-----------------------------------------------------------------------------
-- |
-- Module      :  Xmobar.Parsers
-- Copyright   :  (c) Andrea Rossato
-- License     :  BSD-style (see LICENSE)
--
-- Maintainer  :  Andrea Rossato <andrea.rossato@unibz.it>
-- Stability   :  unstable
-- Portability :  unportable
--
-- Parsers needed for Xmobar, a text based status bar
--
-----------------------------------------------------------------------------

module Parsers (
               -- * Parsing
               -- $parser
               parseString
               , stringParser
               , defaultColors
               , colorsAndText
               , templateStringParser
               , templateCommandParser
               , templateParser
               , parseTemplate
               ) where

import Config
import Commands
import Runnable
import Text.ParserCombinators.Parsec
import qualified Data.Map as Map


{- $parser
These are the neede parsers. Don't trust them too much.

There are parsers for the commands output and parsers for the
formatting template.
 -}

-- | Runs the actual string parsers
parseString :: Config -> String -> IO [(String, String)]
parseString c s =
    case (parse (stringParser c) "" s) of
      Left  _ -> return [("Could not parse string: " ++ s, fgColor c)]
      Right x -> return (concat x)

-- | Gets the string and combines the needed parsers
stringParser :: Config -> Parser [[(String, String)]]
stringParser c = manyTill (defaultColors c) eof

-- | Parses a string with the default color (no color set)
defaultColors :: Config -> Parser [(String, String)]
defaultColors c = do
  s <- manyTill anyChar (tryString "<fc" <|> endOfLine "")
  n <- colorsAndText <|> endOfLine ("","")
  return [(s,fgColor c),n]

-- | Parses a string with a color set
colorsAndText :: Parser (String, String)
colorsAndText = do
  string "="
  c <- colorSpec
  string ">"
  s <- manyTill anyChar (tryString "</fc>")
  return (s,c)

endOfLine :: a -> Parser a
endOfLine r = eof >> return r

tryString :: String -> Parser String
tryString = try . string

-- | Parses a color specification (hex or named)
colorSpec :: Parser String
colorSpec = many1 (alphaNum <|> char ',' <|> char '#')

-- | Parses the output template string
templateStringParser :: Config -> Parser (String,String,String)
templateStringParser c = do
  s         <- many $ noneOf (sepChar c)
  (com,_,_) <- templateCommandParser  c
  ss        <- many $ noneOf (sepChar c)
  return (com, s, ss)

-- | Parses the command part of the template string
templateCommandParser :: Config -> Parser (String,String,String)
templateCommandParser c = do
  let chr = head $ sepChar c
  char chr
  com <- many $ noneOf (sepChar c)
  char chr
  return $ (com,"","")

-- | Combines the template parsers
templateParser :: Config -> Parser [(String,String,String)]
templateParser c = many (templateStringParser c)

-- | Actually runs the template parsers
parseTemplate :: Config -> String -> IO [(Runnable,String,String)]
parseTemplate config s =
    do str <- case (parse (templateParser config) "" s) of
                Left _  -> return [("","","")]
                Right x -> return x
       let comList = map alias (commands config)
           m       = Map.fromList $ zip comList (commands config)
       return $ combine config m str

-- | Given a finite "Map" and a parsed templatet produces the
-- | resulting output string.
combine :: Config -> Map.Map String Runnable -> [(String, String, String)] -> [(Runnable,String,String)]
combine _ _ [] = []
combine config m ((ts,s,ss):xs) =
    [(com, s, ss)] ++ combine config m xs
        where com  = Map.findWithDefault dflt ts m
              dflt = Run $ Com ts [] [] 10