{-# LANGUAGE OverloadedStrings #-}

module Darcs.Util.Text
    (
    -- * Text construction.
      sentence
    -- * Text formatting.
    , formatText
    , formatParas
    , formatPara
    , chompTrailingNewline
    -- * Text processing
    , breakCommand
    , quote
    , pathlist
    , showCommandLine
    ) where

import Prelude ()
import Darcs.Prelude

import Control.Arrow ( first )
import Data.List ( intercalate )

import Darcs.Util.Printer ( Doc, renderString, quoted, hsep )

sentence :: Doc -> Doc
sentence = (<> ".")

-- |Take a list of paragraphs and format them to the given line length, with
-- a blank line between paragraphs.
formatText :: Int -> [String] -> String
formatText linelen = unlines . formatParas linelen

formatParas :: Int -> [String] -> [String]
formatParas linelen = intercalate [""] .
                      map (map unwords . formatPara linelen . words)

-- |Take a list of words and split it up so that each chunk fits into the specified width
-- when spaces are included. Any words longer than the specified width end up in a chunk
-- of their own.
formatPara :: Int -> [[a]] -> [[[a]]]
formatPara w = para'
  where para' [] = []
        para' xs = uncurry (:) $ para'' w xs
        para'' r (x:xs) | w == r || length x < r = first (x:) $ para'' (r - length x - 1) xs
        para'' _ xs = ([], para' xs)

breakCommand :: String -> (String, [String])
breakCommand s = case words s of
                   (arg0:args) -> (arg0,args)
                   [] -> (s,[])

chompTrailingNewline :: String -> String
chompTrailingNewline "" = ""
chompTrailingNewline s = if last s == '\n' then init s else s

-- | Quote a string for screen output.
quote :: String -> String
quote = renderString . quoted

-- | Format a list of 'FilePath's as quoted text. It deliberately refuses to
-- use English.andClauses but rather separates the quoted strings only with a
-- space, because this makes it usable for copy and paste e.g. as arguments to
-- another shell command.
pathlist :: [FilePath] -> Doc
pathlist paths = hsep (map quoted paths)

-- | Produce a String composed by the elements of [String] each enclosed in
-- double quotes.
showCommandLine :: [String] -> String
showCommandLine strings = showCommandLine' ['"'] strings
            where showCommandLine' x xs =
                        x ++ intercalate (x ++ " " ++ x) xs ++ x