{-|
Module      : Gargantext.Database.Tree
Description : Tree of Resource Nodes built from Database
Copyright   : (c) CNRS, 2017-Present
License     : AGPL + CECILL v3
Maintainer  : team@gargantext.org
Stability   : experimental
Portability : POSIX

Let a Root Node, return the Tree of the Node as a directed acyclic graph
(Tree).

-- TODO delete node, if not owned, then suppress the link only
-- see Action/Delete.hs
-}

{-# LANGUAGE QuasiQuotes       #-}
{-# LANGUAGE TemplateHaskell   #-}

module Gargantext.Database.Query.Tree
  ( module Gargantext.Database.Query.Tree.Error
  , isDescendantOf
  , isOwnedBy
  , isSharedWith
  , isIn
  , tree
  , tree_flat
  , TreeMode(..)
  , findNodesId
  , DbTreeNode(..)
  , dt_name
  , dt_nodeId
  , dt_typeId
  , findShared
  , findNodes
  , findNodesWithType
  , NodeMode(..)

  , sharedTreeUpdate
  , dbTree
  , updateTree
  , recursiveParents
  )
  where

import Control.Lens (view, toListOf, at, each, _Just, to, set)
import Data.List (tail, nub)
import Data.List qualified as List
import Data.Map.Strict (fromListWith, lookup)
import Data.Text qualified as Text
import Database.PostgreSQL.Simple ( Only(Only), In(In) )
import Database.PostgreSQL.Simple.SqlQQ ( sql )
import Gargantext.Core ( fromDBid, HasDBid(toDBid) )
import Gargantext.Core.Types.Main (NodeTree(..), Tree(..))
import Gargantext.Database.Admin.Config ()
import Gargantext.Database.Admin.Types.Hyperdata.Any (HyperdataAny)
import Gargantext.Database.Admin.Types.Node
import Gargantext.Database.Prelude (runPGSQuery, DBCmd)
import Gargantext.Database.Query.Table.Node (getNodeWith)
import Gargantext.Database.Query.Table.Node.Error (HasNodeError)
import Gargantext.Database.Query.Table.NodeNode (getNodeNode)
import Gargantext.Database.Query.Tree.Error
import Gargantext.Database.Schema.Node (NodePoly(..))
import Gargantext.Database.Schema.NodeNode (NodeNodePoly(..))
import Gargantext.Prelude hiding (to)
import qualified Data.List.NonEmpty as NE

------------------------------------------------------------------------
data DbTreeNode = DbTreeNode { _dt_nodeId   :: NodeId
                             , _dt_typeId   :: Int
                             , _dt_parentId :: Maybe NodeId
                             , _dt_name     :: Text
                             } deriving (Show)

makeLenses ''DbTreeNode

instance Eq DbTreeNode where
  (==) d1 d2 = (==) (_dt_nodeId d1) (_dt_nodeId d2)

------------------------------------------------------------------------

data TreeMode = TreeBasic | TreeAdvanced | TreeFirstLevel

-- | Returns the Tree of Nodes in Database
tree :: (HasTreeError err, HasNodeError err)
     => TreeMode
     -> RootId
     -> [NodeType]
     -> DBCmd err (Tree NodeTree)
tree TreeBasic    = tree_basic
tree TreeAdvanced = tree_advanced
tree TreeFirstLevel = tree_first_level

-- | Tree basic returns the Tree of Nodes in Database
-- (without shared folders)
-- keeping this for teaching purpose only
tree_basic :: (HasTreeError err, HasNodeError err)
           => RootId
           -> [NodeType]
           -> DBCmd err (Tree NodeTree)
tree_basic r nodeTypes =
  (dbTree r nodeTypes <&> toTreeParent) >>= toTree
  -- Same as (but easier to read) :
  -- toTree =<< (toTreeParent <$> dbTree r nodeTypes)

-- | Advanced mode of the Tree enables shared nodes
tree_advanced :: (HasTreeError err, HasNodeError err)
              => RootId
              -> [NodeType]
              -> DBCmd err (Tree NodeTree)
tree_advanced r nodeTypes = do
  -- let rPrefix s = "[tree_advanced] root = " <> show r <> " " <> s
  mainRoot    <- findNodes r Private nodeTypes
  -- printDebug (rPrefix "mainRoot") mainRoot
  publicRoots <- findNodes r Public  nodeTypes
  -- printDebug (rPrefix "publicRoots") publicRoots
  sharedRoots <- findNodes r Shared  nodeTypes
  -- printDebug (rPrefix "sharedRoots") sharedRoots
  -- let ret = toSubtreeParent r (mainRoot <> sharedRoots <> publicRoots)
  -- printDebug (rPrefix "treeParent") ret
  -- toTree ret
  toTree $ toSubtreeParent r (mainRoot <> sharedRoots <> publicRoots)

