sub init()
    m.top.setFocus(true)
    m.backend = m.top.findNode("backend")
    m.status = m.top.findNode("status")
    m.help = m.top.findNode("help")
    m.refreshTimer = m.top.findNode("refreshTimer")
    m.liveVideo = m.top.findNode("liveVideo")
    m.cameraPosters = [
        m.top.findNode("poster1"),
        m.top.findNode("poster2"),
        m.top.findNode("poster3"),
        m.top.findNode("poster4")
    ]
    m.cameraFrames = [
        m.top.findNode("frame1"),
        m.top.findNode("frame2"),
        m.top.findNode("frame3"),
        m.top.findNode("frame4")
    ]
    m.cameraNodes = [
        m.top.findNode("cam1"),
        m.top.findNode("cam2"),
        m.top.findNode("cam3"),
        m.top.findNode("cam4")
    ]
    m.refreshToken = 0
    m.selectedIndex = 0
    m.isLiveView = false

    loadConfig()
end sub

sub loadConfig()
    raw = ReadAsciiFile("pkg:/config/cameras.json")
    config = ParseJson(raw)

    if type(config) <> "roAssociativeArray" then
        m.status.text = "Unable to parse cameras.json"
        return
    end if

    m.config = config

    if config.doesExist("backend") and config.backend.doesExist("baseUrl") then
        m.backend.text = "Direct Frigate"
    end if

    if not config.doesExist("cameras") then
        m.status.text = "No cameras found in config"
        return
    end if

    if config.doesExist("backend") and config.backend.doesExist("refreshSeconds") then
        m.refreshTimer.duration = config.backend.refreshSeconds
    end if

    m.refreshTimer.observeField("fire", "onRefreshTimerFire")
    m.refreshTimer.control = "start"

    renderCameras()
    updateSelection()
end sub

sub renderCameras()
    if m.config = invalid or not m.config.doesExist("cameras") then
        return
    end if

    cameras = m.config.cameras
    m.status.text = "Refreshing every " + m.refreshTimer.duration.toStr() + "s"

    for i = 0 to m.cameraNodes.count() - 1
        poster = m.cameraPosters[i]
        node = m.cameraNodes[i]

        if i < cameras.count() then
            camera = cameras[i]
            poster.uri = addCacheBust(buildSnapshotUrl(m.config, camera))
            node.text = camera.name
        else
            poster.uri = ""
            node.text = "Empty slot"
        end if
    end for
end sub

sub onRefreshTimerFire()
    if m.isLiveView then
        return
    end if

    m.refreshToken = m.refreshToken + 1
    renderCameras()
end sub

function onKeyEvent(key as String, press as Boolean) as Boolean
    if not press then
        return false
    end if

    lower = LCase(key)

    if m.isLiveView then
        if lower = "back" then
            closeLiveView()
            return true
        end if

        return false
    end if

    if lower = "right" and m.selectedIndex mod 2 = 0 and m.selectedIndex + 1 < m.config.cameras.count() then
        m.selectedIndex = m.selectedIndex + 1
        updateSelection()
        return true
    else if lower = "left" and m.selectedIndex mod 2 = 1 then
        m.selectedIndex = m.selectedIndex - 1
        updateSelection()
        return true
    else if lower = "down" and m.selectedIndex < 2 and m.selectedIndex + 2 < m.config.cameras.count() then
        m.selectedIndex = m.selectedIndex + 2
        updateSelection()
        return true
    else if lower = "up" and m.selectedIndex >= 2 then
        m.selectedIndex = m.selectedIndex - 2
        updateSelection()
        return true
    else if lower = "ok" then
        openLiveView()
        return true
    end if

    return false
end function

sub updateSelection()
    for i = 0 to m.cameraFrames.count() - 1
        if i = m.selectedIndex then
            m.cameraFrames[i].color = "0x2EA043FF"
        else
            m.cameraFrames[i].color = "0x1F262DFF"
        end if
    end for
end sub

sub openLiveView()
    if m.config = invalid or not m.config.doesExist("cameras") or m.selectedIndex >= m.config.cameras.count() then
        return
    end if

    camera = m.config.cameras[m.selectedIndex]
    liveUrl = buildLiveUrl(m.config, camera)
    content = CreateObject("roSGNode", "ContentNode")
    content.url = liveUrl
    content.streamformat = "hls"
    content.title = camera.name

    m.liveVideo.content = content
    m.liveVideo.visible = true
    m.liveVideo.control = "play"
    m.isLiveView = true
    m.status.text = "Live view: " + camera.name
    m.help.text = "Press Back to return to the snapshot wall."
end sub

sub closeLiveView()
    m.liveVideo.control = "stop"
    m.liveVideo.visible = false
    m.isLiveView = false
    m.status.text = "Refreshing every " + m.refreshTimer.duration.toStr() + "s"
    m.help.text = "Use arrows to choose a camera. Press OK for live view. Press Back to return."
    m.top.setFocus(true)
end sub

function buildSnapshotUrl(config as Object, camera as Object) as String
    if not config.doesExist("backend") or not config.backend.doesExist("baseUrl") then
        return ""
    end if

    baseUrl = config.backend.baseUrl
    path = ""

    if camera.doesExist("snapshotPath") then
        path = camera.snapshotPath
    else if camera.doesExist("frigateCamera") then
        path = "/api/" + camera.frigateCamera + "/latest.jpg"
    else
        return ""
    end if

    if right(baseUrl, 1) = "/" and left(path, 1) = "/" then
        return left(baseUrl, len(baseUrl) - 1) + path
    else if right(baseUrl, 1) <> "/" and left(path, 1) <> "/" then
        return baseUrl + "/" + path
    end if

    return baseUrl + path
end function

function addCacheBust(url as String) as String
    token = m.refreshToken.toStr()

    if instr(1, url, "?") > 0 then
        return url + "&cb=" + token
    end if

    return url + "?cb=" + token
end function

function buildLiveUrl(config as Object, camera as Object) as String
    if not config.doesExist("live") or not config.live.doesExist("baseUrl") or not camera.doesExist("frigateCamera") then
        return ""
    end if

    baseUrl = config.live.baseUrl
    path = "/api/stream.m3u8?src=" + camera.frigateCamera

    if right(baseUrl, 1) = "/" and left(path, 1) = "/" then
        return left(baseUrl, len(baseUrl) - 1) + path
    else if right(baseUrl, 1) <> "/" and left(path, 1) <> "/" then
        return baseUrl + "/" + path
    end if

    return baseUrl + path
end function