--Maps incoming (playerID, sample, channels) to (preloaderID, sample, channels)
--Taking care of all bad things, 
--in the code below, "player" is a bad name for "preloader".
--and "id" is perhaps the $0 of the sampleplayer abstraction.
--Johannes Burstrรถm 2009. (excuse the code soup)

return function(self, sel, atoms)
    local id2sample = {}
    local sample2player = {}
    local maxplayers = atoms[1] or 16
    if not atoms[1] then pd.post("Safeload-logic: Setting max number of loaders to 16") end
    self.inlets = 1
    self.outlets = 1
    function self:in_1(id,atoms) 
        local id = atoms[1]
        local file = atoms[2]
        local chs = atoms[3]
        local player = nil
        local op = nil
      
        if id2sample[file] == nil then id2sample[file] = {} end

        -- check what id is playing now
        local oldsample = id2sample[id]
        if oldsample == file then 
            return 
        end
        id2sample[id] = file
        -- check if sample is alredy loaded
        -- if loaded, add id to id2sample 
        if sample2player[file] ~= nil then
            player = sample2player[file]
            id2sample[file] = { [id] = id }
            id2sample[id] =  file 
            sample2player[player].count = sample2player[player].count + 1
        else
            -- if not loaded, check for free player
            for i = 1, maxplayers do
              if sample2player[i] == nil then
                  player = i
                  sample2player[file] = i
                  sample2player[i] = { [file] = file, count = 1 }
                  break
              end
            end
        end
        if not player then 
            player = sample2player[oldsample] 
        else
            op = sample2player[oldsample]
            if op then
                sample2player[op].count = sample2player[op].count - 1
            end
        end
        if not player then
            pd.post("No free player! (and I don't know what to do)")
        else
            if oldsample and op then
                if sample2player[op].count == 0 then 
                    sample2player[op] = nil 
                    sample2player[oldsample] = nil
                end
            end
            self:outlet(1, "list", { player, file, chs, id })
        end
    end

    return true
end