-- | Fetch only first level of tree
tree_first_level :: (HasTreeError err, HasNodeError err)
                 => RootId
                 -> [NodeType]
                 -> DBCmd err (Tree NodeTree)
tree_first_level r nodeTypes = do
  -- let rPrefix s = mconcat [ "[tree_first_level] root = "
  --                         , show r
  --                         , ", nodeTypes = "
  --                         , show nodeTypes
  --                         , " "
  --                         , s ]
  mainRoot    <- findNodes r Private nodeTypes
  -- printDebug (rPrefix "mainRoot") mainRoot
  publicRoots <- findNodes r PublicDirect  nodeTypes
  -- printDebug (rPrefix "publicRoots") publicRoots
  sharedRoots <- findNodes r SharedDirect  nodeTypes
  -- printDebug (rPrefix "sharedRoots") sharedRoots
  ret <- toTree $ toSubtreeParent r (mainRoot <> sharedRoots <> publicRoots)
  -- printDebug (rPrefix "tree") ret
  pure ret

-- | Fetch tree in a flattened form
tree_flat :: (HasTreeError err, HasNodeError err)
          => RootId
          -> [NodeType]
          -> Maybe Text
          -> DBCmd err [NodeTree]
tree_flat r nodeTypes q = do
  mainRoot <- findNodes r Private nodeTypes
  publicRoots <- findNodes r Public nodeTypes
  sharedRoots <- findNodes r Shared nodeTypes
  let ret = map toNodeTree (mainRoot <> sharedRoots <> publicRoots)
  case q of
    Just v -> pure $ filter (\(NodeTree {_nt_name}) -> Text.isInfixOf (Text.toLower v) (Text.toLower _nt_name)) ret
    Nothing -> pure $ ret


------------------------------------------------------------------------
data NodeMode = Private | Shared | Public | SharedDirect | PublicDirect

findNodes :: (HasTreeError err, HasNodeError err)
          => RootId
          -> NodeMode
          -> [NodeType]
          -> DBCmd err [DbTreeNode]
findNodes r Private nt       = dbTree r nt
findNodes r Shared  nt       = findShared r NodeFolderShared nt sharedTreeUpdate
findNodes r SharedDirect  nt = findSharedDirect r NodeFolderShared nt sharedTreeUpdate
findNodes r Public  nt       = findShared r NodeFolderPublic nt publicTreeUpdate
findNodes r PublicDirect  nt = findSharedDirect r NodeFolderPublic nt publicTreeUpdate

------------------------------------------------------------------------
-- | Collaborative Nodes in the Tree
--   Queries the `nodes_nodes` table.
findShared :: HasTreeError err
           => RootId -> NodeType -> [NodeType] -> UpdateTree err
           -> DBCmd err [DbTreeNode]
findShared r nt nts fun = do
  foldersSharedId <- findNodesId r [nt]
  trees           <- mapM (updateTree nts fun) foldersSharedId
  pure $ concat trees

-- | Find shared folders with "direct" access, i.e. when fetching only
-- first-level subcomponents. This works in a simplified manner: fetch the node
-- and get the tree for its parent.
findSharedDirect :: (HasTreeError err, HasNodeError err)
                 => RootId -> NodeType -> [NodeType] -> UpdateTree err
                 -> DBCmd err [DbTreeNode]
findSharedDirect r nt nts fun = do
  -- let rPrefix s = mconcat [ "[findSharedDirect] r = "
  --                         , show r
  --                         , ", nt = "
  --                         , show nt
  --                         , ", nts = "
  --                         , show nts
  --                         , " "
  --                         , s ]
  parent <- getNodeWith r (Proxy :: Proxy HyperdataAny)
  let mParent = _node_parent_id parent
  case mParent of
    Nothing -> pure []
    Just parentId -> do
      foldersSharedId <- findNodesId parentId [nt]
      -- printDebug (rPrefix "foldersSharedId") foldersSharedId
      trees           <- mapM (updateTree nts fun) foldersSharedId
      -- printDebug (rPrefix "trees") trees
      pure $ concat trees


type UpdateTree err = ParentId -> [NodeType] -> NodeId -> DBCmd err [DbTreeNode]

updateTree :: HasTreeError err
           => [NodeType] -> UpdateTree err -> RootId
           -> DBCmd err [DbTreeNode]
updateTree nts fun r = do
  folders       <- getNodeNode r
  nodesSharedId <- mapM (fun r nts)
                 $ map _nn_node2_id folders
  pure $ concat nodesSharedId


