-- vi: ft=lua

-- ============================================================================
-- DRACONIC REACTOR CONTROLLER & OPTIMIZER
-- For ATM9 / Draconic Evolution
-- ============================================================================

-- ============================================================================
-- CONFIGURATION - EDIT THESE VALUES TO MATCH YOUR SETUP
-- ============================================================================

local CONFIG = {
    -- =======================================================================
    -- PERIPHERAL NAMES (REQUIRED)
    -- =======================================================================
    -- Run "peripherals" in the ComputerCraft terminal to find these names
    -- All three must be set for the controller to work!
    reactor_name = "draconic_reactor_0",    -- The reactor itself
    input_gate_name = "flow_gate_0",        -- Flux gate feeding containment field
    output_gate_name = "flow_gate_1",       -- Flux gate for power output
    monitor_name = "right",                 -- Monitor side or network name (optional)

    -- =======================================================================
    -- FAIL-SAFE: Hardcoded emergency field input (RF/t)
    -- =======================================================================
    -- This is used if we can't read reactor data - set HIGH ENOUGH to sustain field!
    -- For a typical reactor, 5-50 million RF/t is safe for emergency containment
    -- If your reactor is very large, increase this value!
    emergency_field_input = 50000000,  -- 50M RF/t fail-safe

    -- =======================================================================
    -- FIELD STRENGTH TARGET (this is the main optimization setting)
    -- =======================================================================
    -- CONSERVATIVE: 50% (0.50) - Very safe, lower efficiency
    --   Pros: Large safety margin, slow temperature rise, forgiving
    --   Cons: Less power output, uses more fuel per RF generated
    --
    -- BALANCED: 30% (0.30) - Good balance of safety and output
    --   Pros: Decent output, still reasonably safe
    --   Cons: Need to pay some attention
    --
    -- AGGRESSIVE: 15-20% (0.15-0.20) - Maximum efficiency
    --   Pros: Maximum power output, best fuel efficiency
    --   Cons: Less margin for error, requires fast computer response
    --
    -- EXTREME: 8-10% (0.08-0.10) - Danger zone, not recommended
    --   Pros: Absolute maximum output
    --   Cons: Very easy to explode, not worth the risk
    -- =======================================================================
    target_field_strength = 0.30,

    -- Safety thresholds
    min_field_strength = 0.20,     -- Emergency shutdown below this (8%)
    max_temperature = 8000,        -- Emergency shutdown above this (Kelvin)
    critical_temperature = 7500,   -- Start reducing output at this temp

    -- Saturation threshold for fuel conversion
    min_saturation = 0.20,         -- Below this, reactor produces less power

    -- Update intervals (in seconds)
    update_interval = 0.1,         -- Main loop speed (faster = more responsive)
    display_interval = 0.5,        -- Monitor refresh rate

    -- Field strength control
    field_strength_tolerance = 0.01,  -- Acceptable deviation from target (1%)

    -- Startup settings
    charge_field_target = 0.55,    -- Charge field to this before starting (55%)
}

-- ============================================================================
-- STATE MACHINE STATES
-- ============================================================================

local STATES = {
    OFFLINE = "OFFLINE",           -- Reactor is off
    CONNECTING = "CONNECTING",     -- Finding peripherals
    CHARGING = "CHARGING",         -- Charging containment field
    WARMING_UP = "WARMING UP",     -- Initial temperature ramp
    RUNNING = "RUNNING",           -- Normal optimized operation
    COOLING = "COOLING",           -- Temperature too high, reducing output
    EMERGENCY = "EMERGENCY",       -- Emergency shutdown in progress
    SHUTDOWN = "SHUTDOWN",         -- Manual shutdown requested
    ERROR = "ERROR",               -- Peripheral error
}

-- ============================================================================
-- GLOBAL VARIABLES
-- ============================================================================

local state = STATES.OFFLINE
local reactor = nil
local inputGate = nil
local outputGate = nil
local monitor = nil

local lastDisplayUpdate = 0
local reactorInfo = {}
local shutdownRequested = false
local chargeRequested = false  -- Track when user requests charging
local errorMessage = ""
local fieldErrors = {}  -- Track specific field read errors

-- Retry rate limiting for peripheral reconnection
local lastPeripheralRetry = 0
local peripheralRetryDelay = 1  -- Start with 1 second, exponential backoff up to 30s

-- Flux gate rate limiting
local lastFluxUpdate = 0
local lastInputRate = -1
local lastOutputRate = -1

-- ============================================================================
-- UTILITY FUNCTIONS
-- ============================================================================

local function formatNumber(num)
    if num >= 1e12 then
        return string.format("%.2fT", num / 1e12)
    elseif num >= 1e9 then
        return string.format("%.2fG", num / 1e9)
    elseif num >= 1e6 then
        return string.format("%.2fM", num / 1e6)
    elseif num >= 1e3 then
        return string.format("%.2fK", num / 1e3)
    else
        return string.format("%.2f", num)
    end
end

local function formatPercent(decimal)
    return string.format("%.2f%%", decimal * 100)
end

local function formatTemp(kelvin)
    return string.format("%.0fK", kelvin)
end

local function clamp(value, min, max)
    return math.max(min, math.min(max, value))
end

