-- |
-- Module      : Slab.Run
-- Description : Implementation of Slab's CLI
--
-- @Slab.Run@ accepts commands defined in the "Slab.Command" module and
-- runs them.
module Slab.Run
  ( run
  , parse
  , eval
  , render
  , calc
  ) where

import Control.Monad (when)
import Control.Monad.Trans.Except (ExceptT, except, runExceptT, withExceptT)
import Data.Text (Text)
import Data.Text qualified as T
import Data.Text.IO qualified as T
import Data.Text.Lazy.IO qualified as TL
import Slab.Build qualified as Build
import Slab.Command qualified as Command
import Slab.Error qualified as Error
import Slab.Evaluate qualified as Evaluate
import Slab.Execute qualified as Execute
import Slab.Generate.Haskell qualified as Generate
import Slab.Parse qualified as Parse
import Slab.PreProcess qualified as PreProcess
import Slab.Render qualified as Render
import Slab.Report qualified as Report
import Slab.Serve qualified as Serve
import Slab.Syntax qualified as Syntax
import Slab.Watch qualified as Watch
import System.FilePath (takeExtension)
import Text.Pretty.Simple (pPrintNoColor, pShowNoColor)

--------------------------------------------------------------------------------
run :: Command.Command -> IO ()
run (Command.Build srcDir renderMode passthrough distDir) =
  Build.buildDir srcDir renderMode passthrough distDir
run (Command.Watch srcDir renderMode passthrough distDir) =
  Watch.run srcDir $ \path -> do
    when (takeExtension path == ".slab") $
      Build.buildFile srcDir renderMode passthrough distDir path
run (Command.Serve srcDir distDir) = Serve.run srcDir distDir
run (Command.ReportPages srcDir) = Report.reportPages srcDir
run (Command.ReportHeadings path) = Report.reportHeadings path
run (Command.Generate path) = Generate.renderHs path
run (Command.CommandWithPath path pmode (Command.Render Command.RenderNormal passthrough)) = do
  nodes <- executeWithMode path pmode passthrough >>= Error.unwrap
  TL.putStrLn . Render.renderHtmls $ Render.renderBlocks nodes
run (Command.CommandWithPath path pmode (Command.Render Command.RenderPretty passthrough)) = do
  nodes <- executeWithMode path pmode passthrough >>= Error.unwrap
  T.putStr . Render.prettyHtmls $ Render.renderBlocks nodes
run (Command.CommandWithPath path pmode (Command.Execute simpl passthrough)) = do
  nodes <- executeWithMode path pmode passthrough >>= Error.unwrap
  if simpl
    then TL.putStrLn $ pShowNoColor $ Evaluate.simplify nodes
    else TL.putStrLn $ pShowNoColor nodes
run (Command.CommandWithPath path pmode (Command.Evaluate simpl)) = do
  nodes <- evaluateWithMode path pmode >>= Error.unwrap
  if simpl
    then TL.putStrLn $ pShowNoColor $ Evaluate.simplify nodes
    else TL.putStrLn $ pShowNoColor nodes
run (Command.CommandWithPath path pmode Command.Parse) = do
  nodes <- parseWithMode path pmode >>= Error.unwrap
  TL.putStrLn $ pShowNoColor nodes
run (Command.CommandWithPath path pmode Command.Classes) = do
  nodes <- parseWithMode path pmode >>= Error.unwrap
  mapM_ T.putStrLn $ Syntax.extractClasses nodes
run (Command.CommandWithPath path pmode (Command.Fragments mname)) = do
  nodes <- parseWithMode path pmode >>= Error.unwrap
  let ms = Syntax.extractFragments nodes
  case mname of
    Just name -> case Syntax.findFragment name ms of
      Just m -> TL.putStrLn $ pShowNoColor m
      Nothing -> putStrLn "No such fragment."
    Nothing -> TL.putStrLn $ pShowNoColor ms

--------------------------------------------------------------------------------
parseWithMode
  :: FilePath
  -> Command.ParseMode
  -> IO (Either Error.Error [Syntax.Block])
parseWithMode path pmode = runExceptT $ parseWithModeE path pmode

evaluateWithMode
  :: FilePath
  -> Command.ParseMode
  -> IO (Either Error.Error [Syntax.Block])
evaluateWithMode path pmode = runExceptT $ evaluateWithModeE path pmode

executeWithMode
  :: FilePath
  -> Command.ParseMode
  -> Command.RunMode
  -> IO (Either Error.Error [Syntax.Block])
executeWithMode path pmode passthrough = runExceptT $ executeWithModeE path pmode passthrough

--------------------------------------------------------------------------------
parseWithModeE
  :: FilePath
  -> Command.ParseMode
  -> ExceptT Error.Error IO [Syntax.Block]
parseWithModeE path pmode =
  case pmode of
    Command.ParseShallow -> Parse.parseFileE path
    Command.ParseDeep -> PreProcess.preprocessFileE path

evaluateWithModeE
  :: FilePath
  -> Command.ParseMode
  -> ExceptT Error.Error IO [Syntax.Block]
evaluateWithModeE path pmode = do
  parsed <- parseWithModeE path pmode
  Evaluate.evaluate Evaluate.defaultEnv [T.pack path] parsed

executeWithModeE
  :: FilePath
  -> Command.ParseMode
  -> Command.RunMode
  -> ExceptT Error.Error IO [Syntax.Block]
executeWithModeE path pmode passthrough =
  evaluateWithModeE path pmode >>= Execute.execute (Execute.Context path passthrough)

--------------------------------------------------------------------------------
-- Play with the whole language.

parse :: Text -> IO ()
parse s = do
  blocks <- runExceptT $ withExceptT Error.ParseError . except $ Parse.parse "-" s
  pPrintNoColor blocks

-- | "eval" parses a string as a "Syntax.Syntax", and evaluates it. This doesn't
-- run the proprocessing stage.
--
-- @
--     Run.eval "p= 1 + 2 * 3"
-- @
eval :: Text -> IO ()
eval s = do
  x <- runExceptT $ parseAndEvaluateBlocks s
  pPrintNoColor x

-- | Run "eval" and render the result.
render :: Text -> IO ()
render s = do
  x <- runExceptT (parseAndEvaluateBlocks s) >>= Error.unwrap
  T.putStr . Render.prettyHtmls $ Render.renderBlocks x

parseAndEvaluateBlocks :: Text -> ExceptT Error.Error IO [Syntax.Block]
parseAndEvaluateBlocks s = do
  blocks <- withExceptT Error.ParseError . except $ Parse.parse "-" s
  Evaluate.evaluate Evaluate.defaultEnv [] blocks

--------------------------------------------------------------------------------
-- Play with the expression language.

-- | "calc" parses a string as a "Syntax.Expr", and evaluates it. I.e. it
-- doens't use the fragment syntax, or imports and includes.
--
-- @
--     Run.calc "1 + 2 * 3"
-- @
calc :: Text -> IO ()
calc s = do
  x <- runExceptT $ parseAndEvaluateExpr s
  pPrintNoColor x

parseAndEvaluateExpr :: Text -> ExceptT Error.Error IO Syntax.Expr
parseAndEvaluateExpr s = do
  expr <- withExceptT Error.ParseError . except $ Parse.parseExpr s
  Evaluate.evalExpr Evaluate.defaultEnv expr