xban = { MP = minetest.get_modpath(minetest.get_current_modname()) }

dofile(xban.MP.."/serialize.lua")

local db = { }
local tempbans = { }

local DEF_SAVE_INTERVAL = 300 -- 5 minutes
local DEF_DB_FILENAME = minetest.get_worldpath().."/xban.db"
local CLEAN_IP_SECONDS = 24*60*60*7 -- time after which innocent player IPs should get removed
local CLEAN_INTERVAL = 3600 -- interval at which the db should be purged of old IPs

local DB_FILENAME = minetest.settings:get("xban.db_filename")
local SAVE_INTERVAL = tonumber(
  minetest.settings:get("xban.db_save_interval")) or DEF_SAVE_INTERVAL

if (not DB_FILENAME) or (DB_FILENAME == "") then
	DB_FILENAME = DEF_DB_FILENAME
end

local function make_logger(level)
	return function(text, ...)
		minetest.log(level, "[xban] "..text:format(...))
	end
end

local ACTION = make_logger("action")
local WARNING = make_logger("warning")

local unit_to_secs = {
	s = 1, m = 60, h = 3600,
	D = 86400, W = 604800, M = 2592000, Y = 31104000,
	[""] = 1,
}

local function parse_time(t) --> secs
	local secs = 0
	for num, unit in t:gmatch("(%d+)([smhDWMY]?)") do
		secs = secs + (tonumber(num) * (unit_to_secs[unit] or 1))
	end
	return secs
end

function xban.is_ip(name)
	-- checks if name is an ipv4 or ipv6 address
	return string.match(name, "%.") or string.match(name, "%:")
end

function xban.find_entry(player, create) --> entry, index
	for index, e in ipairs(db) do
		for name in pairs(e.names) do
			if name == player then
				return e, index
			end
		end
	end
	if create then
		print(("Created new entry for `%s'"):format(player))
		local e = {
			names = { [player]=true },
			banned = false,
			record = { },
		}
		table.insert(db, e)
		return e, #db
	end
	return nil
end

function xban.get_info(player) --> ip_name_list, banned, last_record
	local e = xban.find_entry(player)
	if not e then
		return nil, "No such entry"
	end
	return e.names, e.banned, e.record[#e.record]
end

function xban.add_record(player, record)
   -- Add records for other punishments banned.
   local e = xban.find_entry(player, true)
   table.insert(e.record, record)
end

function xban.add_property(player, property, value)
   -- adds a property to a player, for instance a "jailed" property which indicates that a player is jailed
   local e = xban.find_entry(player, true)
   e[property] = value
end
function xban.get_property(player, property)
   local e = xban.find_entry(player, true)
   return e[property] 
end


function xban.ban_player(player, source, expires, reason) --> bool, err
	if xban.get_whitelist(player) then
		return nil, "Player is whitelisted; remove from whitelist first"
	end
	local e = xban.find_entry(player, true)
	if e.banned then
		return nil, "Already banned"
	end
	local rec = {
		source = source,
		time = os.time(),
		expires = expires,
		reason = reason,
		type = "ban",
	}
	table.insert(e.record, rec)
	e.names[player] = true
	local pl = minetest.get_player_by_name(player)
	if pl then
		local ip = minetest.get_player_ip(player)
		if ip then
			e.names[ip] = os.time()
		end
		e.last_pos = pl:getpos()
	end
	e.reason = reason
	e.time = rec.time
	e.expires = expires
	e.banned = true
	local msg
	local date = (expires and os.date("%c", expires)
	  or "the end of time")
	if expires then
		table.insert(tempbans, e)
		msg = ("Banned: Expires: %s, Reason: %s"):format(date, reason)
	else
		msg = ("Banned: Reason: %s"):format(reason)
	end
	for nm in pairs(e.names) do
		minetest.kick_player(nm, msg)
	end
	ACTION("%s bans %s until %s for reason: %s", source, player,
	  date, reason)
	ACTION("Banned Names/IPs: %s", table.concat(e.names, ", "))
	return true
end

function xban.unban_player(player, source, reason) --> bool, err
	local e = xban.find_entry(player)
	if not e then
		return nil, "No such entry"
	end
	local rec = {
		source = source,
		time = os.time(),
		reason = (reason or ""),
		type = "unban"
	}
	table.insert(e.record, rec)
	e.banned = false
	e.reason = nil
	e.expires = nil
	e.time = nil
	ACTION("%s unbans %s", source, player)
	ACTION("Unbanned Names/IPs: %s", table.concat(e.names, ", "))
	return true
end

function xban.get_whitelist(name_or_ip)
	return db.whitelist and db.whitelist[name_or_ip]
end

function xban.remove_whitelist(name_or_ip)
	if db.whitelist then
		db.whitelist[name_or_ip] = nil
	end
end

