#!/usr/bin/env ruby

require "serialport"

#
# Keep an updated buffer of anchor configurations from cloud
# Provide a serial API towards ble-gateway to support update requests
# Install:
# Most recent ruby version should work e.g. 2.6 or later:
#     ruby --version
# Serial port package/gem is required dependency:
#     sudo gem install serialport
#

class AnchorConf

	# Keep static configuration for now
	# MAC => config hash
	# name - popular name
	# utime - last update time
	# ...
	# TODO: Replace by cloud connection
	CFG = {
		"09:03:2F:2F:9A:37" => { name: "c2m",  utime: 0, kind: :master, :id => 5, :slave_cnt => 3 },
		"64:FB:DB:06:4A:2C" => { name: "c2s1", utime: 0, kind: :slave , :master_id => 5, :slave_ix => 0, :slave_cnt => 3 },
		"78:31:2E:13:A9:02" => { name: "c2s2", utime: 1, kind: :slave , :master_id => 5, :slave_ix => 1, :slave_cnt => 3 },
		"9E:B3:AD:ED:B7:68" => { name: "c2s3", utime: 1, kind: :slave , :master_id => 5, :slave_ix => 2, :slave_cnt => 3 },
		"95:A2:35:CD:CA:2F" => { name: "t2",   utime: 2, kind: :tag },
		"92:A0:75:A8:AE:AA" => { name: "m3",   utime: 2, kind: :master, :id => 3, :slave_cnt => 4 },
		"5A:7E:15:83:EC:E6" => { name: "s31",  utime: 3, kind: :slave , :master_id => 3, :slave_ix => 0, :slave_cnt => 4 },
		"28:B8:4F:67:5E:6F" => { name: "s32",  utime: 3, kind: :slave , :master_id => 3, :slave_ix => 1, :slave_cnt => 4 },
		"99:77:A3:79:79:AD" => { name: "s33",  utime: 4, kind: :slave , :master_id => 3, :slave_ix => 2, :slave_cnt => 4 },
		"E4:D6:08:63:26:5B" => { name: "s34",  utime: 4, kind: :slave , :master_id => 3, :slave_ix => 3, :slave_cnt => 4 },
	}

	# Get all config values as configuration string
	def all_to_str
		self.class.to_str(all)
	end

	# Get config values with :utime grater than gt_utime as configuration string
	def recent_to_str(gt_utime)
		self.class.to_str(recent(gt_utime))
	end

	private 		# only helpers below ...
	
	# Get all config items
	def all
		CFG
	end

	# Get all config items where :utime is grater than gt_utime
	def recent(gt_utime)
		CFG.select { |_, x| x[:utime] > gt_utime }
	end

	# Convert MAC formatted as "09:03:2F:2F:9A:37" with colons removed "09032F2F9A37"
	def self.mac_format(s)
		s.split(':').join
	end

	# Convert GFG key value item to config string
	# Sample format for master: "\x37\x9A\x2F\x2F\x03\x09,M,1,5;"
	def self.item_to_str(k, v)
		s = ""
		mac = mac_format(k)
		case v[:kind]
		when :master
			"#{mac},M,#{v[:id]},#{v[:slave_cnt]}"
		when :slave
			"#{mac},S,#{v[:master_id]},#{v[:slave_ix]},#{v[:slave_cnt]}"
		when :tag
			"#{mac},T"
		end
	end


	# Get max utime value of items
	def self.utime_max(items)
		items.values.max { |a, b| a[:utime] <=> b[:utime] }[:utime]
	end

	# Helper: Convert items to string format
	def self.to_str(items)
		ans = ""
		unless items.empty? then
			# Items using semicolon as separator
			ans = items.map { |k, v| item_to_str(k, v) }.join(';') + ";"
			# add max utime for transmission
			ans << "TIME:" + utime_max(items).to_s + ";"
		end
		# add explicit EOT and semicolon as message end
		ans << "EOT;"
	end
	
end

# Debug output
def show(s)
	puts s
end

if ARGV[0] == "help" then
	puts "usage:"
	puts "1. Start BLE gateway device connected via USB"
	puts "2. Determine which device is connected"
	puts "  * Look for \"Product: USB CDC For PALOS\" using e.g. dmesg"
	puts "3. Start this script with corresponding device as first argument e.g."
	puts "    ./cloud-link.rb /dev/ttyACM0"
	exit
end

db = AnchorConf.new

# Test: print database records
# show "get all:"
# show db.all_to_str

serial_dev="/dev/ttyACM2" 						# typical Linux device
# serial_dev="/dev/cu.usbmodemC9032F2F9A371"	# typical macOS device

serial_dev=ARGV[0] if ARGV.size == 1

# Test using regular file
# Term1: ./cloud-link.rb
# Term2: echo "get:0;" >> ./tmp/pipefile
# serial_dev="./tmp/pipefile"

show "Start protocol on device: " + serial_dev

# Basic test of serial port
# sp = SerialPort.new(serial_dev, 115200, 8, 1, SerialPort::NONE)
# while true do
#   message = sp.read(3)
#   if message
#     # message.chomp!
#     puts "message:"+message
#   end
# end

# Open protocol towards serial client
# 
# For basic testing ...
# macOS e.g.
# ioreg -p IOUSB
# sudo cu -l /dev/cu.usbmodemC9032F2F9A371
# Linux e.g.
# cu -l /dev/ttyACM0 -s 115200
#
sp = SerialPort.new(serial_dev, 115200, 8, 1, SerialPort::NONE)

buffer = ""
cmds = []
loop do
	# add data to buffer
	# data = sp.read(1)
	data = sp.getc
	# show "data: #{data}"
	if data then
		if data.size > 0 then
			buffer << data
		else
			sleep 0.1
		end
	else
		show "serial closed"
		exit
	end
	# extract zero or more commands
	while (not buffer.empty?) && buffer.include?(';') do
		cmd, rest = buffer.split(';', 2)
		cmds << cmd
		buffer = rest
	end
	# print/execute commands
	cmds.each do |cmd|
		show "command: #{cmd}"
		token, n = cmd.split(':', 2)
		case token
		when "nop"
			show "response: N/A"
		when "get"
			# print response
			resp = db.recent_to_str(n.to_i)
			show "response: #{resp}"
			# Note: write seems to give problems at reponse end
			# sp.write(resp)
			# Note: loop delay also makes it more robust
			resp.each_char { |c| 
				sp.putc(c)
				sleep 0.001
			}
		else
			show "unsupported command: #{token}"
		end
	end
	cmds = []
end