-- ============================================================================
-- PERIPHERAL DETECTION
-- ============================================================================

local function findPeripherals()
    state = STATES.CONNECTING
    errorMessage = ""

    -- Validate configuration
    if not CONFIG.reactor_name then
        errorMessage = "CONFIG.reactor_name not set!"
        state = STATES.ERROR
        return false
    end

    if not CONFIG.input_gate_name then
        errorMessage = "CONFIG.input_gate_name not set!"
        state = STATES.ERROR
        return false
    end

    if not CONFIG.output_gate_name then
        errorMessage = "CONFIG.output_gate_name not set!"
        state = STATES.ERROR
        return false
    end

    -- Connect to reactor
    reactor = peripheral.wrap(CONFIG.reactor_name)
    if not reactor then
        errorMessage = "Reactor not found: " .. CONFIG.reactor_name
        state = STATES.ERROR
        return false
    end

    -- Connect to input flux gate (feeds containment field)
    inputGate = peripheral.wrap(CONFIG.input_gate_name)
    if not inputGate then
        errorMessage = "Input flux gate not found: " .. CONFIG.input_gate_name
        state = STATES.ERROR
        return false
    end

    -- Connect to output flux gate (power output)
    outputGate = peripheral.wrap(CONFIG.output_gate_name)
    if not outputGate then
        errorMessage = "Output flux gate not found: " .. CONFIG.output_gate_name
        state = STATES.ERROR
        return false
    end

    -- Enable override mode on flux gates (required for setFlowOverride to work)
    pcall(function() inputGate.setOverrideEnabled(true) end)
    pcall(function() outputGate.setOverrideEnabled(true) end)
    print("Flux gate overrides enabled")

    -- Connect to monitor (optional)
    monitor = peripheral.wrap(CONFIG.monitor_name)
    if monitor then
        monitor.setTextScale(0.5)
        monitor.clear()
    else
        print("Warning: Monitor not found at '" .. CONFIG.monitor_name .. "', using terminal only")
    end

    return true
end

-- ============================================================================
-- REACTOR INFORMATION GATHERING
-- ============================================================================

local function updateReactorInfo()
    if not reactor then return false end

    -- Clear previous field errors
    fieldErrors = {}

    local success, err = pcall(function()
        reactorInfo = reactor.getReactorInfo()
    end)

    if not success then
        errorMessage = "Failed to read reactor: " .. tostring(err)
        state = STATES.ERROR
        return false
    end

    -- Validate critical fields and track errors
    if not reactorInfo then
        table.insert(fieldErrors, "reactorInfo is nil")
        errorMessage = "Reactor returned no data"
        state = STATES.ERROR
        return false
    end

    -- Check each critical field
    local criticalFields = {
        "status", "temperature", "fieldStrength", "maxFieldStrength",
        "fieldDrainRate", "energySaturation", "maxEnergySaturation",
        "generationRate", "fuelConversion", "maxFuelConversion"
    }

    for _, field in ipairs(criticalFields) do
        if reactorInfo[field] == nil then
            table.insert(fieldErrors, field .. " = nil")
        elseif type(reactorInfo[field]) == "number" and reactorInfo[field] ~= reactorInfo[field] then
            -- NaN check (NaN ~= NaN is true)
            table.insert(fieldErrors, field .. " = NaN")
        end
    end

    -- Check for invalid numeric values
    local numericFields = {
        "temperature", "fieldStrength", "maxFieldStrength",
        "fieldDrainRate", "energySaturation", "maxEnergySaturation",
        "generationRate"
    }

    for _, field in ipairs(numericFields) do
        local val = reactorInfo[field]
        if val ~= nil and type(val) == "number" then
            if val < 0 then
                table.insert(fieldErrors, field .. " < 0 (" .. tostring(val) .. ")")
            end
            if val == math.huge or val == -math.huge then
                table.insert(fieldErrors, field .. " = infinity")
            end
        end
    end

    -- -- Check for zero max values (would cause division by zero)
    -- -- Only flag as error if reactor is not offline (these are expected to be 0 when cold)
    -- local isOffline = reactorInfo.status == "cold" or reactorInfo.status == "invalid"
    -- if not isOffline then
    --     if reactorInfo.maxFieldStrength ~= nil and reactorInfo.maxFieldStrength <= 0 then
    --         table.insert(fieldErrors, "maxFieldStrength <= 0")
    --     end
    --     if reactorInfo.maxEnergySaturation ~= nil and reactorInfo.maxEnergySaturation <= 0 then
    --         table.insert(fieldErrors, "maxEnergySaturation <= 0")
    --     end
    -- end

    -- Set error message if we have field errors
    if #fieldErrors > 0 then
        errorMessage = "Field errors: " .. #fieldErrors .. " issues"
    else
        errorMessage = ""
    end

