{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE CPP #-}

module Data.Aviation.Metar(
  getBOMTAF
, getNOAAMETAR
, getAllMETAR
, getAllTAF
, runMETAR
) where

import Control.Applicative(pure)
import Control.Category((.))
import Control.Exception(catch)
import Control.Lens(view, _Wrapped, (&), (.~), (^.))
import Control.Monad(Monad((>>=)))
import Data.Aviation.Metar.BOMTAFResult(BOMTAFResponse(BOMTAFResponse), bomMETAR, bomTAF)
import Data.Aviation.Metar.TAFResult(TAFResult(ConnErrorResult, ParseErrorResult, TAFResultValue))
import Data.Aviation.Metar.TAFResultT(TAFResultT(TAFResultT))
import Data.ByteString.Lazy(ByteString)
import Data.ByteString.Lazy.Char8(unpack)
import Data.Char(toUpper)
import Data.Either(Either(Left, Right))
import Data.Foldable(length)
import Data.Function(($))
import Data.Functor(fmap)
import Data.List(intercalate)
import Data.Maybe(Maybe(Nothing, Just))
import Data.String(String, lines)
import Data.Semigroup((<>))
import Network.HTTP(Request, Response, setHeaders, setRequestBody, mkRequest, RequestMethod(POST), Header(Header), HeaderName(..), rspBody, simpleHTTP)
import Network.HTTP.Client(HttpException)
import Network.Stream(ConnError(ErrorMisc))
import Network.URI(URI(URI), URIAuth(URIAuth))
import Network.Wreq(getWith, defaults, headers, Options, responseBody)
import qualified Network.Wreq as Wreq(Response)
import Prelude(show)
import System.IO(IO, hPutStrLn, putStrLn, stderr)
import Text.HTML.TagSoup(Tag(TagText))
import Text.HTML.TagSoup.Tree(TagTree(TagBranch, TagLeaf), parseTree)

withResult ::
  (r -> Maybe a) ->
  Either ConnError r ->
  TAFResult a
withResult _ (Left e) =
  ConnErrorResult e
withResult k (Right s) =
  case k s of
    Nothing ->
      ParseErrorResult
    Just z ->
      TAFResultValue z

getBOMTAF ::
  String
  -> TAFResultT IO BOMTAFResponse
getBOMTAF =
  let mkTAFResponse ::
        [TagTree String]
        -> Maybe BOMTAFResponse
      mkTAFResponse (TagBranch "h3" [] [TagLeaf (TagText title)] : TagBranch "p" [("class","product")] tafs : TagBranch "p" [("class","product")] metars:_) =
        let tagTexts q =
              q >>= \r ->
                case r of
                  TagLeaf (TagText v) ->
                    [v]
                  _ ->
                    []
        in  Just (BOMTAFResponse title (tagTexts tafs) (tagTexts metars))
      mkTAFResponse _ =
        Nothing
      request ::
        String
        -> Request String
      request yxxx =
        let reqBody =
              "keyword=" <> yxxx <> "&type=search&page=TAF"
        in  setHeaders
              (
                setRequestBody
                  (
                    mkRequest
                      POST
                      (URI "http" (Just (URIAuth "" "www.bom.gov.au" "")) "/aviation/php/process.php" "" "")
                  )
                  ("application/x-www-form-urlencoded", reqBody)
              )
              [
                Header HdrHost                        "www.bom.gov.au"
              , Header HdrUserAgent                   "tonymorris/metar"
              , Header HdrAccept                      "*/*"
              , Header HdrAcceptLanguage              "en-US,en;q=0.5"
              , Header HdrAcceptEncoding              "text/html"
              , Header HdrReferer                     "http://www.bom.gov.au/aviation/forecasts/taf/"
              , Header HdrConnection                  "keep-alive"
              , Header HdrContentType                 "application/x-www-form-urlencoded"
              , Header HdrContentLength               (show (length reqBody))
              , Header HdrCookie                      "check=ok; bom_meteye_windspeed_units_knots=yes"
              , Header HdrPragma                      "no-cache"
              , Header HdrCacheControl                "no-cache"
              , Header (HdrCustom "DNT")              "1"
              , Header (HdrCustom "X-Requested-With") "XMLHttpRequest"
              ]
      respTAF ::
        Response String
        -> Maybe BOMTAFResponse
      respTAF =
        mkTAFResponse . parseTree . rspBody
  in  TAFResultT . fmap (withResult respTAF) . simpleHTTP . request

getNOAAMETAR ::
  String
  -> TAFResultT IO String
getNOAAMETAR =
  let options ::
        Options
      options =
        defaults & headers .~
          [
            (
              "Host"
            , "tgftp.nws.noaa.gov"
            )
          , (
              "User-Agent"
            , "tonymorris/metar"
            )
          , (
              "Accept"
            , "*/*"
            )
          , (
              "Accept-Language"
            , "en-US,en;q=0.5"
            )
          , (
              "Accept-Encoding"
            , "text/html"
            )
          , (
              "Connection"
            , "keep-alive"
            )
          , (
              "Pragma"
            , "no-cache"
            )
          , (
              "Cache-Control"
            , "no-cache"
            )
          , (
              "DNT"
            , "1"
            )
          ]
      request xxxx =
        catch (fmap Right (getWith options ("https://tgftp.nws.noaa.gov/data/observations/metar/stations/" <> fmap toUpper xxxx <> ".TXT")))
          (\e ->  let e' :: HttpException
                      e' = e
                  in pure . Left . ErrorMisc . show $ e')
      respMETAR ::
        Wreq.Response ByteString
        -> Maybe String
      respMETAR r =
        case lines . unpack $ r ^. responseBody of
          [_, r'] -> Just r'
          _ -> Nothing
  in TAFResultT . fmap (withResult respMETAR) . request

getAllMETAR ::
  String
  -> TAFResultT IO [String]
getAllMETAR x = 
  fmap (view bomMETAR) (getBOMTAF x) <>
  fmap pure (getNOAAMETAR x)

getAllTAF ::
  String
  -> TAFResultT IO [String]
getAllTAF x = 
  fmap (view bomTAF) (getBOMTAF x)

runMETAR ::
  [String]
  -> IO ()
runMETAR x =
  let stderr' =
        hPutStrLn stderr
  in  case x of
        [] ->
          do  putStrLn ("metar version " <> VERSION_metar)
              stderr' "enter an argument (ICAO code)"
        (r:_) ->
          let s = view _Wrapped (fmap (intercalate "\n") (getAllMETAR r))
          in  s >>= \s' ->
              case s' of
                TAFResultValue a ->
                  putStrLn a
                ParseErrorResult ->
                  stderr' ("No METAR for " <> r)
                ConnErrorResult e ->
                  stderr' ("Network connection error " <> show e)