Draw.hs

-- | Drawing functions and the page state lifecycle.
module Ansiform.Draw ( start, draw, redraw
                , amend, amend'
                , replace, replace'
                , startOn, drawOn, redrawOn
                , amendOn, amendOn'
                , replaceOn, replaceOn'
                , State
                ) where

--------------------------------------------------------------------------------
import           System.IO (Handle, stdout)
import           Ansiform.Internal.Number
import           Ansiform.Internal.Page
import           Ansiform.Internal.Section
import           Ansiform.Internal.Settings
import           Ansiform.Internal.State
import           Ansiform.Internal.Terminal
import           Ansiform.Page


-- Drawing Functions
--------------------------------------------------------------------------------

-- | Prints the first page and generates the initial state on stdout.
start :: Page -> Settings -> IO State 
start = startOn stdout

-- | Prints the first page to a given handle.
startOn :: Handle -> Page -> Settings -> IO State
startOn h p s = drawOn h p $ formState s p []


-- | Draws a new page on stdout, erasing the current printed page.
draw :: Page -> State -> IO State
draw = drawOn stdout

-- | Draws a new page to a given handle.
drawOn :: Handle -> Page -> State -> IO State
drawOn h p st = clr h 0 >> unStateSettingsOn h st >>= \cfg ->
                     runPageIOOn h (return cfg) p
                     >>= \ns -> return $ updateState st p ns

-- | Redraws the last printed page on stdout.
redraw :: State -> IO State
redraw = redrawOn stdout

-- | Redraws the last printed page on a given handle.
redrawOn :: Handle -> State -> IO State
redrawOn h st = drawOn h (unStatePage st) st


-- | Amends a page on stdout, erasing the current page.
amend :: Section -> Number -> State -> IO State
amend = amendOn stdout

-- | Amends a page on a given handle.
amendOn :: Handle -> Section -> Number -> State -> IO State
amendOn h s n st = amendOn' h [s] n st

-- | Amends several sections on stdout.
amend' :: [Section] -> Number -> State -> IO State
amend' = amendOn' stdout

-- | Amends several sections on a given handle.
amendOn' :: Handle -> [Section] -> Number -> State -> IO State
amendOn' h ss n st = drawOn h (amendPage' (unStatePage st) ss n) st


-- | Replaces a single section on stdout, preserving what is above.
replace :: Section -> Number -> State -> IO State
replace = replaceOn stdout

-- | Replaces a single section on a given handle.
replaceOn :: Handle -> Section -> Number -> State -> IO State
replaceOn h s n st = replaceOn' h [s] n st

-- | Replaces a list of sections on stdout, preserving what is above.
replace' :: [Section] -> Number -> State -> IO State
replace' = replaceOn' stdout

-- | Replaces a list of sections on a given handle.
replaceOn' :: Handle -> [Section] -> Number -> State -> IO State
replaceOn' h ss n st = clr h preserve
            >> unStateSettingsOn h st
            >>= \cfg -> runPageIOOn h (return cfg) remainder
            >>= \ns -> return $ updateState st newPage (take n' oldResults ++ ns)
    where n' = unn n
          sections = unPage $ unStatePage st
          oldResults = unStateResults st
          preserve = sum $ take n' oldResults
          remainder = page $ ss ++ drop (n'+length ss) sections
          newPage = amendPage' (unStatePage st) ss n