{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE NoImplicitPrelude #-}

-- | Status of the agent for the UI
module Omni.Agent.Log where

import Alpha
import Data.Aeson ((.:), (.:?))
import qualified Data.Aeson as Aeson
import qualified Data.ByteString.Lazy as BL
import Data.IORef (IORef, modifyIORef', newIORef, readIORef, writeIORef)
import qualified Data.Text as Text
import qualified Data.Text.Encoding as TE
import qualified Data.Text.IO as TIO
import Data.Time.Clock (NominalDiffTime, UTCTime, diffUTCTime, getCurrentTime)
import Data.Time.Format (defaultTimeLocale, parseTimeOrError)
import qualified System.Console.ANSI as ANSI
import qualified System.IO as IO
import System.IO.Unsafe (unsafePerformIO)
import Text.Printf (printf)

-- | Status of the agent for the UI
data Status = Status
  { statusWorker :: Text,
    statusTask :: Maybe Text,
    statusThread :: Maybe Text,
    statusFiles :: Int,
    statusCredits :: Double,
    statusStartTime :: UTCTime,
    statusActivity :: Text
  }
  deriving (Show, Eq)

emptyStatus :: Text -> UTCTime -> Status
emptyStatus workerName startTime =
  Status
    { statusWorker = workerName,
      statusTask = Nothing,
      statusThread = Nothing,
      statusFiles = 0,
      statusCredits = 0.0,
      statusStartTime = startTime,
      statusActivity = "Idle"
    }

-- | Global state for the status bar
{-# NOINLINE currentStatus #-}
currentStatus :: IORef Status
currentStatus = unsafePerformIO (newIORef (emptyStatus "Unknown" defaultStartTime))

defaultStartTime :: UTCTime
defaultStartTime = parseTimeOrError True defaultTimeLocale "%Y-%m-%d %H:%M:%S %Z" "2000-01-01 00:00:00 UTC"

-- | Initialize the status bar system
init :: Text -> IO ()
init workerName = do
  IO.hSetBuffering IO.stderr IO.LineBuffering
  startTime <- getCurrentTime
  writeIORef currentStatus (emptyStatus workerName startTime)
  -- Reserve 5 lines at bottom
  IO.hPutStrLn IO.stderr ""
  IO.hPutStrLn IO.stderr ""
  IO.hPutStrLn IO.stderr ""
  IO.hPutStrLn IO.stderr ""
  IO.hPutStrLn IO.stderr ""
  ANSI.hCursorUp IO.stderr 5

-- | Update the status
update :: (Status -> Status) -> IO ()
update f = do
  modifyIORef' currentStatus f
  render

-- | Set the activity message
updateActivity :: Text -> IO ()
updateActivity msg = update (\s -> s {statusActivity = msg})

-- | Log a scrolling message (appears above status bars)
log :: Text -> IO ()
log msg = do
  -- Clear status bars
  ANSI.hClearLine IO.stderr
  ANSI.hCursorDown IO.stderr 1
  ANSI.hClearLine IO.stderr
  ANSI.hCursorDown IO.stderr 1
  ANSI.hClearLine IO.stderr
  ANSI.hCursorDown IO.stderr 1
  ANSI.hClearLine IO.stderr
  ANSI.hCursorDown IO.stderr 1
  ANSI.hClearLine IO.stderr
  ANSI.hCursorUp IO.stderr 4

  -- Print message (scrolls screen)
  TIO.hPutStrLn IO.stderr msg

  -- Re-render status bars at bottom
  -- (Since we scrolled, we are now on the line above where the first status line should be)
  render

-- | Render the five status lines
render :: IO ()
render = do
  Status {..} <- readIORef currentStatus
  now <- getCurrentTime
  let taskStr = maybe "None" identity statusTask
      threadStr = maybe "None" identity statusThread
      elapsed = diffUTCTime now statusStartTime
      elapsedStr = formatElapsed elapsed

  -- Line 1: Worker | Thread
  ANSI.hSetCursorColumn IO.stderr 0
  ANSI.hClearLine IO.stderr
  TIO.hPutStr IO.stderr ("[Worker: " <> statusWorker <> "] Thread: " <> threadStr)

  -- Line 2: Task
  ANSI.hCursorDown IO.stderr 1
  ANSI.hSetCursorColumn IO.stderr 0
  ANSI.hClearLine IO.stderr
  TIO.hPutStr IO.stderr ("Task: " <> taskStr)

  -- Line 3: Files | Credits
  ANSI.hCursorDown IO.stderr 1
  ANSI.hSetCursorColumn IO.stderr 0
  ANSI.hClearLine IO.stderr
  let creditsStr = Text.pack (printf "%.2f" statusCredits)
  TIO.hPutStr IO.stderr ("Files: " <> tshow statusFiles <> " | Credits: $" <> creditsStr)

  -- Line 4: Time (elapsed duration)
  ANSI.hCursorDown IO.stderr 1
  ANSI.hSetCursorColumn IO.stderr 0
  ANSI.hClearLine IO.stderr
  TIO.hPutStr IO.stderr ("Time: " <> elapsedStr)

  -- Line 5: Activity
  ANSI.hCursorDown IO.stderr 1
  ANSI.hSetCursorColumn IO.stderr 0
  ANSI.hClearLine IO.stderr
  TIO.hPutStr IO.stderr ("> " <> statusActivity)

  -- Return cursor to line 1
  ANSI.hCursorUp IO.stderr 4
  IO.hFlush IO.stderr

-- | Log Entry from JSON
data LogEntry = LogEntry
  { leMessage :: Text,
    leThreadId :: Maybe Text,
    leCredits :: Maybe Double,
    leTotalCredits :: Maybe Double,
    leTimestamp :: Maybe Text
  }
  deriving (Show, Eq)

instance Aeson.FromJSON LogEntry where
  parseJSON =
    Aeson.withObject "LogEntry" <| \v ->
      (LogEntry </ (v .: "message"))
        <*> v
        .:? "threadId"
        <*> v
        .:? "credits"
        <*> v
        .:? "totalCredits"
        <*> v
        .:? "timestamp"

-- | Parse a log line and update status
processLogLine :: Text -> IO ()
processLogLine line = do
  let bs = BL.fromStrict <| TE.encodeUtf8 line
  case Aeson.decode bs of
    Just entry -> update (updateFromEntry entry)
    Nothing -> pure () -- Ignore invalid JSON

updateFromEntry :: LogEntry -> Status -> Status
updateFromEntry LogEntry {..} s =
  s
    { statusThread = leThreadId <|> statusThread s,
      statusCredits = maybe (statusCredits s) (/ 100.0) leTotalCredits -- Only update if totalCredits is present
    }

-- | Format elapsed time as MM:SS or HH:MM:SS
formatElapsed :: NominalDiffTime -> Text
formatElapsed elapsed =
  let totalSecs = floor elapsed :: Int
      hours = totalSecs `div` 3600
      mins = (totalSecs `mod` 3600) `div` 60
      secs = totalSecs `mod` 60
   in if hours > 0
        then Text.pack (printf "%02d:%02d:%02d" hours mins secs)
        else Text.pack (printf "%02d:%02d" mins secs)