#!/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 collections import namedtuple
from logging import getLogger, basicConfig, CRITICAL, DEBUG, INFO
from networkx import (dijkstra_path, NetworkXNoPath)
from numpy import mean
from examples.convert_service_sheet import convert_service_sheet, Request_element, Element
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

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+lin2db(self.path_request.baud_rate/12.5e9)),2)
                       },
                       {
                       'metric-type': 'OSNR@bandwidth',
                       'accumulative-value': round(mean(self.computed_path[-1].osnr_ase),2)
                       },
                       {
                       'metric-type': 'OSNR@0.1nm',
                       'accumulative-value': round(mean(self.computed_path[-1].osnr_ase_01nm),2)
                       },
                       {
                       'metric-type': 'reference_power',
                       'accumulative-value': self.path_request.power
                       }
                    ],
                    '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):
    #update roadm loss in case of power sweep (power mode only)
    set_roadm_loss(path, equipment, lin2db(req.power*1e3))
    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