##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2019, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
##########################################################################

"""Implements Grant Wizard"""

import simplejson as json
from flask import Response, url_for
from flask import render_template, request, current_app
from flask_babelex import gettext
from flask_security import login_required
from pgadmin.browser.server_groups.servers.utils import parse_priv_to_db
from pgadmin.utils import PgAdminModule
from pgadmin.utils.ajax import make_response as ajax_response, \
    make_json_response, internal_server_error
from pgadmin.utils.driver import get_driver

from config import PG_DEFAULT_DRIVER

try:
    from urllib import unquote
except ImportError:
    from urllib.parse import unquote
from pgadmin.utils.ajax import precondition_required
from functools import wraps
from pgadmin.utils.preferences import Preferences

# set template path for sql scripts
MODULE_NAME = 'grant_wizard'
server_info = {}


class GrantWizardModule(PgAdminModule):
    """
    class GrantWizardModule(Object):

        It is a wizard which inherits PgAdminModule
        class and define methods to load its own
        javascript file.

    LABEL = gettext('Browser')
    """

    def get_own_stylesheets(self):
        """
        Returns:
            list: the stylesheets used by this module.
        """
        stylesheets = []
        return stylesheets

    def get_own_javascripts(self):
        """"
        Returns:
            list: js files used by this module
        """
        scripts = []
        scripts.append({
            'name': 'pgadmin.tools.grant_wizard',
            'path': url_for('grant_wizard.index') + 'grant_wizard',
            'when': None
        })
        scripts.append({
            'name': 'pgadmin.browser.wizard',
            'path': url_for('browser.static', filename='js/wizard'),
            'when': None
        })
        return scripts

    def show_system_objects(self):
        """
        return system preference objects
        """
        return self.pref_show_system_objects

    def register_preferences(self):
        """
        Get show_system_objects preference
        """
        self.browser_preference = Preferences.module('browser')
        self.pref_show_system_objects = self.browser_preference.preference(
            'show_system_objects'
        )

    def get_exposed_url_endpoints(self):
        """
        Returns:
            list: URL endpoints for grant-wizard module
        """
        return [
            'grant_wizard.acl', 'grant_wizard.objects', 'grant_wizard.apply',
            'grant_wizard.modified_sql'
        ]


# Create blueprint for GrantWizardModule class
blueprint = GrantWizardModule(
    MODULE_NAME, __name__, static_url_path='')


def check_precondition(f):
    """
    This function will behave as a decorator which will checks
    database connection before running view, it will also attaches
    manager,conn & template_path properties to instance of the method.

    Assumptions:
        This function will always be used as decorator of a class method.
    """

    @wraps(f)
    def wrap(*args, **kwargs):
        # Here args[0] will hold self & kwargs will hold sid,did

        server_info.clear()
        server_info['manager'] = get_driver(PG_DEFAULT_DRIVER)\
            .connection_manager(kwargs['sid'])
        server_info['conn'] = server_info['manager'].connection(
            did=kwargs['did']
        )
        # If DB not connected then return error to browser
        if not server_info['conn'].connected():
            return precondition_required(
                gettext("Connection to the server has been lost.")
            )

        # Set template path for sql scripts
        server_info['server_type'] = server_info['manager'].server_type
        server_info['version'] = server_info['manager'].version
        if server_info['server_type'] == 'pg':
            server_info['template_path'] = 'grant_wizard/pg/#{0}#'.format(
                server_info['version'])
        elif server_info['server_type'] == 'ppas':
            server_info['template_path'] = 'grant_wizard/ppas/#{0}#'.format(
                server_info['version'])

        return f(*args, **kwargs)

    return wrap


@blueprint.route("/")
@login_required
def index():
    pass


@blueprint.route("/grant_wizard.js")
@login_required
def script():
    """render own javascript"""
    return Response(response=render_template(
        "grant_wizard/js/grant_wizard.js", _=gettext),
        status=200,
        mimetype="application/javascript")


@blueprint.route(
    '/acl/<int:sid>/<int:did>/', methods=['GET'], endpoint='acl'
)
@login_required
@check_precondition
def acl_list(sid, did):
    """render list of acls"""
    server_prop = server_info
    return Response(response=render_template(
        server_prop['template_path'] + "/acl.json", _=gettext),
        status=200,
        mimetype="application/json")


