--[[ Bitcoin Lua script for Conky, by Rena. Build #92704.
Usage: Add a "lua_load" line to your .conkyrc to load this script,
then add variables to your config:

${lua bitcoin_balance [account name]}
 (You can also use lua_bar, lua_graph, etc. A graph might be interesting for
  those who perform a lot of transactions!)

${lua bitcoin_info format string} (or lua_parse)
 Format string is any string (can contain line breaks), in which any instance of
 %foo% is replaced with the value of the variable foo output by
 "bitcoin getinfo". Cannot contain multiple spaces; use ${tab} for alignment.
 (This is a limitation of how Conky passes strings to Lua.)

${lua bitcoin_transactions account num format} (or lua_parse)
 List up to 'num' recent transactions (most recent first) on an account. Account
 name must be quoted if it contains a space, can be * for all accounts. Format
 works same as bitcoin_info.

${if_empty ${lua bitcoin_running}}...${else}...${endif}
 To display text only if Bitcoin is/isn't running. bitcoin_running returns an
 empty string when Bitcoin running and '0' when it isn't, so that if_empty can
 be used like a normal 'if'.

${lua mtgox_ticker format string} (or lua_parse)
 Works same as bitcoin_info. Field names are those under 'ticker', so e.g.
 write %high%, not %ticker.high%.

Send bug reports, suggestions, flames, cat photos and whatever else
to ('moc.liamg\064rekcahrepyh'):reverse().
Send spare change to 15R7dpxfWuDrQY9CtUzMsg6A7sKMdWbTd3 why not.

Version history:
-92704:
 -Added mtgox_ticker() and ability to fetch JSON URLs. (Adds dependency on
  LuaSocket.)
 -Changed keypoololdest to a formatted date. Raw timestamp is keypoololdest_raw.
-92432: Initial release. ]]

local json = require('json') --http://json.luaforge.net/
local http = require('socket.http') --http://luaforge.net/projects/luasocket/

--options
local UpdateFreq = 5*60 --only update once every this many seconds
local SignPlus = '${color3}+' --prefix for positive numbers
local SignMinus = '${color2}-' --prefix for negative numbers
local DateFmt = '%H:%M:%S %y/%m/%d' --strftime date format
local FeeEmpty = '-.--' --string to display for %fee% when empty

--state
local Account = {} --indexed by account name
local LastQuery = 0 --last time bitcoin was called
local QueryCache = {}
local URLCache = {}

--[[ Send a query to bitcoin.
This function caches queries so that bitcoin is only called once per UpdateFreq
to avoid creating a lot of needless overhead by spawning processes over and
over. ]]
local function bitcoin_query(query)
	local now = os.time()
	LastQuery = now
	local cache = QueryCache[query]
	if cache then
		if os.difftime(now, cache.Time) < UpdateFreq then
			return cache.Result
		end
	else
		QueryCache[query] = {}
		cache = QueryCache[query]
	end
	
	--hack: redirect stderr to stdout and look for either an error message or
	--what looks like JSON data.
	local data, found = '', false
	local app = io.popen('bitcoin ' .. query .. ' 2>&1')
	for line in app:lines() do
		if line:sub(1,6) == 'error:' then
			if line == "error: no response from server"
			or line == "error: couldn't connect to server" then
				Running = false
				return nil, "Bitcoin not running"
			else
				Running = false --presumably...
				io.stderr:write("Bitcoin: " .. line .. "\n")
				return nil, line
			end
		elseif found then data = data .. line
		elseif line:sub(1,1) == '{' or line:sub(1,1) == '[' then
			found = true
			data = data .. line
		end
	end
	app:close()
	Running = true --well it must be, we just talked to it.
	
	cache.Time, cache.Result = now, json.decode(data)
	return cache.Result
end

--[[ Fetch JSON data from a HTTP URL.
This function caches queries in URLCache so that the same URL isn't accessed
more than once per UpdateFreq. This is a simple naive cache that only works if
the URL is exactly the same each time.
On success, returns JSON data as table.
On failure, returns nil and error message. ]]
local function get_json_url(url)
	if not URLCache[url] then URLCache[url] = {LastQuery=0} end
	
	local now = os.time()
	if (now - URLCache[url].LastQuery) < UpdateFreq then
		return URLCache[url].LastResult
	end
	URLCache[url].LastQuery = now
	
	local text, status = http.request(url)
	if (not text) or (status < 200) or (status >= 300) then
		URLCache[url].LastResult = 'Error: ' .. tostring(status)
		return nil, URLCache[url].LastResult
	end
	
	local err
	URLCache[url].LastResult, err = json.decode(text)
	if URLCache[url].LastResult then return URLCache[url].LastResult
	else return nil, err
	end
end

