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#!/usr/bin/env gosh
(use rfc.http)
(use rfc.uri)
(use rfc.json)
(use file.util)
(use srfi-19)
(use gauche.collection)
(use gauche.parseopt)
(use gauche.process)
(define (main args)
(let-args
(cdr args)
((adir "d|dir=s")
(baseurl "u|url=s")
(statefile "s|statefile=s")
(help "h|help" => (cut show-help (car args)))
. restargs)
(if (equal? baseurl #f)
(show-help (car args))
(guesstimate
(if (equal? adir #f) "." adir)
baseurl
(if statefile statefile "./obu-state.edn")))
(exit 0)))
(define (show-help progname)
(display (format
"~a: tracktrain's on-board guesstimater for which trip you're on
Arguments:
-u --url: base url of the tracktrain server [required]
-s --statefile: state file
-c --config: config file (default is /etc/tracktrain/obu.conf)
-h --help: display this help
" progname))
(exit 0))
(define (guesstimate dir url statefile)
(define stops (fetch-stations url))
(define pos
(with-input-from-process `(obu-ping -s ,statefile -n 1 -d) read))
(define trip (assoc-ref (closest-stop-to stops pos) 'trip))
(display trip))
(define (closest-stop-to stops pos)
(define stops-by-station
(apply vector-append (vector->list
(vector-map (lambda (trip)
(vector-map
(lambda (stop) (cons `(trip . ,(assoc-ref trip 'trip)) stop))
(assoc-ref trip 'stops)))
stops))))
(find-min
stops-by-station
:key (lambda (stop)
(+ (square (- (assoc-ref pos 'lat) (assoc-ref stop 'lat)))
(square (- (assoc-ref pos 'lon) (assoc-ref stop 'lon)))))
:default (vector-ref stops 0)))
(define (fetch-stations url)
(define day (date->string (current-date) "~1"))
(define tls
(equal? (uri-ref url 'scheme) "https"))
(parameterize
; replace all json keys with symbols; everything else is confusing
([json-object-handler
(cut map (lambda p `(,(string->symbol (car (car p))) . ,(cdr (car p)))) <>)])
(parse-json-string
(values-ref (http-get (uri-ref url 'host+port)
(format "/api/timetable/stops/~a" day)
:secure tls) 2))))
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