-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local server = require"net.http.server";

local lfs = require "lfs";

local new_cache = require "util.cache".new;

local log = require "util.logger".init("net.http.files");

local os_date = os.date;

local open = io.open;

local stat = lfs.attributes;

local build_path = require"socket.url".build_path;

local path_sep = package.config:sub(1,1);

local forbidden_chars_pattern = "[/%z]";

if package.config:sub(1,1) == "\\" then

	forbidden_chars_pattern = "[/%z\001-\031\127\"*:<>?|]"

end

local urldecode = require "util.http".urldecode;

local function sanitize_path(path) --> util.paths or util.http?

	if not path then return end

	local out = {};

	local c = 0;

	for component in path:gmatch("([^/]+)") do

		component = urldecode(component);

		if component:find(forbidden_chars_pattern) then

			return nil;

		elseif component == ".." then

			if c <= 0 then

				return nil;

			end

			out[c] = nil;

			c = c - 1;

		elseif component ~= "." then

			c = c + 1;

			out[c] = component;

		end

	end

	if path:sub(-1,-1) == "/" then

		out[c+1] = "";

	end

	return "/"..table.concat(out, "/");

end

local function serve(opts)

	if type(opts) ~= "table" then -- assume path string

		opts = { path = opts };

	end

	local mime_map = opts.mime_map or { html = "text/html" };

	local cache = new_cache(opts.cache_size or 256);

	local cache_max_file_size = tonumber(opts.cache_max_file_size) or 1024

	-- luacheck: ignore 431

	local dir_indices = opts.index_files or { "index.html", "index.htm" };

	local directory_index = opts.directory_index;

	local function serve_file(event, path)

		local request, response = event.request, event.response;

		local sanitized_path = sanitize_path(path);

		if path and not sanitized_path then

			return 400;

		end

		path = sanitized_path;

		local orig_path = sanitize_path(request.path);

		local full_path = base_path .. (path or ""):gsub("/", path_sep);

		local attr = stat(full_path:match("^.*[^\\/]")); -- Strip trailing path separator because Windows

		if not attr then

			return 404;

		end

		local request_headers, response_headers = request.headers, response.headers;

		local last_modified = os_date('!%a, %d %b %Y %H:%M:%S GMT', attr.modification);

		response_headers.last_modified = last_modified;

		local etag = ('"%x-%x-%x"'):format(attr.change or 0, attr.size or 0, attr.modification or 0);

		response_headers.etag = etag;

		local if_none_match = request_headers.if_none_match

		local if_modified_since = request_headers.if_modified_since;

		if etag == if_none_match

		or (not if_none_match and last_modified == if_modified_since) then

			return 304;

		end

		local data = cache:get(orig_path);

		if data and data.etag == etag then

			response_headers.content_type = data.content_type;

			data = data.data;

			cache:set(orig_path, data);

		elseif attr.mode == "directory" and path then

			if full_path:sub(-1) ~= "/" then

				local dir_path = { is_absolute = true, is_directory = true };

				for dir in orig_path:gmatch("[^/]+") do dir_path[#dir_path+1]=dir; end

				response_headers.location = build_path(dir_path);

				return 301;

			end

			for i=1,#dir_indices do

				if stat(full_path..dir_indices[i], "mode") == "file" then

					return serve_file(event, path..dir_indices[i]);

				end

			end

			if directory_index then

				data = server._events.fire_event("directory-index", { path = request.path, full_path = full_path });

			end

			if not data then

				return 403;

			end

			cache:set(orig_path, { data = data, content_type = mime_map.html; etag = etag; });

			response_headers.content_type = mime_map.html;

		else

			local f, err = open(full_path, "rb");

			if not f then

				log("debug", "Could not open %s. Error was %s", full_path, err);

				return 403;

			end

			local ext = full_path:match("%.([^./]+)$");

			local content_type = ext and mime_map[ext];

			response_headers.content_type = content_type;

			if attr.size > cache_max_file_size then

				response_headers.content_length = ("%d"):format(attr.size);

				log("debug", "%d > cache_max_file_size", attr.size);

				return response:send_file(f);

			else

				data = f:read("*a");

				f:close();

			end

			cache:set(orig_path, { data = data; content_type = content_type; etag = etag });

		end

		return response:send(data);

	end

	return serve_file;

end

return {

	serve = serve;

}