Path = {}

function Path:new(p)
	local is_absolute = p:sub(1, 1) == "/"
	p = p:gsub("/+", "/")
	p = p:gsub("(/%./", "/")
	p = p:gsub("/%.$", "")
	p = p:gsub("/$", "")
	p = p:gsub("^%./", "")
	p = p:gsub("/[^/]+/%.%.", "")

	local path = {
		segments = p:split('/'),
		is_absolute = is_absolute
	}

	setmetatable(path, self)
	self.__index = self

	return path
end

function Path:name()
	return self.segments[#self.segments]
end

function Path:stem()
	return self.segments[#self.segments]:match('[^.]+')
end

function Path:parent()
	return self / ".."
end

function Path:__tostring()
	return (self.is_absolute and "/" or "") .. table.concat(self.segments, "/")
end

function Path:__div(next)
	if next.is_absolute then
		error("cannot concat with absolute path")
	end

	return Path:new(self:__tostring() .. "/" .. tostring(next))
end

function Path:open(mode)
	return io.open(tostring(self), mode)
end

function Path:exists()
	local f = self:open('r')

	if f ~= nil then
		f:close()
		return true
	end
	return false
end

function Path:is_directory()
	local f = self:open('r')

	if not f then
		return false
	end

	local value, err, code = f:read()
	f:close()

	return code == 21
end

function Path:entries()
	if not self:is_directory() then
		return function() end
	end

	local pipe = io.popen('ls' .. ' "' .. tostring(self) .. '"')
	local lines = pipe:lines()

	return function()
		local value = lines()
		if value == nil then
			pipe:close()
			return nil
		end
		return self / value
	end
end

function Path:children()
	if not self:is_directory() then
		return function() end
	end

	local pipe = io.popen('find' .. ' "' .. tostring(self) .. '"')
	local lines = pipe:lines()

	return function()
		local value = lines()
		if value == nil then
			pipe:close()
			return nil
		end
		return Path:new(value)
	end
end

function Path:make_directory(opts)
	local pipe = io.popen('mkdir ' .. (opts.create_parents and '-p ' or ' ') .. tostring(self))
	pipe:close()
end

return {
	tests = {
		function()
			local path = Path:new("some/path/here")
			assert.equals("here", path:name())
		end,
		function()
			local path = Path:new("some/path/here.txt")
			assert.equals("here", path:stem())
		end,
		function()
			local path = Path:new("some/path/here.txt")
			assert.equals("some/path", path:parent():__tostring())
		end,
		function()
			local path = Path:new("some/path/here.txt")
			assert.equals("some/path/here.txt", path:__tostring())
		end,
		function()
			local path = Path:new("some/path/here")
			path = path / 'next.txt'
			assert.equals("some/path/here/next.txt", path:__tostring())
		end,
		function()
			local path = Path:new("./src")
			assert.equals(true, path:is_directory())
		end,
		function()
			local path = Path:new("./src/blueprint")
			assert.equals(false, path:is_directory())
		end,
		function()
			local path = Path:new("./src/blueprint")
			assert.equals(true, path:exists())
		end,
		function()
			local path = Path:new("./src/blueprint__")
			assert.equals(false, path:exists())
		end
	}
}