#!/usr/bin/env python

import sys

from aman.types.ArrivalRoute import ArrivalRoute
from aman.types.Waypoint import Waypoint

class SctEseFormat:
    def readFile(filename : str):
        fileBlocks = {}
        block = None

        # read the file line by line and create segments based on []-entries
        with open(filename) as file:
            for line in file:
                line = line.strip()

                # found a new segment
                if line.startswith('['):
                    block = line[1:-1]
                    fileBlocks.setdefault(block, [])
                # append the last backend
                elif None != block and 0 != len(line):
                    fileBlocks[block].append(line)

        return fileBlocks

    def parseWaypoint(waypoint : str, nameIdx : int, latitudeIdx : int, longitudeIdx : int):
        split = list(filter(None, waypoint.split(' ')))
        if len(split) <= longitudeIdx:
            sys.stderr.write('Invalid waypoint format: ' + waypoint)
            sys.exit(-1)
        return Waypoint(split[nameIdx], Waypoint.dms2dd(split[latitudeIdx]), Waypoint.dms2dd(split[longitudeIdx]))

    def extractWaypoints(self, sctFilepath : str):
        config = SctEseFormat.readFile(sctFilepath)
        foundAirports = False
        foundVOR = False
        foundNDB = False
        foundFix = False

        for key in config:
            if 'VOR' == key:
                foundVOR = True
            elif 'NDB' == key:
                foundNDB = True
            elif 'FIXES' == key:
                foundFix = True
            elif 'AIRPORT' == key:
                foundAirports = True

        if False == foundVOR:
            sys.stderr.write('Unable to find VOR-entries in the sector file')
            sys.exit(-1)
        if False == foundNDB:
            sys.stderr.write('Unable to find NDB-entries in the sector file')
            sys.exit(-1)
        if False == foundFix:
            sys.stderr.write('Unable to find FIX-entries in the sector file')
            sys.exit(-1)
        if False == foundAirports:
            sys.stderr.write('Unable to find AIRPORT-entries in the sector file')
            sys.exit(-1)

        # extract all waypoints
        for waypoint in config['VOR']:
            waypoint = SctEseFormat.parseWaypoint(waypoint, 0, 2, 3)
            self.waypoints.setdefault(waypoint.name, []).append(waypoint)
        for waypoint in config['NDB']:
            waypoint = SctEseFormat.parseWaypoint(waypoint, 0, 1, 2)
            self.waypoints.setdefault(waypoint.name, []).append(waypoint)
        for waypoint in config['FIXES']:
            waypoint = SctEseFormat.parseWaypoint(waypoint, 0, 1, 2)
            self.waypoints.setdefault(waypoint.name, []).append(waypoint)

        # extract the airports
        for airport in config['AIRPORT']:
            airport  = SctEseFormat.parseWaypoint(airport,0, 2, 3)
            self.airports.setdefault(airport.name, []).append(airport)

    def parseArrivalRoute(self, route : str, airport : Waypoint):
        # split the route and validate that it is a STAR for the airport
        split = route.split(':')
        if 5 != len(split) or 'STAR' != split[0] or split[1] != airport.name:
            return None

        # find all waypoints
        waypoints = []
        route = list(filter(None, split[4].split(' ')))
        for waypoint in route:
            # find the waypoint in the route
            coordinates = self.waypoints[waypoint]
            # no waypoint with this name defined
            if None == coordinates:
                sys.stderr.write('Unable to find waypoint ' + waypoint)
                sys.exit(-1)
            # multiple waypoints, but use Haversine distance to distinct between candidates
            elif 1 != len(coordinates):
                minDistance = sys.float_info.max
                nearest = None

                # we assume that waypoints with the same name are not close each other
                for coordinate in coordinates:
                    distance = coordinate.haversine(airport)
                    # found a closer waypoint
                    if minDistance > distance:
                        minDistance = distance
                        nearest = coordinate

                if None == nearest:
                    sys.stderr.write('Unable to find a close waypoint for ' + waypoint)
                    sys.exit(-1)

                waypoints.append(nearest)
            # extend the list of waypoints
            else:
                waypoints.append(coordinates[0])

        # create the arrival route
        return ArrivalRoute(split[3], split[2], waypoints)

    def extractArrivalRoutes(self, eseFilepath : str, airport : str, allowedRoutes : list):
        config = SctEseFormat.readFile(eseFilepath)
        foundSidsStars = False

        # search the airport in the extracted list
        if not airport in self.airports:
            sys.stderr.write(airport + 'in self.airports', 'Unable to find the requested airport')
            sys.exit(-1)
        airport = self.airports[airport][0]

        for key in config:
            if 'SIDSSTARS' == key:
                foundSidsStars = True

        if False == foundSidsStars:
            sys.stderr.write('Unable to find SIDSSTARS-entries in the sector file')
            sys.exit(-1)

        # parse all arrival routes
        for line in config['SIDSSTARS']:
            route = self.parseArrivalRoute(line, airport)
            if None != route and route.name in allowedRoutes:
                self.arrivalRoutes.setdefault(route.runway, []).append(route)

    def __init__(self, sctFilepath : str, eseFilepath : str, airport : str, allowedRoutes : list):
        self.arrivalRoutes = {}
        self.waypoints = {}
        self.airports = {}

        self.extractWaypoints(sctFilepath)
        self.extractArrivalRoutes(eseFilepath, airport, allowedRoutes)