module Chelleport where

import Chelleport.AppShell (MonadAppShell (hideWindow, showWindow, shutdownApp), setupAppShell)
import Chelleport.Context (initializeContext)
import Chelleport.Control
  ( MonadControl (clickMouseButton, getMousePointerPosition, moveMousePointer, pressMouseButton, releaseMouseButton),
    directionalIncrement,
    eventToKeycode,
    isKeyPressWith,
    isKeyPressed,
    isKeyReleaseWith,
    withCtrl,
    withShift,
  )
import Chelleport.Draw (MonadDraw (windowPosition), cellSize)
import Chelleport.KeySequence (findMatchPosition, generateGrid, isKeycodeDigit, isValidKey, keycodeToInt, nextChars, toKeyChar)
import Chelleport.OCR (MonadOCR, getWordsOnScreen)
import Chelleport.Types
import Chelleport.Utils (cIntToInt, clamp, intToCInt, isEmpty, isNotEmpty, itemAt)
import qualified Chelleport.View
import Control.Monad (forM_)
import Control.Monad.IO.Class (MonadIO)
import Control.Monad.Reader (ReaderT (runReaderT))
import Data.Char (toLower)
import Data.List (isInfixOf)
import Data.Maybe (fromMaybe, isJust)
import qualified SDL

run :: IO ()
run = do
  ctx <- initializeContext
  runAppWithCtx ctx $
    setupAppShell
      ctx
      initialState
      update
      eventHandler
      Chelleport.View.render
  where
    runAppWithCtx :: (MonadIO m) => DrawContext -> AppM m x -> m x
    runAppWithCtx ctx = (`runReaderT` ctx) . runAppM

initialState :: (Monad m) => m (State, Maybe AppAction)
initialState = do
  let cells = fromMaybe (pure undefined) $ generateGrid 0 (rows, columns) hintKeys
  pure (defaultAppState {stateGrid = cells}, Just $ SetMode defaultHintsMode)
  where
    rows = 9
    columns = 16
    hintKeys = ['A' .. 'Z']

eventHandler :: State -> SDL.Event -> Maybe AppAction
eventHandler state event =
  case SDL.eventPayload event of
    SDL.QuitEvent -> Just ShutdownApp
    SDL.KeyboardEvent ev
      -- Escape
      | isKeyPressWith ev SDL.KeycodeEscape ->
          Just ShutdownApp
      -- minus / underscore
      | isKeyPressWith ev SDL.KeycodeMinus || isKeyPressWith ev SDL.KeycodeUnderscore ->
          if withShift ev
            then Just $ ChainMouseClick RightClick
            else Just $ TriggerMouseClick RightClick
      -- 0-9
      | isKeycodeDigit (eventToKeycode ev) ->
          Just $ UpdateRepetition (fromMaybe 0 $ keycodeToInt $ eventToKeycode ev)
      -- Enable search mode
      | withCtrl ev && isKeyPressWith ev SDL.KeycodeS ->
          Just $ SetMode defaultSearchMode
      -- Enable hints mode
      | withCtrl ev && isKeyPressWith ev SDL.KeycodeH ->
          Just $ SetMode defaultHintsMode
      -- Search increment next/prev
      | withCtrl ev && isKeyPressWith ev SDL.KeycodeN -> Just $ IncrementHighlightIndex (stateRepetition state)
      | withCtrl ev && isKeyPressWith ev SDL.KeycodeP -> Just $ IncrementHighlightIndex (-1 * stateRepetition state)
      -- Space / Shift+Space
      | isKeyPressWith ev SDL.KeycodeSpace ->
          if withShift ev
            then Just $ ChainMouseClick LeftClick
            else Just $ TriggerMouseClick LeftClick
      -- Tab / Backspace
      | isKeyPressWith ev SDL.KeycodeTab || isKeyPressWith ev SDL.KeycodeBackspace ->
          Just ResetKeys
      -- Ctrl + V
      | withCtrl ev && isKeyPressWith ev SDL.KeycodeV ->
          Just MouseDragToggle
      -- A-Z
      | isKeyPressed ev && isValidKey (eventToKeycode ev) ->
          Just $ HandleKeyInput $ eventToKeycode ev
      -- Shift press
      | isKeyPressWith ev SDL.KeycodeLShift || isKeyPressWith ev SDL.KeycodeRShift ->
          Just $ UpdateShiftState True
      -- Shift release
      | isKeyReleaseWith ev SDL.KeycodeLShift || isKeyReleaseWith ev SDL.KeycodeRShift ->
          Just $ UpdateShiftState False
    _ -> Nothing

wordPosition :: (MonadDraw m) => OCRMatch -> m (Int, Int)
wordPosition (OCRMatch {matchStartX, matchStartY}) = do
  (x, y) <- windowPosition
  pure (cIntToInt $ x + matchStartX, cIntToInt $ y + matchStartY)

update :: (MonadAppShell m, MonadDraw m, MonadControl m, MonadOCR m) => State -> AppAction -> m (State, Maybe AppAction)
-- Set mode
update state (SetMode mode) = do
  case mode of
    ModeHints -> pure (state {stateMode = mode}, Nothing)
    ModeSearch {} -> do
      wordsOnScreen <- getWordsOnScreen
      let updatedMode = mode {searchWords = wordsOnScreen, searchFilteredWords = wordsOnScreen}
      pure (state {stateMode = updatedMode}, Nothing)

