import datetime
import logging

from flask import g
from flask_login import current_user
from werkzeug.security import generate_password_hash, check_password_hash
from flask_login import LoginManager
from flask_openid import OpenID
from flask_babelpkg import lazy_gettext as _
from sqlalchemy.engine.reflection import Inspector

from .. import Base
from ..basemanager import BaseManager

from .models import User, Role, PermissionView, Permission, ViewMenu
from .views import AuthDBView, AuthOIDView, ResetMyPasswordView, AuthLDAPView, \
    ResetPasswordView, UserDBModelView, UserLDAPModelView, UserOIDModelView, RoleModelView, \
    PermissionViewModelView, ViewMenuModelView, PermissionModelView, UserStatsChartView

log = logging.getLogger(__name__)

AUTH_OID = 0
AUTH_DB = 1
AUTH_LDAP = 2

ADMIN_USER_NAME = 'admin'
ADMIN_USER_PASSWORD = 'general'
ADMIN_USER_EMAIL = 'admin@fab.org'
ADMIN_USER_FIRST_NAME = 'Admin'
ADMIN_USER_LAST_NAME = 'User'


class SecurityManager(BaseManager):
    """
        Responsible for authentication, registering security views,
        role and permission auto management

        If you want to change anything just inherit and override, then
        pass your own security manager to AppBuilder.
    """
    auth_view = None
    user_view = None
    lm = None
    oid = None

    userdbmodelview = UserDBModelView
    """ Override if you want your own user db view """
    userldapmodelview = UserLDAPModelView
    """ Override if you want your own user ldap view """
    useroidmodelview = UserOIDModelView
    """ Override if you want your own user OID view """
    authdbview = AuthDBView
    """ Override if you want your own Authentication DB view """
    authldapview = AuthLDAPView
    """ Override if you want your own Authentication LDAP view """
    authoidview = AuthOIDView
    """ Override if you want your own Authentication OID view """

    def __init__(self, appbuilder):
        """
            SecurityManager contructor
            param appbuilder:
                F.A.B AppBuilder main object
            """
        super(SecurityManager, self).__init__(appbuilder)
        app = self.appbuilder.get_app
        app.config.setdefault('AUTH_ROLE_ADMIN', 'Admin')
        app.config.setdefault('AUTH_ROLE_PUBLIC', 'Public')
        app.config.setdefault('AUTH_TYPE', AUTH_DB)

        if app.config['AUTH_TYPE'] == AUTH_LDAP:
            if 'AUTH_LDAP_SERVER' not in app.config:
                raise Exception("No AUTH_LDAP_SERVER defined on config with AUTH_LDAP authentication type.")

        self.lm = LoginManager(app)
        self.lm.login_view = 'login'
        self.oid = OpenID(app)
        self.lm.user_loader(self.load_user)
        self.create_db()

    @property
    def get_session(self):
        return self.appbuilder.get_session

    @property
    def auth_type(self):
        return self.appbuilder.get_app.config['AUTH_TYPE']

    @property
    def auth_role_admin(self):
        return self.appbuilder.get_app.config['AUTH_ROLE_ADMIN']

    @property
    def auth_role_public(self):
        return self.appbuilder.get_app.config['AUTH_ROLE_PUBLIC']

    @property
    def auth_ldap_server(self):
        return self.appbuilder.get_app.config['AUTH_LDAP_SERVER']

    def register_views(self):
        self.appbuilder.add_view_no_menu(ResetPasswordView())
        self.appbuilder.add_view_no_menu(ResetMyPasswordView())

        if self.auth_type == AUTH_DB:
            self.user_view = self.userdbmodelview
            self.auth_view = self.authdbview()
        elif self.auth_type == AUTH_LDAP:
            self.user_view = self.userldapmodelview
            self.auth_view = self.authldapview()
        else:
            self.user_view = self.useroidmodelview
            self.auth_view = self.authoidview()
            self.oid.after_login_func = self.auth_view.after_login

        self.appbuilder.add_view_no_menu(self.auth_view)

        self.user_view = self.appbuilder.add_view(self.user_view, "List Users",
                                                  icon="fa-user", label=_("List Users"),
                                                  category="Security", category_icon="fa-cogs",
                                                  category_label=_('Security'))
        
