('utf-8'))
            if not (attach.author_name in registered_users):
                yt_user, registered_users = process_non_authorised_user(target, registered_users, attach.author_name)
                if yt_user is None:
                    attach.author_name = "guest"
                else:
                    attach.author_name = yt_user
            content = open(urllib.quote(attach.filename.encode('utf-8')))
            target.createAttachment(str(project_ID) + "-" + str(issue.id), attach.name, content, attach.author_name,
                                    created=attach.time)
    print("Importing attachments finished")

    print("Importing workitems")
    tt_enabled = False
    for issue in trac_issues:
        if issue.workitems:
            if not tt_enabled:
                tt_settings = target.getProjectTimeTrackingSettings(str(project_ID))
                if not tt_settings.Enabled:
                    print("Enabling TimeTracking for the project")
                    target.setProjectTimeTrackingSettings(str(project_ID), enabled=True)
                tt_enabled = True
            print("Processing issue [ %s ]" % (str(issue.id)))
            workitems = [to_youtrack_workitem(w) for w in issue.workitems]
            target.importWorkItems(str(project_ID) + "-" + str(issue.id), workitems)
    print("Importing workitems finished")
def trac2youtrack(target_url, target_login, target_password, project_ID, project_name, env_path):
    # creating connection to trac to import issues to
    client = Client(env_path)
    # creating connection to youtrack to import issues in
    target = Connection(target_url, target_login, target_password)

    #create project
    print "Creating project[%s]" % project_name
    try :
        target.getProject(project_ID)
    except youtrack.YouTrackException:
        target.createProjectDetailed(project_ID, project_name, client.get_project_description(), target_login)

    #importing users
    trac_users = client.get_users()
    print "Importing users"
    yt_users = list([])
    # converting trac users to yt users
    registered_users = set([])
    for user in trac_users :
        print "Processing user [ %s ]" % user.name
        registered_users.add(user.name)
        yt_users.append(to_youtrack_user(user))
        # adding users to yt project
    target.importUsers(yt_users)
    print "Importing users finished"

    print "Creating project custom fields"

    create_yt_custom_field(target, project_ID, "Priority", client.get_issue_priorities())

    create_yt_custom_field(target, project_ID, "Type", client.get_issue_types())

    trac_resolution_to_yt_state = lambda track_field, yt_bundle : to_youtrack_state(track_field, yt_bundle)
    create_yt_bundle_custom_field(target, project_ID, "Resolution", client.get_issue_resolutions(), trac_resolution_to_yt_state)

    trac_versions = client.get_versions()
    trac_version_to_yt_version = lambda trac_field, yt_bundle : to_youtrack_version(trac_field, yt_bundle)
    create_yt_bundle_custom_field(target, project_ID, "Version", trac_versions, trac_version_to_yt_version)
    #create_yt_bundle_custom_field(target, project_ID, "Affected versions", trac_versions, trac_version_to_yt_version)

    trac_components = client.get_components()
    for cmp in trac_components :
        if cmp.owner not in registered_users :
            cmp.owner, registered_users = process_non_authorised_user(target, registered_users, cmp.owner)
    trac_component_to_yt_subsystem = lambda trac_field, yt_bundle : to_youtrack_subsystem(trac_field, yt_bundle)
    create_yt_bundle_custom_field(target, project_ID, "Component", trac_components, trac_component_to_yt_subsystem)

    create_yt_custom_field(target, project_ID, "Severity", client.get_severities())

    trac_custom_fields = client.get_custom_fields_declared()
    check_box_fields = dict([])
    for elem in trac_custom_fields:
        print "Processing custom field [ %s ]" % elem.name
        type_name = None
        if elem.type == "checkbox":
            if len(elem.label) > 0:
                opt = elem.label
            else:
                opt = elem.name
            options = list([opt])
            check_box_fields[elem.name] = opt
        else:
            options = elem.options

        values = None
        if len(options):
            values = options

        field_name = elem.name
        if field_name in tracLib.FIELD_NAMES.keys() :
            field_name = tracLib.FIELD_NAMES[field_name]

