#!/usr/bin/env python3
# TelecomInfraProject/gnpy/examples
# Module name : path_requests_run.py
# Version : 
# License : BSD 3-Clause Licence
# Copyright (c) 2018, Telecom Infra Project

"""
@author: esther.lerouzic
@author: jeanluc-auge
read json request file in accordance with:
    Yang model for requesting Path Computation
    draft-ietf-teas-yang-path-computation-01.txt. 
and returns path results in terms of path and feasibility

"""

from sys import exit
from argparse import ArgumentParser
from pathlib import Path
from collections import namedtuple
from logging import getLogger, basicConfig, CRITICAL, DEBUG, INFO
from json import dumps, loads
from networkx import (draw_networkx_nodes, draw_networkx_edges,
                      draw_networkx_labels, dijkstra_path, NetworkXNoPath)
from numpy import mean
from examples.convert_service_sheet import convert_service_sheet, Request_element, Element
from gnpy.core.utils import load_json
from gnpy.core.network import load_network, build_network
from gnpy.core.equipment import load_equipment
from gnpy.core.elements import Transceiver, Roadm, Edfa, Fused
from gnpy.core.network import set_roadm_loss
from gnpy.core.utils import db2lin, lin2db
from gnpy.core.info import create_input_spectral_information, SpectralInformation, Channel, Power
from copy import copy, deepcopy
from numpy import log10

RequestParams = namedtuple('RequestParams','request_id source destination trx_type'+
' trx_mode nodes_list loose_list spacing power nb_channel frequency format baud_rate OSNR bit_rate roll_off')

class Path_request:
    def __init__(self, *args, **params):
        params = RequestParams(**params)
        self.request_id = params.request_id
        self.source     = params.source
        self.destination = params.destination
        self.tsp        = params.trx_type
        self.tsp_mode   = params.trx_mode
        self.baud_rate   = params.baud_rate
        self.nodes_list = params.nodes_list
        self.loose_list = params.loose_list
        self.spacing    = params.spacing
        self.power      = params.power
        self.nb_channel = params.nb_channel
        self.frequency  = params.frequency
        self.format     = params.format
        self.OSNR       = params.OSNR
        self.bit_rate   = params.bit_rate
        self.roll_off   = params.roll_off

    def __str__(self):
        return '\n\t'.join([  f'{type(self).__name__} {self.request_id}',
                            f'source:       {self.source}',
                            f'destination:  {self.destination}'])
    def __repr__(self):
        return '\n\t'.join([  f'{type(self).__name__} {self.request_id}',
                            f'source:       {self.source}',
                            f'destination:  {self.destination}',
                            f'trx type:     {self.tsp}',
                            f'baud_rate:     {self.baud_rate}',
                            f'spacing:      {self.spacing}',
                            f'power:        {self.power}'
                            '\n'])

class Result_element(Element):
    def __init__(self,path_request,computed_path):
        self.path_id = int(path_request.request_id)
        self.path_request = path_request
        self.computed_path = computed_path
        hop_type = []
        for e in computed_path :
            if isinstance(e, Transceiver) : 
                hop_type.append(' - '.join([path_request.tsp,path_request.tsp_mode])) 
            else:
                hop_type.append('not recorded')
        self.hop_type = hop_type
    uid = property(lambda self: repr(self))
    @property
    def pathresult(self):
        return {
               'path-id': self.path_id,
               'path-properties':{
                   'path-metric': [
                       {
                       'metric-type': 'SNR@bandwidth',
                       'accumulative-value': round(mean(self.computed_path[-1].snr),2)
                       },
                       {
                       'metric-type': 'SNR@0.1nm',
                       'accumulative-value': round(mean(self.computed_path[-1].snr+10*log10(self.path_request.baud_rate/12.5e9)),2)
                       }
                    ],
                    'path-srlgs': {
                        'usage': 'not used yet',
                        'values': 'not used yet'
                    },
                    'path-route-objects': [
                        {
                        'path-route-object': {
                            'index': self.computed_path.index(n),
                            'unnumbered-hop': {
                                'node-id': n.uid,
                                'link-tp-id': n.uid,
                                'hop-type': self.hop_type[self.computed_path.index(n)],
                                'direction': 'not used'
                            },
                            'label-hop': {
                                'te-label': {
                                    'generic': 'not used yet',
                                    'direction': 'not used yet'
                                    }
                                }
                            }
                        } for n in self.computed_path
                        ]
                }
            }
                    
    @property
    def json(self):
        return self.pathresult 

def compute_constrained_path(network, req):
    trx = [n for n in network.nodes() if isinstance(n, Transceiver)]
    roadm = [n for n in network.nodes() if isinstance(n, Roadm)]
    edfa = [n for n in network.nodes() if isinstance(n, Edfa)]
    source = next(el for el in trx if el.uid == req.source)
    # start the path with its source
    total_path = [source]
    for n in req.nodes_list:
        # print(n)
        try :
            node = next(el for el in trx if el.uid == n)
        except StopIteration:
            try:
                node = next(el for el in roadm if el.uid == f'roadm {n}')
            except StopIteration:
                try:
                    node = next(el for el in edfa 
                        if el.uid.startswith(f'egress edfa in {n}'))
                except StopIteration:
                    msg = f'could not find node : {n} in network topology: \
                        not a trx, roadm, edfa or fused element'
                    logger.critical(msg)
                    raise ValueError(msg)
        # extend path list without repeating source -> skip first element in the list
        try:
            total_path.extend(dijkstra_path(network, source, node)[1:])
            source = node
        except NetworkXNoPath:
            # for debug
            # print(req.loose_list)
            # print(req.nodes_list.index(n))
            if req.loose_list[req.nodes_list.index(n)] == 'loose':
                print(f'could not find a path from {source.uid} to loose node : {n} in network topology')
                print(f'node  {n} is skipped')
            else:
                msg = f'could not find a path from {source.uid} to node : {n} in network topology'
                logger.critical(msg)
                raise ValueError(msg)
    return total_path 

def propagate(path, req, equipment, show=False):
    p_db = lin2db(req.power*1e3)    
    pref_roadm_db = equipment['Roadms']['default'].power_mode_pref
    power_mode = equipment['Spans']['default'].power_mode
    roadm_loss = p_db - pref_roadm_db #dynamic update the ROADM loss wrto power sweep to keep the same pref_roadm
    set_roadm_loss(path, equipment, power_mode, roadm_loss)        
    
    si = create_input_spectral_information(
        req.frequency['min'], req.roll_off,
        req.baud_rate, req.power, req.spacing, req.nb_channel)
    for el in path:
        si = el(si)
        if show :
            print(el)
    return path