function handle_request(env)
    uhttpd.send("Status: 200 OK\r\n")
    uhttpd.send("Content-Type: application/json\r\n\r\n")
    local ip = env.REMOTE_HOST
    local url = env.headers.URL 
    local prefix = "/nds/"
    if url == prefix.."clients" then
        local resp = os.capture("ndsctl json")
        resp = resp:gsub("} {", ",")
        print(resp)
    end
    if url == prefix.."me" then
        url = prefix.."client/"..ip
    end
    if string.starts(url, prefix.."client/") then
        local id = string.sub(url,string.len(prefix)+8)
        if checkipv4(id) or checkmac(id) or checktoken(id) then
            os.execute("ndsctl json "..id)
        end
    end
end

function checkipv4(ip)
    local chunks = {ip:match("^(%d+)%.(%d+)%.(%d+)%.(%d+)$")}
    if (#chunks == 4) then
        for _,v in pairs(chunks) do
            if (tonumber(v) < 0 or tonumber(v) > 255) then
                return true
            end
        end
        return true
    else
        return false
    end
end

function checkmac(str)
    local s = str
    if not s:find("^%w+:%w+:%w+:%w+:%w+:%w+$") then
        return false
    end
    for substr in s:gmatch("(%w+)") do
        if not substr:find("^[0-9A-Fa-f][0-9A-Fa-f]$") then
            return false
        end
    end
    return true
end

function checktoken(t)
    if not t:find("^[0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f]$") then
        return false
    end
    return true
end

function string.starts(String,Start)
    return string.sub(String,1,string.len(Start))==Start
end 

function os.capture(cmd, raw)
    local f = assert(io.popen(cmd, 'r'))
    local s = assert(f:read('*a'))
    f:close()
    if raw then return s end
    s = string.gsub(s, '^%s+', '')
    s = string.gsub(s, '%s+$', '')
    s = string.gsub(s, '[\n\r]+', ' ')
    return s
end

function table_to_string(tbl)
    local result = "{"
    for k, v in pairs(tbl) do
        -- Check the key type (ignore any numerical keys - assume its an array)
        if type(k) == "string" then
            result = result.."[\""..k.."\"]".."="
        end

        -- Check the value type
        if type(v) == "table" then
            result = result..table_to_string(v)
        elseif type(v) == "boolean" then
            result = result..tostring(v)
        else
            result = result.."\""..v.."\""
        end
        result = result..","
    end
    -- Remove leading commas from the result
    if result ~= "{" then
        result = result:sub(1, result:len()-1)
    end
    return result.."}"
end