open Http_client.Convenience
open OUnit
  
(* A data structure to hold forecast information. *)  
type forecast =
    {
      date : string;
      skyCond : string;
      highTemp : string;
      lowTemp : string;
      pop : string;
    }

(* A variable used to store the URL where the forecast is found.
 *
 * string
 *)
let forecastURL = "http://www.wrh.noaa.gov/Saltlake/forecast/SFT.shtml"

(* Get the raw text from the given url.
 *
 * string -> string
 *)
let getPage url = http_get url

(* Get the test data and put it into a string.
 *
 * string
 *)                  
let getTestPage =
  let fileName = "testFcst.txt" in
  let fin = open_in fileName in
  let buf = Buffer.create 4096 in
  let rec loop() =
    let line = input_line fin in
      Buffer.add_string buf line;
      Buffer.add_char buf '\n';
      loop()
  in
    try
      loop()
    with
        End_of_file -> Buffer.contents buf
                    
(* A helper function that takes a string and prints the string
 * followed by a space.
 * string -> unit
 *)
let printL s = Printf.printf "[%s]" s

(* Takes a string s and gets the nth line beginning from position p.
 *
 * int -> int -> string -> string
 *)
let rec findLine n p s =
  let j = Str.search_forward (Str.regexp ".*") s p in 
  match n with
      1 -> Str.matched_string s
    | _ -> findLine (n-1) (Str.match_end()+1) s

(* A function that takes the forecast web page and parses out the
 * useful information.
 *
 * string -> string
 *)
let getPreData data =
  let startPrePos = Str.search_forward (Str.regexp "<pre>") data 0 in
  let firstPre = Str.string_after data startPrePos in
  let endPrePos = Str.search_forward (Str.regexp "</pre>") firstPre 0 in
  let preTagData = Str.string_before firstPre endPrePos in
  let startFcst = Str.search_forward (Str.regexp "FCST.*") preTagData 0 in
  let dayStr = Str.string_after preTagData (Str.match_end() + 1) in
  let endSLC = Str.search_forward (Str.regexp "POP [0-9]+.*") dayStr 0 in
    Str.string_before dayStr (Str.match_end())

    
(* Take the list of l/h temperatures and extract the high temps
 *
 * string list -> string list
 *)
let getHighTempL tL =
  List.flatten (List.map (Str.split (Str.regexp "[0-9]*/")) tL)

(* Take the list of l/h temperatures and extract the low temps
 *
 * string list -> string list
 *)
let getLowTempL tL =
  let ftL = List.flatten (List.map (Str.split (Str.regexp "/[0-9]+")) tL) in
    if (List.length ftL) = 7 then
      ftL
    else
      "-" :: ftL
    
(* Take the list of POP # and extract the #s
 *
 * string list -> string list
 *)
let getPrecipNum pL =
  List.flatten (List.map (Str.split (Str.regexp "POP ")) pL)

(* Given lists of the date, sky condition, high temp, low temp, and
 * chance of precipitation, a forecast list, and build a forecast list
 * 
 * int -> string list -> string list -> string list -> string list ->
 * string list -> forecast list -> forecast list
 *)
let rec createFcstL n dL cL htL ltL pL fL =
  match n with
      6 -> let fcst = { date = List.nth dL 6;
                        skyCond = List.nth cL 6;
                        highTemp = List.nth htL 6;
                        lowTemp = List.nth ltL 6;
                        pop = List.nth pL 6
                      } in
        List.append fL (fcst :: [])
    | i -> let fcst = { date = List.nth dL i;
                        skyCond = List.nth cL i;
                        highTemp = List.nth htL i;
                        lowTemp = List.nth ltL i;
                        pop = List.nth pL i
                      } in
        createFcstL (n+1) dL cL htL ltL pL (List.append fL  (fcst :: []))
          
(* Parse the data generated by getPreData.
 *
 * string -> forecast list
 *)
let parsePreData s =
  let dates = findLine 2 0 s in
  let datesL = Str.split (Str.regexp "  +") dates in
  let cond = findLine 6 0 s in
  let condL = Str.split (Str.regexp "  +") cond in
  let temp = findLine 7 0 s in
  let tempL = Str.split (Str.regexp "  +") temp in
  let hTempL = getHighTempL tempL in
  let lTempL = getLowTempL tempL in
  let precip = findLine 8 0 s in
  let precipL = Str.split (Str.regexp "  +") precip in
  let precipNumL = getPrecipNum precipL in
    createFcstL 0 datesL condL hTempL lTempL precipNumL []

