module Components.QueryComposers.SQLQueryComposer (makeSqlQueries) where

import Model.ServerObjectTypes (RootObject,NestedObject,SubFields)
import Model.ServerExceptions (QueryException(CreatingSqlQueryObjectsException,CreatingSqlQueryObjectFieldsException,InvalidObjectException,InvalidScalarException,RelationshipConfigurationException))
import Components.ObjectHandlers.ObjectsHandler (translateServerObjectToDBName,getSubSelectionArgument,getSubSelectionField,withSubSelection,getDBObjectRelationships,getServerObject,getInlinefragmentObject,getInlinefragmentFields,isServerObjectTable,getSubFields,getScalarName,isServerObjectTable)
import Data.Either (fromLeft,fromRight,isRight,isLeft)
import Data.Map.Strict (fromList,Map,(!),insertWith)
import Control.Exception (throw)


makeSqlQueries :: [RootObject] -> [(String,String)] -> [(String,String,[String])] -> [(String,[String],[String])] -> ([[[String]]],[[String]])
makeSqlQueries [] _ _ _ = ([],[])
makeSqlQueries rojs sodn sor soa = unzip $ map unzip $ map (makeSqlQuerySet sodn sor soa) rojs
makeSqlQuerySet :: [(String,String)] -> [(String,String,[String])] -> [(String,[String],[String])] -> RootObject -> [([String],String)]
makeSqlQuerySet sodn sor soa obj = if (length dbNames)==1 then (addSqlQueryFields (getSubFields obj) (fromList [(firstTable,1)]) ("select "++firstTable++(show 1)++".id,") (" from"++(makeSqlTablePhrase obj firstTable 1)) (" order by "++firstTable++(show 1)++".id asc") (((firstTable,1):[])) [] sodn sor soa (firstTable:[])) else (foldr (\x y -> x++y) [] [(addSqlQueryFields (getSubFields obj) (fromList [(x,1)]) ("select "++x++(show 1)++".id,") (" from"++(makeSqlTablePhrase obj x 1)) (" order by "++x++(show 1)++".id asc") ((x,1):[]) [] sodn sor soa (x:[])) | x<-dbNames])
                           where
                             dbNames = translateServerObjectToDBName (getServerObject obj) sodn soa
                             firstTable = head dbNames
-- making table phrase when there is only one sql table
makeSqlTablePhrase :: NestedObject -> String -> Int -> String
makeSqlTablePhrase obj name number = if (withSubSelection obj)==True then " (select * from "++name++" where "++(getSubSelectionField obj)++"="++(getSubSelectionArgument obj)++") as "++name++(show number) else " "++name++" as "++name++(show number)
addSqlQueryFields :: SubFields -> Map String Int -> String -> String -> String -> [(String,Int)] -> [SubFields] -> [(String,String)] -> [(String,String,[String])] -> [(String,[String],[String])] -> [String] -> [([String],String)]
addSqlQueryFields [] counts select from order [] [] _ _ _ tbls = [(tbls,(removeLastChar select)++from++order++";")]
addSqlQueryFields [] counts select from order [] _ _ _ _ _ = throw CreatingSqlQueryObjectFieldsException
addSqlQueryFields [] counts select from order _ [] _ _ _ tbls = [(tbls,(removeLastChar select)++from++order++";")]
addSqlQueryFields [] counts select from order (_:b) (h:t) sodn sor soa tbls = addSqlQueryFields h counts select from order b t sodn sor soa tbls
addSqlQueryFields (h:t) counts select from order [] _ _ _ _ _ = throw CreatingSqlQueryObjectsException  -- fields without objects
addSqlQueryFields (h:t) counts select from order ((ltable,ltableNo):names) fields sodn sor soa tbls
    | (isLeft h)==True&&scalarName=="__typename" = addSqlQueryFields t counts select from order ((ltable,ltableNo):names) fields sodn sor soa tbls
    | (isLeft h)==True = addSqlQueryFields t counts (select++(ltable++(show ltableNo))++"."++(getScalarName $ fromLeft (throw InvalidScalarException) h)++",") from order ((ltable,ltableNo):names) fields sodn sor soa tbls
    -- since only difference is table name, I should remove repeated computations by changing only name...