        role_view = self.appbuilder.add_view(RoleModelView, "List Roles", icon="fa-group", label=_('List Roles'),
                                             category="Security", category_icon="fa-cogs")
        role_view.related_views = [self.user_view.__class__]
        
        self.appbuilder.add_view(UserStatsChartView,
                                 "User's Statistics", icon="fa-bar-chart-o", label=_("User's Statistics"),
                                 category="Security")
        
        self.appbuilder.menu.add_separator("Security")
        self.appbuilder.add_view(PermissionModelView,
                                 "Base Permissions", icon="fa-lock",
                                 label=_("Base Permissions"), category="Security")
        self.appbuilder.add_view(ViewMenuModelView,
                                 "Views/Menus", icon="fa-list-alt",
                                 label=_('Views/Menus'), category="Security")
        self.appbuilder.add_view(PermissionViewModelView,
                                 "Permission on Views/Menus", icon="fa-link",
                                 label=_('Permission on Views/Menus'), category="Security")

    def load_user(self, pk):
        return self.get_user_by_id(int(pk))

    @staticmethod
    def before_request():
        g.user = current_user

    def _migrate_db(self): # pragma: no cover
        """
            Migrate from 0.8 to 0.9, change GeneralView to ModelView
            on ViewMenus
        """
        sec_view_prefixes = ['Permission', 'ViewMenu', 'PermissionView',
                             'UserOID', 'UserLDAP', 'UserDB',
                             'Role']
        sec_view_old_sufix = 'GeneralView'
        sec_view_new_sufix = 'ModelView'
        for sec_view_prefix in sec_view_prefixes:
            sec_view = self._find_view_menu('{0}{1}'.format(sec_view_prefix, sec_view_old_sufix))
            if sec_view:
                try:
                    log.info("Migrate from 0.8 to 0.9 Changing {0}{1}".format(sec_view_prefix, sec_view_old_sufix))
                    sec_view.name = '{0}{1}'.format(sec_view_prefix, sec_view_new_sufix)
                    self.get_session.merge(sec_view)
                    self.get_session.commit()
                except Exception as e:
                    log.error("Update ViewMenu error: {0}".format(str(e)))
                    self.get_session.rollback()


    def create_db(self):
        try:
            engine = self.get_session.get_bind(mapper=None, clause=None)
            inspector = Inspector.from_engine(engine)
            if 'ab_user' not in inspector.get_table_names():
                log.info("Security DB not found Creating all Models from Base")
                Base.metadata.create_all(engine)
                log.info("Security DB Created")
            else:
                self._migrate_db()
            if not self.get_session.query(Role).filter_by(name=self.auth_role_admin).first():
                role = Role()
                role.name = self.auth_role_admin
                self.get_session.add(role)
                self.get_session.commit()
                log.info("Inserted Role for public access %s" % (self.auth_role_admin))
            if not self.get_session.query(Role).filter_by(name=self.auth_role_public).first():
                role = Role()
                role.name = self.auth_role_public
                self.get_session.add(role)
                self.get_session.commit()
                log.info("Inserted Role for public access %s" % (self.auth_role_public))
            if not self.get_session.query(User).all():
                user = User()
                user.first_name = ADMIN_USER_FIRST_NAME
                user.last_name = ADMIN_USER_LAST_NAME
                user.username = ADMIN_USER_NAME
                user.password = generate_password_hash(ADMIN_USER_PASSWORD)
                user.email = ADMIN_USER_EMAIL
                user.active = True
                user.role = self.get_session.query(Role).filter_by(name=self.auth_role_admin).first()
                self.get_session.add(user)
                self.get_session.commit()
                log.info("Inserted initial Admin user")
                log.info("Login using {0}/{1}".format(ADMIN_USER_NAME, ADMIN_USER_PASSWORD))
        except Exception as e:
            log.error(
                "DB Creation and initialization failed, if just upgraded to 0.7.X you must migrate the DB. {0}".format(
                    str(e)))


    """
    ----------------------------------------
        AUTHENTICATION METHODS
    ----------------------------------------
    """

    def auth_user_db(self, username, password):
        """
            Method for authenticating user, auth db style

            :param username:
                The username
            :param password:
                The password, will be tested against hashed password on db
        """
        if username is None or username == "":
            return None
        user = self.get_session.query(User).filter_by(username=username).first()
        if user is None or (not user.is_active()):
            return None
        elif check_password_hash(user.password, password):
            self._update_user_auth_stat(user, True)
            return user
        else:
            self._update_user_auth_stat(user, False)
            return None

    def auth_user_ldap(self, username, password):
        """
            Method for authenticating user, auth LDAP style.
            depends on ldap module that is not mandatory requirement
            for F.A.B.

