--[[

    Mandelbrot set:  Iterate through the following function

    fc(z) z^2 + c



    Case1, blows up:

    c = 1
    f1(0) 0^2 + 1 --> 1
    f1(1) 1^2 + 1 --> 2
    f1(2) 2^2 + 1 --> 5
    f1(5) 5^2 + 1 --> 26


    Case2, is always <= 2:

    c = -1
    f-1(0) 0^2 - 1 --> -1
    f-1(-1) -1^2 - 1 --> 0
    f-1(0) 0^2 - 1 --> -1

]]

function love.load()

    maxIter = 1000
    gridSize = 50

    default = 10
    default2 = 5
    box = 1

    colorScale = 13

    scale = 1
    transX = 0
    transY = 0

    power = 2

    iterationCount = 0
    pixelCount = 0


    love.graphics.setBackgroundColor(255, 255, 255)
    screenshot = nil
    points = {}
    loops = 0
    width, height = love.graphics.getWidth(), love.graphics.getHeight()
    processing = true
    zoomCol = width / 2
    zoomRow = height / 2
    nowH, nowW = 10, 10

    function love.keypressed(key)
        if key == "escape" then
            love.event.quit()
        end
    end

    function love.mousepressed(x, y, button)
        if button == "wu" and not processing then
            scale = scale + (scale / 4)
        elseif button == "wd" and not processing then
            scale = scale - (scale / 4)
        end
    end

    function toRealNumber(imaginary)
        return imaginary ^ 2
    end

    function f(z, c)
        return z ^ power + c
    end

    function comma(number)
        repeat number, count = tostring(number):gsub("^(%d+)(%d%d%d)", "%1,%2") until count == 0
        return number
    end

    function redraw(zoom)

    end
end

function love.draw()
    love.graphics.scale(scale, scale)
    love.graphics.translate(transX, transY)
    if loops == 0 then
        for _, point in ipairs(points) do
            local green = point[4] * colorScale
            local red = 0
            if green > 255 then
                red = green - 255
                green = 255
            end
            love.graphics.setColor(point[3] == "white" and {red, green, 0} or {0, 0, 0})
            love.graphics.rectangle("fill", point[1], point[2], default, default)
        end
    elseif loops == 1 or loops == 2 then
        love.graphics.draw(screenshot, 0, 0)
        for _, point in ipairs(points) do
            local green = point[4] * colorScale
            local red = 0
            if green > 255 then
                red = green - 255
                green = 255
            end
            love.graphics.setColor(point[3] == "white" and {red, green, 0} or {0, 0, 0})
            love.graphics.rectangle("fill", point[1], point[2], default, default)
        end
    else
        love.graphics.draw(screenshot, 0, 0)
    end
    love.graphics.setColor(255, 255, 255)
    love.graphics.rectangle("line", nowW - gridSize, nowH - gridSize, gridSize, gridSize)
    if loops < 3 then
        love.graphics.printf("Iterations: " .. comma(iterationCount), 25, 25, 500, "left")
        love.graphics.printf("Pixels: " .. comma(pixelCount), 25, 50, 500, "left")
    end
end

function love.update()
    if processing then
        for row = nowH - gridSize, nowH, default do
            for col = nowW - gridSize, nowW, default do
                pixelCount = pixelCount + 1
                local real = (col - zoomCol) * 4 / width
                local imaginary = (row - zoomRow) * 4 / width
                local z, c, iter = 0, 0, 0
                while (f(z, toRealNumber(c)) <= 4 and iter < maxIter) do
                    iterationCount = iterationCount + 1
                    local zNew = z^2 - toRealNumber(c) + real
                    c = 2*z*c + imaginary
                    z = zNew
                    iter = iter + 1
                end
                if iter < maxIter then
                    table.insert(points, {col, row, "white", iter})
                else
                    table.insert(points, {col, row, "black", iter})
                end
            end
        end
        nowW = nowW + gridSize
        if nowW >= width + (gridSize * 3) then
            nowW = 1
            nowH = nowH + gridSize
        end
        if nowH - gridSize >= height then
            nowW = 1
            nowH = 1
            screenshot = love.graphics.newImage(love.graphics.newScreenshot(true))
            points = {}
            loops = loops + 1
            if loops == 1 then
                pixelCount = 0
                iterationCount = 0
                processing = true
                default = default2
            elseif loops == 2 then
                pixelCount = 0
                iterationCount = 0
                default = box
            else
                processing = false
            end
        end
    else
        if love.keyboard.isDown("w") then
            transY = transY + (5*(1/scale))
        end
        if love.keyboard.isDown("s") then
            transY = transY - (5*(1/scale))
        end
        if love.keyboard.isDown("d") then
            transX = transX - (5*(1/scale))
        end
        if love.keyboard.isDown("a") then
            transX = transX + (5*(1/scale))
        end
    end
end