-- This module powers {{interval}}.


local
 p
 =
 {}


-- Constants

local
 lang
 =
 mw
.
language
.
getContentLanguage
()

local
 getArgs
 =
 require
(
'Module:Arguments'
).
getArgs


local
 function
 getArgNums
(
args
)

    -- Returns an array containing the keys of all positional arguments

    -- that contain data (i.e. non-whitespace values).

    -- (from Module:Unbulleted_list)

    local
 nums
 =
 {}

    for
 k
,
 v
 in
 pairs
(
args
)
 do

        if
 type
(
k
)
 ==
 'number'
 and

            k
 >=
 1
 and

            math.floor
(
k
)
 ==
 k
 and

            mw
.
ustring
.
match
(
v
,
 '%S'
)
 then

                table.insert
(
nums
,
 k
)

        end

    end

    table.sort
(
nums
)

    return
 nums

end


function
 p
.
main
(
frame
)

    local
 args
 =
 getArgs
(
frame
)

    return
 p
.
_main
(
args
)

end


function
 p
.
_main
(
args
)

    local
 n
,
 rule
,
 format
 =
 args
.
n
,
 args
.
rule
,
 args
.
format

    local
 numbers
 =
 getArgNums
(
args
)

    local
 low
,
 high
,
 lowpos
,
 highpos
 =
 nil
,
 nil
,
 0
,
 #
numbers
 +
 1


    -- If comparing times, convert them all to seconds after the epoch

    if
 format
 ==
 'time'
 then

        if
 n
 then

            n
 =
 lang
:
formatDate
(
'U'
,
 '@'
 ..
 n
)

        else

            n
 =
 os.time
()
 -- Set n to now if no time provided

        end

    end


    n
 =
 tonumber
(
n
)


    for
 i
,
 num
 in
 ipairs
(
numbers
)
 do

        local
 interval

        if
 format
 ==
 'time'
 then

            interval
 =
 tonumber
(
lang
:
formatDate
(
'U'
,
 '@'
 ..
 args
[
num
]))

        else

            interval
 =
 tonumber
(
args
[
num
])

        end


        if
 n
 and
 ((
n
 >=
 interval
 and
 not
 rule
)
 or
 (
n
 >
 interval
 and
 rule
 ==
 '>'
))
 then

            low
 =
 interval

            lowpos
 =
 num

        else

            high
 =
 high
 and
 math.min
(
interval
,
 high
)
 or
 interval

            if
 high
 ==
 interval
 then
 highpos
 =
 num
 end

        end

    end

    return
 lowpos
 ..
 '-'
 ..
 highpos

end


return
 p