-- For shared code between REPL and LSP
module Commands

import Prelude
import Lib.ProcessModule
import Lib.Types
import Lib.TopContext
import Lib.Common
import Data.List1
import Lib.Tokenizer
import Lib.Token
import Lib.Elab
import Data.String
import Lib.Eval
import Data.SortedMap

-- For now we cheat and assume capitalized directories are a module component
decomposeName : String → String × String
decomposeName fn =
    go Nil $ Lin <>< split (fst $ splitFileName fn) "/"
    where
        go : List String → SnocList String → String × String
        go acc Lin = (".", joinBy "." acc)
        go acc (xs :< x) = if isUpper $ strIndex x 0
            then go (x :: acc) xs
            else (joinBy "/" (xs :< x <>> Nil), joinBy "." acc)

-- The cheap version of type at point, find the token, lookup in global context
-- Later we will either get good FC for entries or scan them all and build a cache.
getHoverInfo : FileSource → String → Int → Int → M (Maybe (String × FC))
getHoverInfo repo modns row col = do
    -- REVIEW consider not running processModule and returning empty if it hasn't been processed yet
    -- For Elab.newt, there would be a 1.5s delay...
    mod <- processModule emptyFC repo Nil modns

    -- not necessarily loaded into top... (Maybe push this down into that branch of processModule)
    -- FIXME - fragile - this is why we don't want this stuff directly in TopContext
    modifyTop [ defs := mod.modDefs; metaCtx := mod.modMetaCtx; ops := mod.ctxOps; imported := mod.modDeps; infos := mod.modInfos]
    top <- getTop

    -- Find the token at the point
    let lines = split mod.modSource "\n"
    let line = fromMaybe "" (getAt' row lines)
    let (Right toks) = tokenise "" line | Left _ => pure Nothing
    let (Just name) = getTok toks       | _ => pure Nothing

    -- Lookup the name
    let (Just e) = lookupRaw name top   | _ => pure Nothing
    pure $ Just ("\{show e.name} : \{rpprint Nil e.type}", e.fc)

    where
        getTok : List BTok → Maybe String
        getTok Nil = Nothing
        getTok (tok :: toks) =
            if tok.bounds.startCol <= col && (col <= tok.bounds.endCol)
            then Just $ value tok else getTok toks

data FileEdit = MkEdit FC String
data CodeAction
  = CaseSplitAction (List FileEdit)
  | AddMissingAction (List FileEdit)


applyDCon : QName × Int × Tm → List String
applyDCon (QN _ nm, _, tm) = go (Lin :< nm) tm
  where
    go : SnocList String → Tm → List String
    go acc (Pi _ nm Explicit _ _ u) = go (acc :< nm) u
    go acc (Pi _ _ _ _ _ u) = go acc u
    go acc _ = acc <>> Nil

-- Not quite right, we also need to check for let...
-- But it's a first pass
splitEquals : SnocList Char → List Char → (Bool × String × String)
splitEquals acc Nil = (True, pack (acc <>> Nil), "")
splitEquals acc xs@('=' :: _) = (True, pack (acc <>> Nil), pack xs)
splitEquals acc xs@('<' :: '-' :: _) = (False, pack (acc <>> Nil), pack xs)
splitEquals acc (x :: xs) = splitEquals (acc :< x) xs

needParens : SnocList Char → List Char → Bool
needParens (xs :< ' ') ys = needParens xs ys
needParens xs (' ' :: ys) = needParens xs ys
needParens (xs :< '(') (')' :: ys) = False
needParens _ _ = True

addParens : Bool → List String → String
addParens _ (x :: Nil) = x
addParens False s = unwords s
addParens True s = "(\{unwords s})"

-- REVIEW - maybe pass in QName and use applyDCon in here, especially if we want to get better names?
makeEdits : FC → List QName → Bool → M (List FileEdit)
makeEdits fc@(MkFC uri (MkBounds sr sc er ec)) names inPlace = do
  cons <- map applyDCon <$> traverse lookupDCon names
  top <- getTop
  let (Just mod) = lookupMap' top.ns top.modules | _ => pure Nil
  let lines = split mod.modSource "\n"
  let (Just line) = getAt' sr lines | _ => pure Nil
  let cs = unpack line
  let head = take (cast sc) cs
  let tail = drop (S $ cast (ec - 1)) cs
  let (isEq, before, after) = splitEquals Lin tail
  let np = needParens (Lin <>< head) tail
  let cons = map (addParens np) cons
  let phead = pack head

  -- No init or first :: rest for add missing case
  let (edits, rest) = doFirst inPlace cons

  let phead = pack head
  let fc' = MkFC uri (MkBounds (sr + 1) 0 (sr + 1) 0)
  let srest =
    if isEq
      then joinBy "" $ map (\ap => phead ++ ap ++ before ++ "= ?\n") rest
      else joinBy "" $ map (\ap => "  | \{pack head}\{ap}\{before}=> ?\n") rest

  putStrLn "Split \{show line} HD '\{show head}' TL '\{show tail}'"
  putStrLn srest
  let edits = MkEdit fc' (srest) :: edits
  putStrLn "edits \{debugStr edits}"
  pure edits
  where
    doFirst : Bool → List String → (List FileEdit × List String)
    doFirst True (first :: rest) = (MkEdit fc first :: Nil, rest)
    doFirst _ cons = (Nil, cons)

addMissingCases : Int → Int → FC → Context → List QName → M (Maybe CodeAction)
addMissingCases _ _ fc@(MkFC uri (MkBounds sr sc er ec)) ctx names = do
  top <- getTop
  edits <- makeEdits fc names False
  putStrLn "Add Missing \{show fc} \{show names}"
  pure $ Just $ AddMissingAction edits

getCaseSplit : Int → Int → FC → Context → String → Val → M (Maybe CodeAction)
getCaseSplit row col fc@(MkFC uri (MkBounds sr sc er ec)) ctx nm scty = do
  top <- getTop
  -- It's getting vars for the type
  scty <- unlet ctx.env scty
  cons <- getConstructors ctx fc scty
  ty <- quote (length' ctx.env) scty
  cons <- filterM (checkCase ctx nm scty) cons
  let names = map fst cons
  edits <- makeEdits fc names True
  pure $ Just $ CaseSplitAction edits

posInFC : Int → Int → FC → Bool
-- FIXME ec + 1 again...
posInFC row col (MkFC _ (MkBounds sr sc er ec)) = (sr <= row && row <= er) && (sc <= col && col <= ec + 1)

getActions : FileSource → String → Int → Int → M (List CodeAction)
getActions repo modns row col = do
  mod <- processModule emptyFC repo Nil modns
  -- not necessarily loaded into top... (Maybe push this down into that branch of processModule)
  modifyTop [ defs := mod.modDefs; metaCtx := mod.modMetaCtx; ops := mod.ctxOps; imported := mod.modDeps; infos := mod.modInfos]
  top <- getTop
  let xx = filter (posInFC row col ∘ getFC) top.infos
  putStrLn "Filter got \{show $ length' xx}"
  go Nil $ xx
  where
    getAction : EditorInfo → M (Maybe CodeAction)
    getAction (CaseSplit fc ctx nm scty) = getCaseSplit row col fc ctx nm scty
    getAction (MissingCases fc ctx names) = addMissingCases row col fc ctx names

    go : List CodeAction → List EditorInfo → M (List CodeAction)
    go acc Nil = pure acc
    go acc (x :: xs) = do
      Right (Just res) <- tryError $ getAction x
        | _ => go acc xs
      go (res :: acc) xs