IC2 Energy Monitor

-- Usage: em <monitorSide> <redstoneSide> [activate%] [deactivate%]
-- Example: em right back 30 80

local tArgs = {...}
if #tArgs < 2 then
    print("Usage: em <monitorSide> <redstoneSide> [activate%] [deactivate%]")
    return
end

local monitorSide = tArgs[1]
local redstoneSide = tArgs[2]
local activateThreshold = tonumber(tArgs[3]) or 25
local deactivateThreshold = tonumber(tArgs[4]) or 75

local monitor = peripheral.wrap(monitorSide)
if not monitor then
    print("Error: No monitor on side '" .. monitorSide .. "'")
    return
end

monitor.setTextScale(0.8)
local w, h = monitor.getSize()

-- Smart line redraw (no flicker)
local lastDrawn = {}
local function smartWriteLine(y, text, colour, bg)
    if lastDrawn[y] ~= text then
        monitor.setCursorPos(1, y)
        monitor.setTextColour(colour or colours.white)
        monitor.setBackgroundColour(bg or colours.black)
        monitor.clearLine()
        monitor.write(text)
        monitor.setTextColour(colours.white)
        monitor.setBackgroundColour(colours.black)
        lastDrawn[y] = text
    end
end

local function divider(y)
    smartWriteLine(y, string.rep("-", w))
end

-- Fill bar with colour ramp
local function drawFillBar(y, percent)
    local barWidth = w - 2
    local filledBars = math.floor((percent / 100) * barWidth)
    monitor.setCursorPos(1, y)
    monitor.write("[")
    for i = 1, barWidth do
        if i <= filledBars then
            local p = (i / barWidth) * 100
            local colour = colours.red
            if p > 80 then colour = colours.green
            elseif p > 50 then colour = colours.yellow
            elseif p > 20 then colour = colours.orange end
            monitor.setBackgroundColour(colour)
            monitor.write(" ")
            monitor.setBackgroundColour(colours.black)
        else
            monitor.write(" ")
        end
    end
    monitor.write("]")
end

-- Discover IC2 storage blocks
local function findStorages()
    local list = {}
    for _, name in ipairs(peripheral.getNames()) do
        if string.find(name, "ic2:batbox") or
           string.find(name, "ic2:cesu") or
           string.find(name, "ic2:mfe") or
           string.find(name, "ic2:mfsu") then
            table.insert(list, {peripheral.wrap(name), name})
        end
    end
    return list
end

local function formatEU(energy)
    if energy >= 1000000 then
        return string.format("%.1f M EU", energy / 1000000)
    elseif energy >= 1000 then
        return string.format("%.1f k EU", energy / 1000)
    else
        return string.format("%.0f EU", energy)
    end
end

local function formatTime(seconds)
    seconds = math.max(0, math.floor(seconds))
    local hh = math.floor(seconds / 3600)
    local mm = math.floor((seconds % 3600) / 60)
    local ss = seconds % 60
    return string.format("%02d:%02d:%02d", hh, mm, ss)
end

-- State
local lastTotals = {}   -- stores last total and per-block stored values
local redstoneActive = false
local currentPage = 1
local totalPages = 1
local lastPage = nil

-- Combined totals across all storages
local function getTotals(storages)
    local cap, stored = 0, 0
    for _, s in ipairs(storages) do
        cap = cap + (s[1].getEUCapacity() or 0)
        stored = stored + (s[1].getEUStored() or 0)
    end
    return cap, stored
end

-- Page 1: Combined overview
local function drawCombined(storages)
    local cap, stored = getTotals(storages)
    local fill = (cap > 0) and (stored / cap * 100) or 0
    local change = stored - (lastTotals.total or stored)
    lastTotals.total = stored

    local status = "Stable"
    if change > 0 then status = "Charging"
    elseif change < 0 then status = "Discharging" end

    -- Time estimate (in seconds, assuming 1s cadence)
    local timeString = "Stable"
    if change > 0 then
        local secondsToFull = (cap - stored) / change
        timeString = "Full in " .. formatTime(secondsToFull)
    elseif change < 0 then
        local secondsToEmpty = stored / math.abs(change)
        timeString = "Empty in " .. formatTime(secondsToEmpty)
    end

    -- Redstone hysteresis by fill %
    if fill < activateThreshold then
        redstone.setOutput(redstoneSide, true)
        redstoneActive = true
    elseif fill > deactivateThreshold then
        redstone.setOutput(redstoneSide, false)
        redstoneActive = false
    end

    smartWriteLine(1, "IC2 Network Storage (Combined)")
    smartWriteLine(2, "Capacity : " .. formatEU(cap))
    smartWriteLine(3, "Stored   : " .. formatEU(stored))
    smartWriteLine(4, string.format("Filled   : %.2f%%", fill), fill < activateThreshold and colours.red or colours.white)

    -- Fill bar line cleared explicitly to avoid artifacts
    monitor.setCursorPos(1, 5); monitor.clearLine()
    drawFillBar(5, fill)

    divider(6)
    smartWriteLine(7, "Status   : " .. status .. " (" .. change .. " EU/t)")
    divider(8)
    smartWriteLine(9, timeString)

    if change >= 0 then
        smartWriteLine(10, "Actual In : " .. change .. " EU/t")
        smartWriteLine(11, "Actual Out: 0 EU/t")
    else
        smartWriteLine(10, "Actual In : 0 EU/t")
        smartWriteLine(11, "Actual Out: " .. math.abs(change) .. " EU/t")
    end

    smartWriteLine(12, redstoneActive and "Redstone: ACTIVE" or "Redstone: Inactive",
                   redstoneActive and colours.red or colours.white)
end

