---------------------------------------------------
-- Licensed under the GNU General Public License v2
--  * (c) 2010, Adrian C. <anrxc@sysphere.org>
--  * (c) 2009, Lucas de Vries <lucas@glacicle.com>
---------------------------------------------------

-- {{{ Grab environment
local tonumber = tonumber
local os = { time = os.time }
local io = { open = io.open }
local setmetatable = setmetatable
local string = { match = string.match }
local helpers = require("vicious.helpers")
-- }}}


-- Net: provides usage statistics for all network interfaces
module("vicious.net")


-- Initialise function tables
local nets = {}
-- Variable definitions
local unit = { ["b"] = 1, ["kb"] = 1024,
    ["mb"] = 1024^2, ["gb"] = 1024^3
}

-- {{{ Net widget type
local function worker(format)
    -- Get /proc/net/dev
    local f = io.open("/proc/net/dev")
    local args = {}

    for line in f:lines() do
        -- Match wmaster0 as well as rt0 (multiple leading spaces)
        if string.match(line, "^[%s]?[%s]?[%s]?[%s]?[%w]+:") then
            local name = string.match(line, "^[%s]?[%s]?[%s]?[%s]?([%w]+):")
            -- Received bytes, first value after the name
            local recv = tonumber(string.match(line, ":[%s]*([%d]+)"))
            -- Transmited bytes, 7 fields from end of the line
            local send = tonumber(string.match(line,
             "([%d]+)%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d+%s+%d$"))

            helpers.uformat(args, name .. " rx", recv, unit)
            helpers.uformat(args, name .. " tx", send, unit)

            if nets[name] == nil then
                -- Default values on the first run
                nets[name] = {}
                helpers.uformat(args, name .. " down", 0, unit)
                helpers.uformat(args, name .. " up",   0, unit)

                nets[name].time = os.time()
            else -- Net stats are absolute, substract our last reading
                local interval  = os.time() - nets[name].time >  0 and
                                  os.time() - nets[name].time or 1
                nets[name].time = os.time()

                local down = (recv - nets[name][1]) / interval
                local up   = (send - nets[name][2]) / interval

                helpers.uformat(args, name .. " down", down, unit)
                helpers.uformat(args, name .. " up",   up,   unit)
            end

            -- Store totals
            nets[name][1] = recv
            nets[name][2] = send
        end
    end
    f:close()

    return args
end
-- }}}

setmetatable(_M, { __call = function(_, ...) return worker(...) end })