function love.load()

    require "cjrcle"
    windowwidth = 1000
    windowheight = 1000
    love.graphics.setBackgroundColor(0, 0, 0)
    sucess = love.window.setMode(windowwidth, windowheight) -- what does this line do? ... will work but the circle is offset

    ctheta = math.pi/2
    x = 0
    y = 0
    b = math.pi/ctheta

    sinxloc = 0
    startposX = 0
    discr = 50
    hr = 10

    speed = 1

    thrown = false -- a variable to check if the hammer has been let go

    -- hammer position
    hxpos = startposX + discr*math.cos(math.pi/2)/math.pi
    hypos = y - discr*math.sin(math.pi/2)
    rv = 1 -- rotational velocity
end

function love.update(dt)
   -- smaller angle = slower rotspeed
    ctheta = ctheta - rv*math.pi*dt/3
    if ctheta < math.pi/2 - 2*math.pi then
        ctheta = math.pi/2
    end
    --if speed < 10 then
        --speed = speed*1.01
        --startposX = startposX + speed
    --end


    hxpos = startposX + discr*math.cos(ctheta)
    hypos = y - discr*math.sin(ctheta)
    local m = math.pow(2, dt)
    if love.keyboard.isDown("up") then
        b = b*m   --the period of the sine wave is  pi/delthe... i think?
    end
    if love.keyboard.isDown("down") then
        b = b/m
    end
end

function love.keypressed(key)
    if key == "space" and startposX < 0 then
        thrown = true
    end
    if key == "r" then
        b = math.pi/2
    end
end

function arccirc(r, x, y, delthe)
    arcang = math.atan(y + r/x + r)
	for theta = 0, arcang, delthe do
		love.graphics.line(discr*math.cos(theta) + x, discr*math.sin(theta) + y, discr*math.cos(theta + delthe) + x, discr*math.sin(theta + delthe) + y)
	end
end

function love.draw()
    --love.graphics.push()
    love.graphics.translate(windowwidth/2, windowheight/2)

    love.graphics.setColor(0, 1, 0)
    love.graphics.print("sine = " .. -hypos/50, -400, -400)
    love.graphics.setColor(1, 0, 0)
    love.graphics.print("cosine = " .. hxpos/50, -400, -390)
    love.graphics.setColor(.6, 0, .6)
    love.graphics.print("tangent = " .. math.tan(ctheta), -400, -380)
    love.graphics.setColor(.9, 0, .9)
    love.graphics.print("cotangent = " .. 1/math.tan(ctheta),-400, -370)
    love.graphics.setColor(.7,1,.7)
    love.graphics.print("secant = " .. 1/math.cos(ctheta), -400, -360)
    love.graphics.setColor(0,1,0)
    love.graphics.print("cosecant = " .. 1/math.sin(ctheta) , -400, -350)
    love.graphics.print("b: " .. b, -400, -340)
    love.graphics.print("Ø: ".. ctheta .. " radians, or ", -400, -330 )
    love.graphics.print("which is also " .. ctheta*180/math.pi .. " degrees!", -400, -320)

    -- orange cjrcle
    --
    love.graphics.setColor(.7, .6, .3)
    cjrcle(discr, startposX, 0, 32)
    --cjrcle(discr, startposX, 0, )

    -- blue cjrcle for player
    love.graphics.setColor(0, 0, 1)
    cjrcle(10, hxpos, hypos)


    -- violet tangent and cotantgent lines
    love.graphics.setColor(.6,0,.6)
    love.graphics.line(50*math.cos(ctheta), -50*math.sin(ctheta), 0, -50/math.sin(ctheta))
    love.graphics.setColor(0,.9,.9)
    love.graphics.line(50*math.cos(ctheta), -50*math.sin(ctheta), 50/math.cos(ctheta), 0)

    -- secant and cosecant
    love.graphics.setColor(0, 1, 0)
    love.graphics.line(0,0,0,-50/math.sin(ctheta)) --csc
    love.graphics.setColor(0, 1, 1)
    love.graphics.line(0,0,50/math.cos(ctheta),0) --sec

    --different triangle

    --red horizontal cosine line
    love.graphics.setColor(1, 0, 0)
    love.graphics.line(0, 0, hxpos, 0)

    -- yellow vertical sine line
    love.graphics.setColor(0, 1, 0)
    love.graphics.line(hxpos, hypos, 50*math.cos(ctheta), 0)


    -- radius
    love.graphics.setColor(.5, .3, 0)
    love.graphics.line(0, 0, hxpos, hypos)




    for thetarc = math.atan(hypos/hxpos), math.sin(ctheta), -math.pi/60 do -- arctan is both plus and minus?
        love.graphics.setColor(0,1,0)
        love.graphics.line(10*math.cos(thetarc), 10*math.sin(thetarc), 10*math.cos(thetarc + math.pi/60), 10*math.sin(thetarc + math.pi/60))
        thetarc = thetarc + math.pi/60
    end

    -- sincurve
    sinxloc = 50
    cosyloc = 50
    love.graphics.setColor(1, 0, 0.4)
    for theta = -32*math.pi, 32*math.pi, math.pi/180 do
        love.graphics.line(25 + sinxloc, -50*math.sin(b*theta), 25 +sinxloc + math.pi/360, -50*math.sin(b*theta + math.pi/360))

        sinxloc = sinxloc + 1

    end

    --[[
        N.B!
        theta = arctan sin/cos
        the period of the sine wave is  pi/delthe... i think?
        if theta is < arctan
    ]]

    love.graphics.setColor(1,0,0)
    love.graphics.print("x: " .. hxpos/50, hxpos, hypos)
    love.graphics.print("y: " .. -hypos/50, hxpos, hypos+10)

end