widget.cal: added option for displaying week numbers

Author: methodical-marmot

README.rst

@@ -24,11 +24,11 @@ If you want to create a pull request, make sure that:
 
 - Your code fits with the general style of the module. In particular, you should use the same indentation pattern that the code uses, and also avoid adding space at the ends of lines.
 
-- Your code its easy to understand, maintainable, and modularized. You should also avoid code duplication wherever possible by adding functions to or using lain.helpers_. If something is unclear, or you can't write it in such a way that it will be clear, explain it with a comment.
+- Your code its easy to understand, maintainable, and modularized. You should also avoid code duplication wherever possible by adding functions to or using lain.helpers_. If something is unclear, or you can not write it in such a way that it will be clear, explain it with a comment.
 
 - You test your changes before submitting to make sure that you code works and does not break other parts of the module.
 
-- You eventually update ``wiki`` submodule with a thorough section.
+- You update ``wiki`` submodule with a thorough section, if necessary.
 
 Contributed widgets have to be put in ``widget/contrib``.
 

widget/cal.lua

@@ -28,12 +28,22 @@ local function factory(args)
         week_start          = args.week_start or 2,
         three               = args.three or false,
         followtag           = args.followtag or false,
+        week_number         = args.week_number or "none",
+        week_number_format  = args.week_number_format or args.week_number == "left" and "%3d | " or "| %-3d",
         icons               = args.icons or helpers.icons_dir .. "cal/white/",
         notification_preset = args.notification_preset or {
             font = "Monospace 10", fg = "#FFFFFF", bg = "#000000"
         }
     }
 
+    function cal.get_week_number(m, st_day, x)
+        return string.format(cal.week_number_format, os.date("%V", m) + (x ~= 0 and floor((x + st_day) / 7) - 1 or 0))
+    end
+
+    function cal.sum_week_days(x, y)
+        return (x + y) % 7
+    end
+
     function cal.build(month, year)
         local current_month, current_year = tonumber(os.date("%m")), tonumber(os.date("%Y"))
         local is_current_month = (not month or not year) or (month == current_month and year == current_year)
@@ -44,13 +54,47 @@ local function factory(args)
         local notifytable = { [1] = string.format("%s%s\n", string.rep(" ", floor((28 - this_month:len())/2)), markup.bold(this_month)) }
         for x = 0,6 do notifytable[#notifytable+1] = os.date("%a ", os.time { year=2006, month=1, day=x+cal.week_start }) end
         notifytable[#notifytable] = string.format("%s\n%s", notifytable[#notifytable]:sub(1, -2), string.rep(" ", st_day*4))
+        local strx
         for x = 1,mth_days do
-            local strx = x ~= today and x or markup.bold(markup.color(cal.notification_preset.bg, cal.notification_preset.fg, x) .. " ")
+            strx = x
+            if x == today then
+                if x < 10 then x = " " .. x end
+                strx = markup.bold(markup.color(cal.notification_preset.bg, cal.notification_preset.fg, x) .. " ")
+            end
             strx = string.format("%s%s", string.rep(" ", 3 - tostring(x):len()), strx)
             notifytable[#notifytable+1] = string.format("%-4s%s", strx, (x+st_day)%7==0 and x ~= mth_days and "\n" or "")
         end
         if string.len(cal.icons or "") > 0 and today then cal.icon = cal.icons .. today .. ".png" end
         cal.month, cal.year = d.month, d.year
+
+        if cal.week_number ~= "none" then
+            local m = os.time { year = year or current_year, month = month and month or current_month, day = 0 }
+            local head_prepend = string.rep(" ", tostring(string.format(cal.week_number_format, 0)):len())
+
+            if cal.week_number == "left" then
+                notifytable[1] = head_prepend .. notifytable[1] -- month-year row
+                notifytable[2] = head_prepend .. notifytable[2] -- weekdays row
+                notifytable[8] = notifytable[8]:gsub("\n", "\n" .. cal.get_week_number(m, st_day, 0)) -- first week of the month
+
+                for x = 10,#notifytable do
+                    if cal.sum_week_days(st_day, x) == 2 then
+                        notifytable[x] = cal.get_week_number(m, st_day, x) .. notifytable[x]
+                    end
+                end
+            elseif cal.week_number == "right" then
+                notifytable[8] = notifytable[8]:gsub("\n", head_prepend .. "\n") -- weekdays row
+                for x = 9,#notifytable do
+                    if cal.sum_week_days(st_day, x) == 1 then
+                        notifytable[x] = notifytable[x]:gsub("\n", cal.get_week_number(m, st_day, x - 7) .. "\n")
+                    end
+                end
+                -- last week of the month
+                local end_days = cal.sum_week_days(st_day, mth_days)
+                if end_days ~= 0 then end_days = 7 - end_days end
+                notifytable[#notifytable] = notifytable[#notifytable] .. string.rep(" ", 4 * end_days) .. cal.get_week_number(m, st_day, mth_days + end_days)
+            end
+        end
+
         return notifytable
     end