    -- Check for critical field errors that require EMERGENCY state
    -- These fields are essential for safe reactor control
    local criticalForSafety = {"fieldStrength", "maxFieldStrength", "fieldDrainRate", "temperature"}
    for _, field in ipairs(criticalForSafety) do
        if reactorInfo[field] == nil then
            errorMessage = "CRITICAL: " .. field .. " is nil!"
            -- Only go to emergency if reactor is not offline
            if reactorInfo.status ~= "cold" and reactorInfo.status ~= "invalid" then
                state = STATES.EMERGENCY
                return false
            end
        end
    end

    return true
end

-- Calculate required field input to maintain current field
local function calculateFieldInput()
    -- SAFETY: If we can't read reactor data, return emergency high value
    if not reactorInfo then
        return CONFIG.emergency_field_input
    end

    -- SAFETY: If critical fields are missing, use emergency input
    if not reactorInfo.fieldDrainRate or not reactorInfo.fieldStrength or not reactorInfo.maxFieldStrength then
        return CONFIG.emergency_field_input
    end

    -- SAFETY: Prevent division by zero
    if reactorInfo.maxFieldStrength <= 0 then
        return CONFIG.emergency_field_input
    end

    local drainRate = reactorInfo.fieldDrainRate
    local currentStrength = reactorInfo.fieldStrength / reactorInfo.maxFieldStrength

    -- Use charge target during warmup/charging, operational target when running
    local targetStrength = CONFIG.target_field_strength
    if state == STATES.CHARGING or state == STATES.WARMING_UP then
        targetStrength = CONFIG.charge_field_target
    end

    -- Base input = drain rate to maintain current level
    local baseInput = drainRate

    -- Add correction factor to move toward target
    local strengthError = targetStrength - currentStrength
    local correction = strengthError * reactorInfo.maxFieldStrength * 0.5

    -- Total input needed
    local totalInput = baseInput + correction

    -- If field is above target, allow input to go very low (just above drain rate)
    -- If field is below target, ensure minimum input to build field
    local minimumInput
    if currentStrength > targetStrength then
        -- Above target - only maintain drain rate, let field drop
        minimumInput = drainRate * 1.1
    else
        -- Below target - ensure some input even if drain is 0
        minimumInput = math.max(drainRate * 1.1, 1000000)
    end

    local result = math.max(0, math.floor(math.max(minimumInput, totalInput)))

    -- Verbose output
    local fieldPct = string.format("%.1f%%", currentStrength * 100)
    local targetPct = string.format("%.1f%%", targetStrength * 100)
    if currentStrength < targetStrength - 0.01 then
        print("[FIELD] " .. fieldPct .. " < " .. targetPct .. " target -> increasing input to " .. formatNumber(result) .. " RF/t (drain=" .. formatNumber(drainRate) .. ")")
    elseif currentStrength > targetStrength + 0.01 then
        print("[FIELD] " .. fieldPct .. " > " .. targetPct .. " target -> reducing input to " .. formatNumber(result) .. " RF/t (drain=" .. formatNumber(drainRate) .. ")")
    else
        print("[FIELD] " .. fieldPct .. " at target -> maintaining " .. formatNumber(result) .. " RF/t")
    end

    return result
end

-- Calculate safe output rate based on temperature and saturation
local function calculateOutputRate()
    -- SAFETY: If we can't read reactor data, output nothing (conservative)
    if not reactorInfo then return 0 end

    -- SAFETY: If critical fields are missing, output nothing
    if not reactorInfo.energySaturation or not reactorInfo.maxEnergySaturation then
        return 0
    end

    -- SAFETY: Prevent division by zero
    if reactorInfo.maxEnergySaturation <= 0 then
        return 0
    end

    local temp = reactorInfo.temperature or 0
    local saturation = reactorInfo.energySaturation / reactorInfo.maxEnergySaturation
    local generationRate = reactorInfo.generationRate or 0
    local result = 0
    local reason = ""

    -- If we're in emergency or cooling, limit output
    if state == STATES.EMERGENCY then
        result = 0
        reason = "EMERGENCY state"
    elseif state == STATES.COOLING then
        result = math.floor(generationRate * 0.5)
        reason = "COOLING - 50% of generation"
    elseif state == STATES.CHARGING or state == STATES.WARMING_UP then
        result = math.floor(generationRate * 0.8)
        reason = state .. " - 80% of generation"
    else
        -- Normal operation
        local tempFactor = 1.0
        if temp > CONFIG.critical_temperature then
            local overTemp = temp - CONFIG.critical_temperature
            local tempRange = CONFIG.max_temperature - CONFIG.critical_temperature
            tempFactor = 1.0 - (overTemp / tempRange) * 0.5
            reason = "temp " .. formatTemp(temp) .. " > critical, factor=" .. string.format("%.2f", tempFactor)
        end

