-- Chase behavior: chase nearest opposing team member and attack when in range
local BaseBehavior = require("behaviors.enemy")
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);
}
]]

local moveDelayTime = 1.25
local attackWindUpTime = .35

function Behavior:new(combatant)
  self = setmetatable(BaseBehavior:new(combatant), Behavior)
  self.moveNextTimer = 0
  self.attackTimer = attackWindUpTime
  self.wasGrounded = true
  self.squashTimer = 0
  self.squashScaleY = 1
  self.combatant.facing = -1
  self.attackSkill = self.context.assetLoader:loadSkill("attack")
  return self
end

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

  if not self:isAlive() then return end

  if not self:isDisabled() then
    local opponents = self:getOpponents()
    local nearest, nearestDist = self:getNearestCombatant(opponents)
    if not nearest then return end

    local dx = nearest.x - self.combatant.x
    local dy = nearest.y - self.combatant.y

    if self.moveNextTimer > 0 then
      self.moveNextTimer = self.moveNextTimer - dt
      self.combatant.velX = self.combatant.facing * (self.combatant.speed * self.moveNextTimer)
      if self.combatant.grounded then
        self.combatant.moveX = 0
        self.combatant.velX = 0
      end
    end

    if self.moveNextTimer <= 0 and self.combatant.knockbackTimer <= 0 then
      if nearestDist > self.attackRange then
        self.attackTimer = attackWindUpTime
        self.combatant.hitFlash = 0

        if dx > self.attackRange then
          self.combatant.moveX = 1
          self.combatant.facing = 1
        elseif dx < -self.attackRange then
          self.combatant.moveX = -1
          self.combatant.facing = -1
        end
        if self.combatant.grounded and nearestDist > 50 then
          self.combatant.velY = -250
          self.combatant.velX = self.combatant.facing * (self.combatant.speed * 8)
          self.moveNextTimer = moveDelayTime
        end
      else
        self.combatant.moveX = 0
        if dx > 0 then
          self.combatant.facing = 1
        elseif dx < 0 then
          self.combatant.facing = -1
        end
      end

      if nearestDist <= self.attackRange then
        self.attackTimer = self.attackTimer - dt
        self.combatant.hitFlash = (math.floor(self.attackTimer * 10) % 2 == 0) and 1 or 0
        if self.attackTimer <= 0 then
          self.combatant:activateSkillByAsset(self.attackSkill, opponents, {})
          self.moveNextTimer = moveDelayTime
          self.attackTimer = attackWindUpTime
          self.combatant.hitFlash = 0
        end
      end
    end
  end

  -- Squash/stretch on jump and land
  if not self.wasGrounded and self.combatant.grounded then
    -- landing
    self.squashTimer = 0.1
    self.squashScaleY = 1.1
  elseif self.wasGrounded and not self.combatant.grounded and self.combatant.velY < 0 then
    -- jumping
    self.squashTimer = 0.1
    self.squashScaleY = 0.7
  end
  self.wasGrounded = self.combatant.grounded

  if self.squashTimer > 0 then
    self.squashTimer = self.squashTimer - dt
  end

  -- Animation: skill > charging > jump > walk > idle
  local targetAnim = "idle"
  if self.combatant.velX ~= 0 then targetAnim = "walk" end
  if self.combatant.velY < 0 then targetAnim = "jump" end
  if self.combatant.velY > 0 then targetAnim = "fall" end
  if self.combatant.skillAnimation then targetAnim = self.combatant.skillAnimation end
  self.combatant.sprite:setAnimation(targetAnim)
end

function Behavior:draw()
  local oy = self.combatant.visualOffsetY or 0
  local scaleX = self.combatant.facing
  local scaleY = 1
  if self.squashTimer > 0 then
    scaleY = 1 + (self.squashScaleY - 1) * (self.squashTimer / 0.33)
  end

  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