#!/usr/bin/lua5.2
telemver = "0.3 // 2018-05-04"

io = require("io")
os = require("os")
lfs = require("lfs")
string = require("string")
table = require("table")

bad_topics = {}
bad_topics["."] = true
bad_topics[".."] = true
bad_topics["topic"] = true

current_board = ""
current_thread_index = nil

function cat_file(filename)
	io.input(filename)
	welcome = io.read("*all")
	io.input(io.stdin)
	io.write(welcome)
end

function show_welcome()
	print("::::::::::: This is telem ver."..telemver.." :::::::::::")
	cat_file("/var/bbs/docs/welcome")
end

function show_prompt()
	io.write("["..current_board.."] COMMAND :> ")
end

function getchar()
	local char
	os.execute("/bin/stty -icanon")
	char = io.read(1)
	os.execute("/bin/stty icanon")
	return char
end

function get_threads(board)
	local threads = {}
	for topic in lfs.dir("/var/bbs/boards/"..board) do
		if bad_topics[topic] == nil then
			thread = {}
			thread.filename = topic
			thread.directory = "/var/bbs/boards/"..board.."/"..topic
			_, _, timestamp, thread.author = string.find(topic, "(%d+)-(%a+)")
			thread.timestamp = tonumber(timestamp)

			io.input(thread.directory.."/original")
			io.read("*line")
			thread.subject = io.read("*line")
			_, _, thread.subject = string.find(thread.subject, "%[SUBJECT%] (.+)")
			io.input(io.stdin)

			posts = get_posts(thread)
			thread.post_count = #posts
			thread.updated = 0
			for _, post in ipairs(posts) do
				if post.timestamp > thread.updated then
					thread.updated = post.timestamp
				end
			end
			table.insert(threads, thread)
			
		end
	end
	table.sort(threads, function(x,y) return x.updated > y.updated end)
	return threads
end

function get_posts(thread)
	local posts = {}
	for reply in lfs.dir(thread.directory) do
		if string.sub(reply, 1,1) ~= "." then
			post = {}
			post.filename = thread.directory .. "/" .. reply
			if reply == "original" then
				post.author = thread.author
				post.timestamp = thread.timestamp
			else
				_, _, timestamp, post.author = string.find(reply, "(%d+)-(%a+)")
				post.timestamp = tonumber(timestamp)
			end
			table.insert(posts, post)
		end
	end
	table.sort(posts, function(x,y) return x.timestamp < y.timestamp end)
	return posts
end

function do_go()
	print("Which board?")
	board = string.upper(io.read())
	-- TODO: display list of boards only if no board entered
	if board == "" then
		do_list()
	elseif boards[board] == nil then
		print("No such board")
	else
		current_board = board
	end
end

function do_help()
	cat_file("/var/bbs/docs/help")
end

function do_help2()
	cat_file("/var/bbs/docs/help2")
end

function do_unimplemented()
	print("Sorry, this command is not (yet) implemented!")
end

function do_list()
	for _,b in pairs(board_names) do
		posts = -3 -- Don't want to count "topic" file or "." or ".."
		for topic in lfs.dir("/var/bbs/boards/"..b) do
			posts = posts +1
		end
		print(string.format("%s    [%d posts]", b, posts))
	end
end

function do_messages()
	if current_board == "" then
		print("Not at any board")
	else
		threads = get_threads(current_board)
		for i, thread in ipairs(threads) do
			print(tostring(i), os.date("%x %H:%M", thread.timestamp), thread.author, thread.subject)
--, tostring(thread.post_count))
		end
	end
	current_thread_index = threads
end

-- Type stuff below

function do_type_first()
	current_thread_index = 1
	do_type_show_post(current_thread_index)
	print(string.format("Viewing post %d of %d in thread", current_thread_index, #current_thread_posts))
end

function do_type_next()
	if current_thread_index ~= #current_thread_posts then
		current_thread_index = current_thread_index + 1
	end
	do_type_show_post(current_thread_index)
	print(string.format("Viewing post %d of %d in thread", current_thread_index, #current_thread_posts))
end

function do_type_prev()
	if current_thread_index ~= 1 then
		current_thread_index = current_thread_index - 1
	end
	do_type_show_post(current_thread_index)
	print(string.format("Viewing post %d of %d in thread", current_thread_index, #current_thread_posts))
end

function do_type_reply()
end

type_dispatch = {}
type_dispatch["f"] = do_type_first
type_dispatch["n"] = do_type_next
type_dispatch["p"] = do_type_prev
type_dispatch["d"] = function() return end

function do_type()
	print("Which thread?")
	local thread_id = string.upper(io.read())
	thread = current_thread_index[tonumber(thread_id)]
	print("I've been asked to type the thread: " .. thread.subject)
	current_thread_posts = get_posts(thread)
	current_thread_index = #current_thread_posts
	do_type_show_post(current_thread_index)
	print(string.format("Viewing post %d of %d in thread", current_thread_index, #current_thread_posts))
--	for i, post in ipairs(posts) do
--		print(tostring(i), os.date("%x %H:%M", post.timestamp), post.author)
		--cat_file(post.filename)
--	end
	repeat
		show_type_prompt()
		c = getchar()
		io.write("\n")
		if type_dispatch[c] == nil then
			print("Eh?")
		else	
			type_dispatch[c]()
		end
	until c == "d"
end

function show_type_prompt()
	io.write("type prompt ([f]irst, [n]ext, [p]rev, [d]one)>")
end

function do_type_show_post(index)
	local post = current_thread_posts[index]
	cat_file(post.filename)
end

function do_quit()
	print("Goodbye!")
end

function do_rules()
	cat_file("/var/bbs/docs/rules")
end

function do_stub()
	print("Stub!")
end

function do_who()
	os.execute("/usr/bin/w")
end

-- MAIN PROGRAM BODY BELOW

show_welcome()

boards, board_names = {}, {}
for board in lfs.dir("/var/bbs/boards") do
	if string.sub(board, 1, 1) ~= "." then
		boards[board] = true
		table.insert(board_names, board)
	end
end
table.sort(board_names)
message_index = {}

-- Build dispatch table mapping chars to functions
dispatch = {}
dispatch["h"] = do_help
dispatch["g"] = do_go
dispatch["l"] = do_list
dispatch["m"] = do_messages
dispatch["q"] = do_quit
dispatch["t"] = do_type
dispatch["?"] = do_help2
dispatch["!"] = do_rules
dispatch["w"] = do_who
dispatch["s"] = do_unimplemented
dispatch["="] = do_unimplemented
dispatch["M"] = do_unimplemented
dispatch["n"] = do_unimplemented
dispatch["r"] = do_unimplemented
dispatch["b"] = do_unimplemented
dispatch["c"] = do_unimplemented

-- Infinite loop of command dispatch
repeat
	show_prompt()
	c = getchar()
	io.write("\n")
	if dispatch[c] == nil then
		print("What?")
	else	
		dispatch[c]()
	end
until c == "q"