effect = nil
video = nil
ctx = nil

timeDisplayText = ""
dateDisplayText = ""

timer = 0.0

function _create()
    video = Texture.FromGStreamer("filesrc location=" .. Resolve("video.mkv"))

    local fxSrc = [[uniform sampler2D uTexture;

        void main() {
            vec2 uv = vUV;

            for (int i = 0; i < uNumDisplays; i++) {
                vec4 displayNorm = uDisplayNorm[i];

                if (vUV.x >= displayNorm.x && vUV.x <= displayNorm.x + displayNorm.z &&
                    vUV.y >= displayNorm.y && vUV.y <= displayNorm.y + displayNorm.w) {
                    FragColor = texture(uTexture, GetDisplayUV(uTexture, i));
                    break;
                }
            }
        }
    ]]
    effect = Effect.new(fxSrc)

    ctx = GraphicsContext.new()

    local fontPath = Resolve("font.otf")
    ctx:CreateFont("font", fontPath)

    UpdateTimeAndDate()
end

function UpdateTimeAndDate()
    local now = os.date("*t")
    timeDisplayText = string.format("%02d:%02d", now.hour, now.min)
    dateDisplayText = os.date("%A, %B %d, %Y")
end

function _update(dt)
    timer = timer + dt

    if timer >= 0.5 then
        timer = 0.0
        UpdateTimeAndDate()
    end
end

function _render()
    gl.Clear(0, 0, 0, 1.0)
    effect:Use()
    effect:SetTexture("uTexture", video, 0)
    effect:Render()

    ctx:BeginFrame(DesktopSize.x, DesktopSize.y, DesktopSize.x / DesktopSize.y)

    local xPos = 80.0
    local yPos = 120.0
    local timeFontSize = 80
    local dateFontSize = 28

    ctx:FontSize(timeFontSize)
    ctx:FontFace("font")
    ctx:FillColor(RGBAf(1, 1, 1, 0.75))
    ctx:TextAlign(Align.RIGHT | Align.BOTTOM)
    ctx:Text(Displays[1].x + Displays[1].z - xPos, Displays[1].y + Displays[1].w - yPos, timeDisplayText)

    ctx:FontSize(dateFontSize)
    ctx:FillColor(RGBAf(1, 1, 1, 0.45))
    ctx:Text(Displays[1].x + Displays[1].z - xPos, Displays[1].y + Displays[1].w - (yPos + timeFontSize + 8), dateDisplayText)

    ctx:EndFrame()
end