{-# LANGUAGE OverloadedStrings #-}
{- | Utility functions to launch and connect to the view server

-}
module Adb(
      startViewServer
    , stopViewServer 
    , isViewServerRunning
    , whenViewServer
    , adbForward
    ) where 


import System.Process 
import Control.Concurrent.MVar
import qualified Control.Exception as C
import System.IO
import System.Exit      ( ExitCode(..) )
import Control.Concurrent hiding(yield)
import Control.Monad(when)
import Control.Monad.Writer 
import Types

-- | Run a command using arguments and a standard input 
-- Return a result or an error
maybeProcess 
    :: FilePath                 -- ^ command to run
    -> [String]                 -- ^ any arguments
    -> String                   -- ^ standard input
    -> IO (Either String String)                -- ^ stdout
maybeProcess cmd args input = do
    (Just inh, Just outh, _, pid) <-
        createProcess (proc cmd args){ std_in  = CreatePipe,
                                       std_out = CreatePipe,
                                       std_err = CreatePipe }

    -- fork off a thread to start consuming the output
    output  <- hGetContents outh
    outMVar <- newEmptyMVar
    _ <- forkIO $ C.evaluate (length output) >> putMVar outMVar ()

    -- now write and flush any input
    when (not (null input)) $ do hPutStr inh input; hFlush inh
    hClose inh -- done with stdin

    -- wait on the output
    takeMVar outMVar
    hClose outh

    -- wait on the process
    ex <- waitForProcess pid

    case ex of
     ExitSuccess   -> return (Right output)
     ExitFailure r -> return (Left (show r))

-- | Android command to start the view server on a given port
startViewServer :: Config -> IO ()
startViewServer c = do 
    maybeProcess "adb" ["shell","service","call","window","1","i32",show (port c)] ""
    return ()

-- | Android command to stop the view server
stopViewServer :: IO ()
stopViewServer = do 
    maybeProcess "adb" ["shell","service","call","window","2"] ""
    return ()

-- | Android command to forward a port
adbForward :: Config -> IO ()
adbForward c = do 
    maybeProcess "adb" ["forward", "tcp:" ++ show (port c), "tcp:" ++ show (port c)] ""
    return ()

-- | Android command to test if the view server is running
-- (the code to parse the result is quick and dirty)
isViewServerRunning :: IO Bool 
isViewServerRunning = do
    r <- maybeProcess "adb" ["shell","service","call","window","3"] ""
    either (const $ return False) (const $ return True) $ do 
        mp <- r
        let nb = read . take 8 . drop 1 . drop 8 . drop 15 $ mp
        if nb == 1 
            then Right ""
            else Left ""

-- | When the view server is running, execute the action.
whenViewServer :: IO a -> IO ()
whenViewServer action = do 
    r <- isViewServerRunning 
    if r 
        then do 
            action 
            return ()
        else return ()


-- adb shell service call window 1 i32 4939 
-- adb shell service call window 3
-- adb shell service call window 2
-- adb forward tcp:4939 tcp:4939

-- base/core/java/Android/view/ViewDebug.java
--    private static final String REMOTE_COMMAND_CAPTURE = "CAPTURE";
--    private static final String REMOTE_COMMAND_DUMP = "DUMP";
--    private static final String REMOTE_COMMAND_INVALIDATE = "INVALIDATE";
--    private static final String REMOTE_COMMAND_REQUEST_LAYOUT = "REQUEST_LAYOUT";
--    private static final String REMOTE_PROFILE = "PROFILE";
--    private static final String REMOTE_COMMAND_CAPTURE_LAYERS = "CAPTURE_LAYERS";
--    private static final String REMOTE_COMMAND_OUTPUT_DISPLAYLIST = "OUTPUT_DISPLAYLIST";

-- Dump give property:length,value (length is length of value)
-- Number of front spaces before the view name are used to define the tree structure of this view with parents
--        id = namedProperties.get("mID").value;
--
--        left = getInt("mLeft", 0);
--        top = getInt("mTop", 0);
--        width = getInt("getWidth()", 0);
--        height = getInt("getHeight()", 0);
--        scrollX = getInt("mScrollX", 0);
--        scrollY = getInt("mScrollY", 0);
--        paddingLeft = getInt("mPaddingLeft", 0);
--        paddingRight = getInt("mPaddingRight", 0);
--        paddingTop = getInt("mPaddingTop", 0);
--        paddingBottom = getInt("mPaddingBottom", 0);
--        marginLeft = getInt("layout_leftMargin", Integer.MIN_VALUE);
--        marginRight = getInt("layout_rightMargin", Integer.MIN_VALUE);
--        marginTop = getInt("layout_topMargin", Integer.MIN_VALUE);
--        marginBottom = getInt("layout_bottomMargin", Integer.MIN_VALUE);
--        baseline = getInt("getBaseline()", 0);
--        willNotDraw = getBoolean("willNotDraw()", false);
--        hasFocus = getBoolean("hasFocus()", false);
--
--        hasMargins = marginLeft != Integer.MIN_VALUE &&
--                marginRight != Integer.MIN_VALUE &&
--                marginTop != Integer.MIN_VALUE &&
--                marginBottom != Integer.MIN_VALUE;