let opt_files = ref ([] : string list)

let opt_taken = ref "sail_coverage"
let opt_all = ref "all_branches"

let opt_tab_width = ref 4

let opt_index = ref None
let opt_index_default = ref None
let opt_prefix = ref ""
                  
type color = {
    hue: int;
    saturation: int;
  }

let opt_bad_color = ref { hue = 0; saturation = 85 }
let opt_good_color = ref { hue = 120; saturation = 85 }
let opt_darken = ref 5
                   
let clamp_degree n = max 0 (min n 360)
let clamp_percent n = max 0 (min n 100)

let use_alt_colors () = 
  opt_good_color := { !opt_good_color with hue = 220 };
  opt_bad_color := { !opt_good_color with hue = 50 }

let options =
  Arg.align [
      ( "-t",
        Arg.String (fun str -> opt_taken := str),
        "<file> coverage information for branches taken while executing the model (default: sail_coverage)");
      ( "--taken",
        Arg.String (fun str -> opt_taken := str),
        " long form of -t");
      ( "-a",
        Arg.String (fun str -> opt_all := str),
        "<file> information about all possible branches (default: all_branches)");
      ( "--all",
        Arg.String (fun str -> opt_all := str),
        " long form of -a");
      ( "--tab-width",
        Arg.Int (fun n -> opt_tab_width := n),
        "<integer> set the tab width for html output (default: 4)");
      ( "--index",
        Arg.String (fun str -> opt_index := Some str),
        "<name> create a <name>.html page as an index");
      ( "--index-default",
        Arg.String (fun str -> opt_index_default := Some str),
        "<file> The .sail file that will be displayed by the generated index page by default");
      ( "--prefix",
        Arg.String (fun str -> opt_prefix := str),
        "<string> Prepend a prefix to all generated html coverage files");
      ( "--covered-hue",
        Arg.Int (fun n -> opt_good_color := { !opt_good_color with hue = clamp_degree n }),
        "<int> set the hue (between 0 and 360) of the color used for code that is covered (default: 120 (green))");
      ( "--uncovered-hue",
        Arg.Int (fun n -> opt_bad_color := { !opt_bad_color with hue = clamp_degree n }),
        "<int> set the hue (between 0 and 360) of the color used for code that is not covered (default: 0 (red))");
      ( "--covered-saturation",
        Arg.Int (fun n -> opt_good_color := { !opt_good_color with saturation = clamp_percent n }),
        "<int> set the saturation (between 0 and 100) of the color used for code that is covered (default: 85)");
      ( "--uncovered-saturation",
        Arg.Int (fun n -> opt_bad_color := { !opt_bad_color with saturation = clamp_percent n }),
        "<int> set the hue (between 0 and 100) of the color used for code that is not covered (default: 85)");
      ( "--nesting-darkness",
        Arg.Int (fun n -> opt_darken := n),
        "<int> factor which controls how much darker nested spans of the same color become (default: 5)");
      ( "--alt-colors",
        Arg.Unit use_alt_colors,
        " swap default colors from red/green into alternate yellow/blue theme");
      ( "--alt-colours",
        Arg.Unit use_alt_colors,
        "")
    ]

type span = {
    file : string;
    l1 : int;
    c1 : int;
    l2 : int;
    c2 : int;
  }

let string_of_span span =
  Printf.sprintf "\"%s\" %d:%d - %d:%d" span.file span.l1 span.c1 span.l2 span.c2

module Span = struct
  type t = span
  let compare s1 s2 = compare s1 s2
end

module SpanSet = Set.Make(Span)
module SpanMap = Map.Make(Span)

let mk_span _ file l1 c1 l2 c2 = { file = Filename.basename file; l1 = l1; c1 = c1; l2 = l2; c2 = c2 }
               
let read_coverage filename = 
  let spans = ref SpanSet.empty in
  let chan = open_in filename in
  try
    let rec loop () =
      let line = input_line chan in
      spans := SpanSet.add (Scanf.sscanf line "%c %S, %d, %d, %d, %d" mk_span) !spans;
      loop ()
    in
    loop ()
  with End_of_file ->
    close_in chan;
    !spans