        local outputRate = generationRate * tempFactor

        if saturation > 0.8 then
            outputRate = generationRate * 1.1 * tempFactor
            if reason == "" then reason = "high saturation (110%)" end
        elseif reason == "" then
            reason = "normal operation"
        end

        result = math.max(0, math.floor(outputRate))
    end

    if generationRate > 0 then
        print("[OUTPUT] " .. formatNumber(result) .. " RF/t (" .. reason .. ")")
    end

    return result
end

-- ============================================================================
-- STATE MACHINE LOGIC
-- ============================================================================

local lastState = nil

local function setState(newState, reason)
    if state ~= newState then
        print("[STATE] " .. state .. " -> " .. newState .. " (" .. reason .. ")")
        state = newState
    end
end

local function processStateMachine()
    if not reactorInfo or not reactorInfo.status then
        -- SAFETY: Can't read reactor, go to emergency to maintain field
        if state ~= STATES.OFFLINE and state ~= STATES.ERROR then
            setState(STATES.EMERGENCY, "cannot read reactor data")
        end
        return
    end

    local reactorStatus = reactorInfo.status
    local temp = reactorInfo.temperature or 0

    -- SAFETY: Prevent division by zero
    local maxField = reactorInfo.maxFieldStrength or 1
    local maxSat = reactorInfo.maxEnergySaturation or 1
    if maxField <= 0 then maxField = 1 end
    if maxSat <= 0 then maxSat = 1 end

    local fieldStrength = (reactorInfo.fieldStrength or 0) / maxField
    local saturation = (reactorInfo.energySaturation or 0) / maxSat
    local fieldPct = string.format("%.1f%%", fieldStrength * 100)

    -- Check for emergency conditions first (always)
    if reactorStatus ~= "cold" and reactorStatus ~= "cooling" then
        if fieldStrength < CONFIG.min_field_strength then
            setState(STATES.EMERGENCY, "field " .. fieldPct .. " below minimum " .. formatPercent(CONFIG.min_field_strength))
            return
        end
        if temp > CONFIG.max_temperature then
            setState(STATES.EMERGENCY, "temp " .. formatTemp(temp) .. " exceeds max " .. formatTemp(CONFIG.max_temperature))
            return
        end
    end

    -- Check for shutdown request
    if shutdownRequested then
        if reactorStatus == "cold" or reactorStatus == "cooling" then
            setState(STATES.SHUTDOWN, "shutdown requested, reactor cooling")
            shutdownRequested = false
        elseif state ~= STATES.EMERGENCY then
            setState(STATES.SHUTDOWN, "shutdown requested")
        end
        return
    end

    -- State transitions based on reactor status
    if reactorStatus == "cold" or reactorStatus == "invalid" then
        setState(STATES.OFFLINE, "reactor status: " .. reactorStatus)
        return
    end

    -- Clear charge request flag once field is sufficiently charged
    if chargeRequested then
        if fieldStrength >= CONFIG.charge_field_target then
            chargeRequested = false
            print("[INFO] Field charged to " .. fieldPct .. ", charge request cleared")
        end
    end

    if reactorStatus == "cooling" then
        if state == STATES.EMERGENCY or state == STATES.SHUTDOWN then
            -- Keep current state during cooldown
            return
        end
        setState(STATES.COOLING, "reactor cooling down")
        return
    end

    if reactorStatus == "warming_up" then
        -- Use 0.9 multiplier for hysteresis (consistent with RUNNING state)
        if fieldStrength < CONFIG.charge_field_target * 0.9 then
            setState(STATES.CHARGING, "field " .. fieldPct .. " below charge target")
        else
            setState(STATES.WARMING_UP, "field " .. fieldPct .. " sufficient, warming up")
        end
        return
    end

    if reactorStatus == "running" then
        if fieldStrength < CONFIG.charge_field_target * 0.9 then
            setState(STATES.CHARGING, "field " .. fieldPct .. " dropped below threshold while running")
        elseif temp > CONFIG.critical_temperature then
            setState(STATES.COOLING, "temp " .. formatTemp(temp) .. " above critical " .. formatTemp(CONFIG.critical_temperature))
        else
            setState(STATES.RUNNING, "normal operation")
        end
        return
    end

    if reactorStatus == "stopping" then
        setState(STATES.SHUTDOWN, "reactor stopping")
        return
    end
end

-- ============================================================================
-- REACTOR CONTROL
-- ============================================================================

local function controlReactor()
    if not reactor or not inputGate or not outputGate then
        return
    end

    if not reactorInfo or not reactorInfo.status then
        return
    end

    local inputRate = 0
    local outputRate = 0

    if state == STATES.EMERGENCY then
        -- EMERGENCY: Maximum field input, stop the reactor
        -- SAFETY: Use 2x maxFieldStrength or our fail-safe constant, whichever is higher
        local maxField = reactorInfo.maxFieldStrength or 0
        inputRate = math.max(maxField * 2, CONFIG.emergency_field_input)
        outputRate = 0