        field_type = tracLib.CUSTOM_FIELD_TYPES[elem.type]
        if field_name in tracLib.FIELD_TYPES.keys():
            field_type = tracLib.FIELD_TYPES[field_name]

        process_custom_field(target, project_ID, field_type, field_name, trac_values_to_youtrack_values(field_name, values))
        print "Creating project custom fields finished"

    print "Importing issues"
    trac_issues = client.get_issues()
    yt_issues = list([])
    counter = 0
    max = 100
    for issue in trac_issues:
        print "Processing issue [ %s ]" % (str(issue.id))
        counter += 1
        if not (issue.reporter in registered_users):
            yt_user, registered_users = process_non_authorised_user(target, registered_users, issue.reporter)
            if yt_user is None :
                issue.reporter = "guest"
            else:
                issue.reporter = yt_user
        if not (issue.owner in registered_users):
            yt_user, registered_users = process_non_authorised_user(target, registered_users, issue.owner)
            if yt_user is None :
                issue.owner = ""
            else:
                issue.owner = yt_user
        legal_cc = set([])
        for cc in issue.cc:
            if cc in registered_users:
                legal_cc.add(cc)
        issue.cc = legal_cc

        yt_issues.append(to_youtrack_issue(issue, check_box_fields))
        if counter == max:
            counter = 0
            print target.importIssues(project_ID, project_name + ' Assignees', yt_issues)
            yt_issues = list([])
    print target.importIssues(project_ID, project_name + ' Assignees', yt_issues)
    print 'Importing issues finished'
    #importing tags
    print "Importing keywords"
    for issue in trac_issues:
        print "Importing tags from issue [ %s ]" % (str(issue.id))
        tags = issue.keywords
        for t in tags:
            target.executeCommand(str(project_ID) + "-" + str(issue.id), "tag " + t.encode('utf-8'))
    print "Importing keywords finished"

    print "Importing attachments"
    for issue in trac_issues:
        print "Processing issue [ %s ]" % (str(issue.id))
        issue_attach = issue.attachment
        for attach in issue_attach:
            print "Processing attachment [ %s ]" % attach.filename.encode('utf-8')
            if not (attach.author_name in registered_users):
                yt_user, registered_users = process_non_authorised_user(target, registered_users, attach.author_name)
                if yt_user is None :
                    attach.author_name = "guest"
                else:
                    attach.author_name = yt_user
            content = open(urllib.quote(attach.filename.encode('utf-8')))
            target.createAttachment(str(project_ID) + "-" + str(issue.id), attach.name, content, attach.author_name,
                                    created=attach.time)
    print "Importing attachments finished"

    print "Importing workitems"
    tt_enabled = False
    for issue in trac_issues:
        if issue.workitems:
            if not tt_enabled:
                tt_settings = target.getProjectTimeTrackingSettings(str(project_ID))
                if not tt_settings.Enabled:
                    print "Enabling TimeTracking for the prject"
                    target.setProjectTimeTrackingSettings(str(project_ID), enabled=True)
                tt_enabled = True
            print "Processing issue [ %s ]" % (str(issue.id))
            workitems = [to_youtrack_workitem(w) for w in issue.workitems]
            target.importWorkItems(str(project_ID) + "-" + str(issue.id), workitems)
    print "Importing workitems finished"
class RedmineImporter(object):
    def __init__(self, params):
        self._params = params
        self._projects = None
        self._max_issue_ids = {}
        self._issue_ids = {}
        self._relations = {}
        self._users = {}
        self._groups = {}
        self._subsystems = {}
        self._versions = {}

        # Connecting to Redmine
        if 'rm_api_key' in params:
            self._source = youtrackutils.redmine.RedmineClient(
                params['rm_api_key'], params['rm_url'])
        elif 'rm_login' in params:
            self._source = youtrackutils.redmine.RedmineClient(
                None, params['rm_url'], params.get('rm_login'),
                params.get('rm_password'))
        else:
            print("You have to provide Redmine API key or login/password")
            sys.exit(1)