(* Test the parsePreData function.
 *
 * 'a -> unit
 *)
let testParsePreData _ =
  let p = getTestPage in
  let s = getPreData p in
  let dates = findLine 2 0 s in
  let datesL = Str.split (Str.regexp "  +") dates in
  let cond = findLine 6 0 s in
  let condL = Str.split (Str.regexp "  +") cond in
  let temp = findLine 7 0 s in
  let tempL = Str.split (Str.regexp "  +") temp in
  let hTempL = getHighTempL tempL in
  let lTempL = getLowTempL tempL in
  let precip = findLine 8 0 s in
  let precipL = Str.split (Str.regexp "  +") precip in
  let precipNumL = getPrecipNum precipL in
    assert_equal 7 (List.length datesL);
    assert_equal datesL ["FEB 11"; "FEB 12"; "FEB 13"; "FEB 14";
                         "FEB 15"; "FEB 16"; "FEB 17"];
    assert_equal 7 (List.length condL);
    assert_equal condL ["FLRRYS"; "SUNNY"; "SUNNY"; "PTCLDY";
                        "PTCLDY"; "PTCLDY"; "SUNNY"];
    assert_equal 7 (List.length tempL);
    assert_equal tempL ["/25"; "7/28"; "11/28"; "18/35"; "21/35";
                        "18/34"; "18/33"];
    assert_equal 7 (List.length hTempL);
    assert_equal hTempL ["25"; "28"; "28"; "35"; "35"; "34"; "33"];
    assert_equal 7 (List.length lTempL);
    assert_equal lTempL ["-"; "7"; "11"; "18"; "21"; "18"; "18"];
    assert_equal 7 (List.length precipL);
    assert_equal precipL ["POP 10"; "POP 0"; "POP 0"; "POP 10"; "POP 0";
                        "POP 0"; "POP 0"];
    assert_equal 7 (List.length precipNumL);
    assert_equal precipNumL ["10"; "0"; "0"; "10"; "0"; "0"; "0"]
      
(* Output the forecast to a string.
 *
 * forecast -> string
 *)
let printFcstOut f =
  Printf.sprintf "%s\t" f.date ^
  Printf.sprintf "%s\t" f.skyCond ^
  Printf.sprintf "%s\t" f.highTemp ^
  Printf.sprintf "%s\t" f.lowTemp ^
  Printf.sprintf "%s\n" f.pop
    
(* Output the forecastList data structure to the given channel.
 *
 * forecast list -> out_channel -> unit
 *)
let outputFcstL l chan =
  let time = Unix.localtime (Unix.time ()) in
  let { Unix.tm_mon = mon;
        Unix.tm_mday = mday;
        Unix.tm_year = year;
        Unix.tm_yday = yday;
        Unix.tm_hour = hour;
        Unix.tm_min = min} = time in
    Printf.fprintf chan "Collected: %02d-%02d-%d @ %d:%d\n"
      (mon+1) mday (year+1900) hour min;
    Printf.fprintf chan "Date\tWeather\tHigh\tLow\tProb. of Precip.\n";
    Printf.fprintf chan "%s" (String.concat "" (List.map printFcstOut l))

(* Write the forecastList data structure to a file
 *
 * forecast list -> unit
 *)
let fOutputFcstL l =
  let time = Unix.localtime (Unix.time ()) in
  let { Unix.tm_year = year;
        Unix.tm_yday = yday; } = time in
  let fileName =  Printf.sprintf "%d-%d.fcst"
                    yday (year+1900) in
  let fout = open_out fileName in
    Printf.printf "fileName: %s\n" fileName;
    outputFcstL l fout;
    close_out fout
                    
(* The main function for grabbing the forecast
 *
 * unit
 *)
let genFcst =
  let p = getPage forecastURL in
  let p1 = getTestPage in
  let s = getPreData p1 in
  let preStr = getPreData p in
  let res = parsePreData preStr in
    Printf.printf ":%s:" s;
    outputFcstL res stdout;
    fOutputFcstL res
      
(* Test the top level function.
 *
 * 'a -> unit
 *) 
let testGenFcst _ =
  let p = getTestPage in
  let preStr = getPreData p in
  let res = parsePreData preStr in
    assert_equal 7 (List.length res);
    assert_equal res [{date = "FEB 11"; skyCond = "FLRRYS"; highTemp = "25";
                       lowTemp = "-"; pop = "10"};
                      {date = "FEB 12"; skyCond = "SUNNY"; highTemp = "28";
                       lowTemp = "7"; pop = "0"};
                      {date = "FEB 13"; skyCond = "SUNNY"; highTemp = "28";
                       lowTemp = "11"; pop = "0"};
                      {date = "FEB 14"; skyCond = "PTCLDY"; highTemp = "35";
                       lowTemp = "18"; pop = "10"};
                      {date = "FEB 15"; skyCond = "PTCLDY"; highTemp = "35";
                       lowTemp = "21"; pop = "0"};
                      {date = "FEB 16"; skyCond = "PTCLDY"; highTemp = "34";
                       lowTemp = "18"; pop = "0"};
                      {date = "FEB 17"; skyCond = "SUNNY"; highTemp = "33";
                       lowTemp = "18"; pop = "0"}
                     ]
      
let suite = "Testing genFcst" >::: ["testGenFcst" >:: testGenFcst;
                  "testParsePreData" >:: testParsePreData
                                   ]
      
let _ =
  let verbose = ref false in
  let set_verbose _ = verbose := true in
    Arg.parse
      [("-verbose", Arg.Unit set_verbose, "Run the test in verbose mode.");]
      (fun x -> raise (Arg.Bad ("Bad argument : " ^ x)))
      ("usage: " ^ Sys.argv.(0) ^ " [-verbose]");
    if not (was_successful (run_test_tt ~verbose:!verbose suite)) then
      exit 1