@blueprint.route(
    '/<int:sid>/<int:did>/<int:node_id>/<node_type>/',
    methods=['GET'], endpoint='objects'
)
@login_required
@check_precondition
def properties(sid, did, node_id, node_type):
    """It fetches the properties of object types
       and render into selection page of wizard
    """

    # unquote encoded url parameter
    node_type = unquote(node_type)

    server_prop = server_info

    res_data = []
    failed_objects = []
    manager = get_driver(PG_DEFAULT_DRIVER).connection_manager(sid)
    conn = manager.connection(did=did)

    node_types = []
    show_sysobj = blueprint.show_system_objects().get()
    if node_type == 'database':

        # Fetch list of schemas
        # Get sys_obj_values and get list of schemas
        ntype = 'schema'
        SQL = render_template("/".join(
            [server_prop['template_path'], '/sql/get_schemas.sql']),
            show_sysobj=show_sysobj)
        status, res = conn.execute_dict(SQL)

        if not status:
            return internal_server_error(errormsg=res)
        node_types = res['rows']
    else:
        SQL = render_template("/".join(
            [server_prop['template_path'], '/sql/get_schemas.sql']),
            nspid=node_id, show_sysobj=False)
        status, res = conn.execute_dict(SQL)

        if not status:
            return internal_server_error(errormsg=res)
        node_types = res['rows']
        ntype = node_type

    for row in node_types:
        if 'oid' in row:
            node_id = row['oid']

        # Fetch functions against schema
        if ntype in ['schema', 'function']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/function.sql']),
                node_id=node_id, type='function')

            status, res = conn.execute_dict(SQL)
            if not status:
                current_app.logger.error(res)
                failed_objects.append('function')
            else:
                res_data.extend(res['rows'])

        # Fetch procedures only if server type is EPAS or PG >= 11
        if (len(server_prop) > 0 and
            (server_prop['server_type'] == 'ppas' or
             (server_prop['server_type'] == 'pg' and
              server_prop['version'] >= 11000)) and
                ntype in ['schema', 'procedure']):
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/function.sql']),
                node_id=node_id, type='procedure')

            status, res = conn.execute_dict(SQL)

            if not status:
                current_app.logger.error(res)
                failed_objects.append('procedure')
            else:
                res_data.extend(res['rows'])

        # Fetch trigger functions
        if ntype in ['schema', 'trigger_function']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/function.sql']),
                node_id=node_id, type='trigger_function')
            status, res = conn.execute_dict(SQL)

            if not status:
                current_app.logger.error(res)
                failed_objects.append('trigger function')
            else:
                res_data.extend(res['rows'])

        # Fetch Sequences against schema
        if ntype in ['schema', 'sequence']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/sequence.sql']),
                node_id=node_id)

            status, res = conn.execute_dict(SQL)
            if not status:
                current_app.logger.error(res)
                failed_objects.append('sequence')
            else:
                res_data.extend(res['rows'])

        # Fetch Tables against schema
        if ntype in ['schema', 'table']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/table.sql']),
                node_id=node_id)

            status, res = conn.execute_dict(SQL)
            if not status:
                current_app.logger.error(res)
                failed_objects.append('table')
            else:
                res_data.extend(res['rows'])

        # Fetch Views against schema
        if ntype in ['schema', 'view']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/view.sql']),
                node_id=node_id, node_type='v')

            status, res = conn.execute_dict(SQL)
            if not status:
                current_app.logger.error(res)
                failed_objects.append('view')
            else:
                res_data.extend(res['rows'])

        # Fetch Materialzed Views against schema
        if ntype in ['schema', 'mview']:
            SQL = render_template("/".join(
                [server_prop['template_path'], '/sql/view.sql']),
                node_id=node_id, node_type='m')

            status, res = conn.execute_dict(SQL)
            if not status:
                current_app.logger.error(res)
                failed_objects.append('materialized view')
            else:
                res_data.extend(res['rows'])

    msg = None
    if len(failed_objects) > 0:
        msg = gettext('Unable to fetch the {} objects'.format(
            ", ".join(failed_objects))
        )

    return make_json_response(
        result=res_data,
        info=msg,
        status=200
    )


