-- Chase behavior: chase nearest opposing team member and attack when in range
local BaseBehavior = require("behaviors.base")
local Behavior = {}
Behavior.__index = Behavior
setmetatable(Behavior, { __index = BaseBehavior })

local flashShader = love.graphics.newShader [[
vec4 effect(vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords) {
    vec4 pixel = Texel(texture, texture_coords);
    if (pixel.a > 0.0) {
        return vec4(1.0, 1.0, 1.0, pixel.a) * color;
    }
    return vec4(0.0, 0.0, 0.0, 0.0);
}
]]

function Behavior:new(combatant)
  self = setmetatable(BaseBehavior:new(combatant), Behavior)
  self.attackRange = self.combatant.config.attackRange or 24
  self.chaseRange = self.combatant.config.chaseRange or 200
  self.moveNextTimer = 0
  self.attackTimer = 0
  self.combatant.facing = -1
  return self
end

function Behavior:update(dt)
  BaseBehavior.update(self, dt)

  -- Enemy death drops
  if not self.combatant.hasDropped and self.combatant.state == CombatantState.DYING and self.combatant.drops then
    self.combatant.hasDropped = true
    local dropKey = Utils.pickRandomKeyFromWeightedTable(self.combatant.drops)
    local dropType = self.combatant.drops[dropKey].type or "weapon"
    self.combatant.drops = nil
    if dropType == "weapon" then
      local asset = self.context.assetLoader:loadWeapon(dropKey)
      local weapon = Weapon:generate(asset)
      local drop = Drop:new(weapon.drop, {
        type = DropType.WEAPON,
        item = weapon,
        state = DropState.FALLING,
        x = self.combatant.x + (self.combatant.width / 2) - (weapon.sprite.width / 2),
        y = self.combatant.y + (self.combatant.height / 2) - (weapon.sprite.height / 2),
      })
      table.insert(self.context.drops, drop)
    elseif dropType == "consumable" then
      local asset = self.context.assetLoader:loadSkill(dropKey)
      local drop = Drop:new(asset.drop, {
        type = DropType.CONSUMABLE,
        item = asset.name,
        state = DropState.FALLING,
        x = self.combatant.x + (self.combatant.width / 2) - (asset.drop:getWidth() / 2),
        y = self.combatant.y + (self.combatant.height / 2) - (asset.drop:getHeight() / 2),
      })
      table.insert(self.context.drops, drop)
    end
  end
end

function Behavior:draw()
  local oy = self.combatant.visualOffsetY or 0
  local scaleX = self.combatant.facing
  local scaleY = 1

  local drawY = self.combatant.y + self.combatant.visualOffsetY
  if scaleY ~= 1 then
    drawY = drawY + self.combatant.height - (self.combatant.height * scaleY)
  end
  local drawX = self.combatant.x
  if self.combatant.facing == -1 then
    drawX = drawX + self.combatant.width
  end
  if self.combatant.hitFlash > 0 then
    love.graphics.setShader(flashShader)
  end
  self.combatant.sprite:drawAnimationFrame(drawX, drawY, { scale = { scaleX, scaleY } })
  love.graphics.setShader()
  if self.combatant.health < self.combatant.maxHealth then
    self.combatant:drawHealthBar(self.combatant.x, self.combatant.y + oy - 5, self.combatant.width, 3,
      { 0.8, 0.2, 0.2 })
  end
end

return Behavior