local lfs = require("lfs")
require("ext")
local ret = {}

ret.options = {
	paths = {
		type = "folder",
		multiple = true,
		short = "-p",
		long = "--path",
		consumes = 1,
	},
	output = {
		type = "folder",
		short = "-o",
		long = "--output",
		consumes = 1,
		default = ".",
	},
	title = {
		type = "string",
		short = "-t",
		long = "--tile",
		consumes = 1,
		default = "Mdoc Generated Page",
	},
	index = {
		type = "file",
		short = "-i",
		long = "--index",
		consumes = 1,
	},
	document_paths = {
		type = "folder",
		multiple = true,
		short = "-d",
		long = "--document",
		consumes = 1,
	},
	parser = {
		type = "executable",
		short = "-m",
		long = "--markup-parser",
		consumes = 1,
		default = "markdown",
	},
	--append = {
		--type = "file",
		--short = "-a",
		--long = "--append",
		--consumes = 1,
		--multiple = true,
	--},
	verbose = {
		type = "flag",
		short = "-v",
		long = "--verbose"
	},
	help = {
		type = "flag",
		short = "-h",
		long = "--help",
	}
}

local function check_file_type(path, type)
	local attr, err = lfs.attributes(path)
	if attr == nil then
		return attr, err
	end
	if attr.mode == type then
		return path
	else
		return false, string.format("%s was not a folder, it was a %s",path, attr.mode)
	end
end

ret.check_flag = function(...)
	return true
end

ret.check_folder = function(path)
	if path:match("/$") then
		path = path:sub(1,-2)
	end
	return check_file_type(path,"directory")
end

ret.check_string = function(str)
	if type(str) == "string" then
		return str
	else
		return false, string.format("%s was not a string, it was a %s",tostring(str), type(str))
	end
end

ret.check_file = function(path)
	return check_file_type(path,"file")
end

ret.check_executable = function(name)
	local tmpname = "./" .. os.tmpname()
	local pd = assert(io.popen(name .. " > " .. tmpname, "w"))
	pd:write("Hello, world!")
	pd:close()
	local id = assert(io.open(tmpname,"r"))
	local dat = id:read("*a")
	id:close()
	assert(os.remove(tmpname))
	if string.len(dat) > 0 then
		return name
	else
		return false, string.format("Tried to execute %q, but it did not create any data with the input 'Hello, world!', are you sure it's an executale on your PATH?", name)
	end
end

local option_lookup = {}
for k,v in pairs(ret.options) do
	if v.short then
		option_lookup[v.short] = k
	end
	if v.long then
		option_lookup[v.long] = k
	end
end

ret.parse_options = function(args)
	print("parsing args:",args)
	local parsed = {}
	local i = 1
	while i <= #args do
		local option_name = option_lookup[args[i]]
		print("found option:",option_name)
		if not option_name then
			errorf("Unknown option #%d: %q",i, args[i])
		end
		local option = ret.options[option_name]
		assertf(#args > i + (option.consumes or 0) - 1, "Option #%d (%q) consumes %d arguments, but found end of arguments",i,args[i],option.consumes)
		local args_for_option = {}
		for j = i, i+(option.consumes or 0) do
			table.insert(args_for_option,args[j+1])
		end
		--special, if we only consume 1 option, just pass that.
		if option.consumes == 1 then
			args_for_option = args_for_option[1]
		end
		print("checking",option.type)
		print("with",args_for_option)
		local check = assert(ret["check_" .. option.type](args_for_option))
		if option.multiple then
			parsed[option_name] = parsed[option_name] or {}
			table.insert(parsed[option_name],check)
		else
			parsed[option_name] = check
		end
		i = i + 1 + (option.consumes or 0)
	end
	--Set defaults for things that don't have them yet
	for option_name, option in pairs(ret.options) do
		if parsed[option_name] == nil then
			if option.multiple and not option.default then
				parsed[option_name] = {}
			else
				parsed[option_name] = option.default
			end
		end
	end
	return parsed
end

ret.help = function()
	print([=[
mdoc - lua documentation
mdoc -p <folder> [-p <folder> ...][ -o <folder>][ -t "title"][ -i <file>][ -d <folder>[ -d <folder> ...]][ -m <executable>][ -h]

	-p | --path <folder>                        : Path to search for source files
	-o | --output <folder> = "."                : Folder to output HTML files to (and a cache folder)
	-t | --title "name" = "Mdoc Generated Page" : Title for the html files
	-i | --index <file>                         : File to use for the index file
	-d | --document <folder>                    : Path to search for files to put inder the References section
	-m | --markup-parser <executable>           : Executable to use to parse the descriptions and refrence documents.
	                                              Executable should accept a file path as it's argument, and generate html as it's output.
	-h | --help                                 : print this help
]=])
end

return ret