CraftOS: Auto-detect peripherals and cache wrappers

-- Auto-detect peripherals and cache wrappers
-- Works in CC:Tweaked / CraftOS

local function detectPeripherals()
    local names = peripheral.getNames()

    local byName = {}     -- byName["left"] = { name="left", type="monitor", methods=..., p=wrapper }
    local byType = {}     -- byType["monitor"] = { entry1, entry2, ... }

    for i = 1, #names do
        local name = names[i]
        local pType = peripheral.getType(name) or "unknown"
        local methods = peripheral.getMethods(name) or {}

        local entry = {
            name = name,
            type = pType,
            methods = methods,
            p = peripheral.wrap(name)
        }

        byName[name] = entry

        if not byType[pType] then
            byType[pType] = {}
        end
        byType[pType][#byType[pType] + 1] = entry
    end

    return {
        byName = byName,
        byType = byType
    }
end

local function pickOne(cache, pType, preferredName)
    if preferredName and cache.byName[preferredName] and cache.byName[preferredName].type == pType then
        return cache.byName[preferredName].p, cache.byName[preferredName]
    end

    local list = cache.byType[pType]
    if list and #list > 0 then
        return list[1].p, list[1]
    end

    return nil, nil
end

-- Example usage:
local cache = detectPeripherals()

local monitor, monInfo = pickOne(cache, "monitor", "top")
if monitor then
    monitor.setTextScale(0.5)
    monitor.clear()
    monitor.setCursorPos(1, 1)
    monitor.write("Monitor: " .. monInfo.name)
end

local modem, modemInfo = pickOne(cache, "modem")
if modem then
    -- example: open a channel if wireless modem etc.
    -- modem.open(123)
end