module VsCodeExtension.SignatureHelp
  ( getSignatureHelp
  , triggerCharacters
  ) where

import Data.Array as Array
import Data.Maybe (Maybe(..))
import Data.UInt as UInt
import Markdown as Markdown
import VsCodeExtension.Evaluate as Evaluate
import VsCodeExtension.Range as Range

triggerCharacters :: Array String
triggerCharacters = [ "(", " " ]

getSignatureHelp ::
  { tree :: Evaluate.EvaluatedTree, position :: Range.Position } ->
  Maybe
    { label :: String
    , documentation :: Markdown.Markdown
    , parameters :: Array { label :: String, documentation :: String }
    , activeParameter :: UInt.UInt
    }
getSignatureHelp { tree: Evaluate.EvaluatedTree { children }, position } = case Array.findMap
    (\(Evaluate.EvaluatedTreeChild { child }) -> getData position child)
    children of
  Just name ->
    Just
      { label: name
      , documentation: Markdown.Markdown []
      , parameters: [ { label: "パラメーター名", documentation: "パラメーターの説明" } ]
      , activeParameter: UInt.fromInt 0
      }
  Nothing -> Nothing

getData :: Range.Position -> Evaluate.EvaluatedTree -> Maybe String
getData position (Evaluate.EvaluatedTree { name, nameRange, children }) =
  if Range.isPositionInsideRange nameRange position then
    Just name
  else
    Array.findMap (\(Evaluate.EvaluatedTreeChild { child }) -> getData position child) children