        -- Try to stop the reactor
        local stopSuccess, stopErr = pcall(function()
            reactor.stopReactor()
        end)
        if not stopSuccess then
            print("[WARNING] Failed to stop reactor: " .. tostring(stopErr))
        end

    elseif state == STATES.SHUTDOWN then
        -- SHUTDOWN: Maintain field with safety margin, no output, let it cool
        -- Use 1.5x normal input to account for increased drain during cooldown
        inputRate = math.floor(calculateFieldInput() * 1.5)
        outputRate = 0

        -- Try to stop the reactor if running
        if reactorInfo.status == "running" or reactorInfo.status == "warming_up" then
            local stopSuccess, stopErr = pcall(function()
                reactor.stopReactor()
            end)
            if not stopSuccess then
                print("[WARNING] Failed to stop reactor: " .. tostring(stopErr))
            end
        end

    elseif state == STATES.CHARGING then
        -- CHARGING: High field input to charge up
        local maxField = reactorInfo.maxFieldStrength or 0

        if maxField > 0 then
            -- Reactor has valid maxFieldStrength - calculate based on charge needed
            local fieldStrength = (reactorInfo.fieldStrength or 0) / maxField
            local chargeNeeded = CONFIG.charge_field_target - fieldStrength

            -- Charge faster when further from target
            inputRate = math.floor(maxField * math.max(0.1, chargeNeeded))
            inputRate = math.max(inputRate, calculateFieldInput())
        else
            -- Reactor is cold/initializing - use emergency input to charge field
            -- This provides enough power to establish the containment field
            inputRate = CONFIG.emergency_field_input
        end
        outputRate = 0

    elseif state == STATES.WARMING_UP then
        -- WARMING UP: Maintain field, slowly ramp output
        local maxField = reactorInfo.maxFieldStrength or 0
        if maxField > 0 then
            inputRate = calculateFieldInput()
        else
            -- maxFieldStrength not available yet - use emergency input
            inputRate = CONFIG.emergency_field_input
        end
        outputRate = calculateOutputRate()

    elseif state == STATES.RUNNING then
        -- RUNNING: Normal optimized operation
        inputRate = calculateFieldInput()
        outputRate = calculateOutputRate()

    elseif state == STATES.COOLING then
        -- COOLING: Maintain field, reduce output
        inputRate = calculateFieldInput()
        outputRate = calculateOutputRate()  -- Already reduced in the function

    elseif state == STATES.ERROR then
        -- ERROR: Peripheral issues - pump maximum into field to be safe!
        inputRate = CONFIG.emergency_field_input
        outputRate = 0

    else
        -- OFFLINE: Reactor is cold
        if chargeRequested then
            -- User requested charge - provide input flux to start charging the field
            inputRate = CONFIG.emergency_field_input
            outputRate = 0
            print("[CHARGE] Providing " .. formatNumber(inputRate) .. " RF/t to charge field")
        else
            -- No action needed
            inputRate = 0
            outputRate = 0
        end
    end

    -- Apply the flow rates with rate limiting
    -- Emergency/Error/Charging states bypass rate limiting for safety
    local now = os.clock()
    local isUrgent = (state == STATES.EMERGENCY or state == STATES.ERROR or chargeRequested)
    local ratesChanged = (inputRate ~= lastInputRate) or (outputRate ~= lastOutputRate)
    local timeSinceUpdate = now - lastFluxUpdate

    -- Update flux gates if: urgent, OR (rates changed AND enough time passed)
    if isUrgent or (ratesChanged and timeSinceUpdate >= 0.5) then
        lastFluxUpdate = now
        lastInputRate = inputRate
        lastOutputRate = outputRate

        local inputSuccess = pcall(function()
            inputGate.setFlowOverride(math.floor(inputRate))
        end)

        -- SAFETY: If we failed to set input gate, that's critical!
        if not inputSuccess and state ~= STATES.OFFLINE then
            errorMessage = "CRITICAL: Failed to set input flux gate!"
            state = STATES.ERROR
        end

        local outputSuccess = pcall(function()
            outputGate.setFlowOverride(math.floor(outputRate))
        end)

        -- Output gate failure is less critical but should be logged
        if not outputSuccess and state ~= STATES.OFFLINE then
            print("[WARNING] Failed to set output flux gate!")
        end
    end
end

