require "util"

local p = Proto("pictochat", "PictoChat")

function p.init()
	local dt = DissectorTable.get("dslmp")
	dt:add(GAMEID.PICTOCHAT, p)
end

local MSG_TYPE = {
	INIT = 0,
	MSG_START = 10,
	MSG_END = 24,
	USER_JOIN = 48,
	STATUS = 52,
	MSG_BODY = 86,
}

local MSG_TYPE_MAP = {
	[MSG_TYPE.INIT] = "Init", -- sent once (init?)
	[MSG_TYPE.MSG_START] = "Message start", -- sent before a message packet
	[MSG_TYPE.MSG_END] = "Message end", -- sent after multi-frame message body packets
	[MSG_TYPE.USER_JOIN] = "User join", -- these packets contain a username
	[MSG_TYPE.STATUS] = "Status", -- constantly spammed (status?)
	[MSG_TYPE.MSG_BODY] = "Message body", -- contains tile data for drawing
}

p.fields.unknown = ProtoField.uint16("pictochat.unknown", "Unknown")

local function dissect_payload(buffer, pinfo, tree)
	tree:add_le(p.fields.payload_len, buffer(0x00, 2))
	local payload_length = buffer(0x00, 2):le_uint()
	buffer = buffer(0x02)
	return buffer, tree:add(buffer(0x00, payload_length), "Payload: " .. payload_length .. " bytes")
end

local dissect_msg_type = { }

p.fields.msg_start_len = ProtoField.uint8("pictochat.msg_start.len", "Total length")
local state = {}
dissect_msg_type[MSG_TYPE.MSG_START] = function (buffer, pinfo, tree)
	local payload
	buffer, payload = dissect_payload(buffer, pinfo, tree)

	payload:add_le(p.fields.msg_start_len, buffer(0x04, 2))
	local start_len = buffer(0x04, 2):le_uint()

	state.data_remaining = start_len
	state.buf = ByteArray.new()
	state.want_next = 0
end

p.fields.user_addr = ProtoField.bytes("pictochat.user.addr", "Address", base.COLON)
p.fields.user_name = ProtoField.string("pictochat.user.name", "Nickname")
p.fields.user_msg = ProtoField.string("pictochat.user.msg", "Message")
p.fields.user_color = ProtoField.uint16("pictochat.user.color", "Color", base.DEC, PROFILE_COLOR_MAP)
p.fields.user_bday_month = ProtoField.uint8("pictochat.user.bday_month", "Month")
p.fields.user_bday_day = ProtoField.uint8("pictochat.user.bday_day", "Day")
dissect_msg_type[MSG_TYPE.USER_JOIN] = function (buffer, pinfo, tree)
	local payload
	buffer, payload = dissect_payload(buffer, pinfo, tree)

	add_addr_le(payload, p.fields.user_addr, buffer(0x0a, 6))
	local user_name = buffer(0x10, 20):le_ustring()
	payload:add(p.fields.user_name, buffer(0x10, 20), user_name)
	register_addr_le(buffer(0x0a, 6):raw(), user_name)
	pinfo.cols.info = string.format("%s (%s)", pinfo.cols.info, user_name)
	payload:add(p.fields.user_msg, buffer(0x24, 52), buffer(0x24, 52):le_ustring())
	payload:add_le(p.fields.user_color, buffer(0x58, 2))
	local bday = payload:add(buffer(0x5a, 2), string.format("Birthday: %02d/%02d", buffer(0x5a, 1):uint(), buffer(0x5b, 1):uint()))
	bday:add(p.fields.user_bday_month, buffer(0x5a, 1))
	bday:add(p.fields.user_bday_day, buffer(0x5b, 1))
end

p.fields.payload_len = ProtoField.uint16("pictochat.payload_len", "Payload length")
p.fields.data_len = ProtoField.uint8("pictochat.data_len", "Data length")
p.fields.data_end = ProtoField.bool("pictochat.data_end", "Data end")
p.fields.data_offset = ProtoField.uint16("pictochat.data_offset", "Data offset")
p.fields.data_sequence = ProtoField.uint16("pictochat.data_sequence", "Data sequence")
p.fields.data = ProtoField.bytes("pictochat.data", "Data")
p.fields.sequence = ProtoField.uint16("pictochat.sequence", "Packet sequence")
dissect_msg_type[MSG_TYPE.MSG_BODY] = function (buffer, pinfo, tree)
	local payload
	buffer, payload = dissect_payload(buffer, pinfo, tree)