        # Connecting to YouTrack
        token = params.get('token')
        if not token and 'token_file' in params:
            try:
                with open(params['token_file'], 'r') as f:
                    token = f.read().strip()
            except (OSError, IOError) as e:
                print("Cannot load token from file: " + str(e))
                sys.exit(1)
        if token:
            self._target = Connection(params['yt_url'], token=token)
        elif 'yt_login' in params:
            self._target = Connection(params['yt_url'], params.get('yt_login'),
                                      params.get('yt_password'))
        else:
            print("You have to provide YouTrack token or login/password")
            sys.exit(1)

        if not params.get('project_lead_login'):
            project_lead = params.get('yt_login')
            if not project_lead:
                for login in ('root', 'admin', 'administrator', 'guest'):
                    try:
                        project_lead = self._target.getUser(login).login
                        break
                    except youtrack.YouTrackException:
                        continue
            self._params['project_lead_login'] = project_lead

    def do_import(self, project_ids):
        try:
            projects2import = self._get_projects(project_ids)
        except youtrackutils.redmine.RedmineException as e:
            print('FATAL:', e)
            sys.exit(1)

        print('===> Import Roles')
        self._import_roles()

        for project in projects2import.values():
            self._import_project(project)

        print('===> Apply Relations')
        self._apply_relations()

    def _get_projects(self, project_ids=None, by_internal_id=False):
        if by_internal_id:
            by = 'by_iid'
        else:
            by = 'by_pid'
        if self._projects is None:
            self._projects = {'by_iid': {}, 'by_pid': {}}
        if project_ids:
            new_projects = [
                pid for pid in project_ids if pid not in self._projects[by]
            ]
        else:
            new_projects = None
        if new_projects is None or new_projects:
            for project in self._source.get_projects(new_projects):
                project.identifier = re.sub('\W', '', project.identifier)
                self._projects['by_iid'][project.id] = project
                self._projects['by_pid'][project.identifier] = project
        if project_ids:
            for pid in project_ids:
                if by == 'by_pid':
                    pid = re.sub('\W', '', pid)
                if pid not in self._projects[by]:
                    raise youtrackutils.redmine.RedmineException(
                        "Project '%s' doesn't exist in Redmine" % pid)
        return self._projects[by]

    def _get_project(self, project_id, by_internal_id=False):
        return self._get_projects([project_id], by_internal_id)[project_id]

    def _get_project_name(self, project):
        name = project.name
        while True:
            if not hasattr(project, 'parent'):
                break
            name = project.parent.name + ' :: ' + name
            project = self._get_project(project.parent.id, True)
        return name

    def _import_project(self, project):
        project_id = project.identifier
        project_name = self._get_project_name(project)
        project_desc = ''
        project_lead = self._params['project_lead_login']

        if hasattr(project, 'description') and project.description is not None:
            project_desc = project.description

        print("===> Importing Project '%s' (%s)" %
              (project_name.encode('utf-8'), project_id.encode('utf-8')))
        try:
            print('Creating project...')
            self._target.getProject(project_id)
            print('Project already exists')
        except youtrack.YouTrackException:
            self._target.createProjectDetailed(project_id, project_name,
                                               project_desc, project_lead)
            print('Project successfully created')
        print('Import project members...')
        self._import_members(project)
        print('Import issues...')
        self._import_issues(project)

    def _to_yt_user(self, redmine_user):
        if isinstance(redmine_user, basestring):
            user_id = redmine_user
        else:
            user_id = redmine_user.id
        if user_id not in self._users:
            try:
                redmine_user = self._source.get_user(user_id)
            except ResourceNotFound:
                redmine_user = None
            user = youtrack.User()

            if redmine_user != None:
                try:
                    user.email = redmine_user.mail
                except AttributeError:
                    pass
                try:
                    # In some cases redmine user login can be empty or missing.
                    # So, both cases should be handled.
                    user.login = redmine_user.login
                except AttributeError:
                    pass

            if not hasattr(user, 'login') or not user.login:
                if hasattr(user, 'email'):
                    user.login = user.email
                else:
                    user.login = '******'
                print('Cannot get login for user id=%s, set it to "%s"' %
                      (user_id, user.login))