            :param username:
                The username
            :param password:
                The password
        """
        if username is None or username == "":
            return None
        user = self.get_session.query(User).filter_by(username=username).first()
        if user is not None and (not user.is_active()):
            return None
        else:
            try:
                import ldap
            except:
                raise Exception("No ldap library for python.")
            try:
                con = ldap.initialize(self.auth_ldap_server)
                con.set_option(ldap.OPT_REFERRALS, 0)
               
                try:
                    app=self.appbuilder.get_app  
                    if 'AUTH_LDAP_SEARCH' not in app.config:
                        bind_username=username
                    else:
                        if app.config['AUTH_LDAP_SEARCH'] == "" :
                            bind_username=username
                        else:
                            app.config.setdefault('AUTH_LDAP_BIND_FIELD', 'cn')
                            app.config.setdefault('AUTH_LDAP_UID_FIELD', 'uid')

                            filter="%s=%s" % (app.config['AUTH_LDAP_UID_FIELD'],username)
                            bind_username_array=con.search_s(app.config['AUTH_LDAP_SEARCH'],ldap.SCOPE_SUBTREE,filter,[app.config['AUTH_LDAP_BIND_FIELD']])
                            if bind_username_array == []:
                                return None
                            else:
                                bind_username=bind_username_array[0][0]

                    con.bind_s(bind_username, password)
                    self._update_user_auth_stat(user)
                    return user
                except ldap.INVALID_CREDENTIALS:
                    self._update_user_auth_stat(user, False)
                    return None
            except ldap.LDAPError as e:
                if type(e.message) == dict and 'desc' in e.message:
                    log.error("LDAP Error {0}".format(e.message['desc']))
                    return None
                else:
                    log.error(e)
                    return None

    def auth_user_oid(self, email):
        """
            OpenID user Authentication

            :type self: User model
        """
        user = self.get_session.query(User).filter_by(email=email).first()
        if user is None:
            self._update_user_auth_stat(user, False)
            return None
        elif not user.is_active():
            return None
        else:
            self._update_user_auth_stat(user)
            return user

    def _update_user_auth_stat(self, user, success=True):
        """
            Update authentication successful to user.

            :param user:
                The authenticated user model
        """
        try:
            if not user.login_count:
                user.login_count = 0
            elif not user.fail_login_count:
                user.fail_login_count = 0
            if success:
                user.login_count += 1
                user.fail_login_count = 0
            else:
                user.fail_login_count += 1
            user.last_login = datetime.datetime.now()
            self.get_session.merge(user)
            self.get_session.commit()
        except Exception as e:
            log.error("Update user login stat: {0}".format(str(e)))
            self.get_session.rollback()


    def reset_password(self, userid, password):
        try:
            user = self.get_user_by_id(userid)
            user.password = generate_password_hash(password)
            self.get_session.commit()
        except Exception as e:
            log.error("Reset password: {0}".format(str(e)))
            self.get_session.rollback()

    def get_user_by_id(self, pk):
        return self.get_session.query(User).get(pk)


    """
        ----------------------------------------
            PERMISSION ACCESS CHECK
        ----------------------------------------
    """

    def is_item_public(self, permission_name, view_name):
        """
            Check if view has public permissions
    
            :param permission_name:
                the permission: can_show, can_edit...
            :param view_name:
                the name of the class view (child of BaseView)
        """
        role = self.get_session.query(Role).filter_by(name=self.auth_role_public).first()
        lst = role.permissions
        if lst:
            for i in lst:
                if (view_name == i.view_menu.name) and (permission_name == i.permission.name):
                    return True
            return False
        else:
            return False


    def has_view_access(self, user, permission_name, view_name):
        lst = user.role.permissions
        if lst:
            for i in lst:
                if (view_name == i.view_menu.name) and (permission_name == i.permission.name):
                    return True
            return False
        else:
            return False


    def has_access(self, permission_name, view_name):
        """
            Check if current user or public has access to view or menu
        """
        if current_user.is_authenticated():
            if self.has_view_access(g.user, permission_name, view_name):
                return True
            else:
                return False
        else:
            if self.is_item_public(permission_name, view_name):
                return True
            else:
                return False
        return False