(** We color the source either red (bad) or green (good) if it's
   covered vs uncovered. If we have nested uncovered branches, they
   will be increasingly bad, whereas nested covered branches will be
   increasingly good. *) 
type source_char = {
    mutable badness : int;
    mutable goodness : int;
    mutable bad_zero_width: bool;
    char : char;
  }

let zero_width span = span.l1 = span.l2 && span.c1 = span.c2

let mark_bad_region source span =
  if zero_width span then (
    source.(span.l2 - 1).(span.c2 - 1).bad_zero_width <- true
  ) else (
    source.(span.l1 - 1).(span.c1).badness <- source.(span.l1 - 1).(span.c1).badness + 1;
    source.(span.l2 - 1).(span.c2 - 1).badness <- source.(span.l2 - 1).(span.c2 - 1).badness - 1
  )

let mark_good_region source span =
  if not (zero_width span) then (
    source.(span.l1 - 1).(span.c1).goodness <- source.(span.l1 - 1).(span.c1).goodness + 1;
    source.(span.l2 - 1).(span.c2 - 1).goodness <- source.(span.l2 - 1).(span.c2 - 1).goodness - 1
  )
    
let process_line l = Array.init (String.length l) (fun n -> { badness = 0; goodness = 0; char = l.[n]; bad_zero_width = false })

let read_source filename =
  let lines = ref [] in
  let chan = open_in filename in
  try
    let rec loop () =
      lines := process_line (input_line chan) :: !lines;
      loop ()
    in
    loop ()
  with End_of_file ->
    close_in chan;
    Array.of_list (List.rev !lines)

let output_html_char chan c =
  if c == ' ' then
    output_string chan "&nbsp;"
  else if c == '<' then
    output_string chan "&lt;"
  else if c == '>' then
    output_string chan "&gt;"
  else if c == '"' then
    output_string chan "&quot;"
  else if c == '\t' then
    output_string chan (String.concat "" (List.init !opt_tab_width (fun _ -> "&nbsp;")))
  else
    output_char chan c

let file_info file all taken =
  let all = SpanSet.filter (fun s -> s.file = Filename.basename file) all in
  let taken = SpanSet.filter (fun s -> s.file = Filename.basename file) taken in
  let not_taken = SpanSet.diff all taken in
  
  let percent =
    if SpanSet.cardinal all != 0 then
      let p = 100. *. (Float.of_int (SpanSet.cardinal taken) /. Float.of_int (SpanSet.cardinal all)) in
      Printf.sprintf "%.0f%%" p
    else
      "-"
  in

  taken,
  not_taken,
  Printf.sprintf "%s (%d/%d) %s" (Filename.basename file) (SpanSet.cardinal taken) (SpanSet.cardinal all) percent

let index_css = "
body, html {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
}

table {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  border-collapse: collapse;
  overflow: hidden;
}

.left {
  width: 20%;
}

.left .scroll {
  height: 100vh;
  overflow-x: hidden;
  overflow-y: auto;
}

.right {
  width: 80%;
}

td {
  padding: 0;
  margin: 0;
}

tr {
  padding: 0;
  margin: 0;
  height: 100%;
  overflow-x: hidden;
  overflow-y: auto;
}

iframe {
  height: 100%;
  width: 100%;
  display: block;
  margin: 0;
  padding: 0;
}
"

let html_file_for file =
  !opt_prefix ^ Filename.remove_extension (Filename.basename file) ^ ".html"
              
let main () =
  let all = read_coverage !opt_all in
  let taken = read_coverage !opt_taken in
  List.iter (fun file ->
      let taken, not_taken, desc = file_info file all taken in
      print_endline desc;
      
      let source = read_source file in
      SpanSet.iter (mark_good_region source) taken;
      SpanSet.iter (mark_bad_region source) not_taken;
      
      let output_file = html_file_for file in
      let chan = open_out output_file in
      
      let current_goodness = ref 0 in
      let current_badness = ref 0 in
      
      let clamp_lightness l = max 30 (min 80 l) in
      
      let html_color color darkness =
        Printf.sprintf "hsl(%d, %d%%, %d%%)"
          color.hue color.saturation (clamp_lightness ((80 + !opt_darken) - darkness * !opt_darken))
      in
      let good_color () = html_color !opt_good_color !current_goodness in
      let bad_color () = html_color !opt_bad_color !current_badness in
      
      output_string chan "<!DOCTYPE html>\n";
      output_string chan "<html lang=\"en\">\n<head>\n<meta charset=\"utf-8\">\n";
      output_string chan (Printf.sprintf "<title>%s</title>" (Filename.remove_extension (Filename.basename file)));
      output_string chan "</head>\n";
      output_string chan "<body>\n";
      output_string chan (Printf.sprintf "<h1>%s</h1>\n" desc);
      output_string chan "<code style=\"display: block\">\n";

