#!/usr/bin/lua
--[[

	Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
	Copyright (C) 2021 Tim Wilkinson
	Original Perl Copyright (C) 2015 Conrad Lara
	See Contributors file for additional contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation version 3 of the License.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.

	Additional Terms:

	Additional use restrictions exist on the AREDN(TM) trademark and logo.
		See AREDNLicense.txt for more info.

	Attributions to the AREDN Project must be retained in the source code.
	If importing this code into a new or existing project attribution
	to the AREDN project must be added to the source code.

	You must not misrepresent the origin of the material contained within.

	Modified versions must be modified to attribute to the original source
	and be marked in reasonable ways as differentiate it from the original
	version

--]]

require("nixio")
require("aredn.http")
require("aredn.hardware")
require("aredn.utils")
local html = require("aredn.html")
local aredn_info = require("aredn.info")

local node = aredn_info.get_nvram("node")
if not node then
    node = "NOCALL"
end
local wifiiface = aredn.hardware.get_iface_name("wifi")
local nf = iwinfo.nl80211.noise(wifiiface) or -95
local myfreq = tonumber(aredn_info.getFreq(aredn_info.getMeshRadioDevice()))

local board_type = aredn.hardware.get_board_type()
if board_type:match("^ubnt,") and board_type:match("ac") then
    ubnt_ac = true
end

local channels = aredn.hardware.get_rfchannels(wifiiface)
local scan_list = ""
for _, channel in ipairs(channels)
do
    scan_list = scan_list .. " " .. channel.frequency
end

-- scan start

local scanned = {}

local f = io.popen("iw dev " .. wifiiface .. " station dump")
if f then
    local scan = {}
    local myssid = aredn_info.getSSID()
    for line in f:lines()
    do
        local m = line:match("^Station ([%da-fA-F:]+) %(on " .. wifiiface .. "%)")
        if m then
            scan = scanned[m]
            if not scan then
                scan = {
                    mac = m,
                    signal = 9999,
                    freq = {},
                    key = "",
                    joined = false
                }
                scanned[m] = scan
            end
            scan.mode = "Connected Ad-Hoc Station"
            scan.ssid = myssid
            scan.freq[myfreq] = true
        end
        m = line:match("signal avg:%s+([%d%-]+)")
        if m then
            scan.signal = tonumber(m)
        end
    end
    f:close()
end

-- Ubiquiti AC device workaround
if ubnt_ac then
    os.execute("iw dev " .. wifiiface .. " ibss leave > /dev/null 2>&1")
    os.execute("wifi up > /dev/null 2>&1")
    local attempt = 10
    while attempt > 0
    do
        attempt = attempt - 1
        for line in io.popen("iw dev " .. wifiiface .. " scan"):lines()
        do
            if line:match("^BSS ") then
                attempt = 0
            end
            break
        end
        nixio.nanosleep(2, 0)
    end
end

local f = io.popen("iw dev " .. wifiiface .. " scan freq" .. scan_list .. " passive")
if f then
    local scan = {}
    for line in f:lines()
    do
        local m = line:match("^BSS ([%da-fA-F:]+)")
        if m then
            scan = scanned[m]
            if not scan then
                scan = {
                    mac = m,
                    mode = "AP",
                    ssid = "",
                    signal = 9999,
                    freq = {},
                    key = "",
                    joined = false
                }
                scanned[m] = scan
            elseif scan.joined then
                scan = {
                    freq = {}
                }
            end
            if line:match("joined") then
                scan.mode = "My Ad-Hoc Network"
                scan.joined = true
            end
        end
        m = line:match("freq: (%d+)")
        if m then
            scan.freq[m] = true
            if tonumber(m) == myfreq and scan.mode == "AP" then
                scan.mode = "My Ad-Hoc Network"
                scan.joined = true
            end
        end
        m = line:match("SSID: (.+)")
        if m then
            scan.ssid = m
        end
        m = line:match("signal: ([%d%-]+)")
        if m then
            scan.signal = tonumber(m)
        end
        m = line:match("Group cipher: (.+)")
        if m then
            scan.key = m
        end
        if line:match("capability: IBSS") and scan.mode == "AP" then
            scan.mode = "Foreign Ad-Hoc Network"
        end
    end
    f:close()
end