sharedTreeUpdate :: HasTreeError err => UpdateTree err
sharedTreeUpdate p nt n = dbTree n nt
               <&> map (\n' -> if (view dt_nodeId n') == n
                                  -- && elem (fromDBid $ _dt_typeId n') [NodeGraph]
                                  -- && not (elem (fromDBid $ _dt_typeId n') [NodeFile])
                                  then set dt_parentId (Just p) n'
                                  else n')

publicTreeUpdate :: HasTreeError err => UpdateTree err
publicTreeUpdate p nt n = dbTree n nt
               <&> map (\n' -> if _dt_nodeId n' == n
                                  -- && (fromDBid $ _dt_typeId n') /= NodeGraph
                                  -- && not (elem (fromDBid $ _dt_typeId n') [NodeFile])
                                  then set dt_parentId (Just p) n'
                                  else n')



-- | findNodesId returns all nodes matching nodeType but the root (Nodeuser)
findNodesId :: RootId -> [NodeType] -> DBCmd err [NodeId]
findNodesId r nt = tail
                <$> map _dt_nodeId
                <$> dbTree r nt

findNodesWithType :: HasCallStack => RootId -> [NodeType] -> [NodeType] -> DBCmd err [DbTreeNode]
findNodesWithType root target through =
  filter isInTarget <$> dbTree root through
    where
      isInTarget n = List.elem (fromDBid $ view dt_typeId n)
                   $ List.nub $ target <> through

treeNodeToNodeId :: DbTreeNode -> NodeId
treeNodeToNodeId = _dt_nodeId

------------------------------------------------------------------------
------------------------------------------------------------------------
toTree :: ( MonadError e m
          , HasTreeError e
          , MonadBase IO m )
       => Map (Maybe ParentId) [DbTreeNode]
       -> m (Tree NodeTree)
toTree m =
    case lookup Nothing m of
        Just [root] -> pure $ toTree' m root
        Nothing     -> treeError NoRoot
        Just []     -> treeError EmptyRoot
        Just r      -> treeError $ TooManyRoots (NE.fromList $ map treeNodeToNodeId r)

      where
        toTree' :: Map (Maybe ParentId) [DbTreeNode]
                -> DbTreeNode
                -> Tree NodeTree
        toTree' m' root =
          TreeN (toNodeTree root) $
            -- Lines below are equivalent computationally but not semantically
            -- m' ^.. at (Just $ _dt_nodeId root) . _Just . each . to (toTree' m')
            toListOf (at (Just $ _dt_nodeId root) . _Just . each . to (toTree' m')) m'

toNodeTree :: HasCallStack => DbTreeNode -> NodeTree
toNodeTree (DbTreeNode nId tId _ n) = NodeTree n (fromDBid tId) nId

------------------------------------------------------------------------
toTreeParent :: [DbTreeNode]
             -> Map (Maybe ParentId) [DbTreeNode]
toTreeParent = fromListWith (\a b -> nub $ a <> b) . map (\n -> (_dt_parentId n, [n]))
------------------------------------------------------------------------
-- toSubtreeParent' :: [DbTreeNode]
--                 -> Map (Maybe ParentId) [DbTreeNode]
-- toSubtreeParent' ns = fromListWith (\a b -> nub $ a <> b) . map (\n -> (_dt_parentId n, [n])) $ nullifiedParents
--   where
--     nodeIds = Set.fromList $ map (\n -> unNodeId $ _dt_nodeId n) ns
--     nullifiedParents = map nullifyParent ns
--     nullifyParent dt@(DbTreeNode { _dt_parentId = Nothing }) = dt
--     nullifyParent dt@(DbTreeNode { _dt_nodeId = nId
--                                  , _dt_parentId = Just pId
--                                  , _dt_typeId = tId
--                                  , _dt_name = name }) =
--       if Set.member (unNodeId pId) nodeIds then
--         dt
--       else
--         DbTreeNode { _dt_nodeId = nId
--                    , _dt_typeId = tId
--                    , _dt_parentId = Nothing
--                    , _dt_name = name }
------------------------------------------------------------------------
toSubtreeParent :: RootId
                -> [DbTreeNode]
                -> Map (Maybe ParentId) [DbTreeNode]
toSubtreeParent r ns = fromListWith (\a b -> nub $ a <> b) . map (\n -> (_dt_parentId n, [n])) $ nullifiedParents
  where
    nullifiedParents = map nullifyParent ns
    nullifyParent dt@(DbTreeNode { _dt_parentId = Nothing }) = dt
    nullifyParent dt@(DbTreeNode { _dt_nodeId = nId
                                 , _dt_parentId = _pId
                                 , _dt_typeId = tId
                                 , _dt_name = name }) =
      if r == nId then
        DbTreeNode { _dt_nodeId = nId
                   , _dt_typeId = tId
                   , _dt_parentId = Nothing
                   , _dt_name = name }
      else
        dt
------------------------------------------------------------------------
-- | Main DB Tree function
dbTree :: RootId
       -> [NodeType]
       -> DBCmd err [DbTreeNode]
dbTree rootId nodeTypes = map (\(nId, tId, pId, n) -> DbTreeNode nId tId pId n)
  <$> runPGSQuery [sql|
    WITH RECURSIVE
        tree (id, typename, parent_id, name) AS
        (
          SELECT p.id, p.typename, p.parent_id, p.name
          FROM nodes AS p
          WHERE p.id = ?

