class Session
    @DNF: -1
    solves = []

    solves: -> solves
    length: -> solves.length
    reset:  -> solves = []

    add: (solve) ->
        solves[solves.length] = solve

    delete: (index) ->
        solves.splice index, 1

    current_average: (n) ->
        average(solves.length - n, n)

    trim_count = (n) ->
        Math.ceil n / 20.0

    average = (index, length) ->
        return Session.DNF if (length - index) < 3

        trim = trim_count length
        copy = solves.slice index, index + length
        copy.sort session_sort
        copy.splice(0, trim)
        copy.splice(copy.length - trim, trim)

        return Session.DNF if copy[copy.length - 1]['DNF']

        sum = copy.reduce ((a, b) -> a + b['time']), 0
        sum / (length - (2 * trim))

    mean = ->
        return Session.DNF if solves.length < 1

        dnfs = 0
        sum = solves.reduce ((t, s) ->
            t + if s['DNF'] then ++dnfs; 0 else s['time']), 0

        return Session.DNF if solves.length == dnfs
        sum / (solves.length - dnfs)

    session_sort = (a, b) ->
        return 1  if a['DNF']
        return -1 if b['DNF']
        return a['time'] - b['time']

@Session = Session