@blueprint.route(
    '/sql/<int:sid>/<int:did>/',
    methods=['GET'], endpoint='modified_sql'
)
@login_required
@check_precondition
def msql(sid, did):
    """
    This function will return modified SQL
    """

    server_prop = server_info
    data = {}
    for k, v in request.args.items():
        try:
            data[k] = json.loads(v)
        except ValueError:
            data[k] = v

    # Form db connection
    manager = get_driver(PG_DEFAULT_DRIVER).connection_manager(sid)
    conn = manager.connection(did=did)

    acls = []
    try:
        acls = render_template(
            "/".join([server_prop['template_path'], '/acl.json'])
        )
        acls = json.loads(acls)
    except Exception as e:
        current_app.logger.exception(e)

    try:

        # Parse privileges
        data['priv'] = {}
        if 'acl' in data:
            # Get function acls
            data['priv']['function'] = parse_priv_to_db(
                data['acl'],
                acls['function']['acl'])

            data['priv']['sequence'] = parse_priv_to_db(
                data['acl'],
                acls['sequence']['acl'])

            data['priv']['table'] = parse_priv_to_db(
                data['acl'],
                acls['table']['acl'])

        # Pass database objects and get SQL for privileges
        SQL_data = ''
        data_func = {'objects': data['objects'],
                     'priv': data['priv']['function']}
        SQL = render_template(
            "/".join([server_prop['template_path'],
                      '/sql/grant_function.sql']),
            data=data_func, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        data_seq = {'objects': data['objects'],
                    'priv': data['priv']['sequence']}
        SQL = render_template(
            "/".join([server_prop['template_path'],
                      '/sql/grant_sequence.sql']),
            data=data_seq, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        data_table = {'objects': data['objects'],
                      'priv': data['priv']['table']}
        SQL = render_template(
            "/".join([server_prop['template_path'], '/sql/grant_table.sql']),
            data=data_table, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        res = {'data': SQL_data}

        return ajax_response(
            response=res,
            status=200
        )

    except Exception as e:
        return make_json_response(
            status=410,
            success=0,
            errormsg=e.message
        )


@blueprint.route(
    '/<int:sid>/<int:did>/', methods=['POST'], endpoint='apply'
)
@login_required
@check_precondition
def save(sid, did):
    """
    This function will apply the privileges to the selected
    Database Objects
    """
    server_prop = server_info
    data = request.form if request.form else json.loads(request.data.decode())

    # Form db connection and we use conn to execute sql
    manager = get_driver(PG_DEFAULT_DRIVER).connection_manager(sid)
    conn = manager.connection(did=did)

    acls = []
    try:
        acls = render_template(
            "/".join([server_prop['template_path'], 'acl.json']),
        )
        acls = json.loads(acls)
    except Exception as e:
        current_app.logger.exception(e)

    try:

        # Parse privileges
        data['priv'] = {}
        if 'acl' in data:
            # Get function acls
            data['priv']['function'] = parse_priv_to_db(
                data['acl'],
                acls['function']['acl'])

            data['priv']['sequence'] = parse_priv_to_db(
                data['acl'],
                acls['sequence']['acl'])

            data['priv']['table'] = parse_priv_to_db(
                data['acl'],
                acls['table']['acl'])

        # Pass database objects and get SQL for privileges
        # Pass database objects and get SQL for privileges
        SQL_data = ''
        data_func = {'objects': data['objects'],
                     'priv': data['priv']['function']}
        SQL = render_template(
            "/".join([server_prop['template_path'],
                      '/sql/grant_function.sql']),
            data=data_func, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        data_seq = {'objects': data['objects'],
                    'priv': data['priv']['sequence']}
        SQL = render_template(
            "/".join([server_prop['template_path'],
                      '/sql/grant_sequence.sql']),
            data=data_seq, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        data_table = {'objects': data['objects'],
                      'priv': data['priv']['table']}
        SQL = render_template(
            "/".join([server_prop['template_path'], '/sql/grant_table.sql']),
            data=data_table, conn=conn)
        if SQL and SQL.strip('\n') != '':
            SQL_data += SQL

        status, res = conn.execute_dict(SQL_data)
        if not status:
            return internal_server_error(errormsg=res)

        return make_json_response(
            success=1,
            info="Privileges applied"
        )

    except Exception as e:
        return internal_server_error(errormsg=e.message)