(local req (require :http.request))
(local { : dict_to_query } (require :http.util))
(local json (require :json))

(import-macros { : define-tests : expect : expect= : expect-near } :assert)
(local { : view } (require :fennel))


(local
 query
 (->
  [
   "[bbox:30.618338,-96.323712,30.591028,-96.330826]"
   "[out:json]"
   "[timeout:90];"
   "("
   "way ("
   "30.626917110746,"
   "-96.348809105664,"
   "30.634468750236,"
   "-96.339893442898"
   ");"
   ");"
   "out ;"
   ]
  (table.concat "\n")))

(let [r 
       (req.new_from_uri
        "https://overpass-api.de/api/interpreter")]
  (tset r.headers ":method" "POST")
  (r:set_body (dict_to_query { :data query }))
  (let [(headers stream) (r:go)]
    (print (view headers))
    (print (view (json.decode (stream:get_body_as_string))))))
      
(fn sinh [x] (/ (- 1 (math.exp (* -2 x))) (* 2 (math.exp (- x)))))

(expect (< (math.abs  (- (sinh 2) 3.626860407847)) 0.001))

(fn tile->latlon [xtile ytile zoom]
  (let [n (^ 2 zoom)
        lon-deg (- (/ (* xtile 360) n) 180.0)
        lat-rad (math.atan
                 (sinh (* math.pi (- 1 (/ (* 2 ytile) n))))
                 )]

    (values (/ (* lat-rad 180) math.pi) lon-deg)))

(let [(lat lon) (tile->latlon 0 0 0)]
  (expect= lon -180)
  (expect-near lat 85.05112877)
  )

(let [(lat lon) (tile->latlon 232798 103246 18)]
  (expect-near lon 139.699401855)
  (expect-near lat 35.6595278648)
  )

(fn latlon->tile [lat lon zoom]
  (let [n (^ 2 zoom)
        x (* n (/ (+ lon 180) 360))
        t1 (/ (* lat math.pi) 180)
        t (math.log (+ (math.tan t1) (/ 1 (math.cos t1))))
        y (* (- 1 (/ t math.pi)) (/ n 2))]
    (values x y)))

(let [(x y) (latlon->tile 52.1234 -0.53 17)]
  (expect= (math.floor x) 65343)
  (expect= (math.floor y) 43221))