-- push.lua v0.3

-- Copyright (c) 2018 Ulysse Ramage
-- 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 love11 = love.getVersion() == 11
local getDPI = love11 and love.window.getDPIScale or love.window.getPixelScale
local windowUpdateMode = love11 and love.window.updateMode or function(width, height, settings)
  local _, _, flags = love.window.getMode()
  for k, v in pairs(settings) do flags[k] = v end
  love.window.setMode(width, height, flags)
end

local push = {
  
  defaults = {
    fullscreen = false,
    resizable = false,
    pixelperfect = false,
    highdpi = true,
    canvas = true,
    stencil = true
  }
  
}
setmetatable(push, push)

function push:applySettings(settings)
  for k, v in pairs(settings) do
    self["_" .. k] = v
  end
end

function push:resetSettings() return self:applySettings(self.defaults) end

function push:setupScreen(WWIDTH, WHEIGHT, RWIDTH, RHEIGHT, settings)

  settings = settings or {}

  self._WWIDTH, self._WHEIGHT = WWIDTH, WHEIGHT
  self._RWIDTH, self._RHEIGHT = RWIDTH, RHEIGHT

  self:applySettings(self.defaults) --set defaults first
  self:applySettings(settings) --then fill with custom settings
  
  windowUpdateMode(self._RWIDTH, self._RHEIGHT, {
    fullscreen = self._fullscreen,
    resizable = self._resizable,
    highdpi = self._highdpi
  })

  self:initValues()

  if self._canvas then
    self:setupCanvas({ "default" }) --setup canvas
  end

  self._borderColor = {0, 0, 0}

  self._drawFunctions = {
    ["start"] = self.start,
    ["end"] = self.finish
  }

  return self
end

function push:setupCanvas(canvases)
  table.insert(canvases, { name = "_render", private = true }) --final render

  self._canvas = true
  self.canvases = {}

  for i = 1, #canvases do
    push:addCanvas(canvases[i])
  end

  return self
end
function push:addCanvas(params)
  table.insert(self.canvases, {
    name = params.name,
    private = params.private,
    shader = params.shader,
    canvas = love.graphics.newCanvas(self._WWIDTH, self._WHEIGHT),
    stencil = params.stencil or self._stencil
  })
end

function push:setCanvas(name)
  if not self._canvas then return true end
  return love.graphics.setCanvas(self:getCanvasTable(name).canvas)
end
function push:getCanvasTable(name)
  for i = 1, #self.canvases do
    if self.canvases[i].name == name then
      return self.canvases[i]
    end
  end
end
function push:setShader(name, shader)
  if not shader then
    self:getCanvasTable("_render").shader = name
  else
    self:getCanvasTable(name).shader = shader
  end
end

function push:initValues()
  self._PSCALE = (not love11 and self._highdpi) and getDPI() or 1
  
  self._SCALE = {
    x = self._RWIDTH/self._WWIDTH * self._PSCALE,
    y = self._RHEIGHT/self._WHEIGHT * self._PSCALE
  }
  
  if self._stretched then --if stretched, no need to apply offset
    self._OFFSET = {x = 0, y = 0}
  else
    local scale = math.min(self._SCALE.x, self._SCALE.y)
    if self._pixelperfect then scale = math.floor(scale) end
    
    self._OFFSET = {x = (self._SCALE.x - scale) * (self._WWIDTH/2), y = (self._SCALE.y - scale) * (self._WHEIGHT/2)}
    self._SCALE.x, self._SCALE.y = scale, scale --apply same scale to X and Y
  end
  
  self._GWIDTH = self._RWIDTH * self._PSCALE - self._OFFSET.x * 2
  self._GHEIGHT = self._RHEIGHT * self._PSCALE - self._OFFSET.y * 2
end

function push:apply(operation, shader)
  self._drawFunctions[operation](self, shader)
end

function push:start()
  if self._canvas then
    love.graphics.push()
    love.graphics.setCanvas({ self.canvases[1].canvas, stencil = self.canvases[1].stencil })

  else
    love.graphics.translate(self._OFFSET.x, self._OFFSET.y)
    love.graphics.setScissor(self._OFFSET.x, self._OFFSET.y, self._WWIDTH*self._SCALE.x, self._WHEIGHT*self._SCALE.y)
    love.graphics.push()
    love.graphics.scale(self._SCALE.x, self._SCALE.y)
  end
end

