-- GPS Client Program to Show Its Own Location Based on Satellite Data

-- Define the satellite IDs
local satellites = {
    536,  -- Example satellite 1
    537,  -- Example satellite 2
    538   -- Example satellite 3
}

-- Function to display status messages on the screen
local function displayStatus(message)
    term.clear()
    term.setCursorPos(1, 1)
    print(message)
end

-- Function to request data from fixed satellite IDs
local function getSatelliteData()
    rednet.open("right")  -- Ensure modem is on the correct side
    local satelliteData = {}

    displayStatus("Requesting data from satellites...")

    for _, satelliteID in ipairs(satellites) do
        rednet.send(satelliteID, "request", "GPS")
        local id, message = rednet.receive(5)  -- Wait for 5 seconds for response

        if message then
            local data = textutils.unserializeJSON(message)
            if data and data.id == satelliteID then
                table.insert(satelliteData, data)
                displayStatus("Received data from satellite ID: " .. data.id)
            end
        else
            displayStatus("No response from satellite ID: " .. satelliteID)
        end
    end

    return satelliteData
end

-- Function to calculate the position of the client based on received satellite data
local function calculatePosition(satelliteData)
    if #satelliteData < 3 then
        return nil
    end

    -- Simple triangulation to estimate position based on received satellites
    -- This example uses an average of coordinates from satellites
    local avgX, avgY, avgZ = 0, 0, 0
    for _, data in ipairs(satelliteData) do
        avgX = avgX + data.x
        avgY = avgY + data.y
        avgZ = avgZ + data.z
    end

    avgX = avgX / #satelliteData
    avgY = avgY / #satelliteData
    avgZ = avgZ / #satelliteData

    return avgX, avgY, avgZ
end

-- Main function to continuously update the client status
local function main()
    while true do
        displayStatus("Locating position...")

        local satelliteData = getSatelliteData()
        local x, y, z = calculatePosition(satelliteData)

        if x and y and z then
            displayStatus("Client Position:\nX: " .. x .. "\nY: " .. y .. "\nZ: " .. z)
        else
            displayStatus("Unable to determine position.\n\n" ..
                "Satellite Data:\n" ..
                "Received: " .. #satelliteData .. "/" .. #satellites .. "\n" ..
                "Waiting for more data...")
        end

        sleep(10)  -- Update every 10 seconds, adjust as needed
    end
end

main()