using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.XR.ARFoundation;

/// <summary>
/// This example shows how to check for AR support before the ARSession is enabled.
/// For ARCore in particular, it is possible for a device to support ARCore but not
/// have it installed. This example will detect this case and prompt the user to install ARCore.
/// To test this feature yourself, use a supported device and uninstall ARCore.
/// (Settings > Search for "ARCore" and uninstall or disable it.)
/// </summary>
public class SupportChecker : MonoBehaviour
{
    [SerializeField]
    ARSession m_Session;

    public ARSession session
    {
        get { return m_Session; }
        set { m_Session = value; }
    }

    [SerializeField]
    Text m_LogText;

    public Text logText
    {
        get { return m_LogText; }
        set { m_LogText = value; }
    }

    [SerializeField]
    Button m_InstallButton;

    public Button installButton
    {
        get { return m_InstallButton; }
        set { m_InstallButton = value; }
    }

    void Log(string message)
    {
        m_LogText.text += $"{message}\n";
    }

    IEnumerator CheckSupport()
    {
        SetInstallButtonActive(false);

        Log("Checking for AR support...");

        yield return ARSession.CheckAvailability();

        if (ARSession.state == ARSessionState.NeedsInstall)
        {
            Log("Your device supports AR, but requires a software update.");
            Log("Attempting install...");
            yield return ARSession.Install();
        }

        if (ARSession.state == ARSessionState.Ready)
        {
            Log("Your device supports AR!");
            Log("Starting AR session...");

            // To start the ARSession, we just need to enable it.
            m_Session.enabled = true;
        }
        else
        {
            switch (ARSession.state)
            {
                case ARSessionState.Unsupported:
                    Log("Your device does not support AR.");
                    break;
                case ARSessionState.NeedsInstall:
                    Log("The software update failed, or you declined the update.");

                    // In this case, we enable a button which allows the user
                    // to try again in the event they decline the update the first time.
                    SetInstallButtonActive(true);
                    break;
            }

            Log("\n[Start non-AR experience instead]");

            //
            // Start a non-AR fallback experience here...
            //
        }
    }

    void SetInstallButtonActive(bool active)
    {
        if (m_InstallButton != null)
            m_InstallButton.gameObject.SetActive(active);
    }

    IEnumerator Install()
    {
        SetInstallButtonActive(false);

        if (ARSession.state == ARSessionState.NeedsInstall)
        {
            Log("Attempting install...");
            yield return ARSession.Install();

            if (ARSession.state == ARSessionState.NeedsInstall)
            {
                Log("The software update failed, or you declined the update.");
                SetInstallButtonActive(true);
            }
            else if (ARSession.state == ARSessionState.Ready)
            {
                Log("Success! Starting AR session...");
                m_Session.enabled = true;
            }
        }
        else
        {
            Log("Error: ARSession does not require install.");
        }
    }

    public void OnInstallButtonPressed()
    {
        StartCoroutine(Install());
    }

    void OnEnable()
    {
        StartCoroutine(CheckSupport());
    }
}