local monitor = peripheral.wrap("top")
local core = peripheral.wrap("draconic_rf_storage_0")

monitor.setTextScale(0.5)
monitor.setBackgroundColor(colors.black)
monitor.setTextColor(colors.white)

local BAR_WIDTH = 40
local BAR_Y = 5

local function formatRF(v)
    if v >= 1e12 then return string.format("%.2f T", v / 1e12) end
    if v >= 1e9 then return string.format("%.2f G", v / 1e9) end
    if v >= 1e6 then return string.format("%.2f M", v / 1e6) end
    if v >= 1e3 then return string.format("%.2f k", v / 1e3) end
    return tostring(v)
end

local function formatTime(seconds)
    if seconds == math.huge then return "∞" end
    local h = math.floor(seconds / 3600)
    local m = math.floor((seconds % 3600) / 60)
    local s = math.floor(seconds % 60)
    return string.format("%02d:%02d:%02d", h, m, s)
end

while true do
    monitor.clear()

    local energy = core.getEnergyStored()
    local maxEnergy = core.getMaxEnergyStored()

    local input = core.getLastInput and core.getLastInput() or 0
    local output = core.getLastOutput and core.getLastOutput() or 0
    local net = input - output

    local percent = energy / maxEnergy
    local filled = math.floor(percent * BAR_WIDTH)

    monitor.setCursorPos(2, 1)
    monitor.write("Draconic Energy Core")

    monitor.setCursorPos(2, BAR_Y)
    monitor.write("[")

    monitor.setCursorPos(3, BAR_Y)
    monitor.setBackgroundColor(colors.green)
    monitor.write(string.rep(" ", filled))

    monitor.setBackgroundColor(colors.gray)
    monitor.write(string.rep(" ", BAR_WIDTH - filled))

    monitor.setBackgroundColor(colors.black)
    monitor.write("]")

    monitor.setCursorPos(2, BAR_Y + 2)
    monitor.write("Stored: " .. formatRF(energy) .. " / " .. formatRF(maxEnergy))

    monitor.setCursorPos(2, BAR_Y + 3)
    monitor.write(string.format("Charge: %.2f%%", percent * 100))

    monitor.setCursorPos(2, BAR_Y + 4)
    monitor.write("Net RF/t: " .. formatRF(net))

    monitor.setCursorPos(2, BAR_Y + 6)
    if net > 0 then
        monitor.write("Time to full: " .. formatTime((maxEnergy - energy) / net / 20))
    elseif net < 0 then
        monitor.write("Time to empty: " .. formatTime(energy / math.abs(net) / 20))
    else
        monitor.write("Time: Stable")
    end

    sleep(1)
end