{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}

{- |
Module      :  Neovim.Debug
Description :  Utilities to debug Neovim and nvim-hs functionality
Copyright   :  (c) Sebastian Witte
License     :  Apache-2.0

Maintainer  :  woozletoff@gmail.com
Stability   :  experimental
Portability :  GHC
-}
module Neovim.Debug (
    debug,
    debug',
    NvimHSDebugInstance (..),
    develMain,
    quitDevelMain,
    restartDevelMain,
    printGlobalFunctionMap,
    runNeovim,
    runNeovim',
    module Neovim,
) where

import Neovim
import Neovim.Classes
import Neovim.Context (runNeovim)
import qualified Neovim.Context.Internal as Internal
import Neovim.Log (disableLogger)
import Neovim.Main (
    CommandLineOptions (..),
    runPluginProvider,
 )
import Neovim.RPC.Common (RPCConfig)

import Control.Monad
import qualified Data.Map as Map
import Foreign.Store

import UnliftIO.Async (
    Async,
    async,
    cancel,
 )
import UnliftIO.Concurrent (putMVar, takeMVar)
import UnliftIO.STM

import Prettyprinter (
    nest,
    softline,
    vcat,
    vsep,
 )

import Prelude

{- | Run a 'Neovim' function.

 This function connects to the socket pointed to by the environment variable
 @$NVIM@ and executes the command. It does not register itself
 as a real plugin provider, you can simply call neovim-functions from the
 module "Neovim.API.String" this way.

 Tip: If you run a terminal inside a neovim instance, then this variable is
 automatically set.
-}
debug :: env -> Internal.Neovim env a -> IO (Either (Doc AnsiStyle) a)
debug env a = disableLogger $ do
    runPluginProvider def{envVar = True} Nothing transitionHandler
  where
    transitionHandler tids cfg =
        takeMVar (Internal.transitionTo cfg) >>= \case
            Internal.Failure e ->
                return $ Left e
            Internal.InitSuccess -> do
                res <-
                    Internal.runNeovimInternal
                        return
                        (cfg{Internal.customConfig = env, Internal.pluginSettings = Nothing})
                        a

                mapM_ cancel tids
                return res
            _ ->
                return . Left $ "Unexpected transition state."

{- | Run a 'Neovim'' function.

 @
 debug' = debug ()
 @

 See documentation for 'debug'.
-}
debug' :: Internal.Neovim () a -> IO (Either (Doc AnsiStyle) a)
debug' = debug ()

{- | Simple datatype storing neccessary information to start, stop and reload a
 set of plugins. This is passed to most of the functions in this module for
 storing state even when the ghci-session has been reloaded.
-}
data NvimHSDebugInstance = NvimHSDebugInstance
    { threads :: [Async ()]
    , neovimConfig :: NeovimConfig
    , internalConfig :: Internal.Config RPCConfig
    }

{- | This function is intended to be run _once_ in a ghci session that to
 give a REPL based workflow when developing a plugin.

 Note that the dyre-based reload mechanisms, i.e. the
 "Neovim.Plugin.ConfigHelper" plugin, is not started this way.

 To use this in ghci, you simply bind the results to some variables. After
 each reload of ghci, you have to rebind those variables.

 Example:

 @
 λ di <- 'develMain' 'Nothing'

 λ 'runNeovim'' di \$ vim_call_function \"getqflist\" []
 'Right' ('Right' ('ObjectArray' []))

 λ :r

 λ di <- 'develMain' 'Nothing'
 @

 You can also create a GHCI alias to get rid of most the busy-work:
 @
 :def! x \\_ -> return \":reload\\nJust di <- develMain 'defaultConfig'{ 'plugins' = [ myDebugPlugin ] }\"
 @
-}
develMain ::
    NeovimConfig ->
    IO (Maybe NvimHSDebugInstance)
develMain neovimConfig =
    lookupStore 0 >>= \case
        Nothing -> do
            x <-
                disableLogger $
                    runPluginProvider
                        def{envVar = True}
                        (Just neovimConfig)
                        transitionHandler
            void $ newStore x
            return x
        Just x ->
            readStore x
  where
    transitionHandler tids cfg =
        takeMVar (Internal.transitionTo cfg) >>= \case
            Internal.Failure e -> do
                putDoc e
                return Nothing
            Internal.InitSuccess -> do
                transitionHandlerThread <- async $ do
                    void $ transitionHandler tids cfg
                return . Just $
                    NvimHSDebugInstance
                        { threads = transitionHandlerThread : tids
                        , neovimConfig = neovimConfig
                        , internalConfig = cfg
                        }
            Internal.Quit -> do
                lookupStore 0 >>= \case
                    Nothing ->
                        return ()
                    Just x ->
                        deleteStore x

                mapM_ cancel tids
                putStrLn "Quit develMain"
                return Nothing
            _ -> do
                putStrLn "Unexpected transition state for develMain."
                return Nothing

-- | Quit a previously started plugin provider.
quitDevelMain :: NvimHSDebugInstance -> IO ()
quitDevelMain NvimHSDebugInstance{internalConfig} =
    putMVar (Internal.transitionTo internalConfig) Internal.Quit

-- | Restart the development plugin provider.
restartDevelMain ::
    NvimHSDebugInstance ->
    IO (Maybe NvimHSDebugInstance)
restartDevelMain di = do
    quitDevelMain di
    develMain (neovimConfig di)

-- | Convenience function to run a stateless 'Neovim' function.
runNeovim' ::
    NFData a =>
    NvimHSDebugInstance ->
    Neovim () a ->
    IO (Either (Doc AnsiStyle) a)
runNeovim' NvimHSDebugInstance{internalConfig} =
    runNeovim (Internal.retypeConfig () internalConfig)

-- | Print the global function map to the console.
printGlobalFunctionMap :: NvimHSDebugInstance -> IO ()
printGlobalFunctionMap NvimHSDebugInstance{internalConfig} = do
    es <-
        fmap Map.toList . atomically $
            readTMVar (Internal.globalFunctionMap internalConfig)
    let header = "Printing global function map:"
        funs =
            map
                ( \(fname, (d, f)) ->
                    nest
                        3
                        ( pretty fname
                            <> softline
                            <> "->"
                            <> softline
                            <> pretty d
                            <+> ":"
                            <+> pretty f
                        )
                )
                es
    putDoc $
        nest 2 $
            vsep [header, vcat funs, mempty]