            # user.login = redmine_user.login or 'guest'
            # user.email = redmine_user.mail or '*****@*****.**'
            if redmine_user != None and user.login != 'guest':
                if redmine_user.firstname is None and redmine_user.lastname is None:
                    user.fullName = user.login
                elif redmine_user.firstname is None:
                    user.fullName = redmine_user.lastname
                elif redmine_user.lastname is None:
                    user.fullName = redmine_user.firstname
                else:
                    user.fullName = redmine_user.firstname + ' ' + redmine_user.lastname
            else:
                user.created = True

            if redmine_user != None and hasattr(redmine_user, 'groups'):
                user.groups = [
                    self._to_yt_group(g) for g in redmine_user.groups
                ]

            self._users[user_id] = user
        return self._users[user_id]

    def _to_yt_group(self, redmine_group, users=None):
        if not isinstance(redmine_group, basestring):
            redmine_group = redmine_group.name
        if redmine_group not in self._groups:
            group = youtrack.Group()
            group.name = redmine_group
            if users is None:
                users = []
            group.users = users
            self._groups[redmine_group] = group
        return self._groups[redmine_group]

    def _to_yt_role(self, name, projects=None):
        role = youtrack.UserRole()
        role.name = name
        if projects:
            if isinstance(projects, list):
                role.projects.extend(projects)
            else:
                role.projects.append(projects)
        return role

    def _to_yt_version(self, version):
        if isinstance(version, basestring):
            vid = version
        else:
            vid = version.id
        if vid not in self._versions:
            redmine_version = self._source.get_version(vid)
            version = youtrack.Version()
            version.name = redmine_version.name
            version.description = redmine_version.description
            if getattr(redmine_version, 'due_date', None):
                version.releaseDate = str(to_unixtime(
                    redmine_version.due_date))
            version.released = str(redmine_version.status == 'closed').lower()
            version.archived = 'false'
            self._versions[vid] = version
        return self._versions[vid]

    def _to_yt_subsystem(self, category):
        if isinstance(category, basestring):
            cid = category
        else:
            cid = category.id
        if cid not in self._subsystems:
            redmine_cat = self._source.get_category(cid)
            subsystem = youtrack.Subsystem()
            subsystem.name = redmine_cat.name
            if hasattr(redmine_cat, 'assigned_to'):
                subsystem.login = self._create_user(
                    redmine_cat.assigned_to).login
            self._subsystems[cid] = subsystem
        return self._subsystems[cid]

    def _get_assignee_group_name(self, project_id):
        return '%s Assignees' % project_id.upper()

    def _get_yt_issue_id(self, issue, as_number_in_project=False):
        project_id = self._projects['by_iid'][issue.project.id].identifier
        new_id = self._max_issue_ids.get(project_id, 0) + 1
        rid = int(issue.id)
        if rid not in self._issue_ids:
            self._max_issue_ids[project_id] = new_id
            self._issue_ids[rid] = {'id': new_id, 'project_id': project_id}
        if as_number_in_project:
            return self._issue_ids[rid]['id']
        return self._to_yt_issue_id(rid)

    def _to_yt_issue_id(self, iid):
        issue = self._issue_ids[iid]
        return '%s-%d' % (issue['project_id'], issue['id'])

    def _get_yt_issue_number(self, issue):
        return self._get_yt_issue_id(issue, True)

    def _import_members(self, project):
        project_id = project.identifier
        members = self._source.get_project_members(project.id)
        users_by_role = {}
        groups_by_role = {}
        if members:
            for member in members:
                # Sometimes roles can be duplicated
                if hasattr(member, 'roles'):
                    roles = set([r.name for r in member.roles])
                    if hasattr(member, 'group'):
                        group = self._to_yt_group(member.group.name)
                        for role in roles:
                            if role not in groups_by_role:
                                groups_by_role[role] = []
                            groups_by_role[role].append(group)
                    else:
                        user = self._to_yt_user(member.user)
                        for role in roles:
                            if role not in users_by_role:
                                users_by_role[role] = []
                            users_by_role[role].append(user)
        for role_name, users in users_by_role.items():
            group = self._to_yt_group('%s %s' %
                                      (project_id.upper(), role_name))
            self._create_group(group)
            self._target.addUserRoleToGroup(
                group, self._to_yt_role(role_name, project_id))
            self._target.importUsers(users)
            for user in users:
                self._target.setUserGroup(user.login, group.name)
        for role_name, groups in groups_by_role.items():
            for group in groups:
                self._create_group(group)
                self._target.addUserRoleToGroup(
                    group, self._to_yt_role(role_name, project_id))