-- HINTS MODE: Act on key inputs
update state@(State {stateMode = ModeHints}) (HandleKeyInput key) = do
  case (toKeyChar key, validChars) of
    (Just keyChar, Just validChars')
      | stateIsMatched state && keyChar `elem` ("HJKL" :: String) -> do
          incr <- incrementValue
          let action = IncrementMouseCursor $ directionalIncrement incr keyChar
          pure (state, Just action)
      | keyChar `elem` validChars' -> do
          let newKeySequence = stateKeySequence state ++ [keyChar]
          let matchPosition = findMatchPosition newKeySequence $ stateGrid state
          let state' = state {stateKeySequence = newKeySequence, stateIsMatched = isJust matchPosition}
          action <- maybe (pure Nothing) (fmap (Just . MoveMousePosition) . getPosition) matchPosition
          pure (state', action)
    _ -> pure (state, Nothing)
  where
    validChars = nextChars (stateKeySequence state) (stateGrid state)
    getPosition (row, col) = do
      (wcell, hcell) <- cellSize state
      let x = (wcell `div` 2) + wcell * intToCInt col
      let y = (hcell `div` 2) + hcell * intToCInt row
      (winx, winy) <- windowPosition
      pure (cIntToInt $ winx + x, cIntToInt $ winy + y)
    incrementValue = do
      (wcell, hcell) <- cellSize state
      if stateIsShiftPressed state
        then pure (wcell `div` 4, hcell `div` 4)
        else pure (wcell `div` 16, hcell `div` 16)

-- SEARCH MODE: Act on key inputs
update state@(State {stateMode = ModeSearch {searchWords, searchInputText}}) (HandleKeyInput key) = do
  case toKeyChar key of
    Just keyChar -> do
      let searchText = searchInputText ++ [toLower keyChar]
      let matches = filterMatches searchText
      let mode = stateMode state
      let highlightedIndex = clamp (0, length matches - 1) (searchHighlightedIndex mode)
      let updatedMode =
            mode
              { searchInputText = searchText,
                searchFilteredWords = matches,
                searchHighlightedIndex = highlightedIndex
              }
      let highlightedWord = matches `itemAt` highlightedIndex
      action <- maybe (pure Nothing) (fmap (Just . MoveMousePosition) . wordPosition) highlightedWord
      pure (state {stateMode = updatedMode}, action)
    _ -> do
      pure (state, Nothing)
  where
    filterMatches text
      | isEmpty text = searchWords
      | otherwise = filter (isInfixOf text . map toLower . matchText) searchWords

-- Increment highlighted index for search mode
update state (IncrementHighlightIndex n) = do
  case stateMode state of
    ModeSearch {} -> do
      let mode = stateMode state
      let index = searchHighlightedIndex mode + n
      let highlightedIndex =
            if index < 0
              then length (searchFilteredWords mode) - 1
              else index `mod` length (searchFilteredWords mode)
      let highlightedWord = searchFilteredWords mode `itemAt` highlightedIndex
      action <- maybe (pure Nothing) (fmap (Just . MoveMousePosition) . wordPosition) highlightedWord
      pure (state {stateRepetition = 1, stateMode = mode {searchHighlightedIndex = highlightedIndex}}, action)
    _ -> pure (state, Nothing)

-- Move mouse incrementally
update state (IncrementMouseCursor (incX, incY)) = do
  (curX, curY) <- getMousePointerPosition
  let count = case stateRepetition state of 0 -> 1; n -> n
  let pos = (cIntToInt curX + count * incX, cIntToInt curY + count * incY)
  pure (state {stateRepetition = 1}, Just $ MoveMousePosition pos)

-- Move mouse to given position
update state (MoveMousePosition (x, y)) = do
  moveMousePointer (intToCInt x) (intToCInt y)
  pure (state, Nothing)

-- Reset entered key sequence and state
update state ResetKeys = do
  pure (state {stateKeySequence = [], stateIsMatched = False, stateRepetition = 1}, Nothing)

-- Trigger click
update state (TriggerMouseClick btn) = do
  hideWindow
  let count = case stateRepetition state of 0 -> 1; n -> n
  forM_ [1 .. count] $ \_ -> do
    clickMouseButton btn
  pure (state {stateRepetition = 1}, Just ShutdownApp)

-- Chain clicks
update state (ChainMouseClick btn) = do
  hideWindow
  let count = case stateRepetition state of 0 -> 1; n -> n
  forM_ [1 .. count] $ \_ -> do
    clickMouseButton btn
  showWindow
  pure (state {stateRepetition = 1}, Just ResetKeys)

-- Cleanup everything and exit
update state ShutdownApp = do
  shutdownApp
  pure (state, Nothing)

-- Mouse dragging
update state MouseDragToggle
  | stateIsDragging state = pure (state {stateIsDragging = False}, Just MouseDragEnd)
  | otherwise = do pure (state {stateIsDragging = True}, Just MouseDragStart)

-- Mouse button press
update state MouseDragStart = do
  hideWindow
  pressMouseButton
  showWindow
  pure (state {stateRepetition = 1}, Nothing)

-- Mouse button release
update state MouseDragEnd = do
  hideWindow
  releaseMouseButton
  showWindow
  pure (state {stateRepetition = 1}, Nothing)

-- Set repetition count
update state (UpdateRepetition count) = do
  pure (state {stateRepetition = count}, Nothing)

-- Set/unset whether shift is pressed
update state (UpdateShiftState shift) =
  pure (state {stateIsShiftPressed = shift}, Nothing)