-- ============================================================================
-- DISPLAY FUNCTIONS
-- ============================================================================

local function getStateColor(s)
    local colors_map = {
        [STATES.OFFLINE] = colors.gray,
        [STATES.CONNECTING] = colors.yellow,
        [STATES.CHARGING] = colors.blue,
        [STATES.WARMING_UP] = colors.orange,
        [STATES.RUNNING] = colors.lime,
        [STATES.COOLING] = colors.cyan,
        [STATES.EMERGENCY] = colors.red,
        [STATES.SHUTDOWN] = colors.purple,
        [STATES.ERROR] = colors.red,
    }
    return colors_map[s] or colors.white
end

local function drawProgressBar(mon, x, y, width, value, maxValue, barColor, bgColor)
    local percent = clamp(value / maxValue, 0, 1)
    local filledWidth = math.floor(width * percent)

    mon.setCursorPos(x, y)
    mon.setBackgroundColor(barColor)
    mon.write(string.rep(" ", filledWidth))
    mon.setBackgroundColor(bgColor or colors.gray)
    mon.write(string.rep(" ", width - filledWidth))
    mon.setBackgroundColor(colors.black)
end

local function updateDisplay()
    if not monitor then
        -- Fallback to terminal
        term.clear()
        term.setCursorPos(1, 1)
        print("=== DRACONIC REACTOR CONTROLLER ===")
        print("State: " .. state)
        if reactorInfo and reactorInfo.status then
            print("Reactor: " .. reactorInfo.status)
            print("Temp: " .. formatTemp(reactorInfo.temperature or 0))
            local fs = (reactorInfo.fieldStrength or 0) / (reactorInfo.maxFieldStrength or 1)
            print("Field: " .. formatPercent(fs))
            print("Gen: " .. formatNumber(reactorInfo.generationRate or 0) .. " RF/t")
        end
        if errorMessage ~= "" then
            print("Error: " .. errorMessage)
        end
        -- Show field errors on terminal
        if #fieldErrors > 0 then
            print("")
            print("--- FIELD READ ERRORS ---")
            for i, err in ipairs(fieldErrors) do
                print("  " .. i .. ". " .. err)
                if i >= 5 then
                    print("  ... and " .. (#fieldErrors - 5) .. " more")
                    break
                end
            end
        end
        return
    end

    local mon = monitor
    local w, h = mon.getSize()

    mon.setBackgroundColor(colors.black)
    mon.clear()

    -- Header
    mon.setCursorPos(1, 1)
    mon.setTextColor(colors.cyan)
    mon.write("=== DRACONIC REACTOR CONTROL ===")

    -- State display (prominent)
    mon.setCursorPos(1, 3)
    mon.setTextColor(colors.white)
    mon.write("OPTIMIZER STATE: ")
    mon.setTextColor(getStateColor(state))
    mon.write(state)

    -- Error message if any
    if errorMessage ~= "" then
        mon.setCursorPos(1, 4)
        mon.setTextColor(colors.red)
        mon.write("! " .. errorMessage)
    end

    -- Show field errors on monitor
    if #fieldErrors > 0 then
        local errorY = 5
        mon.setCursorPos(1, errorY)
        mon.setTextColor(colors.orange)
        mon.write("--- FIELD READ ERRORS ---")
        errorY = errorY + 1
        for i, err in ipairs(fieldErrors) do
            mon.setCursorPos(1, errorY)
            mon.setTextColor(colors.red)
            mon.write("  " .. err)
            errorY = errorY + 1
            if i >= 4 then
                mon.setCursorPos(1, errorY)
                mon.write("  +" .. (#fieldErrors - 4) .. " more errors")
                errorY = errorY + 1
                break
            end
        end
    end

    if not reactorInfo or not reactorInfo.status then
        local waitY = #fieldErrors > 0 and (7 + math.min(#fieldErrors, 5)) or 6
        mon.setCursorPos(1, waitY)
        mon.setTextColor(colors.yellow)
        mon.write("Waiting for reactor data...")
        return
    end

    local y = #fieldErrors > 0 and (7 + math.min(#fieldErrors, 5)) or 5

    -- Reactor status
    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Reactor Status: ")
    mon.setTextColor(colors.yellow)
    mon.write(reactorInfo.status or "unknown")
    y = y + 2

    -- Temperature
    local temp = reactorInfo.temperature or 0
    local tempColor = colors.lime
    if temp > CONFIG.critical_temperature then
        tempColor = colors.orange
    end
    if temp > CONFIG.max_temperature * 0.95 then
        tempColor = colors.red
    end

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Temperature: ")
    mon.setTextColor(tempColor)
    mon.write(formatTemp(temp) .. " / " .. formatTemp(CONFIG.max_temperature))
    y = y + 1

    -- Temperature bar
    drawProgressBar(mon, 1, y, w - 2, temp, CONFIG.max_temperature, tempColor)
    y = y + 2

    -- Field Strength
    local fieldStrength = reactorInfo.fieldStrength or 0
    local maxField = reactorInfo.maxFieldStrength or 1
    if maxField <= 0 then maxField = 1 end  -- SAFETY: prevent division by zero
    local fieldPercent = fieldStrength / maxField
    local fieldColor = colors.lime
    if fieldPercent < CONFIG.target_field_strength then
        fieldColor = colors.yellow
    end
    if fieldPercent < CONFIG.min_field_strength * 2 then
        fieldColor = colors.orange
    end
    if fieldPercent < CONFIG.min_field_strength then
        fieldColor = colors.red
    end

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Field Strength: ")
    mon.setTextColor(fieldColor)
    mon.write(formatPercent(fieldPercent) .. " (Target: " .. formatPercent(CONFIG.target_field_strength) .. ")")
    y = y + 1

