reports: Add initial monthly_expenses

reports/monthly_expenses.lua

@@ -0,0 +1,49 @@
+function account_series_map(accounts, report)
+	map = {}
+
+	for i=1,100 do -- we're not messing with accounts more than 100 levels deep
+		all_handled = true
+		for id, acct in pairs(accounts) do
+			if not map[id] then
+				all_handled = false
+				if not acct.parent then
+					map[id] = report:series(acct.name)
+				elseif map[acct.parent.accountid] then
+					map[id] = map[acct.parent.accountid]:series(acct.name)
+				end
+			end
+		end
+		if all_handled then
+			return map
+		end
+	end
+
+	error("Accounts nested more than 100 levels deep")
+end
+
+function generate()
+	year = date.now().year
+	account_type = account.Expense
+
+	accounts = get_accounts()
+	r = report.new(12)
+	series_map = account_series_map(accounts, r)
+
+	for month=1,12 do
+		balance = nil
+		begin_date = date.new(year, month, 1)
+		end_date = date.new(year, month+1, 1)
+
+		r:label(month, tostring(begin_date))
+
+		for id, acct in pairs(accounts) do
+			series = series_map[id]
+			if acct.type == account_type then
+				balance = acct:balance(begin_date, end_date)
+				series:value(month, balance.amount)
+			end
+		end
+	end
+
+	return r
+end

reports/test.lua

@@ -1,8 +0,0 @@
-accounts = get_accounts()
-
-for id, account in pairs(accounts) do
-	print(account, account.security)
-	a = account:balance(date.new("2015-12-01"), date.new("2017-12-01"))
-	b = account:balance(date.new("2015-06-01"), date.new("2015-12-01"))
-	print(a, b, a+b, account:balance())
-end