function push:applyShaders(canvas, shaders)
  local _shader = love.graphics.getShader()
  if #shaders <= 1 then
    love.graphics.setShader(shaders[1])
    love.graphics.draw(canvas)
  else
    local _canvas = love.graphics.getCanvas()

    local _tmp = self:getCanvasTable("_tmp")
    if not _tmp then --create temp canvas only if needed
      self:addCanvas({ name = "_tmp", private = true, shader = nil })
      _tmp = self:getCanvasTable("_tmp")
    end

    love.graphics.push()
    love.graphics.origin()
    local outputCanvas
    for i = 1, #shaders do
      local inputCanvas = i % 2 == 1 and canvas or _tmp.canvas
      outputCanvas = i % 2 == 0 and canvas or _tmp.canvas
      love.graphics.setCanvas(outputCanvas)
      love.graphics.clear()
      love.graphics.setShader(shaders[i])
      love.graphics.draw(inputCanvas)
      love.graphics.setCanvas(inputCanvas)
    end
    love.graphics.pop()

    love.graphics.setCanvas(_canvas)
    love.graphics.draw(outputCanvas)
  end
  love.graphics.setShader(_shader)
end

function push:finish(shader)
  love.graphics.setBackgroundColor(unpack(self._borderColor))
  if self._canvas then
    local _render = self:getCanvasTable("_render")

    love.graphics.pop()

    local white = love11 and 1 or 255
    love.graphics.setColor(white, white, white)

    --draw canvas
    love.graphics.setCanvas(_render.canvas)
    for i = 1, #self.canvases do --do not draw _render yet
      local _table = self.canvases[i]
      if not _table.private then
        local _canvas = _table.canvas
        local _shader = _table.shader
        self:applyShaders(_canvas, type(_shader) == "table" and _shader or { _shader })
      end
    end
    love.graphics.setCanvas()
    
    --draw render
    love.graphics.translate(self._OFFSET.x, self._OFFSET.y)
    local shader = shader or _render.shader
    love.graphics.push()
    love.graphics.scale(self._SCALE.x, self._SCALE.y)
    self:applyShaders(_render.canvas, type(shader) == "table" and shader or { shader })
    love.graphics.pop()

    --clear canvas
    for i = 1, #self.canvases do
      love.graphics.setCanvas(self.canvases[i].canvas)
      love.graphics.clear()
    end

    love.graphics.setCanvas()
    love.graphics.setShader()
  else
    love.graphics.pop()
    love.graphics.setScissor()
  end
end

function push:setBorderColor(color, g, b)
  self._borderColor = g and {color, g, b} or color
end

function push:toGame(x, y)
  x, y = x - self._OFFSET.x, y - self._OFFSET.y
  local normalX, normalY = x / self._GWIDTH, y / self._GHEIGHT
  
  x = (x >= 0 and x <= self._WWIDTH * self._SCALE.x) and normalX * self._WWIDTH or nil
  y = (y >= 0 and y <= self._WHEIGHT * self._SCALE.y) and normalY * self._WHEIGHT or nil
  
  return x, y
end

--doesn't work - TODO
function push:toReal(x, y)
  return x + self._OFFSET.x, y + self._OFFSET.y
end

function push:switchFullscreen(winw, winh)
  self._fullscreen = not self._fullscreen
  local windowWidth, windowHeight = love.window.getDesktopDimensions()
  
  if self._fullscreen then --save windowed dimensions for later
    self._WINWIDTH, self._WINHEIGHT = self._RWIDTH, self._RHEIGHT
  elseif not self._WINWIDTH or not self._WINHEIGHT then
    self._WINWIDTH, self._WINHEIGHT = windowWidth * .5, windowHeight * .5
  end
  
  self._RWIDTH = self._fullscreen and windowWidth or winw or self._WINWIDTH
  self._RHEIGHT = self._fullscreen and windowHeight or winh or self._WINHEIGHT
  
  self:initValues()
  
  love.window.setFullscreen(self._fullscreen, "desktop")
  if not self._fullscreen and (winw or winh) then
    windowUpdateMode(self._RWIDTH, self._RHEIGHT) --set window dimensions
  end
end

function push:resize(w, h)
  if self._highdpi then w, h = w / self._PSCALE, h / self._PSCALE end
  self._RWIDTH = w
  self._RHEIGHT = h
  self:initValues()
end

function push:getWidth() return self._WWIDTH end
function push:getHeight() return self._WHEIGHT end
function push:getDimensions() return self._WWIDTH, self._WHEIGHT end

return push
