#!/usr/bin/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, "hwt:", { help = "h" })

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

    -h          Print this message
    -w          Watch file/directory
    -t path     Specify where to place compiled files
]]

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

	local tree, err = parse.string(text)
	if not tree then
		return nil, err
	end

	local code = compile.tree(tree)

	mkdir(get_dir(to))
	local out_f = io.open(to, "w")
	if not out_f then
		return nil, "Failed to write output: "..to
	end
	
	out_f:write(code.."\n")
	out_f:close()

	return true
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 dump(tbl)
	local items = {}
	for k,v in pairs(tbl) do
		table.insert(items, ('%s="%s"'):format(k,v))
	end
	return "{ "..table.concat(items, ", ").." }"
end

if opts.w then
	local inotify
	if not pcall(function()
		inotify = require "inotify"
	end) then
		print_help("inotify not installed")
	end

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

	print(("Starting watch loop, Ctrl-C to exit [%d dirs]"):format(#dirs))

	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 success, events = pcall(handle.read, handle)
		if not success then
			print"\nQuitting..."
			break
		end

		if events then
			for _, ev in ipairs(events) do
				local fname = wd_table[ev.wd]..ev.name
				if fname:match("%.moon$") then
					local target = target_dir..convert_path(fname)
					local success, err = compile_file(fname, target)

					if not success then
						print()
						print("Error: "..fname)
						print(err)
						print()
					else
						print("Built", fname)
					end
				end
			end
		else break end
	end
else
	for _, fname in ipairs(files) do
		local success, err = compile_file(fname, target_dir..convert_path(fname))
		if not success then
			print(fname, err)
			break
		else
			print("Built", fname)
		end
	end
end