#!/usr/bin/env lua

module("moonscript", package.seeall)

require "moonscript.parse"
require "moonscript.compile"
require "moonscript.util"

require "alt_getopt"
require "lfs"

local opts, ind = alt_getopt.get_opts(arg, "vhwt:pTb", {
	print = "p", tree = "T", version = "v", help = "h"
})

local polling_rate = 1.0

local help = [[Usage: %s [options] files...

    -h          Print this message
    -w          Watch file/directory
    -t path     Specify where to place compiled files
    -p          Write output to standard out
    -T          Write parse tree instead of code (to stdout)
    -b          Dump parse and compile time (doesn't write output)
    -v          Print version
]]

if opts.v then
	local v = require "moonscript.version"
	v.print_version()
	os.exit()
end

function print_help(err)
	if err then print("Error: "..err) end
	print(help:format(arg[0]))
	os.exit()
end

function mkdir(path)
	local chunks = util.split(path, "/")
	local accum

	for _, dir in ipairs(chunks) do
		accum = accum and accum.."/"..dir or dir
		lfs.mkdir(accum)
	end

	return lfs.attributes(path, "mode")
end

function normalize(path)
	return path:match("(.-)/*$").."/"
end

function get_dir(fname)
	return fname:match("^(.-)[^/]*$")
end

-- convert .moon to .lua
function convert_path(path)
	return (path:gsub("%.moon$", ".lua"))
end

function msg(...)
	if not opts.p then
		print(...)
	end
end

local gettime = nil
if opts.b then
	pcall(function()
		require "socket"
		gettime = socket.gettime
	end)

	function format_time(time)
		return ("%.3fms"):format(time*1000)
	end
	if not gettime then
		print_help"LuaSocket needed for benchmark"
	end
else
	gettime = function() return 0 end
end

function write_file(fname, code)
	if opts.p then
		if code ~= "" then print(code) end
	else
		mkdir(get_dir(fname))
		local out_f = io.open(fname, "w")
		if not out_f then
			return nil, "Failed to write output: "..fname
		end

		out_f:write(code.."\n")
		out_f:close()
	end
	return true
end

function compile_file(text, fname)
	local parse_time = gettime()
	local tree, err = parse.string(text)
	parse_time = gettime() - parse_time

	if not tree then
		return nil, err
	end

	if opts.T then
		opts.p = true
		dump.tree(tree)
		return ""
	else
		local compile_time = gettime()
		local code, err, pos = compile.tree(tree)
		compile_time = gettime() - compile_time
		if not code then
			return nil, compile.format_error(err, pos, text)
		end

		if opts.b then
			opts.p = true
			return table.concat({
				fname,
				"Parse time  \t" .. format_time(parse_time),
				"Compile time\t" .. format_time(compile_time),
				""
			}, "\n")
		end

		return code
	end
end

function compile_and_write(from, to)
	local f = io.open(from)
	if not f then
		return nil, "Can't find file"
	end
	local text = f:read("*a")

	local code, err = compile_file(text, from)
	if not code then
		return nil, err
	end

	return write_file(to, code)
end

function scan_directory(root, collected)
	root = normalize(root)
	collected = collected or {}

	for fname in lfs.dir(root) do
		if not fname:match("^%.") then 
			local full_path = root..fname

			if lfs.attributes(full_path, "mode") == "directory" then
				scan_directory(full_path, collected)
			end

			if fname:match(".moon") then
				table.insert(collected, full_path)
			end
		end
	end

	return collected
end

function append(a, b)
	for _, v in ipairs(b) do
		table.insert(a, v)
	end
end

function remove_dups(tbl)
	local hash = {}
	local final = {}

	for _, v in ipairs(tbl) do
		if not hash[v] then
			table.insert(final, v)
			hash[v] = true
		end
	end

	return final
end

function get_files(fname, files)
	files = files or {}

	if lfs.attributes(fname, "mode") == "directory" then
		append(files, scan_directory(fname))
	else
		table.insert(files, "./"..fname)
	end

	return files
end

if opts.h then print_help() end

local inputs = {}
for i = ind, #arg do
	table.insert(inputs, arg[i])
end

if #inputs == 0 then
	print_help("No files specified")
end

local target_dir = "."
if opts.t then
	if mkdir(opts.t) ~= "directory" then
		print_help("Invalid target dir")
	end
	target_dir = opts.t
end

target_dir = target_dir.."/"

local files = {}
for _, input in ipairs(inputs) do
	get_files(input, files)
end

files = remove_dups(files)

function get_sleep_func()
	local sleep
	if not pcall(function()
		require "socket"
		sleep = socket.sleep
	end) then
		sleep = moonscript._sleep
	end
	return sleep
end


function plural(count, word)
	if count ~= 1 then
		word = word .. "s"
	end
	return table.concat({count, word}, " ")
end

-- returns an iterator that returns files that have been updated
function create_watcher(files)
	local msg = "Starting watch loop, Ctrl-C to exit"

	local inotify
	pcall(function()
		inotify = require "inotify"
	end)

	if inotify then
		local dirs = {}
		for _, fname in ipairs(files) do
			table.insert(dirs, get_dir(fname))
		end
		dirs = remove_dups(dirs)

		return coroutine.wrap(function()
			print(("%s with inotify [%s]"):format(msg, plural(#dirs, "dir")))

			local wd_table = {}
			local handle = inotify:init()
			for _, dir in ipairs(dirs) do
				local wd = handle:addwatch(dir, inotify.IN_MODIFY)
				wd_table[wd] = dir
			end

			while true do
				local events = handle:read()
				if events then
					for _, ev in ipairs(events) do
						local fname = wd_table[ev.wd]..ev.name
						if fname:match("%.moon$") then
							coroutine.yield(fname)
						end
					end
				else
					break
				end
			end
		end)
	else
		-- poll the filesystem instead
		local sleep = get_sleep_func()
		return coroutine.wrap(function()
			print(("%s with polling [%s]"):format(msg, plural(#files, "file")))

			local mod_time = {}
			while true do
				for _, file in ipairs(files) do
					local time = lfs.attributes(file, "modification")
					if not mod_time[file] then
						mod_time[file] = time
					else
						if time ~= mod_time[file] then
							if time > mod_time[file] then
								coroutine.yield(file)
								mod_time[file] = time
							end
						end
					end
				end
				sleep(polling_rate)
			end
		end)
	end
end

if opts.w then
	local watcher = create_watcher(files)
	-- catches interrupt error for ctl-c
	local protected = function()
		local status, file = pcall(watcher)
		if status then return file end
	end

	for fname in protected do
		local target = target_dir..convert_path(fname)
		local success, err = compile_and_write(fname, target)
		if not success then
			print()
			print("Error:", fname)
			print(err)
			print()
		else
			msg("Built:", fname, "->", target)
		end
	end

	print "\nQuitting..."
else
	for _, fname in ipairs(files) do
		local success, err = compile_and_write(fname, target_dir..convert_path(fname))
		if not success then
			print(fname, err)
			os.exit(1)
		else
			msg("Built", fname)
		end
	end
end