    -- Field bar
    drawProgressBar(mon, 1, y, w - 2, fieldPercent, 1, fieldColor)
    y = y + 2

    -- Energy Saturation
    local saturation = reactorInfo.energySaturation or 0
    local maxSaturation = reactorInfo.maxEnergySaturation or 1
    if maxSaturation <= 0 then maxSaturation = 1 end  -- SAFETY: prevent division by zero
    local satPercent = saturation / maxSaturation

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Saturation: ")
    mon.setTextColor(colors.magenta)
    mon.write(formatPercent(satPercent))
    y = y + 1

    drawProgressBar(mon, 1, y, w - 2, satPercent, 1, colors.magenta)
    y = y + 2

    -- Fuel
    local fuel = reactorInfo.fuelConversion or 0
    local maxFuel = reactorInfo.maxFuelConversion or 1
    if maxFuel <= 0 then maxFuel = 1 end  -- SAFETY: prevent division by zero
    local fuelPercent = fuel / maxFuel

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Fuel Used: ")
    mon.setTextColor(colors.brown)
    mon.write(formatPercent(fuelPercent))
    y = y + 1

    drawProgressBar(mon, 1, y, w - 2, fuelPercent, 1, colors.brown, colors.green)
    y = y + 2

    -- Generation Rate
    local genRate = reactorInfo.generationRate or 0
    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Generation: ")
    mon.setTextColor(colors.lime)
    mon.write(formatNumber(genRate) .. " RF/t")
    y = y + 1

    -- Field Drain Rate
    local drainRate = reactorInfo.fieldDrainRate or 0
    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Field Drain: ")
    mon.setTextColor(colors.orange)
    mon.write(formatNumber(drainRate) .. " RF/t")
    y = y + 2

    -- Flux Gate Info
    mon.setCursorPos(1, y)
    mon.setTextColor(colors.cyan)
    mon.write("--- FLUX GATES ---")
    y = y + 1

    local inputFlow = 0
    local outputFlow = 0
    pcall(function()
        inputFlow = inputGate.getFlow() or 0
    end)
    pcall(function()
        outputFlow = outputGate.getFlow() or 0
    end)

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Input (Field): ")
    mon.setTextColor(colors.blue)
    mon.write(formatNumber(inputFlow) .. " RF/t")
    y = y + 1

    mon.setCursorPos(1, y)
    mon.setTextColor(colors.white)
    mon.write("Output (Power): ")
    mon.setTextColor(colors.lime)
    mon.write(formatNumber(outputFlow) .. " RF/t")
    y = y + 2

    -- Instructions
    mon.setCursorPos(1, y)
    mon.setTextColor(colors.gray)
    mon.write("Press Q to shutdown, C to charge")
end

-- ============================================================================
-- INPUT HANDLING
-- ============================================================================

local function handleInput()
    while true do
        local event, key = os.pullEvent("key")

        if key == keys.q then
            -- Request shutdown
            shutdownRequested = true
            print("Shutdown requested...")
        elseif key == keys.c then
            -- Charge reactor
            if state == STATES.OFFLINE or state == STATES.SHUTDOWN then
                shutdownRequested = false
                chargeRequested = true  -- Flag to provide input flux
                if reactor then
                    pcall(function()
                        reactor.chargeReactor()
                    end)
                end
                print("Charging reactor... providing input flux")
            end
        elseif key == keys.x then
            -- Force exit
            return true
        end
    end
end

-- ============================================================================
-- MAIN LOOP
-- ============================================================================

local lastErrorPrint = 0
local lastFieldErrorCount = 0

local function mainLoop()
    while true do
        -- Update reactor info
        if not updateReactorInfo() then
            -- Try to reconnect with exponential backoff
            local now = os.clock()
            if now - lastPeripheralRetry >= peripheralRetryDelay then
                lastPeripheralRetry = now
                if findPeripherals() then
                    -- Success - reset backoff
                    peripheralRetryDelay = 1
                    print("[INFO] Peripherals reconnected")
                else
                    -- Failure - increase backoff (max 30 seconds)
                    peripheralRetryDelay = math.min(peripheralRetryDelay * 2, 30)
                    print("[WARNING] Peripheral reconnect failed, retry in " .. peripheralRetryDelay .. "s")
                end
            end
        else
            -- Successfully reading reactor - reset backoff
            if peripheralRetryDelay > 1 then
                peripheralRetryDelay = 1
            end
        end

        -- Print field errors to terminal when they change
        local currentTime = os.clock()
        if #fieldErrors > 0 and (#fieldErrors ~= lastFieldErrorCount or currentTime - lastErrorPrint > 5) then
            lastFieldErrorCount = #fieldErrors
            lastErrorPrint = currentTime
            print("[" .. os.date("%H:%M:%S") .. "] Field read errors:")
            for i, err in ipairs(fieldErrors) do
                print("  - " .. err)
                if i >= 5 then
                    print("  ... and " .. (#fieldErrors - 5) .. " more")
                    break
                end
            end
        elseif #fieldErrors == 0 and lastFieldErrorCount > 0 then
            lastFieldErrorCount = 0
            print("[" .. os.date("%H:%M:%S") .. "] Field errors cleared")
        end

