{-| 
A happs-based web UI for hledger.
-}

module WebCommand
where
import Control.Monad.Trans (liftIO)
import Data.ByteString.Lazy.UTF8 (toString)
import qualified Data.Map as M
import Data.Map ((!))
import Data.Time.Clock
import Data.Time.Format
import System.Locale
import Control.Concurrent
import qualified Data.ByteString.Lazy.Char8 as B
import Happstack.Data (defaultValue)
import Happstack.Server
import Happstack.Server.HTTP.FileServe (fileServe)
import Happstack.State.Control (waitForTermination)
import System.Cmd (system)
import System.Info (os)
import System.Exit

import Ledger
import Options
import BalanceCommand
import RegisterCommand
import PrintCommand
import HistogramCommand


tcpport = 5000

web :: [Opt] -> [String] -> Ledger -> IO ()
web opts args l =
  if Debug `elem` opts
     then do
       putStrLn $ printf "starting web server on port %d in debug mode" tcpport
       simpleHTTP nullConf{port=tcpport} handlers
     else do
       putStrLn $ printf "starting web server on port %d" tcpport
       tid <- forkIO $ simpleHTTP nullConf{port=tcpport} handlers
       putStrLn "starting web browser"
       openBrowserOn $ printf "http://localhost:%d/balance" tcpport
       waitForTermination
       putStrLn "shutting down web server..."
       killThread tid
       putStrLn "shutdown complete"

    where
      handlers :: ServerPartT IO Response
      handlers = msum
       [methodSP GET $ withDataFn (look "a") $ \a -> templatise $ balancereport [a]
       ,methodSP GET $ templatise $ balancereport []
       ,dir "print" $ withDataFn (look "a") $ \a -> templatise $ printreport [a]
       ,dir "print" $ templatise $ printreport []
       ,dir "register" $ withDataFn (look "a") $ \a -> templatise $ registerreport [a]
       ,dir "register" $ templatise $ registerreport []
       ,dir "balance" $ withDataFn (look "a") $ \a -> templatise $ balancereport [a]
       ,dir "balance" $ templatise $ balancereport []
       ,dir "histogram" $ withDataFn (look "a") $ \a -> templatise $ histogramreport [a]
       ,dir "histogram" $ templatise $ histogramreport []
       ]
      printreport apats    = showLedgerTransactions opts (apats ++ args) l
      registerreport apats = showRegisterReport opts (apats ++ args) l
      balancereport []  = showBalanceReport opts args l
      balancereport apats  = showBalanceReport opts (apats ++ args) l'
          where l' = cacheLedger apats (rawledger l) -- re-filter by account pattern each time
      histogramreport []  = showHistogram opts args l
      histogramreport apats  = showHistogram opts (apats ++ args) l'
          where l' = cacheLedger apats (rawledger l) -- re-filter by account pattern each time

templatise :: String -> ServerPartT IO Response
templatise s = do
  r <- askRq
  return $ setHeader "Content-Type" "text/html" $ toResponse $ maintemplate r s

maintemplate :: Request -> String -> String
maintemplate r = printf (unlines
  ["<div style=float:right>"
  ,"<form action=%s>search:&nbsp;<input name=a value=%s></form>"
  ,"</div>"
  ,"<div align=center style=width:100%%>"
  ," <a href=balance>balance</a>"
  ,"|"
  ," <a href=register>register</a>"
  ,"|"
  ," <a href=print>print</a>"
  ,"|"
  ," <a href=histogram>histogram</a>"
  ,"</div>"
  ,"<pre>%s</pre>"
  ])
  (dropWhile (=='/') $ rqUri r)
  (fromMaybe "" $ queryValue "a" r)

queryValues :: String -> Request -> [String]
queryValues q r = map (B.unpack . inputValue . snd) $ filter ((==q).fst) $ rqInputs r

queryValue :: String -> Request -> Maybe String
queryValue q r = case filter ((==q).fst) $ rqInputs r of
                   [] -> Nothing
                   is -> Just $ B.unpack $ inputValue $ snd $ head is

-- | Attempt to open a web browser on the given url, all platforms.
openBrowserOn :: String -> IO ExitCode
openBrowserOn u = trybrowsers browsers u
    where
      trybrowsers (b:bs) u = do
        e <- system $ printf "%s %s" b u
        case e of
          ExitSuccess -> return ExitSuccess
          ExitFailure _ -> trybrowsers bs u
      trybrowsers [] u = do
        putStrLn $ printf "Sorry, I could not start a browser (tried: %s)" $ intercalate ", " browsers
        putStrLn $ printf "Please open your browser and visit %s" u
        return $ ExitFailure 127
      browsers | os=="darwin"  = ["open"]
               | os=="mingw32" = ["firefox","safari","opera","iexplore"]
               | otherwise     = ["sensible-browser","firefox"]
    -- jeffz: write a ffi binding for it using the Win32 package as a basis
    -- start by adding System/Win32/Shell.hsc and follow the style of any
    -- other module in that directory for types, headers, error handling and
    -- what not.
    -- ::ShellExecute(NULL, "open", "www.somepage.com", NULL, NULL, SW_SHOWNORMAL);
    -- ::ShellExecute(NULL, "open", "firefox.exe", "www.somepage.com" NULL, SW_SHOWNORMAL);