{-# LANGUAGE FlexibleContexts #-}
module Villefort.Database  where

import Control.Monad.Reader (MonadIO,MonadReader,liftIO,ask)
import Database.HDBC.Sqlite3 (Connection,connectSqlite3)
import Database.HDBC (SqlValue
                     , execute
                     , commit
                     , disconnect
                     , toSql
                     , fromSql
                     , quickQuery'
                     , prepare)
import System.Environment (getArgs)
import Paths_Villefort (getDataDir)
import Villefort.Definitions (VConfig(..))
import Data.Convertible.Base (Convertible)
import Data.List.Utils (replace)

-- | gets list of subjects from local database
getSubjects :: (MonadReader VConfig m, MonadIO m) => m [String]
getSubjects = (\x-> (!! 0) <$> x) <$> makeQuery "select Subject from todo where state = 0 group by Subject"

-- | get paths tests for --custom flag to allow for executing custom builds
path' ::  (MonadReader VConfig m, MonadIO m) => m FilePath
path' = do
  env <- ask
  let s = showDatabase env
  args <- liftIO $ getArgs
  let cont = do
        if length args > 1 then
         if args !! 0 == "--custom" then
           return $ args !! 1
         else liftIO $ getDataDir
         else liftIO $ getDataDir
  if s then (liftIO $ putStrLn =<< getDataDir) >> cont else cont
  

-- | connects to database checks if custom database path is set
getDb :: (MonadReader VConfig m, MonadIO m) => m Connection  
getDb = do
  env <- ask
  let dat = database env
  let isDat = not $ null $ dat
  if isDat then  liftIO $ connectSqlite3 dat else do
    path <- path'
    let fullpath = (path ++ "/data/todo.db")
    liftIO $ connectSqlite3 fullpath
    
-- | converts from sqlValues to Strings
convRow :: [[SqlValue]] -> [[String]]
convRow dat = Prelude.map (\x -> Prelude.map (\y -> fromSql y :: String ) x) dat

-- | takes sqlQuery and returns results as a string
makeQuery :: (MonadReader VConfig m, MonadIO m) => String -> m [[String]]
makeQuery query = do
  conn <- getDb
  taskRaw <- liftIO $ quickQuery' conn query []
  liftIO $ disconnect conn
  return (convRow taskRaw)  

-- | executes a query that changes values in database
execQuery :: (Convertible a SqlValue,
  MonadIO m,
  MonadReader VConfig m) => String -> [a] -> m ()
execQuery query params = do
  conn <- getDb
  stmt <- liftIO $ prepare conn query
  _ <- ($) liftIO $ execute stmt (map toSql params)
  _ <- ($) liftIO $ commit conn
  liftIO $ disconnect conn

-- | gets the task id for the next avaible todo
getNextId :: (MonadReader VConfig m, MonadIO m) => m Integer
getNextId = do
  f <- makeQuery "select id from todo order by id desc"
  let rawid = head $ f
  pure $ (read (rawid !! 0) :: Integer) +1

-- | adds new task sanitizes input to avoid SQL escaping
addTask ::  (MonadReader VConfig m, MonadIO m) => String -> String -> String -> String -> m ()
addTask todoSummary todoTitle date todoSubject = do
  nextSqlId <- getNextId
  execQuery "insert into todo (id,Description,Title,Entered,Due,State,time,Subject) Values (?,?,?,datetime('now', 'localtime'),?,1,0,?)"  [show nextSqlId, (clean todoSummary),(clean todoTitle), date, (clean todoSubject)]
-- | logs new daily entry due on same day
addDaily :: (MonadReader VConfig m, MonadIO m) => [String] -> m ()
addDaily addD= do
  lastRowId <- getNextId
  execQuery "insert into todo (id,Description,Title,Entered,Due,State,time,Subject ) Values (?,?,?,current_date,current_date,1,0,?)" $ [show lastRowId] ++ addD

-- | lists the todo items finished today 
getDone :: (MonadReader VConfig m, MonadIO m) => m [[String]]
getDone = makeQuery  "select Title, time  from todo where substr(Due,1,10) = Date('now','localtime') and time != 0"

-- | rudimentary sanitization
clean :: String -> String
clean = replace "''" "'"