-- Page 2+: Per-block breakdown with overflow paging
local function drawBreakdown(storages, page)
    local line = 1
    local contentBottom = h - 4        -- reserve rows h-3 (label), h-2 (blank), h-1 & h (buttons)
    local perPage = contentBottom      -- usable rows for content
    local startIndex = (page - 2) * perPage + 1
    local endIndex = math.min(startIndex + perPage - 1, #storages)

    for i = startIndex, endIndex do
        local block, name = storages[i][1], storages[i][2]
        local cap = block.getEUCapacity() or 0
        local stored = block.getEUStored() or 0
        local fill = (cap > 0) and (stored / cap * 100) or 0
        local change = stored - (lastTotals[name] or stored)
        lastTotals[name] = stored

        local status = "Stable"
        if change > 0 then status = "Charging"
        elseif change < 0 then status = "Discharging" end

        local timeString = "Stable"
        if change > 0 then
            local secondsToFull = (cap - stored) / change
            timeString = "Full in " .. formatTime(secondsToFull)
        elseif change < 0 then
            local secondsToEmpty = stored / math.abs(change)
            timeString = "Empty in " .. formatTime(secondsToEmpty)
        end

        smartWriteLine(line, name .. " (" .. string.format("%.1f%%", fill) .. ")",
                       fill < activateThreshold and colours.red or colours.white)
        line = line + 1

        monitor.setCursorPos(1, line); monitor.clearLine()
        drawFillBar(line, fill)
        line = line + 1

        smartWriteLine(line, "Status: " .. status .. " (" .. change .. " EU/t)")
        line = line + 1
        smartWriteLine(line, timeString)
        line = line + 1

        if change >= 0 then
            smartWriteLine(line, "In : " .. change .. " EU/t")
            line = line + 1
            smartWriteLine(line, "Out: 0 EU/t")
        else
            smartWriteLine(line, "In : 0 EU/t")
            line = line + 1
            smartWriteLine(line, "Out: " .. math.abs(change) .. " EU/t")
        end
        line = line + 1

        divider(line)
        line = line + 1

        if line > contentBottom then break end
    end
end

-- Two-row navigation bar with centered labels
local function drawNav(currentPageView, totalPagesView)
    -- Page indicator at h-3
    local label = " Page " .. currentPageView .. " / " .. totalPagesView .. " "
    local spacing = math.floor((w - #label) / 2)
    smartWriteLine(h-3, string.rep(" ", spacing) .. label)

    local half = math.floor(w / 2)

    -- Draw button backgrounds (rows h-1 and h)
    monitor.setBackgroundColour(colours.red)
    monitor.setTextColour(colours.white)
    for y = h-1, h do
        monitor.setCursorPos(1, y)
        monitor.write(string.rep(" ", half))
    end

    monitor.setBackgroundColour(colours.green)
    for y = h-1, h do
        monitor.setCursorPos(half + 1, y)
        monitor.write(string.rep(" ", w - half))
    end

    -- Labels on bottom row (center vertically)
    monitor.setBackgroundColour(colours.red)
    monitor.setCursorPos(2, h)
    monitor.write(" Prev ")

    monitor.setBackgroundColour(colours.green)
    monitor.setCursorPos(half + 2, h)
    monitor.write(" Next ")

    monitor.setBackgroundColour(colours.black)
    monitor.setTextColour(colours.white)
end

-- Calculate total pages (1 overview + N breakdown pages)
local function updateTotalPages(storages)
    local contentBottom = h - 4
    local perPage = math.max(1, contentBottom)
    local breakdownPages = math.ceil(#storages / perPage)
    totalPages = 1 + breakdownPages
end

-- Touch handler: detect presses on either row of the buttons
local function handleTouch(x, y)
    local half = math.floor(w / 2)
    if y == h or y == h - 1 then
        if x <= half then
            currentPage = math.max(1, currentPage - 1)
        else
            currentPage = math.min(totalPages, currentPage + 1)
        end
        return true
    end
    return false
end

-- Main loop: refresh, draw current page, draw nav, wait for touch or timer
while true do
    local storages = findStorages()
    updateTotalPages(storages)

    -- One-time clear on page switch to avoid ghost text
    if currentPage ~= lastPage then
        monitor.clear()
        lastDrawn = {}      -- reset cache so smartWriteLine redraws everything
        lastPage = currentPage
    else
        -- Clear content cache each tick so changing lines update properly
        for y = 1, h-4 do
            lastDrawn[y] = nil
        end
    end

    if currentPage == 1 then
        drawCombined(storages)
    else
        drawBreakdown(storages, currentPage)
    end
    drawNav(currentPage, totalPages)

    -- Timer for 1-second cadence while accepting touch
    local timer = os.startTimer(1)
    while true do
        local e, p1, p2, p3 = os.pullEvent()
        if e == "monitor_touch" then
            local side, x, y = p1, p2, p3
            if handleTouch(x, y) then
                break
            end
        elseif e == "timer" and p1 == timer then
            break
        end
    end
end