--[[ Conky splits args at space, regardless of quotes. So if arg begins with a
quote, look for end quote and piece the string together.
note that this fails if there are multiple spaces in a row since Conky
compresses them into one. ]]
local function readquotedarg(args, idx)
	idx = idx or 1
	local str = ''
	if args[idx] and args[idx]:sub(1,1) == '"' then
		if args[idx]:sub(-1) == '"' then
			return table.remove(args, idx):sub(1, -2)
		end
		str = table.remove(args, idx):sub(2)
		while args[idx] and args[idx]:sub(-1) ~= '"' do
			str = str .. ' ' .. table.remove(args, idx)
		end
		return str .. ' ' .. table.remove(args, idx):sub(1, -2)
	elseif args[idx] then return table.remove(args, idx)
	else return nil
	end
end

--[[ Check if Bitcoin is running. ]]
function conky_bitcoin_running(...)
	local now = os.time()
	if Running == nil --don't know
	or os.difftime(now, LastQuery) >= UpdateFreq then
		bitcoin_query('getinfo') --make some random query to find out
	end
	return Running and '' or '0' --for Conky if_empty
end

--[[ Balance for particular account. ]]
function conky_bitcoin_balance(...)
	local args = {...}
	local account = readquotedarg(args) or "Your Address" --default account name
	
	--create status table for this account if not done already.
	if not Account[account] then Account[account] = {
		LastUpdate = 0, LastBalance = 0
	} end
	
	--Query bitcoin to find account balance.
	local info = bitcoin_query('listaccounts')
	
	--display negative balance to signal error, since some Conky functions
	--expect a number.
	if not info then Account[account].LastBalance = -1 end
	
	Account[account].LastUpdate = now
	return tonumber(Account[account].LastBalance)
end

--[[ Recent transaction list. ]]
function conky_bitcoin_transactions(...)
	local args = {...}
	local account = readquotedarg(args) or "Your Address"
	local numshow = tonumber(args[1]) or 5
	local fmt = table.concat(args, ' ', 2) --format string
	
	local info = bitcoin_query(('listtransactions "%s" %d'):
		format(account, numshow))
	
	--add some convenient fields to info
	for i = 1,#info do
		if not info[i].sign then --cache means these may already be set
			info[i].sign = (info[i].amount > 0) and
				SignPlus or SignMinus
			info[i].absamount = math.abs(info[i].amount)
			info[i].absfee = info[i].fee and math.abs(info[i].fee) or
				FeeEmpty
			info[i].rawtime = info[i].time
			info[i].time = os.date(DateFmt, tonumber(info[i].rawtime))
			info[i].fee = info[i].fee or FeeEmpty
		end
	end
	
	--transactions seem to be listed oldest first, so reverse iterate.
	local res = ''
	for i = math.min(numshow,#info), 1, -1 do
		res = res .. fmt:gsub('%%([%w_]+)%%', info[i]) .. '\n'
	end
	return res
end

--[[ General info. ]]
function conky_bitcoin_info(...)
	local args, info = {...}, {}
	local fmt = table.concat(args, ' ') --format string
	
	--query Bitcoin and parse results.
	local info = bitcoin_query('getinfo')
	
	if not info.keypoololdest_raw then
		info.keypoololdest_raw = info.keypoololdest
		info.keypoololdest = os.date(DateFmt, tonumber(info.keypoololdest))
	end
	
	--generate and return output string.
	LastInfoStr = fmt:gsub('%%([%w_]+)%%', info)
	LastInfoUpdate = now
	return LastInfoStr
end

--[[ MtGox info. ]]
function conky_mtgox_ticker(...)
	local args, info = {...}, {}
	local fmt = table.concat(args, ' ') --format string
	
	local data, err = get_json_url('http://mtgox.com/code/data/ticker.php')
	if data then MtGoxLastResult = fmt:gsub('%%([%w_]+)%%', data.ticker)
	else MtGoxLastResult = tostring(err)
	end
	return MtGoxLastResult
end

${color1}BTC${hr}
${if_empty ${lua bitcoin_running}}${lua_parse bitcoin_info Balance:${tab 40}${color0}%balance%${color1}
Tx Fee:${tab 40}${color0}%paytxfee%${color1}
Connections:${tab 10}${color0}%connections%${color1}
Blocks:${tab 40}${color0}%blocks%${color1}
Oldest:${tab 40}${color0}%keypoololdest%${color1}
Difficulty:${tab 20}${color0}%difficulty%${color1}
Version:${tab 40}${color0}%version%${color1}}
${lua_parse bitcoin_transactions * 5 %sign%%absamount% %confirmations%${tab 16}%absfee%${tab 16}%time%}
${else}${color0}NO DATA${endif}