-- Parafield to Renmark Mission for X-Plane 12 - Baron 58
-- Requires FlyWithLua NG

-- Run only if correct aircraft and location
if PLANE_ICAO ~= "BE58" then return end

-- Basic vars
local mission_started = false
local timer = 0
local turbulence_active = false
local severe_turbulence = false
local arrival_announced = false

-- Altitude and safety
local cruise_alt = 7500
local altitude_deviation = 200
local turbulence_alt = 9500
local VNO = 165 -- Max structural cruise speed in KIAS

-- DataRefs
dataref("ias", "sim/cockpit2/gauges/indicators/airspeed_kts_pilot")
dataref("altitude", "sim/cockpit2/gauges/indicators/altitude_ft_pilot")
dataref("latitude", "sim/flightmodel/position/latitude")
dataref("longitude", "sim/flightmodel/position/longitude")
dataref("gps_dest_id", "sim/cockpit/radios/gps_nav_id", "string")

-- Functions
function say(msg)
    if SUPPORTS_SOUND then
        speak(msg)
    end
end

function set_weather(vis, clouds, turb)
    set("sim/weather/visibility_reported_m", vis * 1609.34)
    set("sim/weather/cloud_base_msl_m[0]", clouds * 0.3048)
    set("sim/weather/turbulence[0]", turb)
end

function distance_to(lat1, lon1, lat2, lon2)
    local R = 3440.065 -- NM
    local dlat = math.rad(lat2 - lat1)
    local dlon = math.rad(lon2 - lon1)
    local a = math.sin(dlat/2)^2 + math.cos(math.rad(lat1)) * math.cos(math.rad(lat2)) * math.sin(dlon/2)^2
    local c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
    return R * c
end

-- Renmark Airport Coordinates
local yren_lat = -34.1969
local yren_lon = 140.674

-- Mission Initialization
function start_mission()
    mission_started = true
    timer = 0
    say("Mission started. Cruise at 7500 feet. Weather will deteriorate.")
    set_weather(10, 4000, 0.1)
end

-- Main logic loop
function mission_tick()
    if not mission_started then
        -- Auto-start if near YPPF (Parafield)
        local dist = distance_to(latitude, longitude, -34.7933, 138.628)
        if dist < 3 then
            start_mission()
        end
        return
    end

    timer = timer + get("sim/operation/misc/frame_rate_period")

    -- After 5 minutes
    if timer > 300 and timer < 600 then
        set_weather(6, 3000, 0.2)
    end

    -- After 10 minutes
    if timer > 600 and timer < 900 then
        set_weather(3, 2500, 0.5)
        say("Weather worsening. Turbulence moderate.")
    end

    -- After 15 minutes
    if timer > 900 and not severe_turbulence then
        set_weather(3, 2000, 0.8)
        say("Severe turbulence. Climb above 9500 feet to reduce effects.")
        severe_turbulence = true
    end

    -- Turbulence safety warning
    if severe_turbulence and altitude < turbulence_alt and ias > VNO then
        say("Reduce speed below VNO to prevent structural damage.")
    end

    -- Arrival Detection
    local d = distance_to(latitude, longitude, yren_lat, yren_lon)
    if d < 3 and string.match(gps_dest_id, "YREN") and not arrival_announced then
        say("Arrival at Renmark detected. Mission complete.")
        arrival_announced = true
    end
end

do_every_frame("mission_tick()")