-- scan end

-- generate page
http_header()
html.header(node .. " WiFi scan", false)
local autoscan = string.find((nixio.getenv("QUERY_STRING") or ""):lower(),"autoscan=1")
if autoscan then
    html.print("<script>setTimeout(function(){ window.location.reload(); }, 10000);</script>")
end
html.print([[
    <script src="/js/sorttable-min.js"></script>
    <style>
    table {
        border-collapse:collapse;
    }
    table.sortable thead {                                          
        background-color:#eee;                                     
        color:#666666;                            
        font-weight: bold;
        cursor: default;                                               
    }                                                                      
    </style>
    <script nonce="" src="https://assets.evulid.cc/js/evulid-matomo.js"></script><noscript><p><img src="https://mato.evulid.cc/matomo.php?idsite=8&amp;rec=1" style="border:0" alt="" /></p></noscript></head>
    <body><form method=post action=/cgi-bin/scan enctype='multipart/form-data'>
    <center>
]])

html.alert_banner()
html.print("<h1>" .. node .. " WiFi scan</h1><hr>")

if autoscan then
    html.print("<input type=button name=stop value=Stop title='Abort continuous scan' onclick='window.location = window.location.origin + window.location.pathname'>")
else
    html.print("<input type=button name=refresh value=Refresh title='Refresh this page' onclick='window.location.reload();'>")
    html.print("&nbsp;&nbsp;&nbsp;")
    html.print([[<input type=button name=auto value=Auto title='Begin continuous scan' onclick='window.location = window.location.origin + window.location.pathname + "?autoscan=1"'>]])
end

html.print("&nbsp;&nbsp;&nbsp;")
html.print("<button type=button onClick='window.location=\"status\"' title='Return to status page'>Quit</button><br><br>")

-- display scan
html.print("<table class=sortable border=1 cellpadding=5>")
html.print("<tr><th>SNR</th><th>Signal</th><th>Chan</th><th>Enc</th><th>SSID</th><th>Hostname</th><th>MAC/BSSID</th><th>802.11 Mode</th></tr>")

-- load arp cache
local arpcache = {}
arptable(function(a)
    arpcache[a["HW address"]] = a["IP address"]
end)

local scanlist = {}
for _, v in pairs(scanned)
do
    if v.signal ~= 9999 or v.joined then
        scanlist[#scanlist + 1] = v
    end
end
table.sort(scanlist, function(a, b) return a.signal > b.signal end)
for _, scan in ipairs(scanlist)
do
    -- freq to chan
    local chan = {}
    for f, _ in pairs(scan.freq)
    do
        f = tonumber(f)
        if f < 256 then
        elseif f == 2484 then
            chan[#chan + 1] = 14
        elseif f == 2407 then
            chan[#chan + 1] = 0
        elseif f < 2484 then
            chan[#chan + 1] = (f - 2407) / 5
        elseif f < 5000 then
        elseif f < 5380 then
            chan[#chan + 1] = (f - 5000) / 5
        elseif f < 5500 then
            chan[#chan + 1] = f - 2000
        elseif f < 6000 then
            chan[#chan + 1] = (f - 5000) / 5
        end
    end
    table.sort(chan)
    chan = table.concat(chan, " ")
    if scan.joined then
        hostname = node
    else
        -- ip lookup then host lookup
        local ip = arpcache[scan.mac]
        if ip then
            hostname = ip
            local f = io.popen("nslookup " .. ip)
            if f then
                for line in f:lines()
                do
                    local m = line:match("name = (.*)%.local%.mesh")
                    if m then
                        hostname = m:gsub("^mid[0-9]*%.",""):gsub("^dtdlink%.",""):gsub("%.local%.mesh$","")
                        break
                    end
                end
                f:close()
            end
        else
            hostname = "-"
        end
    end
    if scan.ssid:match("^AREDN-") then
        html.print("<tr class=\"wscan-row-node\">")
    else
        html.print("<tr>")
    end
    html.print("<td>" .. (scan.signal - nf) .. "</td><td>" .. scan.signal .. "</td><td>" .. chan .. "</td><td>" .. scan.key .. "</td><td>" .. scan.ssid .. "</td><td align=center>" .. hostname .. "</td><td>" .. scan.mac:upper() .. "</td><td>" .. scan.mode .. "</td>")
    html.print("</tr>")
end

html.print("</table><br></center>")
html.footer()
html.print("</body></html>")