    def _import_roles(self):
        existed_roles = [role.name for role in self._target.getRoles()]
        new_roles = {}
        for role in self._source.get_roles():
            if role.name in existed_roles:
                continue
            permissions = None
            if hasattr(role, 'permissions'):
                permissions = []
                for perm in role.permissions:
                    if isinstance(perm, basestring):
                        rm_perm = perm
                    else:
                        rm_perm = perm.name
                    yt_perm = \
                        youtrackutils.redmine.Mapping.PERMISSIONS.get(rm_perm)
                    if not yt_perm:
                        continue
                    if isinstance(yt_perm, list):
                        permissions.extend(yt_perm)
                    else:
                        permissions.append(yt_perm)
            new_roles[role.name] = permissions
        for role_name, role_permissions in new_roles.items():
            role = self._to_yt_role(role_name)
            self._target.createRole(role)
            if role_permissions:
                for perm_name in role_permissions:
                    perm = youtrack.Permission()
                    perm.name = perm_name
                    self._target.addPermissionToRole(role, perm)

    def _import_issues(self, project, limit=CHUNK_SIZE):
        project_id = project.identifier
        offset = 0
        assignee_group = self._get_assignee_group_name(project_id)
        while True:
            issues = self._source.get_project_issues(
                project.id, limit, offset,
                self._params.get('skip_on_error', False))
            if not issues:
                break
            issues = [
                issue for issue in issues if issue.project.id == project.id
            ]
            self._target.importIssues(
                project_id, assignee_group,
                [self._make_issue(issue, project_id) for issue in issues])
            for issue in issues:
                self._collect_relations(issue)
                self._add_attachments(issue)
                if self._params.get('import_time_entries', False):
                    self._enable_timetracking(project)
                    self._add_work_items(issue)
            offset += limit

    def _make_issue(self, redmine_issue, project_id):
        issue = youtrack.Issue()
        issue['comments'] = []
        if self._params.get('use_markdown'):
            issue['markdown'] = "true"
        try:
            if self._params.get('create_redmine_linkage', False):
                self._add_field_to_issue(project_id, issue, "redmine_id",
                                         int(redmine_issue.id))
            for name, value in redmine_issue.attributes.items():
                if name in ('project', 'attachments'):
                    continue
                if name == 'assigned_to' and value.name in self._groups:
                    continue
                if name == 'id':
                    value = str(self._get_yt_issue_number(redmine_issue))
                if name == 'custom_fields':
                    for field in value:
                        self._add_field_to_issue(project_id, issue, field.name,
                                                 getattr(field, 'value', None))
                elif name == 'journals':
                    self._add_journals(issue, value)
                else:
                    if name == 'category':
                        value = self._to_yt_subsystem(value)
                    self._add_field_to_issue(project_id, issue, name, value)
        except Exception as e:
            print('Failed to process issue:')
            print(redmine_issue)
            traceback.print_exc()
            raise e
        return issue

    def _convert_value(self, field_name, value):
        conv_map = youtrackutils.redmine.Mapping.CONVERSION.get(field_name)
        if conv_map:
            if hasattr(value, 'value'):
                if value.value in conv_map:
                    value.value = conv_map[value.value]
            elif hasattr(value, 'name'):
                if value.name in conv_map:
                    value.name = conv_map[value.name]
        return value

    def _get_yt_field_name(self, field_name):
        return youtrackutils.redmine.Mapping.FIELD_NAMES.get(
            field_name, field_name)

