var fs = require('fs')
var http = require('http')
var mime = require('mime')
var snmp = require('snmpjs')
var Logger = require('bunyan')
var util = require('util')

var config = JSON.parse(fs.readFileSync(process.argv[2] || 'microcontrold.json'))
config.log = config.log || {}
config.snmp = config.snmp || {}
config.snmp.manager = config.snmp.manager || {}
config.snmp.manager.trap_community = config.snmp.manager.trap_community || null
config.http = config.http || {}
config.http.port = config.http.port || 80
config.http.static_directory = config.http.static_directory || null

var log_options = { name: 'microcontrold' }
switch (typeof config.log)
{
    case 'array':
        log_options.streams = config.log
        break
    case 'object':
        if ('type' in config.log || 'path' in config.log || 'stream' in config.log)
            log_options.streams = [ config.log ]
        else if ('level' in config.log)
            log_options.level = config.log.level
        break
}
var log = new Logger(log_options)

var output_oids = {
    '1.3.6.1.4.1.17095.3.1.0':  'OUT0',
    '1.3.6.1.4.1.17095.3.2.0':  'OUT1',
    '1.3.6.1.4.1.17095.3.3.0':  'OUT2',
    '1.3.6.1.4.1.17095.3.4.0':  'OUT3',
    '1.3.6.1.4.1.17095.3.5.0':  'OUT4',
    '1.3.6.1.4.1.17095.3.6.0':  'OUT5',
}

var input_oids = {
    '1.3.6.1.4.1.17095.4.1.0':  'TEMP',
    '1.3.6.1.4.1.17095.4.2.0':  'VCC',
    '1.3.6.1.4.1.17095.4.3.0':  'INP1',
    '1.3.6.1.4.1.17095.4.4.0':  'INP2',
    '1.3.6.1.4.1.17095.4.5.0':  'INP3',
    '1.3.6.1.4.1.17095.4.6.0':  'INP4',
    '1.3.6.1.4.1.17095.4.7.0':  'INP5',
    '1.3.6.1.4.1.17095.5.1.0':  'INP6',
    '1.3.6.1.4.1.17095.5.2.0':  'INP7',
    '1.3.6.1.4.1.17095.5.3.0':  'INP8',
    '1.3.6.1.4.1.17095.5.4.0':  'INP9',
    '1.3.6.1.4.1.17095.5.5.0':  'INP10',
    '1.3.6.1.4.1.17095.5.6.0':  'INP11',
    '1.3.6.1.4.1.17095.6.1.0':  'DTH22t',
    '1.3.6.1.4.1.17095.6.2.0':  'DTH22h',
//  '1.3.6.1.4.1.17095.7.1.0':  'I3XI5',
//  '1.3.6.1.4.1.17095.7.2.0':  'PXT',
    '1.3.6.1.4.1.17095.10.1.0': 'INP1D',
    '1.3.6.1.4.1.17095.10.2.0': 'INP2D',
    '1.3.6.1.4.1.17095.10.3.0': 'INP3D',
    '1.3.6.1.4.1.17095.10.4.0': 'INP4D',
}

/*
var inputs = {}
for (oid in input_oids)
    inputs[input_oids[oid]] = { name: input_oids[oid], oid: oid, value: null }
*/
var inputs = Object.keys(input_oids).reduce(function(s, oid)
{
    s[input_oids[oid]] = { name: input_oids[oid], oid: oid, value: null }; return s
}, {}) //Object.create(null)

var httpd = http.createServer()
httpd.log = log.child({ component: 'httpd', serializers: { request: Logger.stdSerializers.req } })
httpd.on('request', function(request, response)
{
    if (request.method == 'GET')
    {
        if (status = /^\/status(?:\/(.+))?/.exec(request.url))
        {
            var input = status[1]
            var result = typeof input !== 'undefined' ? result = inputs[input] : inputs
            response.writeHead(200, { 'Content-Type': 'application/json'})
            response.write(JSON.stringify(result))
            response.end()
        }
        else
        {
            if (request.url == '/') request.url = '/index.html'
            var filename = config.http.static_directory + request.url
            fs.readFile(filename, function(error, contents)
            {
                if (error)
                    if (error.code == 'ENOENT')
                        response.writeHead(404, 'File Not Found')
                    else
                    {
                        response.writeHead(500, 'Internal Server Error')
                        response.write(JSON.stringify(error))
                    }
                if (contents)
                {
                    response.writeHead(200, { 'Content-Length': contents.length, 'Content-Type': mime.lookup(filename) })
                    response.write(contents)
                }
                response.end()
            })
        }
    }
})
httpd.listen(config.http.port, function() { httpd.log.info('Listening on port ' + httpd.address().port) })

var socket_io_server = require('socket.io')(httpd)
socket_io_server.on('connection', function(socket)
{
    httpd.log.info({ client_id: socket.client.id, request: socket.client.request }, 'Connect')
    socket.emit('status', inputs)
    socket.join('microcontrold')
})

var snmpd = snmp.createTrapListener({ name: 'snmpd', log: log })
snmpd._log.fields.component = 'snmpd'
snmpd.on('trap', function(snmpmsg)
{
    if (
        // Access Checks
        (snmpmsg.community == config.snmp.manager.trap_community) &&
        (snmpmsg.pdu.agent_addr == '10.98.184.246') &&
        // Trap Checks
        (snmpmsg.pdu.generic_trap == 6) &&
        (snmpmsg.pdu.specific_trap == 768) &&
        (snmpmsg.pdu.enterprise == '1.3.6.1.4.1.17095')
    )
        for (var vb = 0; vb < snmpmsg.pdu.varbinds.length; vb++)
        {
            var oid = snmpmsg.pdu.varbinds[vb].oid
            var name = input_oids[oid]
            var value = snmpmsg.pdu.varbinds[vb].data.value
            var input = inputs[name]

            if (input.value != value)
            {
                snmpd._log.info({ input: { oid: oid, name: name, 'old value': input.value, 'new value': value } }, 'Update')
                input.value = value
                socket_io_server.to('microcontrold').emit('update', input)
            }
        }
})
snmpd.bind({family: 'udp4', port: 162})