      Array.iter (fun line ->
          Array.iter (fun loc ->
              if loc.goodness < 0 && loc.badness < 0 then (
                output_html_char chan loc.char;
                current_goodness := !current_goodness + loc.goodness;
                current_badness := !current_badness + loc.badness;
                for _ = 1 to abs loc.goodness + abs loc.badness do
                  output_string chan (Printf.sprintf "</span>")
                done
              ) else if loc.goodness < 0 then (
                assert (loc.badness >= 0);
                output_html_char chan loc.char;
                current_goodness := !current_goodness + loc.goodness;
                for _ = 1 to abs loc.goodness do
                  output_string chan (Printf.sprintf "</span>")
                done
              ) else if loc.badness < 0 then (
                assert (loc.goodness >= 0);
                output_html_char chan loc.char;
                current_badness := !current_badness + loc.badness;
                for _ = 1 to abs loc.badness do
                  output_string chan (Printf.sprintf "</span>")
                done
              ) else if loc.badness > 0 then (
                assert (loc.goodness <= 0);
                current_badness := !current_badness + loc.badness;
                for _ = 1 to loc.badness do
                  output_string chan (Printf.sprintf "<span style=\"background-color: %s\">" (bad_color ()));
                done;
                output_html_char chan loc.char
              ) else if loc.goodness > 0 then (
                assert (!current_badness == 0);
                current_goodness := !current_goodness + loc.goodness;
                for _ = 1 to loc.goodness do
                  output_string chan (Printf.sprintf "<span style=\"background-color: %s\">" (good_color ()));
                done;
                output_html_char chan loc.char
              ) else (
                output_html_char chan loc.char
              );

              if loc.bad_zero_width then (
                output_string chan (Printf.sprintf "<span style=\"background-color: %s\">" (bad_color ()));
                output_string chan "&#171;Invisible branch not taken here&#187";
                output_string chan "</span>"
              );
              
              assert (!current_goodness >= 0);
              assert (!current_badness >= 0)
                      
            ) line;
          output_string chan "<br>\n"
        ) source;

      output_string chan "</code>\n";
      output_string chan "</body>\n";
      output_string chan "</html>";
      
      close_out chan
    ) !opt_files;

  begin match !opt_index with
  | Some name ->
     let chan = open_out (name ^ ".html") in
    
     output_string chan "<!DOCTYPE html>\n";
     output_string chan "<html lang=\"en\">\n";
     Printf.ksprintf (output_string chan)
       "<head>\n<meta charset=\"utf-8\">\n<title>Coverage Report</title>\n<style>%s</style>\n</head>\n"
       index_css;
     output_string chan "<body>\n";
     
     output_string chan "<table><tr><td class=\"left\"><div class=\"scroll\">";
     List.iter (fun file ->
         let _, _, desc = file_info file all taken in
         Printf.ksprintf (output_string chan) "<a href=\"%s\" target=\"source\">%s</a><br>\n"
           (html_file_for file) desc
       ) !opt_files;
     output_string chan "</div></td>";

     output_string chan "<td class=\"right\">";
     begin match !opt_index_default with
     | Some default_file ->
        Printf.ksprintf (output_string chan) "<iframe src=\"%s\" name=\"source\"></iframe>"
          (html_file_for default_file);
     | None ->
        output_string chan "<iframe name=\"source\"></iframe>"
     end;
     output_string chan "</td></tr></table>\n";
     output_string chan "</body>\n";
     output_string chan "</html>";
     close_out chan
  | None -> ()
  end

let usage_msg = "usage: sailcov -t <file> -a <file> <.sail files>\n"

let _ =
  Arg.parse options
    (fun s -> opt_files := !opt_files @ [s])
    usage_msg;
  try main () with
  | Sys_error msg -> prerr_endline msg; exit 1