    def _get_yt_field_type(self, field_name):
        return youtrackutils.redmine.Mapping.FIELD_TYPES.get(
            field_name, youtrack.EXISTING_FIELD_TYPES.get(field_name))

    def _add_field_to_issue(self, project_id, issue, name, value):
        if value is None:
            return
        field_name = self._get_yt_field_name(name)
        field_type = self._get_yt_field_type(field_name)
        if field_type is None:
            return
        value = self._convert_value(field_name, value)
        if isinstance(value, list):
            if not value:
                return
            issue[field_name] = []
            for v in value:
                v = self._create_field_value(project_id, field_name,
                                             field_type, v)
                issue[field_name].append(
                    self._get_value_presentation(field_type, v))
        else:
            value = self._create_field_value(project_id, field_name,
                                             field_type, value)
            issue[field_name] = self._get_value_presentation(field_type, value)

    def _create_field(self, project_id, field_name, field_type):
        project_fields = self._target.getProjectCustomFields(project_id)
        if field_name.lower() not in [f.name.lower() for f in project_fields]:
            all_fields = self._target.getCustomFields()
            if field_name.lower() not in [f.name.lower() for f in all_fields]:
                self._target.createCustomFieldDetailed(field_name, field_type,
                                                       False, True, False, {})
            if field_type in ('string', 'date', 'integer', 'float', 'period'):
                self._target.createProjectCustomFieldDetailed(
                    project_id, field_name, 'No ' + field_name)
            else:
                bundle_name = field_name + ' bundle'
                create_bundle_safe(self._target, bundle_name, field_type)
                self._target.createProjectCustomFieldDetailed(
                    project_id, field_name, 'No ' + field_name,
                    {'bundle': bundle_name})

    def _create_field_value(self, project_id, field_name, field_type, value):
        if field_type.startswith('user'):
            if hasattr(value, 'name'):
                value.name = self._create_user(value).login
            else:
                value = self._create_user(value).login
        elif field_type.startswith('version'):
            value = self._to_yt_version(value)
        if field_name == 'Assignee':
            return value
        if field_name in youtrack.EXISTING_FIELDS:
            return value
        self._create_field(project_id, field_name, field_type)
        if field_type in ('string', 'date', 'integer', 'float', 'period'):
            return value
        field = self._target.getProjectCustomField(project_id, field_name)
        bundle = self._target.getBundle(field_type, field.bundle)
        try:
            if hasattr(value, 'value'):
                value = value.value
            elif hasattr(value, 'name'):
                if not (field_type.startswith('version')
                        or field_type.startswith('ownedField')):
                    value = value.name
            self._target.addValueToBundle(bundle, value)
        except youtrack.YouTrackException as e:
            if e.response.status != 409 or e.response.reason.lower(
            ) != 'conflict':
                print(e)
        return value

    def _get_value_presentation(self, field_type, value):
        if field_type == 'date':
            return str(to_unixtime(value))
        if field_type == 'integer':
            return '%d' % int(float(value))
        if field_type == 'float':
            return '%.5f' % float(value)
        if field_type == 'string':
            return value
        if field_type == 'period':
            return '%d' % int(float(value) * 60)
        if hasattr(value, 'value'):
            return value.value
        elif hasattr(value, 'name'):
            return value.name
        return value

    def _create_user(self, user):
        user = self._to_yt_user(user)
        if not hasattr(user, 'created'):
            self._target.createUser(user)
            user.created = True
            if hasattr(user, 'groups'):
                for group in user.groups:
                    self._create_group(group)
                    self._target.setUserGroup(user.login, group.name)
        return user

    def _create_group(self, group):
        if isinstance(group, basestring):
            group = self._to_yt_group(group)
        if not hasattr(group, 'created'):
            try:
                self._target.getGroup(group.name)
            except youtrack.YouTrackException:
                self._target.createGroup(group)
            group.created = True
        return group