    """
        ----------------------------------------
            PERMISSION MANAGEMENT
        ----------------------------------------
    """

    def _find_permission(self, name):
        """
            Finds and returns a Permission by name
        """
        return self.get_session.query(Permission).filter_by(name=name).first()


    def _add_permission(self, name):
        """
            Adds a permission to the backend, model permission
            
            :param name:
                name of the permission: 'can_add','can_edit' etc...
        """
        perm = self._find_permission(name)
        if perm is None:
            try:
                perm = Permission()
                perm.name = name
                self.get_session.add(perm)
                self.get_session.commit()
                return perm
            except Exception as e:
                log.error("Add Permission: {0}".format(str(e)))
                self.get_session.rollback()
        return perm

    def _del_permission(self, name):
        """
            Deletes a permission from the backend, model permission

            :param name:
                name of the permission: 'can_add','can_edit' etc...
        """
        perm = self._find_permission(name)
        if perm:
            try:
                self.get_session.delete(perm)
                self.get_session.commit()
            except Exception as e:
                log.error("Del Permission Error: {0}".format(str(e)))
                self.get_session.rollback()

    #----------------------------------------------
    #       PERMITIVES VIEW MENU
    #----------------------------------------------
    def _find_view_menu(self, name):
        """
            Finds and returns a ViewMenu by name
        """
        return self.get_session.query(ViewMenu).filter_by(name=name).first()

    def _add_view_menu(self, name):
        """
            Adds a view or menu to the backend, model view_menu
            param name:
                name of the view menu to add
        """
        view_menu = self._find_view_menu(name)
        if view_menu is None:
            try:
                view_menu = ViewMenu()
                view_menu.name = name
                self.get_session.add(view_menu)
                self.get_session.commit()
                return view_menu
            except Exception as e:
                log.error("Add View Menu Error: {0}".format(str(e)))
                self.get_session.rollback()
        return view_menu

    def _del_view_menu(self, name):
        """
            Deletes a ViewMenu from the backend

            :param name:
                name of the ViewMenu
        """
        obj = self._find_view_menu(name)
        if obj:
            try:
                self.get_session.delete(obj)
                self.get_session.commit()
            except Exception as e:
                log.error("Del Permission Error: {0}".format(str(e)))
                self.get_session.rollback()

    #----------------------------------------------
    #          PERMISSION VIEW MENU
    #----------------------------------------------
    def _find_permission_view_menu(self, permission_name, view_menu_name):
        """
            Finds and returns a PermissionView by names
        """
        permission = self._find_permission(permission_name)
        view_menu = self._find_view_menu(view_menu_name)
        return self.get_session.query(PermissionView).filter_by(permission=permission, view_menu=view_menu).first()


    def _add_permission_view_menu(self, permission_name, view_menu_name):
        """
            Adds a permission on a view or menu to the backend
            
            :param permission_name:
                name of the permission to add: 'can_add','can_edit' etc...
            :param view_menu_name:
                name of the view menu to add
        """
        vm = self._add_view_menu(view_menu_name)
        perm = self._add_permission(permission_name)
        pv = PermissionView()
        pv.view_menu_id, pv.permission_id = vm.id, perm.id
        try:
            self.get_session.add(pv)
            self.get_session.commit()
            log.info("Created Permission View: %s" % (str(pv)))
            return pv
        except Exception as e:
            log.error("Creation of Permission View Error: {0}".format(str(e)))
            self.get_session.rollback()


    def _del_permission_view_menu(self, permission_name, view_menu_name):
        try:
            pv = self._find_permission_view_menu(permission_name, view_menu_name)
            # delete permission on view
            self.get_session.delete(pv)
            self.get_session.commit()
            # if no more permission on permission view, delete permission
            pv = self.get_session.query(PermissionView).filter_by(permission=pv.permission).all()
            if not pv:
                self._del_permission(pv.permission.name)
            log.info("Removed Permission View: %s" % (str(permission_name)))
        except Exception as e:
            log.error("Remove Permission from View Error: {0}".format(str(e)))
            self.get_session.rollback()


    def _find_permission_on_views(self, lst, item):
        for i in lst:
            if i.permission.name == item:
                return True
        return False

    def _find_permission_view(self, lst, permission, view_menu):
        for i in lst:
            if i.permission.name == permission and i.view_menu.name == view_menu:
                return True
        return False

    def add_permission_role(self, role, perm_view):
        """
            Add permission-ViewMenu object to Role
            
