#!/usr/bin/env stack
{- stack script --resolver lts-19.23 --install-ghc -}
{-# OPTIONS_GHC
  -Wall
  -Wno-unused-imports
  -Wno-unused-top-binds
  -Wno-name-shadowing
#-}
{-# language NoImplicitPrelude #-}
{-# language RecordWildCards #-}
{-# language FlexibleContexts #-}
{-# language TemplateHaskell #-}
{-# language ViewPatterns #-}
{-# language OverloadedStrings #-}
import Rebase.Prelude hiding (toList, on, (<+>), Max)
import qualified Rebase.Prelude as Prelude
import Control.Lens hiding ((<|))
import Data.Foldable (toList)
import Data.Ratio
import Text.Printf
import Graphics.Vty
import Data.Time.LocalTime
import Control.Monad.RWS
import Data.Time.Calendar.OrdinalDate
import qualified Data.Text as Text
import Data.Text.Format.Numbers
import Rebase.Data.Map.Strict (Map)
import qualified Rebase.Data.Map.Strict as Map

import Brick
import Brick.Types
import Data.Text (unpack)
import Control.Lens
import Control.Monad (void, forever)
import Control.Concurrent (threadDelay, forkIO)
import qualified Graphics.Vty as V
import Brick.Widgets.ProgressBar as P
import Brick.BChan
import Brick.Widgets.Center
import Brick.Widgets.Border
import Brick.Main
  ( App(..)
  , showFirstCursor
  , customMain
  , continue
  , halt
  )
import Brick.AttrMap
  ( attrMap
  )
import Brick.Types
  ( Widget
  , Next
  , EventM
  , BrickEvent(..)
  )
import Brick.Widgets.Core
  ( (<=>)
  , str
  )
import Brick.AttrMap as A
import Brick.Util (fg, bg, on, clamp)
import Brick.Widgets.Core
import Brick.Widgets.Table

data Performance = Achieved {
  achievedReps :: Integer,
  achievedWeight :: Rational
}

data LiftRecord = LiftRecord {
  liftName :: Text,
  stats :: [Performance]
}

initial :: [LiftRecord]
initial =
  [
    LiftRecord "Squat"    [Achieved 6 270, Achieved 8 255, Achieved 5 285, Achieved 10 255, Achieved 7 280],
    LiftRecord "Bench"    [Achieved 7 190, Achieved 9 180, Achieved 4 205, Achieved 11 180, Achieved 8 200],
    LiftRecord "Deadlift" [Achieved 5 360, Achieved 9 315, Achieved 8 345, Achieved 7 360, Achieved 10 340],
    -- LiftRecord "Press"    [Achieved 6 130, Achieved 9 120, Achieved 4 135]
    LiftRecord "Press"    [Achieved 5 120]
  ]

computeRepGoal :: Rational -> [Performance] -> (Integer)
computeRepGoal targetWeight stats = head $ filter isPR [2..]
  where
    isPR n = computeOneRepMax (Achieved n targetWeight) > computeOneRepMax (bestPerformance stats)

bestPerformance :: [Performance] -> Performance
bestPerformance = head . sortBy (flip $ comparing computeOneRepMax)

-- The formula from Jim Wendler's 5-3-1:
-- 1RM = Weight x Reps x 0.0333 + Weight.
computeOneRepMax :: Performance -> Rational
computeOneRepMax Achieved{..} = achievedWeight * (realToFrac achievedReps * 0.0333 + 1)

showRational :: Rational -> String
showRational n = printf format $ (realToFrac :: Rational -> Float) $ n
  where
    format = if floor (n * 10) `mod` 10 == (0 :: Integer) then "%.0f" else "%.2f"

drawUI :: St -> [Widget ()]
drawUI (St lifts) = [vCenter $ vBox [hCenter oneRepMaxTable, hCenter lastSetTable]]
  where
    lastSetTable = renderTable $ table $ map (padLeftRight 1 . str) ["Lift", "Week", "Last Set", "Goal", "Goal+1"] : concatMap toWeekRows lifts
    oneRepMaxTable = renderTable $ table $ map (padLeftRight 1 . str) ["Lift", "Achieved Best", "Computed 1RM"] : map toRow lifts
    toRow LiftRecord{..} =
      let best@Achieved{..} = bestPerformance stats
      in
      map (padLeftRight 2)
      [
        txt $ liftName,
        str $ printf "%d @ %s" achievedReps (showRational achievedWeight),
        str $ showRational $ computeOneRepMax best
      ]
    toWeekRows lift = (flip map) [1,2,3::Int] $ \week -> toWeekRow week lift
    toWeekRow :: Int -> LiftRecord -> [Widget n]
    toWeekRow week LiftRecord{..} =
      let best              = bestPerformance stats
          targetReps        = case week of 1 -> 5; 2 -> 3; 3 -> 1; _ -> undefined :: Int
          targetPercentage  = case week of 1 -> 85; 2 -> 90; 3 -> 95; _ -> undefined
          computedTarget    = (* (targetPercentage % 100)) $ (* (90 % 100)) $ computeOneRepMax best
          targetWeight      = ceilingN 5 computedTarget
          repGoal           = computeRepGoal (targetWeight % 1) stats
          goalTo1RM g       = computeOneRepMax $ Achieved g (targetWeight % 1)
          showGoal g        = printf "%2d @ %d ≈ 1 @ %s" g targetWeight (showRational (goalTo1RM g))
      in
      map (padLeftRight 2)
      [
        txt $ (if week == 1 then liftName else " "),
        str $ show week,
        str $ printf "%2d+ @ %d" targetReps targetWeight,
        str $ showGoal repGoal,
        str $ showGoal (repGoal + 1)
      ]

ceilingN :: Integer -> Rational -> Integer
ceilingN n x = ceiling (x / toRational n) * n

-- TODO: State contains chosen repmax formula
-- TODO: State contains performances
data St = St {
  lifts :: [LiftRecord]
}

-- TODO: Event for inotify on edited text file (as input interface)
data CustomEvent = CustomEvent

handleEvent :: St -> BrickEvent () CustomEvent -> EventM () (Next St)
handleEvent st e = case e of
  VtyEvent (V.EvKey V.KEsc [])         -> halt st
  VtyEvent _                           -> continue st
  AppEvent _                           -> continue st
  _ -> continue st

theApp :: App St CustomEvent ()
theApp =
    App { appDraw = drawUI
        , appChooseCursor = showFirstCursor
        , appHandleEvent = handleEvent
        , appStartEvent = return
        , appAttrMap = const $ A.attrMap V.defAttr []
        }

main :: IO ()
main = do
    let buildVty = V.mkVty V.defaultConfig
    initialVty <- buildVty
    chan <- newBChan 10
    void $ customMain initialVty buildVty (Just chan) (theApp) (St initial)