    def _add_journals(self, issue, journals):
        if not journals:
            return
        for rec in journals:
            if hasattr(rec,
                       'notes') and rec.notes is not None and rec.notes != '':
                comment = youtrack.Comment()
                if self._params.get('use_markdown'):
                    comment.markdown = "true"
                comment.text = rec.notes
                comment.author = self._create_user(rec.user).login
                comment.created = str(to_unixtime(rec.created_on))
                issue['comments'].append(comment)

    def _enable_timetracking(self, project):
        self._target.setProjectTimeTrackingSettings(project.identifier,
                                                    enabled=True)

    def _add_work_items(self, issue):
        import_data = []
        work_items = self._source.get_time_entries(issue.id)
        flatten_work_items = []
        for item in work_items:
            if 'time_entries' in item.attributes:
                time_entries = item.time_entries
                for time_entry in time_entries:
                    flatten_work_items.append(time_entry)
            else:
                flatten_work_items.append(item)

        for t in sorted(flatten_work_items, key=lambda tt: tt.spent_on):
            work_item = youtrack.WorkItem()
            work_item.authorLogin = self._create_user(t.user).login
            work_item.date = str(to_unixtime(t.spent_on))
            work_item.description = t.comments
            work_item.duration = int(float(t.hours) * 60)
            import_data.append(work_item)
        if import_data:
            self._target.importWorkItems(self._get_yt_issue_id(issue),
                                         import_data)

    def _add_attachments(self, issue):
        if not hasattr(issue, 'attachments'):
            return
        max_attempts = 5
        for attach in issue.attachments:
            attach.author.login = self._create_user(attach.author).login
            if not attach.author.login:
                attach.author.login = '******'
            attempts = max_attempts
            while attempts:
                attempts -= 1
                try:
                    self._target.createAttachmentFromAttachment(
                        self._get_yt_issue_id(issue),
                        RedmineAttachment(attach, self._source))
                    break
                except Exception as e:
                    print(e)
                    if attempts:
                        delay = 30 + (max_attempts - attempts - 1) * 10
                        print("Can't import attachment: %s. Retry in %d s." %
                              (attach.filename, delay))
                        time.sleep(delay)
                    else:
                        print('Failed to import attachment: %s. Skipped.' %
                              attach.filename)

    def _collect_relations(self, issue):
        link_types = {
            'duplicates': 'duplicate',
            'relates': 'relates',
            'blocks': 'depend',
            'precedes': 'depend'
        }
        if hasattr(issue, 'relations'):
            for rel in issue.relations:
                if rel.relation_type not in link_types:
                    print('Unsuitable link type: %s. Skipped' %
                          rel.relation_type)
                    continue
                from_id = rel.issue_id
                to_id = rel.issue_to_id
                if rel.relation_type == 'duplicates':
                    from_id, to_id = to_id, from_id
                self._push_relation(from_id, to_id,
                                    link_types[rel.relation_type])
        if hasattr(issue, 'children'):
            for child in issue.children:
                self._push_relation(issue.id, child.id, 'subtask')

    def _push_relation(self, from_iid, to_iid, relation_type):
        from_iid = int(from_iid)
        to_iid = int(to_iid)
        if relation_type not in self._relations:
            self._relations[relation_type] = {}
        relations = self._relations[relation_type]
        if from_iid not in relations:
            relations[from_iid] = {}
        relations[from_iid][to_iid] = None

    def _apply_relations(self, limit=CHUNK_SIZE):
        links = []
        for link_type, ids in self._relations.items():
            for from_id, to_ids in ids.items():
                for to_id in to_ids:
                    link = youtrack.Link()
                    link.typeName = link_type
                    try:
                        link.source = self._to_yt_issue_id(from_id)
                        link.target = self._to_yt_issue_id(to_id)
                    except KeyError:
                        print("Cannot apply link (%s) to issues: %d and %d" %
                              (link_type, from_id, to_id))
                        if hasattr(link, 'source') and link.source:
                            print("The second issue was not imported")
                            continue
                        else:
                            print("The first issues was not imported")
                            break
                    links.append(link)
                    if len(links) >= limit:
                        self._target.importLinks(links)
                        del links[0:]
        if links:
            self._target.importLinks(links)