Added browser extension support to Nim code

Signed-off-by: Jacob <jacob@torrey.io>

nlzmadetect/nlzmadetect.nimble

@@ -23,3 +23,6 @@ task release, "Build a release version of the CLI application":
 
 task buildjs, "Build a Javascript version of the application":
     exec "nim js -d:release src/nlzmadetect.nim"
+
+task buildext, "Build a Javascript version for use in a browser extension":
+    exec "nim js -d:release -d:extension src/nlzmadetect.nim"

nlzmadetect/src/nlzmadetect.nim

@@ -9,10 +9,12 @@ import strutils
 when isMainModule and defined(c):
   import std/[parseopt, os]
 
-when defined(js):
+when defined(js) and not defined(extension):
   var local_prelude : string = ""
+when defined(extension):
+  var local_prelude {.exportc.} : cstring = ""
 
-const COMPRESSION_PRESET = 1.int32
+var COMPRESSION_PRESET {.exportc.} = 2.int32
 const SHORT_SAMPLE_THRESHOLD = 350
 
 const PRELUDE_FILE = "../../ai-generated.txt"
@@ -22,9 +24,9 @@ var PRELUDE_RATIO = compress_str("")
 
 when defined(js):
   var console {.importc, nodecl.}: JsObject
+  when not defined(extension):
     proc getLocalStorageItem(key : cstring) : JsObject {.importjs: "localStorage.getItem(#)".}
     proc setLocalStorageItem(key : cstring, val : cstring) {.importjs: "localStorage.setItem(#, #)".}
-
   proc compress(str : cstring, mode : int) : seq[byte] {.importjs: "LZMA.compress(#, #)".}
   console.log("Initialized with a prelude compression ratio of: " & $PRELUDE_RATIO)
 
@@ -42,6 +44,9 @@ proc compress_str(s : string, preset = COMPRESSION_PRESET): float64 =
     combined = convert(PRELUDE_STR & s, "us-ascii", "UTF-8").replace(re"[^\x00-\x7F]")
   when defined(js):
     let in_len = PRELUDE_STR.len + local_prelude.len + s.len
+    when defined(extension):
+      var combined : string = PRELUDE_STR & $(local_prelude) & s
+    when not defined(extension):
       var combined : string = PRELUDE_STR & local_prelude & s
     let nonascii = newRegExp(r"[^\x00-\x7F]")
     combined = $combined.cstring.replace(nonascii, "")
@@ -154,6 +159,8 @@ when defined(c) and isMainModule:
       echo "(" & d & ", " & $s.formatFloat(ffDecimal, 8) & ")"
 
 when defined(js) and isMainModule:
+  when not defined(extension):
+    if not document.getElementById("preset_value").isNil:
       document.getElementById("preset_value").value = ($COMPRESSION_PRESET).cstring
     if getLocalStorageItem("local_prelude") != jsNull:
       local_prelude = $(getLocalStorageItem("local_prelude").to(cstring))
@@ -181,4 +188,20 @@ when defined(js) and isMainModule:
       document.getElementById("output_span").textContent = d.cstring & ", confidence score of: " & ($s.round(6)).cstring
       document.getElementById("output_span").style.backgroundColor = color.cstring
   
+  when defined(extension):
+    proc add_to_lp(text : cstring) {.exportc.} =
+      local_prelude = local_prelude & "\n".cstring & text
+      PRELUDE_RATIO = compress_str("")
+      console.log("New prelude compression ratio of: " & $PRELUDE_RATIO)
+
+    proc detect_string(s : cstring) : float {.exportc.} =
+      # Returns the opacity for the element containing the passed string (higher for human-generated)
+      var (d, s) = run_on_text_chunked($s)
+      if d == "Human":
+        return 1.0
+      var opacity = 1.0 - s.round(3) * 10
+      if opacity < 0.0:
+        opacity = 0.0
+      return opacity
+
   #window.onload = on_load