module Model.Level exposing
  ( levelScoreDuration
  , currentLevel
  , currentLevelScore
  , currentLevelNumber
  , progressiveColor
  )

import Time exposing (Time)
import Color as Color exposing (Color)
import List.Nonempty as NE exposing (Nonempty(..), (:::))

import Model.Vec2 as Vec2 exposing (Vec2)

import Utils.Physics as Physics
import Utils.Color as Color

levelScoreDuration : Int
levelScoreDuration = 20

type alias Move = Vec2 -> Vec2 -> Time -> Vec2

type alias Level =
  { moves : Nonempty Move
  }

currentLevelScore : Int -> Int
currentLevelScore currentScore =
  currentScore - (currentLevelNumber currentScore - 1) * levelScoreDuration

currentLevelNumber : Int -> Int
currentLevelNumber currentScore = currentScore // levelScoreDuration + 1

currentLevel : Int -> Level
currentLevel currentScore = NE.get (currentScore // levelScoreDuration) levels

nextLevel : Int -> Level
nextLevel currentScore = currentLevel (currentScore + levelScoreDuration)

progressiveColor : Int -> Color
progressiveColor currentScore =
  let reminder = currentScore `rem` levelScoreDuration
      ratio = progressiveRatio reminder levelScoreDuration
      currentColor = color currentScore
      nextColor = color (currentScore + levelScoreDuration)
  in  Color.merge ratio nextColor currentColor

progressiveRatio : Int -> Int -> Float
progressiveRatio a b = (toFloat a ^ 7) / (toFloat b ^ 7)

initialColor : Color
initialColor = Color.rgb 156 168 233

color : Int -> Color
color score = Color.spin (toFloat <| 20 * (score // levelScoreDuration)) initialColor

levels : Nonempty Level
levels =
  let ma1 = \initPos initDest delta -> Physics.getMove (delta / 20) (initDest `Vec2.sub` initPos)
      ma2 = \initPos initDest delta -> Physics.getWaveMove (delta / 20) (initDest `Vec2.sub` initPos) 10 10
      ma3 = \initPos initDest delta -> Physics.getSawToothMove (delta / 25) (initDest `Vec2.sub` initPos) 30 10
      mb1 = \initPos initDest delta -> Physics.getMove (delta / 18) (initDest `Vec2.sub` initPos)
      mb2 = \initPos initDest delta -> Physics.getWaveMove (delta / 18) (initDest `Vec2.sub` initPos) 20 20
      mb3 = \initPos initDest delta -> Physics.getSawToothMove (delta / 20) (initDest `Vec2.sub` initPos) 30 15
      mc1 = \initPos initDest delta -> Physics.getMove (delta / 13) (initDest `Vec2.sub` initPos)
      mc2 = \initPos initDest delta -> Physics.getWaveMove (delta / 16) (initDest `Vec2.sub` initPos) 10 50
      mc3 = \initPos initDest delta -> Physics.getSawToothMove (delta / 25) (initDest `Vec2.sub` initPos) 100 15
  in  Nonempty
        { moves = NE.fromElement ma1 }
        [ { moves = NE.fromElement ma2 }
        , { moves = NE.fromElement ma3 }
        , { moves = Nonempty ma1 [ ma2, ma3 ] }
        , { moves = NE.fromElement mb1 }
        , { moves = NE.fromElement mb2 }
        , { moves = NE.fromElement mb3 }
        , { moves = Nonempty mb1 [ mb2, mb3 ] }
        , { moves = NE.fromElement mc1 }
        , { moves = NE.fromElement mc2 }
        , { moves = NE.fromElement mc3 }
        , { moves = Nonempty mc1 [ mc2, mc3 ] }
        ]