local gui = require("gui")
local multi, thread = require("multi"):init()
local transition = require("gui.elements.transitions")

-- Triggers press then release
local function getPosition(obj, x, y)
    if not x or y then
        local cx, cy, w, h = obj:getAbsolutes()
        return cx + w/2, cy + h/2
    else
        return x, y
    end
end

proc = gui:getProcessor()

local simulate = {}

function simulate:Press(button, x, y, istouch)
    if self then
        x, y = getPosition(self, x, y)
    elseif x == nil or y == nil then
        x, y = love.mouse.getPosition()
    end
    love.mouse.setPosition(x, y)
    gui.Events.OnMousePressed:Fire(x, y, button or gui.MOUSE_PRIMARY, istouch or false)
end

function simulate:Release(button, x, y, istouch)
    if self then
        x, y = getPosition(self, x, y)
    elseif x == nil or y == nil then
        x, y = love.mouse.getPosition()
    end
    love.mouse.setPosition(x, y)
    gui.Events.OnMouseReleased:Fire(x, y, button or gui.MOUSE_PRIMARY, istouch or false)
end

simulate.Click = proc:newFunction(function(self, button, x, y, istouch)
    if self then
        x, y = getPosition(self, x, y)
    elseif x == nil or y == nil then
        x, y = love.mouse.getPosition()
    end
    love.mouse.setPosition(x, y)
    gui.Events.OnMousePressed:Fire(x, y, button or gui.MOUSE_PRIMARY, istouch or false)
    thread.skip(1)
    gui.Events.OnMouseReleased:Fire(x, y, button or gui.MOUSE_PRIMARY, istouch or false)
end, true)

simulate.Move = proc:newFunction(function(self, dx, dy, x, y, istouch)
    local dx, dy = dx or 0, dy or 0

    if self then
        x, y = getPosition(self, x, y)
    elseif x == nil or y == nil then
        x, y = love.mouse.getPosition()
    end

    if dx == 0 and dy == 0 then
        _x, _y = love.mouse.getPosition()
        if x == _x and y == _y then
            return
        end
        local dx, dy = 0, 0
        dx = x - _x
        dy = y - _y
        return simulate.Move(nil, dx, dy)
    end
    gui.Events.OnMouseMoved:Fire(x, y, 0, 0, istouch or false)
    thread.skip(1)
    local gx = transition.glide(0, dx, .25)
    local gy = transition.glide(0, dy, .25)
    local xx = gx()
    xx.OnStep(function(p)
        _x, _y = love.mouse.getPosition()
        love.mouse.setPosition(x + p, _y)
    end)
    local yy = gy()
    yy.OnStep(function(p)
        _x, _y = love.mouse.getPosition()
        love.mouse.setPosition(_x, y + p)
    end)
    if not(dx==0 and dy == 0) then
        thread.hold(xx.OnStop * yy.OnStop)
    end
    gui.Events.OnMouseMoved:Fire(x + dx, y + dy, 0, 0, istouch or false)
end, true)

return simulate