            :param role:
                The role object
            :param perm_view:
                The PermissionViewMenu object
        """
        if perm_view not in role.permissions:
            try:
                role.permissions.append(perm_view)
                self.get_session.merge(role)
                self.get_session.commit()
                log.info("Added Permission %s to role %s" % (str(perm_view), role.name))
            except Exception as e:
                log.error("Add Permission to Role Error: {0}".format(str(e)))
                self.get_session.rollback()


    def del_permission_role(self, role, perm_view):
        """
            Remove permission-ViewMenu object to Role
            
            :param role:
                The role object
            :param perm_view:
                The PermissionViewMenu object
        """
        if perm_view in role.permissions:
            try:
                role.permissions.remove(perm_view)
                self.get_session.merge(role)
                self.get_session.commit()
                log.info("Removed Permission %s to role %s" % (str(perm_view), role.name))
            except Exception as e:
                log.error("Remove Permission to Role Error: {0}".format(str(e)))
                self.get_session.rollback()


    def add_permissions_view(self, base_permissions, view_menu):
        """
            Adds a permission on a view menu to the backend

            :param base_permissions:
                list of permissions from view (all exposed methods): 'can_add','can_edit' etc...
            :param view_menu:
                name of the view or menu to add
        """
        view_menu_db = self._add_view_menu(view_menu)
        perm_views = self.get_session.query(PermissionView).filter_by(view_menu_id=view_menu_db.id).all()

        if not perm_views:
            # No permissions yet on this view
            for permission in base_permissions:
                pv = self._add_permission_view_menu(permission, view_menu)
                role_admin = self.get_session.query(Role).filter_by(name=self.auth_role_admin).first()
                self.add_permission_role(role_admin, pv)
        else:
            # Permissions on this view exist but....
            role_admin = self.get_session.query(Role).filter_by(name=self.auth_role_admin).first()
            for permission in base_permissions:
                # Check if base view permissions exist
                if not self._find_permission_on_views(perm_views, permission):
                    pv = self._add_permission_view_menu(permission, view_menu)
                    self.add_permission_role(role_admin, pv)
            for perm_view in perm_views:
                if perm_view.permission.name not in base_permissions:
                    # perm to delete
                    roles = self.get_session.query(Role).all()
                    perm = self._find_permission(perm_view.permission.name)
                    # del permission from all roles
                    for role in roles:
                        self.del_permission_role(role, perm)
                    self._del_permission_view_menu(perm_view.permission.name, view_menu)
                elif perm_view not in role_admin.permissions:
                    # Role Admin must have all permissions
                    self.add_permission_role(role_admin, perm_view)


    def add_permissions_menu(self, view_menu_name):
        """
            Adds menu_access to menu on permission_view_menu

            :param view_menu_name:
                The menu name
        """
        self._add_view_menu(view_menu_name)
        pv = self._find_permission_view_menu('menu_access', view_menu_name)
        if not pv:
            pv = self._add_permission_view_menu('menu_access', view_menu_name)
            role_admin = self.get_session.query(Role).filter_by(name=self.auth_role_admin).first()
            self.add_permission_role(role_admin, pv)


    def security_cleanup(self, baseviews, menus):
        viewsmenus = self.get_session.query(ViewMenu).all()
        roles = self.get_session.query(Role).all()
        for viewmenu in viewsmenus:
            found = False
            for baseview in baseviews:
                if viewmenu.name == baseview.__class__.__name__:
                    found = True
                    break
            if menus.find(viewmenu.name):
                found = True
            if not found:
                permissions = self.get_session.query(PermissionView).filter_by(view_menu_id=viewmenu.id).all()
                for permission in permissions:
                    for role in roles:
                        self.del_permission_role(role, permission)
                    self._del_permission_view_menu(permission.permission.name, viewmenu.name)
                self.get_session.delete(viewmenu)
                self.get_session.commit()

