-- EPG Aggregator
-- Required Astra 5.62-rc8 or newer
--
-- Installation:
-- 1. Install Astra: https://cesbo.com/astra/quick-start/
-- 2. Save script into the file: /etc/astra/epg.lua
-- 3. Change options in the script:
-- 3.1. epg_file - full path to the file to save EPG
-- 3.2. epg_save_interval - save EPG into the file each 60 seconds
-- 3.3. epg_server_port - port to receive EPG from Astra
-- 3.4. epg_expire - expiration time. Channel will be excluded from EPG if has no updates more than 24 hours
-- 3.5. epg_stalker - if true, convert <sub-title/> to <desc/>
-- 4. Launch Astra: astra /etc/astra/epg.lua --daemon
-- 5. In the Stream options (on Astra that receives channels), set EPG Export option. Format: JSON and Destination: http://server-address:5000 (server-address - ip address of the server with this script, 5000 - is a port number defined in the epg_server_port)
--

epg_file = "/tmp/epg.xml"
epg_save_interval = 60
epg_server_port = 5000
epg_expire = 24 * 60 * 60
epg_stalker = false

--

epg_list = {}

function epg_save()
    local channels = {}
    local items = {}

    local ctime = os.time()
    for id, data in pairs(epg_list) do
        if data.expire < ctime then
            epg_list[id] = nil
        else
            table.insert(channels, { id = id, name = data.name })
            for _, x in ipairs(data.items) do
                table.insert(items, x)
            end
        end
    end

    table.sort(channels, function(a, b)
        return a.id < b.id
    end)

    table.sort(items, function(a, b)
        return a.start_ut < b.start_ut
    end)

    local result = epg_utils.format["xmltv"]({ channels = channels, items = items })
    local fd = assert(io.open(epg_file, "w"))
    fd:write(result.content)
    fd:close()
end

timer({
    interval = epg_save_interval,
    callback = function()
        epg_save()
    end
})

function on_http_request(server, client, request)
    if not request then
        return nil
    end

    local data = json.decode(request.content)
    if not data or not data.items then
        server:abort(client, 400)
        return nil
    end

    if data.name then
        -- deprecated
        data.channels = {{ id = data.name, name = data.name }}

        for _,x in ipairs(data.items) do
            x.channel = data.name
        end

        data.name = nil
    end

    if not data.channels then
        server:abort(client, 400)
        return nil
    end

    if epg_stalker then
        for _,x in ipairs(data.items) do
            x["desc"], x["subtitle"] = x["subtitle"], nil
        end
    end

    local ch = data.channels[1]
    epg_list[ch.id] = {
        name = ch.name,
        items = data.items,
        expire = os.time() + epg_expire
    }

    server:send(client, {
        code = 200,
        headers = { "Connection: close" }
    })
end

http_server({
    port = epg_server_port,
    route = {{"/", on_http_request}}
})