        -- Process state machine
        processStateMachine()

        -- Control reactor based on state
        controlReactor()

        -- Update display periodically
        local currentTime = os.clock()
        if currentTime - lastDisplayUpdate >= CONFIG.display_interval then
            updateDisplay()
            lastDisplayUpdate = currentTime
        end

        -- Wait for next cycle
        sleep(CONFIG.update_interval)
    end
end

-- ============================================================================
-- SAFETY FUNCTIONS
-- ============================================================================

-- Set fail-safe state on exit (input gate to max, output to 0)
local function emergencyExit()
    print("\n!!! EMERGENCY EXIT - Setting fail-safe flux gate values !!!")

    -- Calculate dynamic emergency input based on reactor info if available
    local emergencyInput = CONFIG.emergency_field_input
    if reactorInfo and reactorInfo.maxFieldStrength then
        emergencyInput = math.max(reactorInfo.maxFieldStrength * 2, CONFIG.emergency_field_input)
    end

    if inputGate then
        pcall(function()
            inputGate.setFlowOverride(emergencyInput)
        end)
        print("Input gate set to " .. formatNumber(emergencyInput) .. " RF/t")
    end

    if outputGate then
        pcall(function()
            outputGate.setFlowOverride(0)
        end)
        print("Output gate set to 0 RF/t")
    end

    if monitor then
        pcall(function()
            monitor.setBackgroundColor(colors.red)
            monitor.clear()
            monitor.setCursorPos(1, 1)
            monitor.setTextColor(colors.white)
            monitor.write("!!! CONTROLLER STOPPED !!!")
            monitor.setCursorPos(1, 3)
            monitor.write("Input gate set to MAXIMUM")
            monitor.setCursorPos(1, 4)
            monitor.write("Restart controller ASAP!")
        end)
    end
end

-- Verify flux gates are likely configured correctly
local function verifyFluxGates()
    if not inputGate or not outputGate or not reactor then
        return false, "Peripherals not connected"
    end

    -- Try to get reactor info
    local info = nil
    pcall(function()
        info = reactor.getReactorInfo()
    end)

    if not info or info.status == "cold" or info.status == "invalid" then
        -- Reactor is off, can't verify
        return true, "Reactor offline - please verify gates manually"
    end

    -- If reactor is running, check that input gate is feeding field
    local inputFlow = 0
    local drainRate = info.fieldDrainRate or 0

    pcall(function()
        inputFlow = inputGate.getFlow() or 0
    end)

    -- Warning if input seems too low for drain rate
    if drainRate > 0 and inputFlow < drainRate * 0.5 then
        return true, "WARNING: Input flow seems low for field drain rate!"
    end

    return true, "Flux gates appear correctly configured"
end

-- ============================================================================
-- STARTUP
-- ============================================================================

local function main()
    print("=== DRACONIC REACTOR CONTROLLER ===")
    print("Initializing...")

    -- Find peripherals
    if not findPeripherals() then
        print("ERROR: " .. errorMessage)
        print("")
        print("To fix this:")
        print("1. Run 'peripherals' to see available peripheral names")
        print("2. Edit this file and set the names in the CONFIG section:")
        print("   - reactor_name")
        print("   - input_gate_name (flux gate TO the reactor field)")
        print("   - output_gate_name (flux gate FROM the reactor)")
        return
    end

    print("Peripherals connected!")

    -- Verify flux gate configuration
    local gatesOk, gateMsg = verifyFluxGates()
    print("Flux gates: " .. gateMsg)

    print("Starting control loop...")
    print("Press Q to shutdown reactor")
    print("Press C to charge reactor")
    print("Press X to exit program")
    print("")
    print("!!! IMPORTANT: If this program stops unexpectedly,")
    print("    input gate will be set to MAXIMUM for safety !!!")
    print("")

    state = STATES.OFFLINE

    -- Run main loop and input handler in parallel
    -- Wrap in pcall to catch any crashes and set fail-safe
    local success, err = pcall(function()
    parallel.waitForAny(mainLoop, handleInput)
    end)

    if not success then
        print("\n!!! PROGRAM CRASHED: " .. tostring(err))
        emergencyExit()
        return
    end

    -- Normal cleanup - still set fail-safe values to be safe
    emergencyExit()
    print("\nController stopped safely.")
end

-- Wrap entire program to catch terminate events
local function safeMain()
    local success, err = pcall(main)
    if not success then
        if err == "Terminated" then
            print("\nProgram terminated by user")
        else
            print("\nUnexpected error: " .. tostring(err))
        end
        emergencyExit()
    end
end

-- Run the program with safety wrapper
safeMain()