function xban.add_whitelist(name_or_ip, source)
	local wl = db.whitelist
	if not wl then
		wl = { }
		db.whitelist = wl
	end
	wl[name_or_ip] = {
		source=source,
	}
	return true
end
function xban.get_account_names(e)
	-- get accounts associated with entry
	local names = {}
	if not e then
		return nil, ("No entry for `%s'"):format(player)
	end
	for name in pairs(e.names) do
		if not xban.is_ip(name) and name ~= player then
			table.insert(names, name)
		end
	end
	return names
end

function xban.get_alt_accounts(player)
	local e = xban.find_entry(player)
	return xban.get_account_names(e)
end

function xban.get_record(player)
	local e = xban.find_entry(player)
	if not e then
		return nil, ("No entry for `%s'"):format(player)
	elseif (not e.record) or (#e.record == 0) then
		return nil, ("`%s' has no ban records"):format(player)
	end
	local record = { }
	for _, rec in ipairs(e.record) do
		local msg = rec.type or "ban"
		msg = msg .. ": " .. rec.reason or "No reason given."
		if rec.expires then
			msg = msg..(", Expires: %s"):format(os.date("%Y-%m-%d %H:%M:%S", rec.expires))
		end
		if rec.source then
			msg = msg..", Source: "..rec.source
		end
		table.insert(record, ("[%s]: %s"):format(os.date("%Y-%m-%d %H:%M:%S", rec.time), msg))
	end
	local last_pos
	if e.last_pos then
		last_pos = ("User was last seen at %s"):format(
		  minetest.pos_to_string(e.last_pos))
	end

	return record, last_pos
end

minetest.register_on_prejoinplayer(function(name, ip)
	local wl = db.whitelist or { }
	if wl[name] or wl[ip] then return end
	local e = xban.find_entry(name) or xban.find_entry(ip)
	if not e then return end
	if e.banned then
		local date = (e.expires and os.date("%c", e.expires)
		  or "the end of time")
		return ("Banned: Expires: %s, Reason: %s"):format(
		  date, e.reason)
	end
end)

minetest.register_on_joinplayer(function(player)
	local name = player:get_player_name()
	local e = xban.find_entry(name)
	local ip = minetest.get_player_ip(name)
	if not e then
		if ip then
			e = xban.find_entry(ip, true)
		else
			return
		end
	end
	e.names[name] = true
	if ip then
		e.names[ip] = os.time()
	end
	e.last_seen = os.time()
end)

minetest.register_chatcommand("xban", {
	description = "XBan a player",
	params = "<player> <reason>",
	privs = { ban=true },
	func = function(name, params)
		local plname, reason = params:match("(%S+)%s+(.+)")
		if not (plname and reason) then
			return false, "Usage: /xban <player> <reason>"
		end
		local ok, e = xban.ban_player(plname, name, nil, reason)
		return ok, ok and ("Banned %s."):format(plname) or e
	end,
})

minetest.register_chatcommand("xtempban", {
	description = "XBan a player temporarily",
	params = "<player> <time> <reason>",
	privs = { ban=true },
	func = function(name, params)
		local plname, time, reason = params:match("(%S+)%s+(%S+)%s+(.+)")
		if not (plname and time and reason) then
			return false, "Usage: /xtempban <player> <time> <reason>"
		end
		time = parse_time(time)
		if time < 60 then
			return false, "You must ban for at least 60 seconds."
		end
		local expires = os.time() + time
		local ok, e = xban.ban_player(plname, name, expires, reason)
		return ok, (ok and ("Banned %s until %s."):format(
				plname, os.date("%c", expires)) or e)
	end,
})

minetest.register_chatcommand("xnote", {
	description = "Add a note to a player's criminal record",
	params = "<player> <note>",
	privs = { kick=true },
	func = function(name, params)
		local plname, note = params:match("(%S+)%s+(.+)")
		if not (plname and note) then
			return false, "Usage: /xnote <player> <note>"
		end
		local record = {
			source = name,
			time = os.time(),
			expires = nil,
			reason = note,
			type = "note",
		}
		xban.add_record(plname, record)
		return true, ("Added note for %s."):format(plname)
	end,
})

minetest.register_chatcommand("xkick", {
	description = "Kicks a player",
	params = "<player> <reason>",
	privs = { kick=true },
	func = function(name, params)
		local plname, note = params:match("(%S+)%s+(.+)")
		if not (plname and note) then
			return false, "Usage: /xkick <player> <reason>"
		end
		local record = {
			source = name,
			time = os.time(),
			expires = nil,
			reason = note,
			type = "kick",
		}
		xban.add_record(plname, record)
		minetest.kick_player(plname)		
		return true, ("Kicked %s."):format(plname)
	end,
})

