-- Code for the player's ship.
import "CoreLibs/object"
import "CoreLibs/graphics"
import "CoreLibs/sprites"
import "CoreLibs/timer"
import "entity"
import "bullet"
import "ui"

local gfx <const> = playdate.graphics

local BASE_CHARGE_FACTOR <const> = 15
local BASE_WEAPON_CHARGE_SPEED <const> = 1000

-- the amount of charge needed to increase the shot power by 1 at each power level
local WEAPON_CHARGE_LOOKUP <const> = {
   [0]=5,
   [1]=15,
   [2]=30,
   [3]=50
}

class("Kani").extends(Entity)

function Kani:init(ui)
   local img = gfx.image.new("images/kani.png")
   Kani.super.init(self, img, 100)

   self.vector = {x=0,y=0} -- movement direction
   self:setGroupMask(0x2)
   self:setCollidesWithGroupsMask(0x19)

   self.reserveCharge = 100

   -- controls the speed the crank recharges the player's reserves. A lower number allows faster charging.
   -- should never be set to 0
   self.chargeFactor = BASE_CHARGE_FACTOR

   -- weapon variables
   self.weaponPower = 0
   self.firingMode = false
   self.weaponChargeSpeed = BASE_WEAPON_CHARGE_SPEED -- speed in ms between weapon charge levels. Level 2 always takes half this time.

   -- the UI gets passed in to Kani so that we can update pieces of it easily.
   self.ui = ui

   self.inputHandlers = {
      upButtonDown =    function() self.vector.y = -3 end,
      downButtonDown =  function() self.vector.y = 3 end,
      leftButtonDown =  function() self.vector.x = -3 end,
      rightButtonDown = function() self.vector.x = 3 end,
      upButtonUp =      function() self.vector.y = 0 end,
      downButtonUp =    function() self.vector.y = 0 end,
      leftButtonUp =    function() self.vector.x = 0 end,
      rightButtonUp =   function() self.vector.x = 0 end,
      cranked = function(change, accelChange) self:chargeReserve(change) end,
      AButtonDown = function()
         self.firingTimer = playdate.timer.keyRepeatTimerWithDelay(self.weaponChargeSpeed / 2,
                                                                   self.weaponChargeSpeed,
                                                                   self.chargeShot, self)
      end,
      AButtonUp = function() self:fire() end,
   }
end

function Kani:chargeReserve(change)
   if change <= 0 then return end
   self.reserveCharge = math.min(self.reserveCharge + change / self.chargeFactor, 100)
   self.ui.chargeMeter:setValue(self.reserveCharge)
end

function Kani:chargeShot()
   if self.weaponPower >= 4 then
      return -- weapon is fully charged
   end

   local requiredPower = WEAPON_CHARGE_LOOKUP[self.weaponPower]

   -- We use math.ceil here so that any fractional charge rounds up.
   -- This ensures we can always use our last bit of juice for a level 1 shot,
   -- and smooths out play experience around fully charged values.
   local effectiveCharge = math.ceil(self.reserveCharge)

   if effectiveCharge >= requiredPower then
      self.reserveCharge = effectiveCharge - requiredPower
      self.weaponPower += 1
      self.ui.chargeMeter:setValue(self.reserveCharge)
      self.ui.weaponPowerMeter:setValue(self.weaponPower-1)
   end
end

function Kani:fire()
   self.firingTimer:remove()

   if self.weaponPower <= 0 then
      return
   end

   local bullet = Bullet(self.weaponPower)
   bullet:moveTo(self.x+16, self.y)
   bullet:add()
   self.weaponPower = 0
   self.ui.weaponPowerMeter:setValue(0)
end

function Kani:damage(amount)
   Kani.super.damage(self, amount)
   self.ui.healthMeter:setValue(self.health)

   if self.health == 0 then
      -- TODO: end game here
   end
end

function Kani:addInputHandlers()
   playdate.inputHandlers.push(self.inputHandlers)
end

function Kani:removeInputHandlers()
   playdate.inputHandlers.pop()
end

-- move that crab!
function Kani:update()
   local collisions = select(3, self:moveWithCollisions(self.x + self.vector.x, self.y + self.vector.y))
   for i=0, #collisions, 1 do
      -- handle player-triggered collisions
   end
end