module Lib.ReplParser

import Prelude
import Lib.Parser.Impl
import Lib.Parser
import Lib.Token
import Lib.Common
import Data.List1

data ReplCommand
    = Load String
    | OutputJS String
    | Verbose (Maybe Int)
    | GetDoc String
    | BrowseCmd QName
    | HelpCmd
    | DumpTop

kw : String → Parser String
kw s = satisfy (\t => t.val.text == s) "Expected \{show s}"

replString : Parser String
replString = do
    token StartQuote
    s <- token StringKind
    token EndQuote
    pure s

replInt : Parser Int
replInt = do
    t <- token Number
    pure $ stringToInt t

replQN : Parser QName
replQN = do
  ident <- uident
  rest <- many $ token Projection
  let name = joinBy "" (ident :: rest)
  let (ns,nm) = unsnoc $ splitBy1 name '.'
  pure $ QN (joinBy "." ns) nm

data ArgType = ArgNone | ArgString | ArgIdent | ArgOptInt | ArgQName

argCon : ArgType → U
argCon ArgNone = ReplCommand
argCon ArgOptInt = Maybe Int → ReplCommand
argCon ArgIdent = String → ReplCommand
argCon ArgString = String → ReplCommand
argCon ArgQName = QName → ReplCommand

data CmdDesc : U where
    MkCmd : String → String → (arg : ArgType) → argCon arg → CmdDesc

commands : List CmdDesc
commands
    = MkCmd ":h" "Show this help" ArgNone HelpCmd
    :: MkCmd ":help" "Show this help" ArgNone HelpCmd
    :: MkCmd ":l" "load file" ArgString Load
    :: MkCmd ":load" "load file" ArgString Load
    :: MkCmd ":o" "write javascript file" ArgString OutputJS
    :: MkCmd ":out" "write javascript file" ArgString OutputJS
    :: MkCmd ":v" "change verbosity" ArgOptInt Verbose
    :: MkCmd ":d" "document function" ArgIdent GetDoc
    :: MkCmd ":doc" "document function" ArgIdent GetDoc
    :: MkCmd ":b" "browse namespace" ArgQName BrowseCmd
    :: MkCmd ":top" "dump top context as json" ArgNone DumpTop
    -- type at point
    -- solve hole
    -- search by prefix (for autocomplete - ideally include types at point, but we'd need recovery)
    --   Ideally we could auto-import too
    -- case split
    :: Nil

parseCommand : Parser ReplCommand
parseCommand = do
    key <- ident
    let (Just cmd) = lookup key commands
        | _ => fail "Unknown command"
    the (Parser ReplCommand) $ case cmd of
        MkCmd _ _ ArgNone cstr => pure cstr
        MkCmd _ _ ArgOptInt cstr => cstr <$> optional replInt
        MkCmd _ _ ArgIdent cstr => cstr <$> (ident <|> uident)
        MkCmd _ _ ArgString cstr => cstr <$> replString
        MkCmd _ _ ArgQName cstr => cstr <$> replQN
    where
        lookup : String → List CmdDesc → Maybe CmdDesc
        lookup key (cmd@(MkCmd nm _ _ _) :: rest) =
            if key == nm then Just cmd else lookup key rest
        lookup key Nil = Nothing