			      

minetest.register_chatcommand("xunban", {
	description = "XUnBan a player",
	params = "<player_or_ip> <reason>",
	privs = { ban=true },
	func = function(name, params)
		local plname, reason = params:match("(%S+)%s+(.+)")
		if not plname then
			minetest.chat_send_player(name,
			  "Usage: /xunban <player_or_ip>")
			return
		end
		local ok, e = xban.unban_player(plname, name, reason)
		return ok, ok and ("Unbanned %s."):format(plname) or e
	end,
})

minetest.register_chatcommand("xban_record", {
	description = "Show the ban records of a player",
	params = "<player_or_ip>",
	privs = { kick=true },
	func = function(name, params)
		local plname = params:match("%S+")
		if not plname then
			return false, "Usage: /xban_record <player_or_ip>"
		end
		local record, last_pos = xban.get_record(plname)
		local alt_accounts = xban.get_alt_accounts(plname)
		local msg 
		if alt_accounts then
			msg = "Alt accounts: " .. table.concat(alt_accounts, ", ")
		end
		if not record then
			local err = last_pos
			minetest.chat_send_player(name, "[xban] "..err)
		else
			for _, e in ipairs(record) do
				minetest.chat_send_player(name, "[xban] "..e)
			end
			if last_pos then
				minetest.chat_send_player(name, "[xban] "..last_pos)
			end
		end
		if msg then
			minetest.chat_send_player(name, "[xban] "..msg)
		end
		return true, "Record listed."
	end,
})

minetest.register_chatcommand("xban_wl", {
	description = "Manages the whitelist",
	params = "(add|del|get) <name_or_ip>",
	privs = { ban=true },
	func = function(name, params)
		local cmd, plname = params:match("%s*(%S+)%s*(%S+)")
		if cmd == "add" then
			xban.add_whitelist(plname, name)
			ACTION("%s adds %s to whitelist", name, plname)
			return true, "Added to whitelist: "..plname
		elseif cmd == "del" then
			xban.remove_whitelist(plname)
			ACTION("%s removes %s to whitelist", name, plname)
			return true, "Removed from whitelist: "..plname
		elseif cmd == "get" then
			local e = xban.get_whitelist(plname)
			if e then
				return true, "Source: "..(e.source or "Unknown")
			else
				return true, "No whitelist for: "..plname
			end
		end
	end,
})


local function clean_db()
	-- Removes old IP addresses for data protection and false positive
	-- prevention
	local cutoff = os.time() - CLEAN_IP_SECONDS
	local cleaned = 0
	for _,entry in ipairs(db) do
		if not entry.banned then
			-- only remove innocent player's ip addresses, rest can be
			-- kept to ensure server security
			for name, time in pairs(entry.names) do				
				if xban.is_ip(name) and (time == true or time < cutoff ) then
					entry.names[name] = nil
					cleaned = cleaned + 1
				end
			end
		end
	end
	ACTION("Cleaned %d old IP addresses.", cleaned)
end

local function check_temp_bans()
	minetest.after(60, check_temp_bans)
	local to_rm = { }
	local now = os.time()
	if not db.nextclean or db.nextclean < now then
		clean_db()
		db.nextclean = now + CLEAN_INTERVAL
	end
	for i, e in ipairs(tempbans) do
		if e.expires and (e.expires <= now) then
			table.insert(to_rm, i)
			e.banned = false
			e.expires = nil
			e.reason = nil
			e.time = nil
		end
	end
	for _, i in ipairs(to_rm) do
		table.remove(tempbans, i)
	end
end


local function save_db()
	minetest.after(SAVE_INTERVAL, save_db)
	local f, e = io.open(DB_FILENAME, "wt")
	db.timestamp = os.time()
	if f then
		local ok, err = f:write(xban.serialize(db))
		if not ok then
			WARNING("Unable to save database: %s", err)
		end
	else
		WARNING("Unable to save database: %s", e)
	end
	if f then f:close() end
	return
end

local function load_db()
	local f, e = io.open(DB_FILENAME, "rt")
	if not f then
		WARNING("Unable to load database: %s", e)
		return
	end
	local cont = f:read("*a")
	if not cont then
		WARNING("Unable to load database: %s", "Read failed")
		return
	end
	local t, e2 = minetest.deserialize(cont)
	if not t then
		WARNING("Unable to load database: %s",
		  "Deserialization failed: "..(e2 or "unknown error"))
		return
	end
	db = t
	tempbans = { }
	for _, entry in ipairs(db) do
		if entry.banned and entry.expires then
			table.insert(tempbans, entry)
		end
	end
end

local function has_alt_accounts (e)
	local a = xban.get_account_names(e)
	return a and #a > 1
end

minetest.register_chatcommand("xban_cleanup", {
	description = "Removes all uninteresting entries from the xban db",
	privs = { server=true },
	func = function(name, params)
		local old_count = #db

		local i = 1
		while i <= #db do
			if #db[i].record == 0 and not has_alt_accounts(db[i]) then
				-- not banned, remove from db
				table.remove(db, i)
			else
				-- banned, hold entry back
				i = i + 1
			end
		end

		-- save immediately
		save_db()
		return true, "Removed " .. (old_count - #db) .. " entries, new db entry-count: " .. #db
	end,
})

minetest.register_on_shutdown(save_db)
minetest.after(SAVE_INTERVAL, save_db)
load_db()
xban.db = db

minetest.after(1, check_temp_bans)

dofile(xban.MP.."/dbimport.lua")
dofile(xban.MP.."/gui.lua")