# Module:DayCalc

## Documentation for DayCalc

DayCalc may evolve into many day/date functions. Right now, it has a case of the Tuesdays.

Examples:

### get_next_tuesday

1. Returns the next Tuesday if today is not Tuesday, otherwise returns today's date.
• wikitext: `{{#invoke:DayCalc|get_next_tuesday}}`
• result: June 04, 2024
2. Returns the next Tuesday if today is not Tuesday, otherwise returns today's date (ISO format)
• wikitext: `{{#invoke:DayCalc|get_next_tuesday|isodate=true}}`
• result: June 04, 2024

### get_first_coming_tuesday_of_month

1. Returns the first upcoming Tuesday which is the first Tuesday of a month.
• wikitext: `{{#invoke:DayCalc|get_first_coming_tuesday_of_month}}`
• result: June 4, 2024
2. Returns the first upcoming Tuesday which is the first Tuesday of a month (ISO format)
• wikitext: `{{#invoke:DayCalc|get_first_coming_tuesday_of_month|isodate=true}}`
• result: 2024-06-04

```-- Module:NextTuesday.lua

local p = {}

function p.get_next_tuesday(frame)
local isodate = frame.args.isodate
local pst_tzoffset = 0 - ( 8 * 60 * 60 )
local current_time = os.time() + pst_tzoffset
local current_day_of_week = tonumber(os.date("%w", current_time))
local days_until_tuesday = (9 - current_day_of_week) % 7
local next_tuesday_time = current_time + days_until_tuesday * 24 * 60 * 60
local retval="UNDEFINED"

if isodate == "true" and current_day_of_week == 2 then
retval = os.date("%Y-%m-%d", current_time)
elseif current_day_of_week == 2 then
retval = os.date("%B %d, %Y", current_time)
elseif isodate == true then
retval = os.date("%Y-%m-%d", next_tuesday_time)
else
retval = os.date("%B %d, %Y", next_tuesday_time)
end
return retval
end

function p.get_first_coming_tuesday_of_month(frame)
local isodate = frame.args.isodate
local current_year = tonumber(os.date("%Y"))
local current_month = tonumber(os.date("%m"))
local current_datenum = tonumber(os.date("%e"))
local day_of_week = tonumber(os.date("%w"))

local first_tuesday_day

if current_datenum > 7 then
current_month = current_month + 1
if current_month > 12 then
current_month = 1
current_year = current_year + 1
end
elseif current_datenum <= 7 and day_of_week == 2 then
if isodate == "true" then
return os.date("%Y-%m-%d")
else
return os.date("%B %e, %Y")
end
end

for day = 1, 7 do
local day_time = os.time({ year = current_year, month = current_month, day = day, hour = 0, min = 0, sec = 0 })
local day_of_week = tonumber(os.date("%w", day_time))
if day_of_week == 2 then -- Tuesday
first_tuesday_day = day
break
end
end

if first_tuesday_day then
local first_tuesday_time = os.time({ year = current_year, month = current_month, day = first_tuesday_day, hour = 0, min = 0, sec = 0 })

if isodate == "true" then
return os.date("%Y-%m-%d", first_tuesday_time)
else
return os.date("%B %e, %Y", first_tuesday_time)
end
else
return "Unable to calculate first Tuesday of the month."
end
end

return p
```