Merge pull request #4 from jalbert-dev/color-ui

Inline text color support + simple coloration of selected line

CliArguments.fs

@@ -11,6 +11,7 @@ type ArgParser =
     | [<AltCommandLine("-a"); CustomCommandLine("--config-paths"); Unique>] AppendConfigs of string list
     | [<AltCommandLine("-r"); CustomCommandLine("--regions"); Unique>] Regions of string list
     | [<AltCommandLine("-p"); CustomCommandLine("--openvpn-path"); Unique>] OpenVpnPath of string
+    | [<AltCommandLine("-nc"); CustomCommandLine("--no-color"); Unique>] NoColor
 with 
     interface IArgParserTemplate with
         member this.Usage = 
@@ -19,6 +20,7 @@ with
             | AppendConfigs _ -> "specify any number of paths to files whose contents should be appended to the OpenVPN config"
             | Regions _ -> "specify any number of region codes to include in the VPN list (by default, shows all regions)"
             | OpenVpnPath _ -> "specify the path to OpenVPN"
+            | NoColor _ -> "disables color output"
 
 let parseArgs argv =
     let parser = ArgumentParser.Create<ArgParser>(checkStructure=true)

Config.fs

@@ -8,6 +8,7 @@ type Config = {
     AllowedRegions: string array;
     ConfigPaths: string array;
     OpenVpnPath: string;
+    NoColor: bool;
 }
 
 module Config =
@@ -17,22 +18,25 @@ module Config =
 
     /// Constructs a configuration object from a completed argument parse.
     let fromArgs (args: ParseResults<Cli.ArgParser>) = { 
-            DataSource = 
-                args.TryGetResult(<@ Cli.Source @>) 
-                |> Option.defaultValue defaultVpnListSource; 
-
-            AllowedRegions = 
-                args.TryGetResult(<@ Cli.Regions @>) 
-                |> Option.map List.toArray 
-                |> Option.defaultValue [||] 
-                |> Array.map (fun x -> x.ToLower()); 
-
-            ConfigPaths = 
-                args.TryGetResult(<@ Cli.AppendConfigs @>) 
-                |> Option.map List.toArray 
-                |> Option.defaultValue [||];
-
-            OpenVpnPath =
-                args.TryGetResult(<@ Cli.OpenVpnPath @>)
-                |> Option.defaultValue DefaultOpenVpnPath
+        DataSource = 
+            args.TryGetResult(<@ Cli.Source @>) 
+            |> Option.defaultValue defaultVpnListSource; 
+
+        AllowedRegions = 
+            args.TryGetResult(<@ Cli.Regions @>) 
+            |> Option.map List.toArray 
+            |> Option.defaultValue [||] 
+            |> Array.map (fun x -> x.ToLower()); 
+
+        ConfigPaths = 
+            args.TryGetResult(<@ Cli.AppendConfigs @>) 
+            |> Option.map List.toArray 
+            |> Option.defaultValue [||];
+
+        OpenVpnPath =
+            args.TryGetResult(<@ Cli.OpenVpnPath @>)
+            |> Option.defaultValue DefaultOpenVpnPath
+
+        NoColor =
+            args.Contains(<@ Cli.NoColor @>)
     }

DomainTypes.fs

@@ -18,3 +18,18 @@ type ErrorType =
     | CsvParseError of string
     | InvalidPath of string
     | CannotOpenFileBecause of string
+
+// The first 16 codepoints of the Unicode private-use area at 0xE000 are used
+// internally as color markers. 0xE000 resets color to default; values 0xE001 to
+// 0xE010 map to the values of the System.ConsoleColor enum.
+[<Literal>]
+let ControlCharRangeStart = 0xE000
+[<Literal>]
+let ControlCharRangeEnd = 0xE010
+
+let encodeDefaultConsoleColor = 
+    ControlCharRangeStart |> char
+let encodeConsoleColor (color: System.ConsoleColor) = 
+    int color + ControlCharRangeStart + 1 |> char
+let decodeConsoleColor (c: char) = 
+    int c - ControlCharRangeStart - 1 |> enum<System.ConsoleColor>

Gui.fs

@@ -30,13 +30,15 @@ let private lineOf width char =
 let private blankLine width = lineOf width ' '
 
 let private renderItem index selected maxWidth (row : VpnList.Row) rtt  =
-    sprintf "  [%c] %3d. %s  %sms, %s (%s)" 
+    sprintf "%c  [%c] %3d. %s  %sms, %s (%s)%c" 
+        (if selected then encodeConsoleColor ConsoleColor.Green else encodeDefaultConsoleColor)
         (if selected then 'X' else ' ')
         index
         row.CountryShort
         (rtt |> Option.defaultValue (string (int row.Ping)) |> padToLength 3 ' ')
         row.``#HostName``
         row.IP
+        encodeDefaultConsoleColor
     |> trimToLength maxWidth
 
 let private resultState result state = 

Program.fs

@@ -12,9 +12,16 @@ let errorToMessage = function
 
 open ProgramFlow.Operators
 
-let private overwriteConsole (str : string) =
-    Console.SetCursorPosition(0, 0)
-    Console.WriteLine str
+let private consoleOverwriter colorDisabled =
+    fun (str : string) ->
+        Console.SetCursorPosition(0, 0)
+        for c in str do
+            match c with
+            | _ when int c >= ControlCharRangeStart && int c <= ControlCharRangeEnd ->
+                if not colorDisabled then
+                    Console.ForegroundColor <- decodeConsoleColor c
+            | _ -> 
+                Console.Write c
 
 let parseArguments argv =
     match argv |> Cli.parseArgs with
@@ -31,15 +38,16 @@ let resetConsoleProperties _ =
     Console.ResetColor()
 
 /// Shows a menu prompting user to select a VPN from those allowed by given filter predicate.
-let promptForSelection filterPredicate rows =
+let promptForSelection colorDisabled filterPredicate rows =
     Console.CancelKeyPress.Add(resetConsoleProperties)
     Console.CursorVisible <- false
     Console.Clear()
 
+    let drawFunction = consoleOverwriter colorDisabled
     let filteredRows = Array.filter filterPredicate rows
 
     let rv = 
-        match Gui.execRowSelectorMenu overwriteConsole filteredRows with
+        match Gui.execRowSelectorMenu drawFunction filteredRows with
         | Some selection -> ContinueData selection
         | None -> ProgramFlow.normalExitWithMsg "No VPN selected"
 
@@ -107,7 +115,7 @@ let execute (config: Config) =
 
     connectToDataSource config.DataSource
     <!> printDataCount
-    >>= promptForSelection regionFilter
+    >>= promptForSelection config.NoColor regionFilter
     <!> printSelectedVpn
     >>= extractOpenVpnConfig
     >>= readAndMergeConfigs config.ConfigPaths