-- anim8 v1.1.1 - 2012-06
-- Copyright (c) 2011 Enrique García Cota
-- 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 Grid = {}

local _frames = {}

local function assertPositiveInteger(value, name)
  if type(value) ~= 'number' then error(("%s should be a number, was %q"):format(name, tostring(value))) end
  if value < 1 then error(("%s should be a positive number, was %d"):format(name, value)) end
  if value ~= math.floor(value) then error(("%s should be an integer, was %d"):format(name, value)) end
end

local function createFrame(self, x, y)
  local fw, fh = self.frameWidth, self.frameHeight
  return love.graphics.newQuad(
    self.left + (x-1) * fw + x * self.border,
    self.top  + (y-1) * fh + y * self.border,
    fw,
    fh,
    self.imageWidth,
    self.imageHeight
  )
end

local function getGridKey(...)
  return table.concat( {...} ,'-' )
end


local function getOrCreateFrame(self, x, y)
  if x < 1 or x > self.width or y < 1 or y > self.height then
    error(("There is no frame for x=%d, y=%d"):format(x, y))
  end
  local key = self._key
  _frames[key]       = _frames[key]       or {}
  _frames[key][x]    = _frames[key][x]    or {}
  _frames[key][x][y] = _frames[key][x][y] or createFrame(self, x, y)
  return _frames[key][x][y]
end

local function parseInterval(str)
  str = str:gsub(' ', '')
  local min, max = str:match("^(%d+)-(%d+)$")
  if not min then
    min = str:match("^%d+$")
    max = min
  end
  assert(min and max, ("Could not parse interval from %q"):format(str))
  min, max = tonumber(min), tonumber(max)
  local step = min <= max and 1 or -1
  return min, max, step
end

local function parseIntervals(str)
  local left, right = str:match("(.+),(.+)")
  assert(left and right, ("Could not parse intervals from %q"):format(str))
  local minx, maxx, stepx = parseInterval(left)
  local miny, maxy, stepy = parseInterval(right)
  return minx, maxx, stepx, miny, maxy, stepy
end

local function parseFrames(self, args, result, position)
  local current = args[position]
  local kind = type(current)

  if kind == 'number' then

    result[#result + 1] = getOrCreateFrame(self, current, args[position + 1])
    return position + 2

  elseif kind == 'string' then

    local minx, maxx, stepx, miny, maxy, stepy  = parseIntervals(current)
    for y = miny, maxy, stepy do
      for x = minx, maxx, stepx do
        result[#result+1] = getOrCreateFrame(self,x,y)
      end
    end

    return position + 1

  else

    error(("Invalid type: %q (%s)"):format(kind, tostring(args[position])))

  end
end

function Grid:getFrames(...)
  local args = {...}
  local length = #args
  local result = {}
  local position = 1

  while position <= length do
    position = parseFrames(self, args, result, position)
  end

  return result
end

local Gridmt = {
  __index = Grid,
  __call  = Grid.getFrames
}

local function newGrid(frameWidth, frameHeight, imageWidth, imageHeight, left, top, border)
  assertPositiveInteger(frameWidth,  "frameWidth")
  assertPositiveInteger(frameHeight, "frameHeight")
  assertPositiveInteger(imageWidth,  "imageWidth")
  assertPositiveInteger(imageHeight, "imageHeight")

  left   = left   or 0
  top    = top    or 0
  border = border or 0

  local key  = getGridKey(frameWidth, frameHeight, imageWidth, imageHeight, left, top, border)

  local grid = setmetatable(
    { frameWidth  = frameWidth,
      frameHeight = frameHeight,
      imageWidth  = imageWidth,
      imageHeight = imageHeight,
      left        = left,
      top         = top,
      border      = border,
      width       = math.floor(imageWidth/frameWidth),
      height      = math.floor(imageHeight/frameHeight),
      _key        = key
    },
    Gridmt
  )
  return grid
end

-----------------------------------------------------------

local Animation = {}

local function cloneArray(arr)
  local result = {}
  for i=1,#arr do result[i] = arr[i] end
  return result
end

local function parseDelays(delays)
  local parsedDelays = {}
  local tk,min,max,step
  for k,v in pairs(delays) do
    tk = type(k)
    if     tk == "number"
      then parsedDelays[k] = v
    elseif tk == "string" then
      min, max, step = parseInterval(k)
      for i = min,max,step do parsedDelays[i] = v end
    else
      error(("Unexpected delay key: [%s]. Expected a number or a string"):format(tostring(k)))
    end
  end
  return parsedDelays
end

local function repeatValue(value, times)
  local result = {}
  for i=1,times do result[i] = value end
  return result
end

local function createDelays(frames, defaultDelay, delays)
  local maxFrames = #frames
  local result = repeatValue(defaultDelay, maxFrames)
  for i,v in pairs(parseDelays(delays)) do
    if i > maxFrames then
      error(("The delay value %d is too high; there are only %d frames"):format(i, maxFrames))
    end
    result[i] = v
  end
  return result
end

local animationModes = {
  loop   = function(self) self.position = 1 end,
  once   = function(self)
    self.position = #self.frames
    self.status = "finished"
  end,
  bounce = function(self)
    self.direction = self.direction * -1
    self.position = self.position + self.direction + self.direction
  end
}

local Animationmt = { __index = Animation }

local function newAnimation(mode, frames, defaultDelay, delays)
  delays = delays or {}
  assert(animationModes[mode], ("%q is not a valid mode"):format(tostring(mode)))
  assert(type(defaultDelay) == 'number' and defaultDelay > 0, "defaultDelay must be a positive number" )
  assert(type(delays) == 'table', "delays must be a table or nil")
  return setmetatable({
      mode        = mode,
      frames      = cloneArray(frames),
      endSequence = animationModes[mode],
      delays      = createDelays(frames, defaultDelay, delays),
      timer       = 0,
      position    = 1,
      direction   = 1,
      status      = "playing"
    },
    Animationmt
  )
end

function Animation:clone()
  return newAnimation(self.mode, self.frames, 1, self.delays)
end

function Animation:update(dt)
  if self.status ~= "playing" then return end

  self.timer = self.timer + dt

  while self.timer > self.delays[self.position] do
    self.timer = self.timer - self.delays[self.position]
    self.position = self.position + self.direction
    if self.position < 1 or self.position > #self.frames then
      self:endSequence()
    end
  end
end

function Animation:pause()
  self.status = "paused"
end

function Animation:resume()
  self.status = "playing"
end

function Animation:gotoFrame(position)
  self.position = position
end

function Animation:draw(image, x, y, r, sx, sy, ox, oy)
  local frame = self.frames[self.position]
  love.graphics.drawq(image, frame, x, y, r, sx, sy, ox, oy)
end

-----------------------------------------------------------

local anim8 = {
  newGrid      = newGrid,
  newAnimation = newAnimation
}
return anim8