function forges.open(player, forge_id, time)
    local working_forge = player.forge.working_forge
    if (not working_forge) or working_forge.id ~= forge_id then
        error("trying to open invalid forge")
    end

    if not model.forges.is_ready(player, forge_id, time) then
        error("forge not ready")
    end

    local overdue = model.forges.get_overdue(player, forge_id, time)

    model.stats.inc(player, "melt_" .. forge_id)

    local owned = player.forge.owned_forges[forge_id]
    owned.melts = (owned.melts or 0) + 1

    local upgrade_level = working_forge.upgrade_level
    local bars = data.forges.get_produced_bars(forge_id, upgrade_level)

    local loot_id = model.resources.add_loot(player, "bars", bars)
    local loot = {{type="bars", amount=bars, loot_id=loot_id}}

    analytics.send("Forge.Open", {
        bars = bars,
        forge = forge_id,
        overdue_minutes = math.floor(overdue/60),
        ad_boost_count = working_forge.boost_ad or 0
    })

    player.forge.working_forge = nil

    return loot
end