          UNION

          SELECT c.id, c.typename, c.parent_id, c.name
          FROM nodes AS c

          INNER JOIN tree AS s ON c.parent_id = s.id
           WHERE c.typename IN ?
        )
    SELECT * from tree;
    |] (rootId, In typename)
  where
    typename = map toDBid ns
    ns = case nodeTypes of
      [] -> allNodeTypes
      _  -> nodeTypes

isDescendantOf :: NodeId -> RootId -> DBCmd err Bool
isDescendantOf childId rootId = (== [Only True])
  <$> runPGSQuery [sql|
                  BEGIN ;
                  SET TRANSACTION READ ONLY;
                  COMMIT;

                  WITH RECURSIVE
      tree (id, parent_id) AS
      (
        SELECT c.id, c.parent_id
        FROM nodes AS c
        WHERE c.id = ?

        UNION

        SELECT p.id, p.parent_id
        FROM nodes AS p
        INNER JOIN tree AS t ON t.parent_id = p.id

      )
  SELECT COUNT(*) = 1 from tree AS t
  WHERE t.id = ?;
  |] (childId, rootId)

isOwnedBy :: NodeId -> UserId -> DBCmd err Bool
isOwnedBy nodeId userId = (== [Only True])
  <$> runPGSQuery [sql| SELECT COUNT(*) = 1 from nodes AS c where c.id = ? AND c.user_id = ? |] (nodeId, userId)

isSharedWith :: NodeId -> NodeId -> DBCmd err Bool
isSharedWith targetNode targetUserNode = (== [Only True])
  <$> runPGSQuery [sql|
      BEGIN;
      SET TRANSACTION READ ONLY;
      COMMIT;

      WITH RECURSIVE SharePath AS (
        SELECT nn.node1_id, nn.node2_id AS shared_node_id
        FROM nodes_nodes nn
        WHERE nn.node1_id IN (SELECT id FROM nodes WHERE parent_id = ?)
        UNION ALL
        SELECT nn.node1_id, nn.node2_id
        FROM nodes_nodes nn
        JOIN SharePath sp ON nn.node1_id = sp.shared_node_id
      ),
      UpwardPath AS (
        SELECT ? AS current_node_id, parent_id
        FROM nodes
        WHERE id = ?
        UNION ALL
        SELECT up.parent_id, n.parent_id
        FROM UpwardPath up
        JOIN nodes n ON up.parent_id = n.id
      )
      SELECT
        EXISTS (
          SELECT 1
          FROM UpwardPath up
          JOIN SharePath sp ON up.current_node_id = sp.shared_node_id
        ) AS share_exists;
  |] (targetUserNode, targetNode, targetNode)

-- TODO should we check the category?
isIn :: NodeId -> DocId -> DBCmd err Bool
isIn cId docId = ( == [Only True])
  <$> runPGSQuery [sql| SELECT COUNT(*) = 1
    FROM nodes_nodes nn
      WHERE nn.node1_id = ?
        AND nn.node2_id = ?;
  |] (cId, docId)

-- Recursive parents function to construct a breadcrumb
recursiveParents :: NodeId
                 -> [NodeType]
                 -> DBCmd err [DbTreeNode]
recursiveParents nodeId nodeTypes = map (\(nId, tId, pId, n) -> DbTreeNode nId tId pId n)
  <$> runPGSQuery [sql|
    WITH RECURSIVE recursiveParents AS
    (
      SELECT id, typename, parent_id, name, 1 as original_order
        FROM public.nodes WHERE id = ?
      UNION ALL
        SELECT n.id, n.typename, n.parent_id, n.name, rp.original_order+1
          FROM public.nodes n 
          INNER JOIN recursiveParents rp ON n.id = rp.parent_id
            WHERE n.typename IN ?
    ) SELECT id, typename, parent_id, name FROM recursiveParents ORDER BY original_order DESC;
    |] (nodeId, In typename)
  where
    typename = map toDBid ns
    ns = case nodeTypes of
      [] -> allNodeTypes
      _  -> nodeTypes
-----------------------------------------------------
