--[[
    client2server-luv - Event-driven using hotplug + ubus
    
    Features:
    - Listens to hotplug events (IMMEDIATE reaction)
    - Falls back to fast state checker if hotplug not available
    - Uses luv for async event loop
    
    Copyright (c) 2026 Luis Rosales - MIT License
]]

local luv_ok, luv = pcall(require, "luv")

local cfg = {
    server_url = os.getenv("SERVER_URL") or "http://163.245.193.47:3843",
    router_id = os.getenv("ROUTER_ID") or "unknown",
    state_file = "/tmp/client2server_state",
    event_fifo = "/tmp/client2server_events",
}

local function log_info(msg)
    os.execute('logger -t client2server -p user.info "' .. msg .. '"')
end

local function http_post(event_type, data)
    local json = '{"router_id":"' .. cfg.router_id .. '","event":"' .. event_type .. '","data":' .. data .. '}'
    local f = io.popen("curl -s -X POST '" .. cfg.server_url .. "/api/events' -H 'Content-Type: application/json' -d '" .. json .. "'", "r")
    local result = f:read("*a")
    f:close()
    return result
end

local function send_event(event_type, data)
    log_info("Event: " .. event_type)
    local resp = http_post(event_type, data)
    if resp and resp:match("OK") then
        log_info("OK")
    else
        log_info("Fail: " .. (resp or "nil"):sub(1, 50))
    end
end

-- State management
local function load_state()
    local f = io.open(cfg.state_file, "r")
    if f then
        local content = f:read("*a")
        f:close()
        local clients = {}
        local dhcp = {}
        for line in content:gmatch("[^\n]+") do
            local t, v = line:match("^([^:]+):(.+)$")
            if t == "client" then
                local mac, iface = v:match("^(.+)|(.+)$")
                if mac then clients[mac] = {iface=iface} end
            elseif t == "dhcp" then
                local mac, ip = v:match("^(.+)->(.+)$")
                if mac and ip then dhcp[mac] = {ip=ip} end
            end
        end
        return { clients = clients, dhcp = dhcp }
    end
    return { clients = {}, dhcp = {} }
end

local function save_state(state)
    local f = io.open(cfg.state_file, "w")
    if f then
        for mac, info in pairs(state.clients) do
            f:write("client:" .. mac .. "|" .. (info.iface or "") .. "\n")
        end
        for mac, info in pairs(state.dhcp) do
            f:write("dhcp:" .. mac .. "->" .. info.ip .. "\n")
        end
        f:close()
    end
end

-- Create FIFO for hotplug events
local function create_event_fifo()
    os.execute("mkfifo " .. cfg.event_fifo .. " 2>/dev/null")
end

-- Listen to hotplug events (event-driven!)
local function listen_hotplug_events()
    log_info("Listening to hotplug events...")
    
    -- Method 1: Listen to /tmp/client2server_events FIFO
    local fifo = io.open(cfg.event_fifo, "r")
    
    if fifo then
        log_info("Reading from FIFO...")
        while true do
            local line = fifo:read("*line")
            if not line then break end
            
            log_info("Hotplug event: " .. line)
            
            -- Parse event
            local event_type = line:match("([^|]+)|")
            local data = line:match("|(.+)$") or "{}"
            
            send_event(event_type, data)
        end
        fifo:close()
    else
        log_info("FIFO not available, using fallback")
    end
end

-- Alternative: use ubus to subscribe to events
local function subscribe_ubus_events()
    if not luv_ok then return false end
    
    log_info("Subscribing to ubus events...")
    
    -- Use a timer to check for new events in a file
    local timer = luv.new_timer()
    local last_check = 0
    
    local function check_hotplug_log()
        -- Read from system log for hotplug events
        local f = io.popen("logread -l 50 2>/dev/null | grep client2server-hotplug")
        if f then
            for line in f:lines() do
                if line:match("WiFi CONNECTED") then
                    local mac = line:match("([a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9])")
                    if mac then
                        send_event("wifi_connected", '{"mac":"' .. mac .. '"}')
                    end
                elseif line:match("WiFi DISCONNECTED") then
                    local mac = line:match("([a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9])")
                    if mac then
                        send_event("wifi_disconnected", '{"mac":"' .. mac .. '"}')
                    end
                elseif line:match("DHCP NEW") then
                    local mac = line:match("([a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9])")
                    local ip = line:match("-> (%d+%.%d+%.%d+%.%d+)")
                    if mac and ip then
                        send_event("dhcp_new", '{"mac":"' .. mac .. '","ip":"' .. ip .. '"}')
                    end
                elseif line:match("DHCP RELEASE") then
                    local mac = line:match("([a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9]:[a-fA-F0-9][a-fA-F0-9])")
                    local ip = line:match("-> (%d+%.%d+%.%d+%.%d+)")
                    if mac and ip then
                        send_event("dhcp_release", '{"mac":"' .. mac .. '","ip":"' .. ip .. '"}')
                    end
                end
            end
            f:close()
        end
    end
    
    -- Check every 1 second
    luv.timer_start(timer, 1000, 1000, check_hotplug_log)
    
    return true
end

-- Main
function main()
    log_info("Starting client2server-luv...")
    log_info("Router: " .. cfg.router_id)
    log_info("Server: " .. cfg.server_url)
    
    if luv_ok then
        log_info("luv available - async mode")
    else
        log_info("luv NOT available")
    end
    
    -- Initial online event
    send_event("router_online", '{"status":"online"}')
    
    if luv_ok then
        -- Start listening to hotplug log
        subscribe_ubus_events()
        
        -- Run event loop
        luv.run()
    else
        while true do
            os.execute("sleep 60")
        end
    end
end

main()