#!/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("luci.jsonc")
require("aredn.http")
require("aredn.hardware")
require("aredn.utils")
local html = require("aredn.html")
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 rescan = string.find((nixio.getenv("QUERY_STRING") or ""):lower(),"rescan=1")

local scanlist = {}
-- Show the last scan if we have one, it's not too old, and we're not rescanning
if not rescan then
    local lscan = io.open("/tmp/last-scan.json")
    if lscan then
        scanlist = luci.jsonc.parse(lscan:read("*a") or "")
        lscan:close()
    end
end

if rescan then
    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[tostring(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

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

    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)
        scan.chan = table.concat(chan, " ")
        if scan.joined then
            scan.hostname = node
        else
            -- ip lookup then host lookup
            local ip = arpcache[scan.mac]
            if ip then
                scan.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
                            scan.hostname = m:gsub("^mid[0-9]*%.",""):gsub("^dtdlink%.",""):gsub("%.local%.mesh$","")
                            break
                        end
                    end
                    f:close()
                end
            else
                scan.hostname = "-"
            end
        end
    end
    lscan = io.open("/tmp/last-scan.json", "w")
    if lscan then
        lscan:write(luci.jsonc.stringify(scanlist, true))
        lscan:close()
    end
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
if rescan then
    html.print([[
        <script>
            if (history.replaceState) {
                history.replaceState(null, "", window.location.origin + window.location.pathname)
            }
        </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>
    <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=Rescan title='Run a new scan' onclick='window.location = window.location.origin + window.location.pathname + "?rescan=1"'>]])
    if not ubnt_ac then
        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
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>")

for _, scan in ipairs(scanlist)
do
    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>" .. scan.chan .. "</td><td>" .. scan.key .. "</td><td>" .. scan.ssid .. "</td><td align=center>" .. scan.hostname .. "</td><td>" .. scan.mac:upper() .. "</td><td>" .. scan.mode .. "</td>")
    html.print("</tr>")
end

html.print("</table><br>")
local lastscan = nixio.fs.stat("/tmp/last-scan.json", "mtime")
if lastscan then
    lastscan = os.time() - lastscan
    if lastscan == 1 then
        html.print("<div>Last scan: 1 second ago")
    elseif lastscan < 60 then
        html.print("<div>Last scan: " .. lastscan .. " seconds ago")
    elseif lastscan < 120 then
        html.print("<div>Last scan: 1 minute ago")
    elseif lastscan < 3600 then
        html.print("<div>Last scan: " .. math.floor(lastscan / 60) .. " minutes ago")
    else
        html.print("<div>Last scan: a long time ago")
    end
else
    html.print("<div>Last scan: none")
end
html.footer()
html.print("</center></body></html>")