# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1314915306 -7200
# Node ID dd8172982299b46c3aa732c517c8ea72243b3b01
# Parent  5a573f1d75928d4a06dd727ba9f7273434e2b049
plugins.factoids: Add plugin for storing text snippets, with multiple backends

diff -r 5a573f1d7592 -r dd8172982299 plugins/factoids.lua
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/factoids.lua	Fri Sep 02 00:15:06 2011 +0200
@@ -0,0 +1,220 @@
+local storage_backends = {};
+function riddim.plugins.factoids(bot)
+	local factoids = {};
+	local conf_backend = bot.config.factoid_backend;
+	local backend;
+
+	-- if backend == nil then forget everything on restart
+
+	if conf_backend and storage_backends[conf_backend] then
+		backend = storage_backends[conf_backend](bot, factoids);
+	end
+
+	bot:hook("unhandled-command", function(cmd)
+		local name, param = cmd.command, cmd.param;
+		local factoid = factoids[name];
+		if factoid then
+			return factoid;
+		elseif param and #param > 4 and param:match("^is ") then
+			factoids[name] = param:sub(4);
+			return "I'll remember that.";
+		end
+	end);
+	bot:hook("commands/forget", function(cmd)
+		local name = cmd.param;
+		local factoid = factoids[name];
+		if factoid then
+			factoids[name] = nil;
+			if backend and backend.del then
+				backend.del(name);
+			end
+			return ("Okay, I'll forget that %s is %s"):format(name, factoid);
+		end
+	end);
+end
+
+-- A simple file backend
+function storage_backends.file(bot, factoids)
+	local factoids_file = bot.config.factoids_file or "./factoids.txt";
+	local function format_line(k, v)
+		return ("%s=%s\n"):format(k, v)
+	end
+	local actions = {
+		load = function()
+			local fd = io.open(factoids_file, "r");
+			if fd then
+				for line in fd:lines() do
+					local k, v = line:match("^(.+)=(.*)$");
+					if k and v then
+						factoids[k] = v;
+					end
+				end
+				fd:close();
+			end
+		end,
+		save = function()
+			local fd = io.open(factoids_file, "w");
+			if fd then
+				for k,v in pairs(factoids) do
+					fd:write(format_line(k, v));
+				end
+				fd:close();
+			end
+		end,
+		add = function(k, v)
+			local fd = io.open(factoids_file, "a");
+			fd:write(format_line(k, v));
+			fd:close();
+		end,
+	};
+	function actions.del(...) actions.save(); end
+	actions.load();
+	setmetatable(factoids, {
+		__newindex = function(t, k, v)
+			v = v:gsub("\n"," ");
+			rawset(t, k, v);
+			actions.add(k, v);
+		end,
+	});
+	return actions;
+end
+
+-- A variant of the above except serializing lua code
+function storage_backends.lua(bot, factoids)
+	local factoids_file = bot.config.factoids_file or "./factoids.dat";
+	local function format_line(k, v)
+		return ("_G[%q] = %q;\n"):format(k, v);
+	end
+	local actions = {
+		load = function()
+			local chunk, err = loadfile(factoids_file);
+			if chunk then
+				local old_mt = getmetatable(factoids);
+				setmetatable(factoids, {
+					__newindex = function (...) rawset(...); print(...) end
+				});
+				setfenv(chunk, {_G = factoids} );
+				chunk();
+				setmetatable(factoids, old_mt);
+			else
+				print(err);
+			end
+		end,
+		save = function()
+			local fd, err = io.open(factoids_file, "w");
+			if err then print(err) end
+			if fd then
+				for k,v in pairs(factoids) do
+					fd:write(format_line(k, v));
+				end
+				fd:close();
+			end
+		end,
+		add = function(k,v)
+			local fd, err = io.open(factoids_file, "a");
+			if err then print(err) end
+			if fd then
+				fd:write(format_line(k, v));
+				fd:close();
+			end
+		end,
+		del = function(k)
+			local fd, err = io.open(factoids_file, "a");
+			if err then print(err) end
+			if fd then
+				fd:write(("_G[%q] = nil;\n"):format(k));
+				fd:close();
+			end
+		end,
+	}
+	actions.load();
+	setmetatable(factoids, {
+		__newindex = function(t, k, v)
+			print("__newindex", t, k, v);
+			rawset(t, k, v);
+			actions.add(k, v);
+		end,
+	});
+	return actions;
+end
+
+-- Yet another variant, using util.serialization
+function storage_backends.serialize(bot, factoids)
+	local serialize   = require "util.serialization".serialize;
+	local deserialize = require "util.serialization".deserialize;
+	local factoids_file = bot.config.factoids_file or "./factoids.dat";
+	local actions = {
+		load = function()
+			local fd = io.open(factoids_file, "r");
+			if fd then
+				local old_mt = getmetatable(factoids);
+				setmetatable(factoids, {});
+				factoids = deserialize(fd:read("*a"));
+				setmetatable(factoids, old_mt);
+				df:close();
+			end
+		end,
+		save = function()
+			local fd, err = io.open(factoids_file, "w");
+			if err then print(err) end
+			if fd then
+				fd:write(serialize(factoids));
+				fd:close();
+			end
+		end,
+	}
+	function actions.add(...) actions.save(); end
+	function actions.del(...) actions.save(); end
+	actions.load();
+	setmetatable(factoids, {
+		__newindex = function(t, k, v)
+			print("__newindex", t, k, v);
+			rawset(t, k, v);
+			actions.add(k, v);
+		end,
+	});
+	return actions;
+end
+
+-- A backend using XEP 49 storage
+function storage_backends.iq_private(bot, factoids)
+	bot.stream:add_plugin("private");
+	local factoids_node = "factoids";
+	local factoids_xmlns = "http://code.zash.se/riddim/plugins/factoids";
+	local actions = {
+		load = function()
+			bot.stream:private_get(factoids_node, factoids_xmlns, function (storage)
+				if storage then
+					local old_mt = getmetatable(factoids);
+					setmetatable(factoids, {
+						__newindex = function (...) rawset(...); print(...) end
+					});
+					for factoid in storage:children() do
+						factoids[factoid.attr.name or "something-invalid"] = factoid:get_text();
+					end
+					setmetatable(factoids, old_mt);
+				end
+			end);
+		end,
+		save = function()
+			local st = verse.stanza(factoids_node, { xmlns = factoids_xmlns });
+			for name, text in pairs(factoids) do
+				st:tag("factoid", { name = name }):text(text):up();
+			end
+			bot.stream:private_set(factoids_node, factoids_xmlns, st);
+		end,
+	}
+	function actions.add(...) actions.save(); end
+	function actions.del(...) actions.save(); end
+	bot:hook("started", function()
+		actions.load();
+		setmetatable(factoids, {
+			__newindex = function(t, k, v)
+				print("__newindex", t, k, v);
+				rawset(t, k, v);
+				actions.add(k, v);
+			end,
+		});
+	end);
+	return actions;
+end