-- camera.lua :: a basic camera adapted to the asset/world system.

--[[
  Copyright © 2019 Kazhnuz

  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in
  the Software without restriction, including without limitation the rights to
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  the Software, and to permit persons to whom the Software is furnished to do so,
  subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

local CameraSystem = Object:extend()

local Vector3D     = require "framework.libs.brinevector3D"
local physicsUtils = require "framework.scenes.world.actors.physics.utils"

-- INIT FUNCTIONS
-- Initialize the camera system

function CameraSystem:new(world, def)
    self.world = world
    self.mustFollowPlayer = true

    def = def or {}
    self.lock = {}
    self:_initView(def.onScreen or {}, def.dimensions or {})
    self:_regenerateCanvas()
end

function CameraSystem:_initView(onScreen, dimensions, target)
    self.onScreen = Vector3D(onScreen.x, onScreen.y, 0)
    local screenw, screenh = core.screen:getDimensions()
    self.dimensions = { w = dimensions.w or screenw, h = dimensions.h or screenh, d = 1 }
    self.position = Vector3D(0, 0, 0)
    self.scale = 1
end

-- SETTER
-- Set some informations

function CameraSystem:lockCoordinates(x, y)
    self.lock.x = x
    self.lock.y = y
end

-- GETTER / COMPUTATION functions
-- Get some informations computations

function CameraSystem:getViewCoordinate()
    local viewDimension = physicsUtils.dimensionsToVector(self.dimensions) / self.scale
    local viewPosition = self.position - (viewDimension / 2)
    return viewPosition, physicsUtils.vectorToDimensions(viewDimension)
end

-- UPDATE and MOVE functions
-- Move and update the camera system

function CameraSystem:update(dt)
    if (self.mustFollowPlayer == true) then
        self:_followPlayer()
    end
end

function CameraSystem:moveView(position)
    self.position = position
    self:_limitView()
end

function CameraSystem:_limitView()
    local worldPosition, worldDimensions = self.world:getBox()

    local min = worldPosition + (physicsUtils.dimensionsToVector(self.dimensions) / 2)
    local max = worldPosition + physicsUtils.dimensionsToVector(worldDimensions) -
        (physicsUtils.dimensionsToVector(self.dimensions) / 2)

    self.position.x = utils.math.between(self.position.x, min.x, max.x)
    self.position.y = utils.math.between(self.position.y, min.y, max.y)

    if (self.lock ~= nil and self.lock.x ~= nil) then
        self.position.x = self.lock.x
    end

    if (self.lock ~= nil and self.lock.y ~= nil) then
        self.position.y = self.lock.y
    end
end

function CameraSystem:_followPlayer()
    local target = self.world.player
    if (target == nil) then
        return
    end

    local position = target:getViewCenter()
    position.x = math.floor(position.x)
    position.y = math.floor(position.y)
    self:moveView(position)
end

-- DRAWING FUNCTIONS

function CameraSystem:_regenerateCanvas()
    self.canvas = love.graphics.newCanvas(self.dimensions.w, self.dimensions.h)
end

function CameraSystem:attachView()
    self.previousCanvas = love.graphics.getCanvas()
    love.graphics.setCanvas(self.canvas)
    love.graphics.clear()

    local t = self:getViewCoordinate()

    love.graphics.push()
    love.graphics.origin()
    love.graphics.translate(math.floor(t.x) * -1, math.floor(t.y) * - 1)
end

function CameraSystem:detachView()
    love.graphics.pop()
    love.graphics.setCanvas(self.previousCanvas)

    love.graphics.push()
    love.graphics.origin()
    love.graphics.translate(math.floor(self.onScreen.x), math.floor(self.onScreen.y))
    love.graphics.scale(core.screen:getScale() * self.scale, core.screen:getScale() * self.scale)

    love.graphics.draw(self.canvas)

    local unscale = 1 / self.scale
    love.graphics.scale(unscale, unscale)

    love.graphics.pop()
end

return CameraSystem