--
-- me.lua
--
-- Reusable ME-network subsystem logic on an Advanced Peripherals ME Bridge.
-- No UI, no comms - collect() returns an aggregate snapshot (power, storage,
-- crafting CPUs) and there are a couple of on-demand item ops.
--
--   local me = require("me").new(cfg)
--   local st = me.collect()
--   local ok, info = me.get_item("minecraft:iron_ingot")
--
-- Aggregate only: listItems() can be thousands of entries, far too big to push
-- over rednet every couple seconds, so item lookups are per-request commands.
--
-- cfg fields used: me_bridge (side/name, optional - auto-detected), bridge_type.
--

local me = {}

function me.new(cfg)
    cfg = cfg or {}
    local BRIDGE_TYPE = cfg.bridge_type or "meBridge"

    local name = cfg.me_bridge
    if not (name and peripheral.isPresent(name) and peripheral.getType(name) == BRIDGE_TYPE) then
        name = nil
        for _, n in ipairs(peripheral.getNames()) do
            if peripheral.getType(n) == BRIDGE_TYPE then name = n; break end
        end
    end
    if not name then
        error("me: no ME Bridge ('" .. BRIDGE_TYPE .. "') found. Place one and attach it to this computer.", 0)
    end
    local b = peripheral.wrap(name)

    -- ME Bridge calls return (value, err) and can throw; guard each one.
    local function num(fn)
        local ok, v = pcall(fn)
        return (ok and type(v) == "number") and v or 0
    end

    local function collect()
        local stored = num(b.getEnergyStorage)
        local emax   = num(b.getMaxEnergyStorage)
        local usage  = num(b.getEnergyUsage)

        local itot   = num(b.getTotalItemStorage)
        local iused  = num(b.getUsedItemStorage)
        local iavail = num(b.getAvailableItemStorage)

        local ftot   = num(b.getTotalFluidStorage)
        local fused  = num(b.getUsedFluidStorage)
        local favail = num(b.getAvailableFluidStorage)

        local cpu_total, cpu_busy = 0, 0
        local ok, cpus = pcall(b.getCraftingCPUs)
        if ok and type(cpus) == "table" then
            cpu_total = #cpus
            for _, c in ipairs(cpus) do if c.isBusy then cpu_busy = cpu_busy + 1 end end
        end

        local epct = emax > 0 and math.floor((stored / emax) * 100) or 0
        local ipct = itot > 0 and math.floor((iused / itot) * 100) or 0

        return {
            headline = string.format("%d%% cells, %d/%d CPU busy", ipct, cpu_busy, cpu_total),
            power  = { stored = stored, max = emax, usage = usage, pct = epct },
            items  = { total = itot, used = iused, available = iavail, pct = ipct },
            fluids = { total = ftot, used = fused, available = favail },
            cpus   = { total = cpu_total, busy = cpu_busy },
        }
    end

    -- On-demand: how much of an item is stored + whether it's craftable.
    local function getItem(item_name)
        if not item_name then return false, "no item name" end
        local ok, info = pcall(b.getItem, { name = item_name })
        if not ok or type(info) ~= "table" then return false, "not found" end
        return true, {
            name        = info.name,
            displayName = info.displayName,
            amount      = info.amount or 0,
            craftable   = info.isCraftable and true or false,
        }
    end

    -- On-demand: kick off an autocraft job.
    local function craftItem(item_name, count)
        if not item_name then return false, "no item name" end
        local ok, started = pcall(b.craftItem, { name = item_name, count = count or 1 })
        if not ok then return false, tostring(started) end
        if not started then return false, "could not start (missing pattern or materials?)" end
        return true, { name = item_name, count = count or 1 }
    end

    return {
        bridge     = name,
        collect    = collect,
        get_item   = getItem,
        craft_item = craftItem,
    }
end

return me