	payload:add_le(p.fields.unknown, buffer(0x00, 2))
	payload:add_le(p.fields.data_len, buffer(0x02, 1))
	local data_length = buffer(0x02, 1):le_uint()

	payload:add_le(p.fields.data_end, buffer(0x03, 1))
	-- This appears to be some kind of offset for indicating where to store the
	-- current frame's data in a larger buffer. Messages sent in multiple parts
	-- increment this value by 160 for each new original (p.fields.original ==
	-- True) message.
	payload:add_le(p.fields.data_offset, buffer(0x04, 2))
	local data_offset = buffer(0x04, 2):le_uint()
	payload:add_le(p.fields.unknown, buffer(0x06, 2)) -- usually 0

	buffer = buffer(0x08)
	-- This appears to be the actual message data (the drawing) sent as an
	-- array of 8x8 tiles.
	payload:add(p.fields.data, buffer(0, data_length))
	if state.want_next == data_offset then
		state.want_next = data_offset + data_length
		state.data_remaining = state.data_remaining - data_length
		state.buf:append(buffer(0, data_length):bytes())
		pinfo.cols.info = "Message body"
		ByteArray.tvb(state.buf, "Complete message")
	end
	buffer = buffer(data_length)

	payload:add_le(p.fields.data_sequence, buffer(0x00, 2))
	payload:add_le(p.fields.unknown, buffer(0x02, 2)) -- copy
end

p.fields.status_addr = ProtoField.bytes("pictochat.status.addr", "Address", base.COLON)
dissect_msg_type[MSG_TYPE.STATUS] = function (buffer, pinfo, tree)
	local payload
	buffer, payload = dissect_payload(buffer, pinfo, tree)

	payload:add_le(p.fields.unknown, buffer(0x00, 2))
	payload:add_le(p.fields.unknown, buffer(0x02, 2))

	buffer = buffer(0x04)

	for _ = 0, 15 do
		-- payload:add(p.fields.status_addr, buffer(0, 6))
		add_addr_le(payload, p.fields.status_addr, buffer(0, 6))
		buffer = buffer(6)
	end

	payload:add_le(p.fields.unknown, buffer(0x00, 2))
	payload:add_le(p.fields.unknown, buffer(0x02, 2))
end

p.fields.magic = ProtoField.bytes("pictochat.magic", "Magic")
p.fields.new = ProtoField.bool("pictochat.new", "New")
p.fields.msg_type = ProtoField.uint8("pictochat.msg_type", "Message type", base.DEC, MSG_TYPE_MAP)
function p.dissector(buffer, pinfo, tree)
	-- check magic
	if buffer(0x00, 2):uint() ~= GAMEID.PICTOCHAT then return 0 end

	local subtree = tree:add(p, buffer(), string.format("%s: %d bytes", p.description, buffer():len()))
	local buffer_len = buffer():len()

  subtree:add_le(p.fields.magic, buffer(0x00, 2))
  subtree:add_le(p.fields.new, buffer(0x02, 2))
	subtree:add_le(p.fields.msg_type, buffer(0x04, 1))
	local msg_type = buffer(0x04, 1):le_uint()
	local msg_type_str = MSG_TYPE_MAP[msg_type]
  subtree:add_le(p.fields.unknown, buffer(0x05, 1))

	-- pretty wireshark shit
	pinfo.cols.protocol = p.name
	if msg_type_str ~= nil then
		pinfo.cols.info = msg_type_str
	end

	if msg_type == 0 then
		-- no more content
		return buffer_len
	end

  subtree:add_le(p.fields.unknown, buffer(0x06, 2))
	buffer = buffer(0x08)

	local subdissector = dissect_msg_type[msg_type]
	if subdissector ~= nil then
		subdissector(buffer, pinfo, subtree)
	end
end