openinghours.fsx

type Time = int*int
type Day = int
type OpeningHour = Day*Time
type DayGroup = 
    {
        Days: int list
        Time: Time
    }

let openingHour day startTime endTime = day,(startTime,endTime)

let openingHours = 
    [
        (openingHour 0 8 18)
        (openingHour 1 8 16)
        (openingHour 2 8 20)
        (openingHour 3 10 18)
        (openingHour 4 10 18)
        (openingHour 5 8 18)
        (openingHour 6 8 18)
    ]

let connectedDays = function
    | 0 -> [6;1]
    | 6 -> [5;0]
    | x -> [x-1;x+1]

let dayToString = function
    | 0 -> "Man"
    | 1 -> "Tirs"
    | 2 -> "Ons"
    | 3 -> "Tors"
    | 4 -> "Fre"
    | 5 -> "Lør"
    | 6 -> "Søn"

let isConnected (day1,day2) = 
    day1 |> connectedDays |> List.contains day2

let partitionGroup grp = 
    let first = grp |> List.head
    let time = first |> snd
    let firstDay = first |> fst
    let rec collect currentDays acc rem = 
        let candidateDays = currentDays |> List.collect connectedDays
        let connectedDays,rem' = rem |> List.partition (fun y -> candidateDays |> List.contains y)
        let accDays = connectedDays @ currentDays
        match connectedDays,rem with
        | [],[] -> [{Days = accDays; Time = time}]::acc
        | _,[] -> [{Days = accDays; Time = time}]::acc
        | _,_ -> 
            collect (currentDays@connectedDays) acc rem'
    collect [firstDay] [] (grp |> List.map fst |> List.tail)

let getStartAndEndDay daysUnordered =
    let days = daysUnordered |> List.sort
    let lastDay = days |> List.last
    let xs = (lastDay::(days |> List.rev |> List.tail |> List.rev)) |> List.zip days
    match xs |> List.tryFind (isConnected>>not) with
    | None ->
        (days |> List.min),(days |> List.max)
    | Some (startDay, endDay) ->  
        (startDay, endDay)

let getDayStringForDays days = 
    let startDay, endDay = getStartAndEndDay days
    if startDay = endDay 
    then sprintf "%s" (startDay |> dayToString)
    else sprintf "%s-%s" (startDay |> dayToString) (endDay |> dayToString)

let getTimeStringForGroup (startTime,endTime) =
    sprintf "%i:00-%i:00" startTime endTime

let printHours dayGroup = 
    let dayString = getDayStringForDays dayGroup.Days
    let timeString = getTimeStringForGroup dayGroup.Time
    printfn "%s %s" dayString timeString

openingHours
|> List.groupBy snd
|> List.map snd
|> List.map partitionGroup
|> List.concat
|> List.concat
|> List.iter printHours