    | (isLeft fobj)&&(length tables)>1 = foldr (\x y -> x++y) [] [(addSqlQueryFields (getSubFields nobj) (calcNewCounts ltable x counts sor) (select++x++(show $ (!) (calcNewCounts ltable x counts sor) x)++".id,") (from++(makeTransitions (calcNewCounts ltable x counts sor) (getDBObjectRelationships ltable x sor) nobj)) (order++","++x++(show $ (!) (calcNewCounts ltable x counts sor) x)++".id asc") ((x,((calcNewCounts ltable x counts sor) ! x)):(ltable,ltableNo):names) (t:fields) sodn sor) soa (x:tbls) | x<-tables]
    | (isLeft fobj)&&(length tables)>0 = addSqlQueryFields (getSubFields nobj) firstTableNewCounts (select++firstSubfieldTable++(show $ (!) firstTableNewCounts firstSubfieldTable)++".id,") (from++(makeTransitions firstTableNewCounts (getDBObjectRelationships ltable firstSubfieldTable sor) nobj)) (order++","++firstSubfieldTable++(show $ (!) firstTableNewCounts firstSubfieldTable)++".id asc") ((firstSubfieldTable,firstTableNewCounts ! firstSubfieldTable):(ltable,ltableNo):names) (t:fields) sodn sor soa (firstSubfieldTable:tbls)
    | (isRight fobj)&&(isServerObjectTable ltable (getInlinefragmentObject ifobj) sodn soa) = addSqlQueryFields ((getInlinefragmentFields ifobj)++t) counts select from order ((ltable,ltableNo):names) fields sodn sor soa tbls
    | otherwise = addSqlQueryFields t counts select from order ((ltable,ltableNo):names) fields sodn sor soa tbls
  where
    scalarName = getScalarName $ fromLeft (throw InvalidScalarException) h
    fobj = fromRight (throw InvalidObjectException) h
    nobj = fromLeft (throw InvalidObjectException) fobj
    ifobj = fromRight (throw InvalidObjectException) fobj
    tables = translateServerObjectToDBName (getServerObject nobj) sodn soa
    firstSubfieldTable = head tables
    firstTableNewCounts = calcNewCounts ltable firstSubfieldTable counts sor
calcNewCounts :: String -> String -> Map String Int -> [(String,String,[String])] -> Map String Int
calcNewCounts from to pcnt sor = foldr (\x y -> insertWith (+) x 1 y) pcnt (getNewTables $ getDBObjectRelationships from to sor)
removeLastChar :: String -> String
removeLastChar [] = []
removeLastChar str = init str
-- get the tables where we need to increment the tables counter
getNewTables :: [String] -> [String]
getNewTables lnk = getNewTablesHelper (tail $ tail lnk) 0
getNewTablesHelper :: [String] -> Int -> [String]
getNewTablesHelper [] _ = []
getNewTablesHelper (h:t) idx
    | (idx==0) = h:getNewTablesHelper (tail t) 3
    | ((mod idx 3)==0) = h:getNewTablesHelper t (idx+1)
    | otherwise = getNewTablesHelper t (idx+1)
makeTransitions :: Map String Int -> [String] -> NestedObject -> String
makeTransitions counts (h1:h2:h3:h4:h5:h6:h7:t) nobj = " left join "++h5++" as "++h5++(show $ (!) counts h5)++" on "++(makeEqColumns (h1++(show $ (!) counts h1)) h2 (h5++(show $ (!) counts h5)) h6)++(completeTransition counts (h3:h4:h5:h6:h7:t) nobj)
makeTransitions counts (h1:h2:h3:h4:t) nobj = " left join "++(if (withSubSelection nobj)==True then ("(select * from "++h3++" where "++(getSubSelectionField nobj)++"="++(getSubSelectionArgument nobj)++")") else h3)++" as "++h3++(show $ (!) counts h3)++" on "++(makeEqColumns (h1++(show $ (!) counts h1)) h2 (h3++(show $ (!) counts h3)) h4)
makeTransitions _ _ _ = throw RelationshipConfigurationException
completeTransition :: Map String Int -> [String] -> NestedObject -> String
completeTransition counts (h1:h2:h3:h4:h5:[]) nobj = " left join "++(if (withSubSelection nobj)==True then ("(select * from "++h1++" where "++(getSubSelectionField nobj)++"="++(getSubSelectionArgument nobj)++")") else h1)++" as "++h1++(show $ (!) counts h1)++" on "++(makeEqColumns (h3++(show $ (!) counts h3)) h5 (h1++(show $ (!) counts h1)) h2)
completeTransition counts (h1:h2:h3:h4:h5:h6:h7:h8:t) nobj = " left join "++h6++" as "++h6++(show $ (!) counts h6)++" on "++(makeEqColumns (h3++(show $ (!) counts h3)) h5 (h6++(show $ (!) counts h6)) h7)++(completeTransition counts (h1:h2:h6:h7:h8:t) nobj)
completeTransition counts _ _ = throw RelationshipConfigurationException
makeEqColumns :: String -> String -> String -> String -> String
makeEqColumns tb1 col1 tb2 col2 = if ((elem ' ' col1)==False&&(elem ' ' col2)==False) then (tb1++"."++col1++"="++tb2++"."++col2) else makeEqColumnsHelper "" tb1 col1 tb2 col2
makeEqColumnsHelper :: String -> String -> String -> String -> String -> String
makeEqColumnsHelper rlt tb1 col1 tb2 col2
    | (elem ' ' col1)&&(elem ' ' col2)&&((length rlt)>0) = makeEqColumnsHelper (rlt++" and "++tb1++"."++fst++"="++tb2++"."++snd) tb1 rmd1 tb2 rmd2
    | (elem ' ' col1)&&(elem ' ' col2) = makeEqColumnsHelper (tb1++"."++fst++"="++tb2++"."++snd) tb1 rmd1 tb2 rmd2
    | (elem ' ' col1) = throw RelationshipConfigurationException
    | (elem ' ' col2) = throw RelationshipConfigurationException
    | ((length rlt)>0) = rlt++" and "++(tb1++"."++col1++"="++tb2++"."++col2)
    | otherwise = (tb1++"."++col1++"="++tb2++"."++col2)
  where
    (fst, rmd1) = getFirstColumn col1
    (snd, rmd2) = getFirstColumn col2
getFirstColumn :: String -> (String,String)
getFirstColumn str = getFirstColumnHelper "" str
getFirstColumnHelper :: String -> String -> (String,String)
getFirstColumnHelper _ [] = ([],[])
getFirstColumnHelper acc (h:t)
    | (h==' ') = (acc,t)
    | otherwise = getFirstColumnHelper (acc++[h]) t